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Building Science

An Interview with Dr. Iain Walker on Ventilation

Another installment in the great debate about residential ventilation and indoor air quality

Iain Walker, a building scientist at Lawrence Berkeley National Laboratory, talks about residential ventilation in this interview with Allison Bailes.
Image Credit: Lawrence Berkeley National Laboratory

The debate over how much to ventilate a home has been going on a long time. Last year, Building Science Corporation introduced its own standard to compete against ASHRAE 62.2 because (according to Dr. Joseph Lstiburek) of problems that weren’t adequately addressed in the ASHRAE standard. I’ve written about the standard and interviewed Lstiburek and ASHRAE 62.2 committee chair Paul Francisco. (See links at bottom.)

Recently I interviewed building scientist and ASHRAE 62.2 committee member Iain Walker, PhD, about the issues. We had a great discussion, but make sure you read to the end. You don’t want to miss what he says about the ERV flaw you’ve probably never heard about. Also, be sure to attend the ACI national conference, where Walker, Lstiburek, and several others will be on a panel debating this issue.

Allison Bailes: What do you think of the great ventilation debate that’s happened over the past year and Joe Lstiburek going rogue and creating his own residential ventilation standard?

Iain Walker: I don’t know that there’s much debate happening really. You know, we have one national standard that is being used more and more, and I think that’s the way it’s going to continue. So I’m not sure there’s very much debate going on.

Bailes: Do you see any value at all in the issues that Joe’s brought up?

Walker: Well, it depends on what you mean by issues. Most of the issues have been discussed at length by the 62.2 committee on and off. Certainly some of them, the 62.2 committee is investigating in great detail.

I’ll give you an example. One is this idea of maybe the standard should require filtration. Currently it has a very weak requirement for something like a MERV 6 filter. But MERV 6 filters don’t really filter out the size of particles we’re concerned about for health. So maybe we should have a requirement for that and we haven’t figured out what that would look like and how to make it equitable across different systems and different climate zones and different homes, so it’s complex to find something in that area that’s suitable for a national standard, but certainly we’re looking into it.

We’re not dismissing Joe’s concerns, and to be fair they’re not just Joe’s concerns. We all know what to do to improve indoor air quality. The question is always how to get it to work right in the standard.

Bailes: OK, getting into what’s probably the biggest difference between 62.2 and Joe’s standard, what do you think of his idea to require different rates for different ventilation types, central-fan-integrated supply vs. exhaust-only vs. balanced?

Walker: Well there’s been a lot of work done in this area, and the difficulty is that different systems are better in different circumstances. This makes it very difficult to say can we always credit one system or another, and I would say, no, we can’t. This is what the 62.2 committee decided also because you can create a scenario in which whatever ventilation system you like is better or worse, but overall the answer is there is no one better system from the point of view of achieving the indoor air quality that we’re looking for here.

Bailes: In Joe’s standard, the system that has to ventilate at a greater rate, because he feels like it’s not as effective, is exhaust-only. He has cited Armin Rudd’s study of two homes in Texas as evidence to support that, but you’ve said there are other studies contradicting that. Can you go into that?

Walker: Sure. Well, on the issue of what’s better, there’s a whole bunch of papers that were published several years ago — Max Sherman and I wrote several of them and a few other people were involved, too — looking at this exact issue: Should you mix? Shouldn’t you mix?

We all agree that there’s certainly an advantage to running a central system that filters the air. I think we all agree on that but the question is, now how do we compare that to the filtration provided to the building by an exhaust system? And people have researched that and found out that the building envelope is something like MERV 9, but it depends a lot on how leaky the envelope is. The tighter the envelope, the more filtration you get. The looser the envelope, the less filtration you get. And indeed that’s what the 62.2 committee has been saying: that if you’re going to give a credit for filtration, we have to figure out the effective filtration for all systems, and it is a little tricky to deal with.

There are other things, like the difference between a balanced system and an unbalanced system. In a balanced system, you can simply add the infiltration rate to whatever ventilation rate you’ve got. But you can’t do that with unbalanced systems. The 62.2 standard has been silent on that issue. It just says, you know, here’s the flow rate. We don’t care if you do balanced or unbalanced. Frankly, I think it’s probably going to continue that way, mostly for simplicity. There’s a big interest in keeping it simple from the users of the standard, builders and contractors.

As we’ve said many times, the standard is just a minimum performance. You can always do better. And the implication there is if you say you use an HRV or ERV that’s balanced, and you provide quite a bit more ventilation, well you go ahead, and that’s great. You’ve complied, and you’ve got a better system. You’re providing heat recovery.

That’s great also because the standard doesn’t say anything about requiring heat recovery either. That’s a better system, and the standard says, go ahead and use it. No problem at all. We don’t have to have anything in the standard that deals with that for that very reason. You can always do better if you want, because the standard is focused on: what’s the worst you can do and still have a reasonable indoor air quality? That’s the basis of the standard. You can always do better than that. That’s why it’s silent on this balanced vs. unbalanced issue.

Bailes: Well, that gets me to my next question. A few weeks ago you said that it’s “dangerous” if you ventilate less than the 62.2 rate. Why do you think it’s dangerous? I think you were talking about less because you kind of confused better and more. You said you can always do better than ASHRAE 62.2, but does that mean more?

Walker: Well, OK, let’s answer that question first. If you’re concerned about diluting indoor air pollutants, you do that by bringing in more outdoor air. But you can also remove pollutants by deliberately filtering for particles. There are also filters that will remove some of the chemicals, but they’re a little obscure and we don’t see them very much.

We certainly see filters all the time, and it’s almost trivial these days to go into a store and buy yourself a better inline filter and stick into your forced air system. Or you can get units that just service a room. You can go out and buy these things now, and that will provide better indoor air quality because you’re deliberately doing something extra to remove those pollutants. So there are all sorts of ways to get to better indoor air quality.

You can also — we do this in California — we say you can’t use high VOC-emitting materials in buildings. That’s a great idea for improving indoor air quality, much better than trying to ventilate it away or to scrub it with a filtration system. If you don’t bring polluting things into the home, that is obviously a great idea.

The final point on this is that sometimes the outdoor air quality isn’t good. It’s very difficult to dilute indoor air pollutants if the outdoor air quality isn’t very good. But that’s something that’s very difficult for us to deal with in an IAQ standard because there’s a lot of regulation for outdoor air that is really beyond the scope of what we’re trying to do with the ASHRAE standard.

Frankly, I think in the U.S., the actions of the EPA are keeping our outdoor air pretty good. It’s not always great, but it’s pretty good in most places. That’s actually great, and I think that the EPA and lots of other people are doing outdoor air research and making that cleaner, and we’ll let them continue to do that.

I don’t think the ASHRAE 62.2 standard is going to try and deal with outdoor air pollutants in any significant way as a minimum standard. I mean you can always do better. You can envision some sort of control system that if you know there’s high ozone outdoors, you might want to turn off your ventilation for an hour or two and control that way. You can certainly do that, but I don’t think we would require that as a minimum performance specification.

Now that was the second part of your question. So there are many aspects to achieving good indoor air quality. It’s not just ventilation. There are all these other possibilities, like source control and filtration and that sort of stuff.

Remind me again what was the first part of your question.

Bailes: The first part was about your comment about it being dangerous to…

Walker: Oh, yeah, yeah, yeah. Well, OK, “dangerous” might be a little bit of a strong word, but I think that the objectives are manifold for the standard. Indoor air quality is sort of a broad term, so I just want to break it down a little bit.

I think we’re getting much more of an emphasis on health than we used to have. Traditionally, we used to ventilate mostly for things like odors and moisture control. They were the prime drivers historically. And by historically, I mean going back thousands of years up until twenty-odd years ago. Just because health is a very difficult thing to deal with because there’s a lot of things that affect health and everybody responds differently. We’re only just getting enough knowledge to make some reasonable health decisions.

The danger, if you will, of not ventilating to the 62.2 level, sort of combines all these things together. We know historically about odor control and we know about moisture control, and you could impact things like mold growth, which is a health problem, or degradation of surfaces, which is a structural problem. But also, we’re ventilating for chemicals we know are problems. I should speak more broadly — pollutants we know are problems, because it’s not just chemicals.

The most significant pollutant from a health perspective is particles, in fact. There have been studies done that have measured concentrations of these things in homes. And we know enough about some of these components of indoor air quality and what their health effects might be and the levels we’re setting in 62.2 are at about the point where we think we’re reasonably dealing with most pollutants and most circumstances.

Now we’re obviously going to be able to deal with extreme events or unusual things, but all a standard can do is work most of the time for most homes for most people, and we’re never going to capture every single possibility. That’s just unreasonable.

The problem with going below that is that the levels of various pollutants could build up to the point where we could not say, “this protects most people most of the time” anymore. This is the consensus of a whole bunch of people on the committee with all sorts of backgrounds representing all sorts of interests.

Our European friends, of course, are occasionally critical of our standard because they say our ventilation rates are actually much too low. They like much higher rates, and their ventilation standards are considerably higher than 62.2.

But, you know, there has to be some sort of judgment applied here and this is where we are now. This is what the knowledge of all the people who have worked in this area for long time is a reasonable number to go for to protect against indoor air quality issues that affect a substantial number of people a substantial amount of time.

I think that if you want to ventilate a home, that’s a good target. If you go below that, you’d better have some pretty good evidence that it’s OK. You better have some pretty good large-scale studies or a reasonable consensus among a lot of people representing a lot of points of view that actually it’s OK to go to, say, half that air flow rate. Currently we can’t say that.

The danger in picking lower numbers without any backing is, is that even real? If you think of yourself as a contractor installing ventilation systems, and you install us a very low flow — one that is below 62.2 — and there is an indoor air quality problem and somebody sues you, the danger there for a contractor is you would be successfully sued, because 62.2 basically represents the current recommendations of good practice in our industry. If you’re going to go significantly below that level, you’d better… [garbled recording]. If you get sued, you’d be in a lot of trouble because you’re not taking the advice of your industry. It just creates a minefield, frankly, that I don’t think anybody should want to walk into.

Bailes: But the minefield is mainly because there’s this standard that says you need to ventilate at this rate, and the standard isn’t based on a lot of hard health data and epidemiological studies. Right?

Walker: That’s right, but it’s based on a lot of knowledge about air flow in buildings and pollutant emission rates and pollutant concentrations and the health impacts of them. We can say a lot of good stuff without needing large-scale epidemiological studies that would answer things with a great deal of certainty.

And frankly, we’ll never have those studies. You’d have to cover so many climates, so many different pollutant generation rates, such a wide group of people, and you’d have to do intervention studies where you ventilate and didn’t ventilate. We’re never going to have that large-scale epidemiological information, so we have to do the best with what we know.

And what we know is we have some pretty basic physics going on about dilution of pollutants if you know their emission rates. And even if you know their emission rates vary, like with formaldehyde, we have good models of how that works. We know the science of how that works. And we have some pretty good health data on — not all the pollutants, I would say, but certainly the significant ones that show up a lot in many houses that have health impacts like particles, oxides of nitrogen, and some things like formaldehyde that people are more familiar with.

Then there are some marginal things like water vapor, which isn’t necessarily directly a health impact, but the effect of water vapor can be a health impact as a second order thing. So I think we know enough to be making reasonable decisions and that is what the ASHRAE committee is all about. It’s about knowing enough about the science of this to make a reasonable decision.

Bailes: One more question about 62.2: What do you think would make the 62.2 standard better, and where do you think the committee is going with it?

Walker: The committee — I mentioned this a few minutes ago — is actively thinking about, should we have some kind of air filtration requirement, mostly to account for particles, because particles are so important from a health perspective. The committee is actively working on this right now. I can’t predict when we’ll have something concrete in the standard. That’s always a very difficult and a dangerous thing to do, but I can tell you that this is a subject that the 62.2 committee is very interested in and is working on very hard at the moment.

We’re bringing some new people onto the committee and getting people to come and give presentations. So I think the issue of filtering air is going to be an interesting topic in the future for the standard. I think that the major change we’re likely to see going forward is that because I think there may be some other detailed things that the standard…

I personally don’t think the standard … isn’t going to have to act on … because of other things happening, but it’s important to talk about and that is issues about combustion safety and this idea of unvented combustion in a home. The reason why this is an issue for the standard is because combustion produces a lot of pollutants that we don’t want to have in our home, a whole broad range of them.

In the home performance community there’s a great interest in this, because when we go into homes and tighten them, we do combustion safety testing, for example, or when homes are rated, there’s combustion safety testing also. I think that this is, from an indoor air quality perspective, burning stuff in your home is crucial.

This leads me to the next point that I think we might see coming in 62.2, and that is a better way of dealing with kitchen exhaust. Here I’m talking primarily about range hoods. Because cooking, whether you’re burning gas or cooking with electricity, produces all sorts of pollutants, and it’s probably the major source of pollutants in your home for most people, unless you’re doing something really extreme.

Venting those pollutants correctly — as in, you want to exhaust them directly to outside — that’s the preferable way of dealing with it. Right now the standard says you’ve got to have a range hood with 100 cfm of exhaust or you can ventilate the kitchen at a higher air flow rate overall. But we’re learning more on how they work.

And range hoods don’t capture all the cooking pollutants when you turn them on. So we’re working with ASTM, not with the ASHRAE 62.2 committee. We have an ASTM committee looking into: Could we develop a capture efficiency test method so range hoods could be rated for their capture efficiency?

Then what the 62.2 standard could do — or any other ventilation standard, or even building codes for that matter — they could say, yes, you’ve got to install a kitchen range hood with a minimum capture efficiency of, say, 75%. But until we have the test method in place that actually rates the range hoods, standards like 62.2 or mechanical codes can’t require a capture efficiency because there’s no test method. I think we will see something along those lines happening in the next couple of years.

We have a really good group of people together developing the ASTM test method for capture efficiency. The industry as a whole — and by industry, I’m including the people who manufacture kitchen ventilation products as well — is very interested in seeing this go forward, and I think we’ll see that change in ventilation standards within a couple of years that deals a lot better with how we deal with capture efficiency of exhaust and does a much better job of ventilating kitchens.

A little add-on to that is this issue of: Well, do people even turn these fans on? Whether it’s in kitchens or even in bathrooms, too. The standard does require that you install exhaust fans in kitchens and bathrooms, but they’re user-operated, so you’re there cooking and you turn it on or you’re having a shower and you turn it on.

Another area that’s developed in 62.2 is, maybe we should automate these things. I’m thinking more particularly about kitchen ventilation and how range hoods operate. If people don’t turn on their high-capture-efficiency range hood, it doesn’t help them at all. We have to know it operates.

There are a few manufacturers out there making automated range hoods. This is another possibility for a requirement. Not only will we have to have good capture efficiency but there will be some specification about how you automate a range hood so that whenever you turn on a burner to boil a pot of water or turn on the oven to bake some bread, the ventilation system in the kitchen turns on automatically.

We’re currently at the beginning steps of that. We’ve done laboratory testing of the current control systems, and there’s a big range of performance. Some are good and some are poor, so we may have to have a standard for that, too, given the range of performance. That’s certainly something I think could have a really good impact on indoor air quality in homes, whether it’s in the 62.2 standard or in the plumbing and mechanical codes.

I’ll be honest with you, when people ask me what’s the single biggest thing they can do to improve the indoor air quality in their homes, I always tell them to use their range hood. That’s so easy to do. You flip a switch. You don’t have to purchase anything. You’re not buying a fancy filtration system. That’s the first thing to do, and I think that the ASHRAE standard and these codes are very interested in these sort of things that are relatively simple but could have a substantial effect on indoor air quality without having to increase ventilation rates. We could really have some big effects there.

Those areas are where I see the whole business of indoor air quality advancing in the near future: active filtration and doing better with kitchen exhaust on several levels. That’s where there’s a lot of activity right now. That’s where I see us improving our indoor air quality efforts in the near future.

Bailes: At the Dry Climate Forum, I think you talked about ERVs recycling formaldehyde and sending it back into the house rather than outdoors because it behaves like water. Can you talk about that?

Walker: Yeah, this is an interesting perspective. I just want to be clear — we’re talking here about ERVs, which exchange moisture as well as heat, not HRVs. This is an issue for ERVs. The issue for ERVs is that as you’re exchanging moisture between the two air streams, maybe other things get transferred, too. The particular pollutant that we’re concerned about is formaldehyde, because formaldehyde, from a chemical point of view, looks a lot like water. It’s quite a similar molecule.

We’ve done some testing to look at this in our laboratory to see how much formaldehyde might get transferred between the incoming and outgoing air streams. In other words, if you operate this ERV, maybe you’re not getting rid of the formaldehyde like you think you are. That was our question.

Indeed we found that there can be substantial transfer, but it depends a lot on the specific materials that are used in the ERV to do that transferring of the moisture. It’s very specific to the particular way of doing it. Also, there are differences between ERVs.

There are basically two ways of exchanging the moisture. Some do it through a membrane, and the second one is with a wheel that spins between the two air flows. The wheel ones we’ve always had some concern because there’s always some bypass about where the wheel goes from one air stream to the other. There’s always a little bit of air leakage there. In fact to be fair to ERV ratings, that bypass is included in the ratings, so the ratings are good. This is all included in that.

The concern from an indoor air quality point of view is what is that bleed air and the fact that you’ve got a wheel rotating from one air stream to another is actually transferring pollutants. The answer is, yes, it is, but unfortunately, I can’t just tell you, well, it’s 10%. There isn’t a number.

It depends a lot on the materials used and how the ERV is designed and how well it’s sealed to prevent that sort of transfer. We’re shortly going to have a paper on that. There was some work done by other people at LBNL. I was only peripherally involved and I did not write the paper.

The ERV manufacturers are taking this very seriously. I can’t make any promises, but we’ve had some very good discussions with them about this issue. Where I think we’re going to end up is, because we can identify the various materials that are used to transfer the moisture and unfortunately some formaldehyde, we can also pick materials that are much better at transferring the moisture and not formaldehyde, and the manufacturers are going to switch the materials they use. This is where I believe we will be shortly because the manufacturers are very aware of this. They’re concerned and they want to do the right thing, so I think that’s what’s going to happen.

Currently it’s a bit of a caveat emptor for ERVs. If you want some advice, I would say try and avoid the ones with the disk wheel if you’re looking at an ERV for now. We believe this issue is going to go away, because we think changing the materials will be able to solve this problem. But right now it is a concern. There are some ERVs that are better than others, and no way for a purchaser to know, because they’re not rated for this.

Make sure you register for the ACI national conference in Detroit because Iain, Joe Lstiburek, Paul Francisco, and several others will be on a panel debating the issue of residential ventilation. Duncan Prahl of Ibacos and I will act as moderators. Register now! The Early Bird deadline is 31 March 2014.

Allison Bailes of Decatur, Georgia, is a speaker, writer, energy consultant, RESNET-certified trainer, and the author of the Energy Vanguard Blog. You can follow him on Twitter at @EnergyVanguard.


  1. Robert Connor | | #1

    Looks like Ian got his head
    Looks like Ian got his head stuck up in a ventilator!

  2. Aj Builder, Upstate NY Zone 6a | | #2

    Define stupid
    Buy offgassing crap to build a home with... then buy machines to remove the crappy gasses.

    Simple is better. Don't install formaldehyde offgassing stuff.

    I don't get it... my relatives... died at close to 100.... lived in the days of coal fired heat in all homes and factories in their city... talk about particles!!!!

    Maybe particles are good for us... I'll take 100.

    The sky is falling... let's mandate MIRV 11 filters and annual formaldehyde testing...

    More more more... we need more regulations...

    Someone needs to filter out my rant... from this blog

  3. Aj Builder, Upstate NY Zone 6a | | #3

    Smarter mandates
    Cities have too many vehicles.

    Mandate 10% reduction of vehicles per year in cities, electric vehicles exempt for now.

    Change all buses to NG/electric hybrids.

    Improve subways till most city travel is by foot, bike or train. Mandate it.

    Block off 10% of streets to vehicle traffic per year.

    Start a commuting tax, increase it 10% per year to solve the highway overloads around cities. An automated congestion tax added as you drive any congested highway...

    This is how to reduce particulates before they are created and released... not with MIRV 11 mandates. That is just stupid. IMO

    Dr, aj PIA (pain in arse)

  4. Terry Lee | | #4

    “ Iain Walker (I’ll take this
    “ Iain Walker" (I’ll take this as legal advice): "The danger in picking lower numbers without any backing is, is that even real? If you think of yourself as a contractor installing ventilation systems, and you install us a very low flow — one that is below 62.2 — and there is an indoor air quality problem and somebody sues you, the danger there for a contractor is you would be successfully sued, because 62.2 basically represents the current recommendations of good practice in our industry. If you’re going to go significantly below that level, you’d better... [garbled recording]. If you get sued, you’d be in a lot of trouble because you’re not taking the advice of your industry. It just creates a minefield, frankly, that I don’t think anybody should want to walk into.”

    TL: For professional builder’s and contractors this is good to know that ASHRAE will share in the liability if they are sued. Lots of contradictions, on one hand the standard(s) lacks sufficient chemical data to determine a rate, on the other, “The danger in picking lower numbers without any backing is, is that even real? “ . You can bet if I follow ASHRA 62.2 and/or BSC-01, 2013 and I end up in court they are going to court with me.

    “The most significant pollutant from a health perspective is particles, in fact. There have been studies done that have measured concentrations of these things in homes. And we know enough about some of these components of indoor air quality and what their health effects might be and the levels we’re setting in 62.2 are at about the point where we think we’re reasonably dealing with most pollutants and most circumstances. “

    “I’ll give you an example. One is this idea of maybe the standard should require filtration. Currently it has a very weak requirement for something like a MERV 6 filter. But MERV 6 filters don’t really filter out the size of particles we’re concerned about for health. So maybe we should have a requirement for that and we haven’t figured out what that would look like and how to make it equitable across different systems and different climate zones and different homes, so it’s complex to find something in that area that’s suitable for a national standard, but certainly we’re looking into it. “

    TL: I’m pretty confused how mechanical blowers, wheels, filtration, address particles sensed by a IAQ meter? Can you or someone please show me national test data? Let me help you out, the standard should point to home specific data determined by professional Industrial Hygienist, and/or chemist, that are building/site specific. Then and only then can a ventilation rate/system be determined.

    You don’t have to look far to see tight homes failing safe levels of IAQ with ventilation systems on,

    Linda: "Ms. Dryden assured us that after August 2009, all new homes will have mechanical ventilation. We explained that most of the homes we tested had mechanical ventilation running at the time we visited. The required 0.35 air changes per hour (ACH) are not adequate. "

    Check out her slide “slideshow” download too.

    Manufactures are not being held accountable to consistent quality control of toxicity material processing standards as Linda’s test and others results show, despite using “low emissivity phenol resign formaldehydes - PF” vs. Urea – Formaldehydes (UF). Do you expect the homes these products are in to perform any better?

    For example, look at Georgia Pacific or Advantech OSB/Plywood MSDS you will find no particle, fungi, CO2, CO,VOC, heat, pressure, humidity, x-ray, ultrasonic, exposure design allowable per USA toxicity zone, third party testing to spec. You will note however this product is ‘chemically unstable’ no testing to determine exactly how and where?

    It does not end with OEM quality control levels of urea-formaldehydes,

    Plastics contain carcinogenic, neurotoxic, hormone-disruptive chems...find way into ecology through water, land, air pollution. Popular are vinyl chloride, doxins in PVC, benzine in polystyrene, phthalates and other plasticizers in PVC, etc...formaldehyde and other besphenol-A (BPA) in polycarbonate. All Persistent Organic Chemicals. Occupation cutting, in place curring that great off gasses are of great concern.

    Halogenated Flame Retardants (HFRs) - Chlorine and bromine fire retardants(C or BFRs) base produce dioxins, are highly carcinogenic human health hazards when exposed to fire. They are also created in the formulation of PVC and found as chlorinated or brominated fire retardants or (BFRs) to a host of products. There is no required labeling or legislation for quantity of HFRs. OEMs need to be pressured to produce less toxic materials. There are alternative non-flammable materials vs foam and halogen-clad wiring. Landscape/home design also plays a role in fire retardants. Try and ignite dirt.

    We need to revert back to history and Natural Building Methods from local resources without the toxins. Get away from manufactured products and plants that are out of control, take control over our own manufacturing and quality. You won’t find most of these safe products at your local Home Depot. Be nice to see a list of alternative safer materials for consumers in these standards and debates, also focus on the core manufactures issues, not some poor mechanical methods to circumvent them. I sure am glad our 2006 IBC and AHJ are not pushing these worthless standards.

  5. Kevin Dickson, MSME | | #5

    The Technological Solution is Coming, Let's Help it Along
    Trying to specify a correct ventilation rate is a stupid way to solve IAQ problems.

    Think about heating systems. Do we calculate how many BTUs to add to a house in the winter? No. We MEASURE, then CONTROL temperature with a thermostat.

    IAQ can be handled the same way, and then any ventilation standard becomes moot.

    NEST is heading in the right direction with smart sensors. Obviously, sensors can be used to control IAQ once they are interfaced with the ventilation equipment.

    So, instead of debating the CFM numbers, we need to use our energy identifying the most important pollutants, and then establish the safe upper limits of those pollutants. Then we can measure, and control.

    We haven't seen significant deaths from most indoor pollutants, and we already have mandated ways to protect people from the bad ones. (Smoke [particulate] detectors and CO detectors, Radon)

    We need the all-in-one IAQ meter, and it can adjust the ventilation rate to keep the IAQ at safe levels, then we kiss ASHRAE 62.2 goodbye forever.

  6. Nick T - 6A (MN) | | #6

    Demand Ventilation
    It is already accepted and done in the commerical spaces - obviously installing a few sensors (200$ ea) makes a much quicker payback and sense when you are talking about 2-10k CFM of O.A.

    However if this was more standard application a CO2, Humidity, CO, IAQ sensor wouldn't be that big of a deal to install. Should likely be required to have a minimum CFM per day to account for other substances/gases that we are not detecting or maybe even know about if all other indicator gases/particles are reading low(without any ventilation (however does it know if windows are open?)....). However in most newer tighter homes (much vox stuff is reduced significantly) and CO2/H20/particulates are the leading 'indicator gas' i would imagine. Which are all three very easily($) sensed via sensor in 2014.

    Just look at how fast the wifi home thermostats have come down in price and increased in features (honeywell) in just the past two years.

    With adoption of code....comes reduction in price shortly after. Hence one of the reasons for energy codes (USA govt is one of the largest users of energy (largest i think)...and also purchaser of motors/fans/lights) So with required efficiencies of equipment...comes eventual reduction in their price of good (benefiting the people who made the code....the US govt)

  7. Terry Lee | | #7

    It’s not a simple matter of
    It’s not a simple matter of smart sensing a mechanical system. Ventilation is not the all-in-one chemical molecular cure to get parts per billion to acceptable levels. Some materials outgas for decades. User control? There are areas of the country with building’s that have worse IAQ than OAQ, and visa-versa. So what good does it do to recirculate bad air? There is also plenty of data out there I posted that show health risk, most people that die of lung cancer and not smokers. Not sure who said IAQ does not kill and it is getting worse as we build tighter homes, but common let’s use common sense here.

    The right filtration could work along this line, but the issue is best resolved at the source, feedstock,

    Airocide Air Filter, NASA Tech….

    Interesting product with claims and indi test that eliminate VOCs and other toxic airborne particles from building materials included.

    Certainly a lot of industrial case studies and white paper peer reviews, see case studies in Healthcare, Food and Floral, Wine….

    Be interesting to do your own before and after test w/a IAQ meter.

    Amazon reviews seem good except one with a meter, not that I ever believe them,

    Also, Autodesktop and Goggle Sketchup feature plug ins for carbon estimating.

    What I’ll do is watch my material sources, blower door and IAQ the envelope and, OAQ site specific to help me decide an approach. The other issue is we cannot control the homeowner as builders, so we provide the provisions (ducts) etc for a HRV/ERV system. Make them aware of the test results, make recommendations based on them, they keep toxic chemicals out of the home as stated in our contracts or they take on the liability. Other thing I am pondering is natural way to recovery ventilated energy without mechanical systems, that, they themselves can be manufactured with toxins, anti-corrosion chem treatments of metals, cores, plastics, wheels, etc….

  8. Peter L | | #8

    I Guess We Should Take Up Smoking...
    My grandfather smoked for 40 years and never got lung cancer and he lived until he was 90. I guess if we take on the anecdotal evidence of some, we should all take up smoking. Also, hiking to school in the middle of winter without shoes and working in the coal mine is a good way to extend your life expectancy.

    Back to reality. Over 7 million people a year die from air pollution according to studies from the WHO, EPA and other organizations. Air pollution and indoor air quality effects my health and the health of my family. I will do my part to make sure the indoor air quality of my home is up to par and not contributing to further health ailments.

    The sky isn't falling, it's just a light shade of brown due to the air pollution.

  9. Aj Builder, Upstate NY Zone 6a | | #9

    Peter L and other MIRV 11 types
    Trying to understand.... I feel I live in an area with outside air that is good enough for me 24/7. Same for air inside any building. Same for most of the country except when I have been in smog in LA.

    As to wanting to have clean air... what are you needing to clean? Are you saying that my home and my town or yours are too dirty or dangerous ... the air is too contaminated?

    What about all those camp fires my family sits around?

    You mentioned cigarettes... most who smoke live through smoking for decades... to do with out one may live a decade longer or not.... then what... we all die. (I don't smoke.)

    And this logic has me scratching my head the most.... if someone lives in a building with air cleaning devices... do they not ever leave that building? Do you hold your breath and run to another building that has air cleaning? Do you worry about and limit time in the dangerous outside world?

    If I worried that much I would have to take up smoking.

    To me, one should live in a home that does not have bad air and does not have air cleaning devices. No particleboard, carpet, new finishes... I just built a home for others that has no carpet, no particleboard, no air cleaners... no gas stoves... I am not going to test the air with lab work. The air seems to be fine. My own home seems to have good air... who knows...

    And what about all of us that build homes... we are right there when the paint is wet, the particleboard is new, the VOCs are at there highest, we're heating with Salamanders breathing the exhaust... We all should be dead in days from ten thousand times higher levels of bad air exposure. I can attest from the fact that I am truly typing this that i am still alive. My lungs are the best in the Adirondacks. Gonna go breathe hard for a run right now... take in some good bad and ugly air.

    I don't get it... please explain bad air to me folks.

  10. Kevin Dickson, MSME | | #10

    Response to AJ
    This air pollution report is worth being aware of:

    According to the report, indoor air pollution is one of the biggest killers.... but only in poor countries where they burn solid fuels inside.

    The earth and the atmosphere are finite, if our pollution production exceeds the earth's ability to handle it, then it could be like "everyone is indoors".

  11. Aj Builder, Upstate NY Zone 6a | | #11

    Kevin, dung stove use has
    Kevin, dung stove use has NOTHING to do with US residents that participate here at GBA. I am glad many are working hard to help those with bad air but, my post is basically saying all of you are wasting your time talking air quality via personal filtering here in the USA. If one lives in LA one can move to my area and not filter. That is my point. Most of the US is an order of magnitude better off than dung burning folks or cigarette smokers... etc.

    Air is not a problem here in the Adirondacks. Nor are the bears and we have no lions or tigers.

  12. Terry Lee | | #12

    AJ you’re not getting it
    Go into your garage shut and seal all the doors and openings, turn your car engine on stay there a while see if you live to post anymore? Now imagine the same effect if you built your houses envelope tighter, what do you think would happen to IAQ in the case of CO entering from the garage or another source? Would you be less or more subjected to its poisonous known in fact to produce death? What if you lived in an area like LA, it would make it worse right? Not that it matters that much since it only takes a fixed amount to kill you. Now we are just getting started, does it matter more or less as we build homes tighter, the content of VOC’s, O2, Eura-formaldehydes, etc. Hint: use the same reasoning you did w/CO. Now does it get better or worse if we synthesize all the toxic gasses and particle compounds together as we air seal homes tighter and tighter? I think the answer should be quite clear, there is plenty of medical science you can find that these toxins are deadly without some means to reduce or ventilate them. Do some homework. No one cares about your home, your relatives 100 yrs, or anything about you. This is about a national standard(s) to resolve a deadly issue.

    Many chemicals are harmful at concentrations lower than we can smell or see, many outgas for decades. Here read this,

  13. Aj Builder, Upstate NY Zone 6a | | #13

    I get it Terry, we both are
    I get it Terry, but we are talking past each other. We both do not desire to breathe crap. What I am saying is that job primarily is with the EPA and they have done an outstanding job.

    As to cars and VOCs from what is in a home... that argument is plain stupid. The solution is absolutely simple. Don't put bad stuff in the home. Then no filter is needed.

    As to LA and all the other cities with crappy air. EPA... laws... get the crap out of the air in the first place. Filter it out is stupid. We can't filter an entire county like LA county can we????

    If you live in LA... that is a choice. No one has to live in LA.. Also time to protest on the streets to get the laws in place to clean up their air.

    I will add one issue to do with bad air here in the Adirondacks, and that is once in a great while there have been ozone warnings. I don't know enough about if any EPA changes could affect ozone days... Post me some thoughts on that if anyone has such.


  14. Aj Builder, Upstate NY Zone 6a | | #14

    Terry Your llnk... caulk...
    A guy adding VOCs to his home is doing harm to himself. There are VOC-less ways to seal a home. I and many in construction have used thousands of tubes of caulk and I can attest that I have no symptoms that your link guy has. The are no VOC caulks, tapes... etc. People make mistakes. People paint while living in a home to save money. The smart solution is to paint when the weather is appropriate to open windows. Have a contractor paint while on a two week vacation... there are ways to avoid high doses of VOCs.

    The solution is not filtering.

    The simple smart best solution is to not put crap in your life. No one is forcing anyone to use VOC off gassing products.

  15. Terry Lee | | #15

    AJ you're
    still not getting it…with cars EPA cannot control people. Dumb people in LA for example, pass smog test afterwards take their catalytic converters off mufflers to get better gas mileage. Their ALA OAQ scores = F’s. Ventilate that air at the same rate as KS persay, where scores are A’s per ASHRAE 62.2 2013? What if the home in LA uses the same building chems how would that rate be the same? No it is not as simple as “ Don’t put bad stuff in homes” that statement is stupid! Did you read the link posted to Linda the CA Industrial Hygienist that tested a cabinet the manufacture said was low emissivity, PS1, PS2? We’ll obviously they lied! Who regulates the manufacturer? A third party, or the manufacturer QAs themselves?

    - American Plywood Association (APA) trademark
    - ANSI/HPVA and U.S. HUD,
    - Install only cabinetry made with component materials that met all the standards above OR registered products produced in plants certified under KCMA’s Environmental Stewardship Certification Program (ESP 05-12).

    So we build homes tighter and tighter, death traps, with no real regs on what we put in them. As I said above where is a list of verified preferred building materials that have a threshold? How about the builder that builds tight only for some homeowner to bring in toxic chemicals or practices and names the builder in a law suit? It is happening.

    Have you seen this EPA certification for homes called “Indoor airPLUS” an onset of Energy Star?

    Interesting EPA has not established a threshold for IAQ calling it ‘complex and evolving’. As we seen with low formaldehyde manufacture claims from Linda, just because they claim “low emission materials” PS 1/PS2 does not mean they are. Note: their ventilation requirements adhere to ASHRA 62.2. Does not look to provide turnkey safe IAQ metered but, may be good for marketing that is about it. I was hoping to find a list of materials by low VOC category and manufacture out here. I’m baffled how a natural materials not factory manufactured get certification to some of approved “third party programs” . I guess they have to work closely with their RESNET inspector and the EPA.

    6. Low-Emission Materials

    Note: The evaluation, certification and labeling of products for indoor emissions of volatile organic compounds (VOCs) is complex and evolving. EPA has not established threshold levels for indoor VOC emissions from any of the product categories addressed in these specifications. The third-party programs referenced in these specifications include U.S. programs that are designed to reduce human exposure indoors to individual VOCs of potential concern for human health effects, compared to similar products not certified as low-VOC or no-VOC. EPA will consider modifying these specifications to include additional third-party programs as appropriate.

    As far as ozone, CO2 from factories, etc, depletes oxygen levels to a point you cannot breath. I grew up back in So CA valleys back in the 60’s-70s when we had smog alerts, our lungs hurt bad when we took deep breaths we’d cough as kids, easy for you to say to move when your job is there and can’t find another elsewhere. Sounds like you live in a closet there in Adirondacks with little OAQ issues, too bad that is not the case in the country. In some places like LA is has improved due to the EPA and CA regs, other it has got worse. IAQ as we build tighter TBD, not looking good based on junk ventilation standards that do nothing to address the real issues that developed since WW2, manufacturing and high embodied energy.

  16. Aj Builder, Upstate NY Zone 6a | | #16

    Terry if the air is bad outside it's too late to fix air in a home like I build. Too late.

    As to VOCs.... None of the homes I have built or been in close up my throat or send me deathly worrying to the internet for solutions.

    If you don't like plywood you can build without it. Same with every product out there. It can be done Terry today and many who are as scared as you have already done so. And you can I suppose build in some kind of amazing filtration... go for it. Not for me. When this Adirondack air kills me you will see the end of my posts here standing up for Adirondack air being pretty good stuff, not perfect but it could be way worse.

    And So. Cal... great place, been there a bit... have relatives there... the air along the shore.... good enough for me... just north of San Diego... I have spent time all over the southwest. Not so nice is...Albuquerque as I hit that town during a massive inversion event.

    Terry if you live in LA... no wonder you are scared of air.

  17. Terry Lee | | #17

    LOL, AJ,
    you are my entertainment for the week. Funny! Scared since I live in LA? I live in KS w/great air quality, have relatives there too. Not sure last time you were in San Diego I just was there a month ago, it has a layer of pollution like LA had back in the 90’s when I moved.

    Don’t build with plywood is your recommendation? Shows how little you know about the building materials out there. I did a recent look see of third party testing of Georgia Pacific and Adantech made with phenolic resign? I can tell you don’t know the difference between it and eura resin so let me help you out. It has low emissivity meaning it is not harmful in a home. Also, it produces little carbon footprint to the atmosphere, also, there are other great plywood and OSB products using bio-bonding natural adhesives with zero emissivity, insulations too, you just have to understand mfg to know what to look for. So take your recommendation and use them to your demise because plywood sheets have many great applications and will further improve in the future with little to harm.

    Sorry buddy no more time for your silly un-researched comments. Have fun in your Adirondack closet. Probably be good idea if you stick to building and leave the chemical and material property issues to the Engineers and PHDs. :)

  18. Aj Builder, Upstate NY Zone 6a | | #18

    Terry you can't read
    I do use plywood and many other materials... my post if you read it again... is for to do with you and your worries not mine. I will say this glad you are smiling as I am too.

    Funny how you reverse all my points to try to make a point... like I am in a closet? No, I am out in my great air... enjoying it... everywhere around here. Maybe crappy air follows you around as my visits to So Cal have had clear sunny skies my friend.

    As to you and your good air in KS... you should be in my camp... sticking up for living in an area where MIRV 11 filtering is ridiculous. PHD which includes a degree of common sense.


  19. Terry Lee | | #19

    I'm with AJ bro
    I just had this vision of you as a hillbilly smoking a corn pipe :)

    Just build with healthy materials and quit smoking corn cob pipes is best, agree! :)

  20. Flitch Plate | | #20

    Are there instruments to ..
    …. detect, measure and monitor indoor air pollutants? Beside the nose, skin rashes and phlegm levels?

    What opened my eyes to a major air quality issue was to visit a house with a self cleaning range hood. These units separate and collect for disposal, the airborne particulate from cooking and periodically, as needed, the homeowner removes and cleans the capture containers and filters.

    What I don’t like is that most of them are 500-700 CFM. That creates a lot of negative pressure inviting fugitive (uncontrolled, unknown) outdoor, basement and garage sourced infiltration as well as potential back-flow of other combustion appliances, dryers, ERV's, etc. This particulate capture design technology seems to been extensively developed in Asian countries where modern gas wok and charcoal frying (i.e. tandoori ovens) releases a high volume of compounded water particles, carbon and oil/fat.

    Here is one that is 300 CFM

    Keep pets and children well back from others:

    What most folks don't understand is that if you can smell a thing, then it is in your breathing zone as a particle. Combustion off-gassing (gasses are simply clouds of particles) is probably the major home-operation, pollution concern that a homeowner can affect. Particularly during cooking; Turn on or us an auto filtration solution.

    Our sense of smell can be quickly saturated by an assault of an odor and within moments to minutes we no longer recognize a distinct odor like we did when first exposed.

    My wife has insisted we change out our current range exhaust for the self cleaning type. I noticed a before-after difference in the smell and oiliness of our friend's kitchen/house with the Cyclone.

    What concerns me are the things Terry Lee talks about (above; "Iain Walker" (I’ll take this as legal advice"). Theses particulates are the effluents of new and evolve with aging and oxidizing building materials; not something a home owner has any ability to measure or control.

    It’s a fools game (but necessary) to control pollution by dilution and filtration; we should be keeping it out of the house in the first place.

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