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Musings of an Energy Nerd

Broken Ventilation Equipment Goes Unnoticed for Years

When an ERV falls in the forest, is there anyone around to notice it’s broken?

This ERV is seriously ill. Joe can hear the motors humming — so why isn't there any air flow through the intake or exhaust grilles?
Image Credit: All photos: Joe Nagan

Years ago, when I worked as a home inspector, I was hired to perform a capital needs assessment at a Buddhist retreat center in rural Vermont. In an obscure mechanical closet I discovered a heat-recovery ventilator that the facilities manager didn’t even know existed.

The HRV had been installed at least a dozen years before. The filter, which had never been changed since the day it was installed, was totally clogged. The HRV was no longer working — perhaps the motor had burned out years ago. I advised the owners to call an HVAC contractor to have the unit serviced.

Who’s going to notice when it conks out?

When a furnace or water heater stops working in January, it only takes a few hours for the homeowners to notice that something is wrong. However, when an HRV stops working, the owners rarely notice.

The HRV failure at the Buddhist center raises several questions:

  • Are there ways that HRV installers can ensure that ventilation equipment is properly maintained?
  • If an HRV can stop working without the owner noticing, is mechanical ventilation even necessary?

I don’t have any ready answers to these questions, but I welcome comments from readers.

An ERV emergency in Wisconsin

Memories of the clogged filters at the Buddhist center came flooding back to me recently when energy consultant Joe Nagan sent me an amusing series of photos by e-mail.

Here’s the story: Joe was walking by his local nature center in Wisconsin — a “green” building equipped with a rooftop PV array — and noticed that the building had a large, commercial-sized energy-recovery ventilator (ERV) mounted on an outdoor slab. Although he could hear the Venmar unit’s three motors humming along, he was surprised to notice that there wasn’t any air flow at the intake or…

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  1. Expert Member
    CARL SEVILLE | | #1

    Love the pictures
    Important issue you raised here Martin. What good is expensive equipment if it doesn't work and isn't maintained? On a related note, I just posted the content of an email string about weatherization and ventilation that is pretty compelling reading, at least for geeks and nerds:

  2. user-1119494 | | #2

    A couple hypotheses
    Both of the buildings sound to me like places that normally are fairly quiet and empty, but had to be engineered for much, much higher occupancy. With nearly no one in the buildings, one might not have a problem. An analog might be a 10-gal aquarium with one gram of goldfish swimming about...To misquote: "HRVs? We don't need no HRVs!".

    If they filled the buildings to capacity they would probably notice within hours that SOMETHING was wrong. (just try filling that aquarium with a kilo of fish and forgetting the filter...)

    The fact that no one noticed really tells me that the 24-7 HRVs were a waste and should have been installed with air-quality sensors. This would have saved a whole lot of energy....not to mention lengthening the lifespan of these expensive devices.

    An owner's handbook, complete with a maintenance schedule, would have been a great idea as well. Every modern building should have one...

  3. GBA Editor
    Martin Holladay | | #3

    Response to Dustin Harris
    An owner's handbook is a great idea, of course, but an owner's handbook might well have been included at these two buildings. This is the problem: the owner's handbook gets filed away on a shelf in the office or maintenance closet where the facilities manager (or custodian, in the case of a school) keeps miscellaneous papers. The facilities manager or custodian quits his job, and a new person takes over. All institutional memory is lost.

    Or, in the case of the homeowner, the house is sold. Do you really think that the realtor knows where the owner's handbook is, and makes sure that the new owner gets it? And if the former homeowners are selling the house because of a bitter divorce, do you think they are concerned about educating the new homeowner?

  4. tamfflcommissioner | | #4

    Joe, when you yell "CLEAR!" -that means you too! You are kneeling on the metal ERV!

    The larger issue in building commissioning is how involved the architect and engineer and builder should want to be. If you are proud of your work, and have done your best with your design, wouldn't you WANT to check in on your baby as it grows up? To rely on the building owner alone is asking for trouble. If problems are to be found later, who better to find them than the design team?

    Typically, there is some follow-up written into the language of the contract, but that doesn't address the "WANT" thing. The "conscience" thing. Architects, engineers and builders who embrace their roles as experts and building scientists are the ones who will not only continue to stand out, but will raise the question to other prospective clients as to why they would ever go to someone else for a project?

  5. GBA Editor
    Martin Holladay | | #5

    Response to Jeffrey Melvin
    If I am understanding you correctly, you are suggesting that HVAC engineers and architects should visit completed projects on a regular schedule -- perhaps annually. For these visits to be useful, presumably the HVAC engineer or architect would inspect and check installed equipment for proper operation.

    That's a great idea, but are you offering these services for free, for the life of the building? Or perhaps until you retire? And are you charging the owners for this annual inspection? If so, how much does it cost? Do all owners agree to pay your fee?

    Or do you do it for no charge, as part of your normal services? After you have completed 50 projects, how much time will these annual inspections take?

  6. dankolbert | | #6

    Great thread
    Carl - thanks for posting that. Haven't had time to read it all, but Rick's initial post alone is worth the price of admission.

  7. RobFisher | | #7

    Response to Jeffrey Melvin
    As an architect I can say that it is entirely out of my responsibility to check in on a project after it is completed. That doesn't mean that I don't do it but that I am not physically able to check on all projects. If I did, I would never get any paying work done.

    That said, I do feel it is my responsibility (or my consulting engineers) to educate and inform the owner(and their staff) of the maintenance responsibilities. A handbook is great, but as Martin said it just gets shelved. I think the best education I can give is to make sure the owner understands that maintenance is essential, and needs to be performed correctly, regularly and probably by a professional. If I can get owners to understand that their new building is like a new car, and they don't do most of the maintenance on their new cars because it requires tools and hands on knowledge that they probably do not have. Its about getting all owners to understand that yes, they need to pay properly educated professional to maintain their buildings, whether that is in house staff or outside professionals.

  8. 5C8rvfuWev | | #8

    things that go blink in the night
    Hereabouts, electrical transformers have a light that blinks when they're overloaded, presumably so someone can do something about the problem before it explodes .... "Presumably," I say because one a mile from where I live has been blinking for weeks.

    Most cars have an alarm system that, when the doors lock, has a blinking light on the dash.

    If it's not immediately dangerous, we don't need sirens. But what about that "home dashboard" I've heard y'all talk about before ... a simple panel with, or near, the thermostat that tells even the mechanically challenged when something in the home needs attention.

    Yeah, it's going to cost. Is it worth it? That's up to you guys. I'm just a consumer.

  9. user-659915 | | #9

    The quest for mechanical performance bites its own tail.
    Maybe we need to be building Honda Accords, not MGB's.

  10. stuccofirst | | #10

    Buddhist Retreat
    Maybe the ERV didn't have enough OMs.

  11. GBA Editor
    Martin Holladay | | #11

    Response to Shane Claflin
    In a remote cave in Ladakh, scholars recently discovered an ancient Buddhist manuscript -- the first evidence that there were really Five Noble Truths, not four.

    The fifth Noble Truth: Suffering of the Nostrils is caused by Failure to Maintain Ventilation Equipment.

  12. user-1119494 | | #12

    OK, if we believe that the
    OK, if we believe that the house requires certain maintenance and accept that paperwork gets shelved or lost or ignored, it seems pretty clear that we need some way to overcome that. The blinking light that Joe suggests is a possibility as long as it is not simply an annoying blinking light that will simply be ignored or taped-over.

    Whatever we do, we need something that will be noticed and remembered when maintenance is required. Perhaps the builder or a service they hire could send out a very small, personalized, and important-looking mailer each year as a reminder, perhaps even pointing at the web site where their user manual pdf is available. Cost to send it out could be only be a few bucks per project per year. Perhaps something on the outside to prevent them tossing it, like

    Have you checked your building's owner's manual lately? An important reminder from XYZ construction, the builder of your home. Take five minutes to check....

    Perhaps the manual could be entirely online with a 3rd party service, one that can integrate later changes to the house to keep the manual readable and simple. The service could even send out email notices to the homeowners for important maint and testing. you think builders would be interested in such a service?

  13. onacurve | | #13

    alerts from an OS for buildings
    Shouldn't a building be built more like a car, with gauges, alarms, warning lights, error codes on a control module, etc? It's not necessary for auto designers/manufacturers to come to your house to check your car's oil level, neither should it be necessary for an architect/civil engineer to go out to personally inspect his building, as Mr Fisher suggests. Automate it. Use sensors. Send text or email alerts to the homeowner or maintenance man.

    Isn't a comprehensive operating system for buildings badly needed? As an example, my Current Cost power meter that tells how much electricity I'm using at all times, updated every 3 seconds. It can be expanded to multiple channels to monitor individual appliances or even production from a solar or wind generator. A device to measure current gas and water consumption would be useful. It used to be cool to check out how I was doing on electricity consumption using Google Powermeter, before they discontinued that service, as Microsoft discontinued their similar Hohm service. Other software is available, but I haven't gotten it to work. A sales manager at Current Cost told me they are working on new software.

    I wonder if Microsoft and Google may come to regret those decisions. Microsoft has tons of money, as evidenced by their $8.5B Skype acquisition, a move that puzzled many. Maybe they could have used some of that dough to double down on their meager investment in Hohm rather than abandoning it. Maybe they will resurrect it someday.

  14. tamfflcommissioner | | #14

    Martin and Rob
    Not free. Nothing is free. But we build these things into the cost of doing business already. Although, we call them "estimates." Yes, I know this too is controversial. The "free" estimate verses the paid estimate. Let's put that aside momentarily and say that we regularly give away time just bidding on work. Work that someone else has completed. Now we are called on to add on to that work. This takes some time -no? We first have to become familiar with the building. We do a walk through. We bring tools to measure. We bring iPads to draw sketches and take notes on our take-offs. Sometimes this involves getting into the mind of someone else. What did the designer intend here? Why put a sub-panel there? Clock is ticking. But we give that away for free. Because the building owner thinks something is wrong with his building and presumably he wants you to fix it. And we hope we get that job. In the event of a new project, we don't have to deal with an existing building, but we are still bidding. And the clock is still ticking.

    Well, once you have actually performed work for someone on a particular building and the transaction is complete, I think we have this dumb tenancy for that to be the end of the relationship. We go on and assume that the building owner will call us if something goes wrong (something we might be on the hook for.) But I think this should be the opposite. It is much easier to come back into a building that you have been very involved with in the past and spot problems. You already have the measurements. You know why the line is run here. And you know what? There will be problems with the building. Yes, some of it you may be on the hook for, but there will be new work there too. Or a new project being planned. Who is the building owner going to go to first for this new work? The new guy? Or the one that has been there consistently from the time the commissioning of the building was complete. This "relationship" does not need a HOBO or a beeping alarm. Although these tools are useful, they are not going to get us more work for less effort by themselves.

    Be the building AND relationship experts. This means we have to WANT to be involved.

  15. user-659915 | | #15

    Occam's razor.

    According to most energy experts, tight buildings need a good ventilation system to assure good indoor air quality. Without a mechanical ventilation system, moisture will condense on windows, odors will accumulate, and rooms will feel stuffy ....... You'd think that once the ventilation system stopped working, the nostrils of a visiting environmentalist or Buddhist might twitch. But no one noticed.

    One has to ask, was there anything to notice? Did the symptoms of condensation, odor and stuffiness actually occur while the ERV systems were down or did they not? Much talk above of the need for system monitoring but no discussion of whether the system was in fact needed in buildings with these particular use patterns.

  16. GBA Editor
    Martin Holladay | | #16

    Response to James Morgan
    I was raising the same question you raise when I wrote, "If an HRV can stop working without the owner noticing, is mechanical ventilation even necessary?"

  17. user-659915 | | #17

    Response to Martin
    Yes, and I am still bewildered why discussion of that question lapsed so early in the thread. Not to mention the further point that relying on complex mechanical systems for environmental performance is a risky business when there is virtually no control of installation quality, let alone long-term maintenance. I'm certain we've all seen instances of high quality equipment installed upside down and backwards, and if even a building with a professional facilities manager cannot meet the most basic maintenance requirements of these (theoretically) high-performance systems, why would we expect the average homeowner to do better?
    Ultimately this is a design failure. I'm not sure what the answer is, but I'm disturbed if the main response to system failures is first implicitly blaming the homeowner and second making the systems ever more complex.

  18. wjrobinson | | #18

    Smart Homes and Passive AQ Homes
    Like my thinking on a similar thread, now that we are attempting to build tight buildings, the likes of Panasonic and all may just come to our aid by continuing to improve their products to fill the needs we have to make tight buildings able to more take care of themselves. Sensor improvements, pressure, air quality, filter management, etc. All the part exist today including easy networking and smart devices. It all just has to be implemented, improved and marketed soon as a complete package by someone. Make it so we the builders and architects and homeowners can read up on it, see marketing about it, cost, use, and finally some good reviews by early adapters. Smart homes are just about here. That is the answer to tight home air quality. And for those that prefer no automation we need to also build less tight homes that include very low VOC materials and proper passive venting along with sealed combustion units, electric ranges, etc. My thoughts anyway... feel free to improve upon this idea...

  19. user-659915 | | #19

    "Smart homes are just about here."
    C'mon A.J., you've been around for a while - you know as well as I do that they've been saying that for about thirty years now. Homes are just as dumb as they ever were, still takes a smart and committed homeowner to properly run some of the overly complex mechanicals that we're throwing at them. Your second option is better. Reduce indoor pollutants (especially high-power gas cooktops), optimize the envelope and allow for good natural ventilation to be available as needed.

  20. RobFisher | | #20

    Jeffery and others
    I was laid off 3 years ago. And at the time my boss was cutting our fee by 5% on all projects and we still were not getting projects. In the end that firm went from about 50 people to about 15 people in 18 months, yes about 70% loss. All of this to point out that there really is no room to add in another service and fee. Regarding relationships, I completely agree that maintaining them is one of the most important aspects of business, and something like 80% of the business at my previous firm was repeat and/or referral.

    It is all about education. As it has always been, being a home owner (or building owner) requires and understanding of the required maintenance. I'll use the car analogy again. If you have a problem with your care and you don't know how to fix it, you take it to a mechanic. If your car is newer, you probably have to take it to the mechanic just to read what the internal computer says is wrong. New homes (or buildings of any type) are the same.

    Building automation is great, and I think it could help, but building owners still need to understand that buildings, and especially their systems need maintenance. I have a new, 9 month old, Weil-Mclain Ultra 105 boiler. Compared to old cast iron boilers this thing is all tricked out. 95% efficient, sealed combustion, stainless steel burner, computer front end. It tells me everything, how its firing, what its heating (hot water or home heating), and when it needs maintenance. But I still have to call my HVAC guy every year to do the maintenance. He's got to clean it every year and every 3 years there is a service pack that needs to be installed. This is way out of my understanding so the HVAC guy does it all.

    In the end, IMO, the only thing that will consistently work is education, education, education.

  21. AndyKosick | | #21

    "Maintenance Free"
    When and how much to ventilate can be a complex issue and perceived air quality is very subjective. I'd say that the modern home absolutely needs a dashboard like alert center, it should probably actually be the thermostat, seeing as people already look at these once in a while. At the same time we professionals don't need to take all the responsibility here. I've spent half my career fixing problems caused solely by homeowners complete ignorance of their house and one of my biggest pet peeves is the epidemic of "Maintenance Free" in our culture. I know the world is increasingly complex but people should have at least an armchair understanding of key things in their life (house, car) and a facilities manager probably ought to know what the giant humming metal box beside the building is.

    Also CO, CO2, O2, and humidity censors are all getting pretty affordable, why not run the ventilator like heat and AC, when it's needed.

  22. user-659915 | | #22

    The automobile comparison is interesting.
    But lets looks at the other way. If we built cars like we build houses we'd go to a dealer/aggregator and point out the body style we like. The dealer would then recommend an assortment of mechanicals to go with it - sure, we can fit a Prius drivetrain into that Porsche body - how about this BMW suspension, it's very good - you can't beat Volvo for braking systems and passive restraints...... Ignoring for the moment just how expensive such an approach would be, imagine the maintenance issues with an agglomeration like that, even with a dashboard alert system to help out. I realize that some of our more technically-minded readers are probably salivating at the idea of a 'dream team' auto, but for the great majority of us, a vehicle with a fully-tested, fully-integrated design and the simplest possible maintenance schedule will be vastly more useful, affordable and resource-efficient.

    You may think I'm making a case here for prefabricated houses built in factories with fully integrated mechanicals. Nothing could be further from my mind - we can send a ten-year-old car to the crusher when its complex systems go out of date or begin to fall apart, heaven forbid we start to do that with our homes. And I happen to like the fact that our homes are the last outpost of skilled local craftwork, built by the same folks you run into at the pub and the PTA meeting. What I am suggesting is that a modern automobile is a very poor model for a truly green home which, a priori, should be as simple to build and operate as possible. We cannot assume that parts and skilled maintenance help will always be available and/or affordable through the life of the building. I'd suggest that mechanical systems that add complexity to the program without clear justification should be rigorously excluded from the green building model. The examples in this blog post of failed ERVs which went unnoticed by the occupants for years raise a question which is still unaddressed by the vast majority of comments here - were these systems ever necessary in the first place?

  23. GBA Editor
    Martin Holladay | | #23

    Response to James Morgan
    Ventilation isn't like space heating. Controlling space heating is fairly straightforward: most people like their homes to be between 65°F and 75°F, and thermostats do a pretty good job of maintaining the desired temperature.

    In contrast, the need for ventilation is all over the map. High-occupancy homes need more ventilation than low-occupancy homes. Some families have smelly teenagers with sloppy housekeeping habits; others have hyper-neat elderly residents who never leave their socks on the floor. Some families take 4 showers a day and cook pasta all the time; other families need only 6 or 7 showers a week, and never cook.

    Finally, it's hard to automate ventilation equipment. While 60% relative humidity may be perfectly acceptable during the summer, the same humidity level during the winter can sometimes cause problems.

    In short, there's no easy answer to the questions raised in this blog.

  24. GBA Editor
    Martin Holladay | | #24

    Response to AJ Builder
    OK, I'm absolutely wrong. Except you admit I'm right today, the day when I am writing. However, you predict that at some point in the future, conditions will change.

    When we discuss any technical matter, AJ, I am always writing about current conditions.

  25. dankolbert | | #25

    Write, right?
    yeah but are you always righting about current conditions?

  26. wjrobinson | | #26

    Martin, I absolutely know you
    Martin, I absolutely know you are wrong. All the components of smart phones including apps are about to take over all of our lives besides cell phones, Facebook, and texting.

    The Nest tstat is the beginning. A title wave of similar tech is seconds behind.
    James, you too are out of touch. Would you let a family member buy a car predating seatbelts, airbags, antilock brakes, computer controlled almost zero emission vehicle? No.
    Air quality in homes can be automated. And the market will eventually package and lower the cost and make it available to those of us that build homes.

    I bet I am right and you two are only right as of today not tomorrow.

    Edit: glad to see we agree again Martin. Need to figure out how to get you thinking about tomorrow more as tomorrows are todays and yesterdays faster than we can post updates in these blogs.

  27. GBA Editor
    Martin Holladay | | #27

    Response to Dan Kolbert and AJ
    Absolutely not. That's why the comment feature of a blog is so useful -- to ferret out my errors.

    And AJ -- once you've got that prototype of an automatic ventilation control unit and associated sensors perfected -- the one that can adjust its response to RH sensors seasonally and can distinguish between good odors like baking apple pie and bad odors like dirty laundry -- send me a unit for Beta testing.

  28. user-963068 | | #28

    An Owner's Perspective
    Martin et all,
    It just so happens that we have a relatively tight house (.42 ACH 50 as of the latest testing) and our ERV is set at about "medium" (Ultimate Air DX200). About 4 weeks ago we had a thunderstorm roll through the area and while I was standing on the deck watching the torrents of rain come down the rain chains, a bolt of lightning "hit" in the woods something around 75' from the house. I hurried (ran like heck) inside at that point and noted that our internet had quit working (rather my wife advised me of the fact). When I went to check on the modem (ADSL) no lights so my next stop was our mech room to see if we had tripped a breaker. No breaker tripped but I did notice the ERV had quit running - it was humming the transformer sonata but nothing else. We returned the unit to UltimateAir for repair and found it had suffered catastrophic failure of all electronics and the motors to boot. While we were without a unit I noticed a bit more "stale" air and humidity in the house increased about 10 points (remember we're in humid North Carolina) so we did the manual ventilation process by opening the clerestory window and a couple others in the house to provide stack effect ventilation. We reinstalled the unit this past weekend and I've already noticed a difference - hard to put my finger on what but I think we're sleeping better at night and feel more comfortable during the day.

    The good news about the UA unit is it does indeed include indicator lights that say "I"m on" and "change my filters" so if you have that control unit in a conspicuous spot, you can see those lights. Our installation happens to be with the controls in the Mech Room so unless like me, you are in the mech room at least one time a week, you might not see the lights. The UA unit also includes an Econo-Cool switch that, when switched on, increases the air circulation when it senses outside temp/RH are lower than inside temp/RH.

    We do have cats so the bathroom ventilation provided by the ERV also draws out that "stale" air which we noticed during it's absence.

    Martin - one thing that is probably worth a separate discussion is the addition of surge protection and lightning protection to houses as a matter of course. I have added the surge protection to the service panel and point-of-use (plug-in) surge suppression but most of those units do NOT cover direct lightning strikes. I have a lightning arrestor on order that should be delivered shortly which is a sacrificial device that "disintegrates" when a lightning strike happens. The cost of these units is lower than my insurance deductible so if they work one time we're in the black and we can still watch TV, surf the net, and make telephone calls without having to wrestle with an insurance claim. Owners manuals for the equipment make nebulous statements like "proper circuit protection is necessary" but that could be construed as a circuit breaker and not surge suppression/lightning arrestor protection.

    I'll be second in line for that lab test of the RH/Odor sensors...

    footnote: The Delta LA-302R lightning arrestors were just dropped off by UPS as I hit the "post" button so they'll be installed as soon as possible!

  29. kim_shanahan | | #29

    NAHB weighs in on the subject
    At last week's Spring Board meeting of NAHB, a resolution was passed relating to ventilation. Many of the "whereas" sections were specious, such as "Whereas, only anecdotal information and small-scale studies are available on health effects of indoor pollutants, pollutant levels and air infiltration in new homes;". Another subjective statement: "Whereas, few occupants complain of inadequate air quality in homes, and unlike office occupants, residential occupants can open windows when the need to;".

    The "Therefore be it it resolved" then calls for more research, which is all well in good, but then concludes: "BE IT FURTHER RESOLVED that NAHB oppose any new indoor air quality ventilation requirements in legislation or construction codes and standards for all residential buildings until such time that it is demonstrated through field studies including pollutant levels and air infiltration rates, that a signficant health problem from inadequate indoor air quality problems exist, is solved by additional ventilation, and that the problem cannot be addressed by source control and/or better design of ventilations systems."

    When I mentioned to the Construction Codes and Standards Subcommittee that we in the People's Republic of Santa Fe, who have had mandatory HERS 70 and tightness requirements in our City Code for three years, recently amended our City Code to add an ASHRAE 62.2 requirement for all new residential construction, there was an audible collective gasp in the room.

    While it may be true that "few occupants complain of inadequate air quality in homes" we also see asthma rates near epidemic levels and it took almost two years of puking before FEMA trailer occupants knew they were being poisoned, not to mention the spectre of odorless Radon.

    Like Martin, I don't know how all this will shake out, but until research like that called for by NAHB is conclusive I will still advocate use of the building science mantra: "Build it tight and ventilate it right". And for those purist who simply say open the windows and allow natural ventilation, the next homeowner may disagree and have severe seasonal allergies and never open the windows.

    We will be debating these ideas for the rest of our careers and beyond.

  30. GBA Editor
    Martin Holladay | | #30

    Response to Kim Shanahan
    Like you, I still advise builders to "build tight and ventilate right."

    In recent years, after NAHB has launched its Green Guidelines and National Green Building Standard (ICC-700), it has appeared that the organization was beginning to rethink its traditional opposition to efforts to raise the bar on construction quality, energy efficiency, or related requirements. However, your report shows that NAHB's knee-jerk oppositional approach is still alive and well.

    In the past, NAHB lobbyists opposed the proposed "Thirty Percent Solution" (raising the bar on energy-efficiency requirements in the code). They also actively opposed the American Clean Energy Security Act, arguing that additional energy savings beyond 30% would be impossible.

    And, as your comments show, NAHB is also opposed to including ASHRAE 62.2 ventilation requirements in the code.

  31. user-659915 | | #31

    Response to Kim Shanahan
    C'mon guys, you can do better than this. That the NAHB, a conservative trade group, is opposed to new regulation perceived as against its members' interest has exactly what bearing on this particular discussion? Kneejerk responses to kneejerk responses get us exactly nowhere. And are you seriously suggesting that an ERV is the best strategy for dealing with a toxic FEMA trailer or a radon-contaminated house? You'll get no argument here with the mantra of 'build tight and ventilate right'. However in any particular instance what does 'ventilate right' actually mean? I'd like to see an evidence-based discussion of the various approaches to the issues of condensation and IAQ, factored for different climates and use patterns, before we just start throwing the additional complexity, expense, maintenance and energy demands of ERVs into all our homes willy-nilly. I'm no more a fan of the NAHB policy arm than you are, but in this case they may have a point. Where are the studies? And are there better ways to achieve the same goals?

  32. JasonMM | | #32

    From a Manufacturer
    Well- I wish I could read these blog's 24/7.. but a quick comment is in order. {UltimateAir} We've had this type of feedback. We do try to listen- but still must weigh design changes/enhancements against what we can sell. Product cost is related to its "bells and whistles". Gadgets that would tell the user that the ERV is not working, will add to the cost, and the north american ERV/HRV residential market is tiny. Thanks for the comments from Clarke above- we have some of the 'less smart' indicator lights. We could build a unit (or a control rather) that would tell the user...'hey- you lost an air stream, or hey- the filter is clogged... ect... " but i'm not sure anyone would buy it (enough to justify design and manufacture costs?). Right now- it just boils down to- all of gods mechanical systems need to be looked at (serviced) on an annual basis. You do have your oil changed in your car- right? You keep putting gas in it? And/or we would need to define what is 'bad' indoor air quality... then we can trigger something that tells you... (RH, particulate level, CO2 level, Radon concentration, VOC concentration, Odor?, ... ) There is no consensus on 'safe' levels for some of these things.. nor is there a economical way to detect and report. And this - coming from an owner/builder of a passive house- if you wanted a house that requires no maintenance- move back into a cave. (laughing of course).
    Again- thanks for the feedback. We are listening.
    PS- i've also seen plenty of ERV's - installed in buildings (homes)- that were never turned on (commissioning?)

  33. [email protected] | | #33

    I'm a believer
    We recently completed a gut reno & addition- adding insulation, triple-glazed windows, and air-sealing with a 1.5 ACH50 result, zone 5. The layout is a bit complicated, and I was put off by expensive HRVs, so opted for exhaust-only ventilation. We ventilate to the ASHRAE 62.2 standard of 7.5 cfm/person + 1.0 cfm for every 100sf. With 7 of us and 3400sf that's about 90cfm (tested & confirmed) which we get with 2 panasonic bath fans running most of the time. When a couple of us are home alone I tend to shut off one of the fans if the bathroom is dry and I think of it.

    When we 1st moved in, one of the fans wasn't on continuously. My wife and I were getting headaches at night. Putting the 2nd fan on continuous operation solved the problem. I don't know how ASHRAE came up with their number, but it seems to be spot on. An ever-so-slight cracked window ensures airflow through the bedroom.

  34. user-242891 | | #34

    Aside from the baseline
    Aside from the baseline question of the need for ventilation, i'd like to revisit how to engage people on the necessity to have people maintain their homes.

    As a green builder/developer and realtor I see all sides of this issue...from building green houses and condos to selling and reselling homes. There are limits to what we, as builders, can do to make people care properly for what they've got. HVAC equipment is the poster child for falls into the category of "mysterious" for most homeowners and as long as it isn't broke, they don't pay attention to it...not even changing the filters.

    I think the answer here is straightforward...not simple, but straightforward. We need to legislate an answer. Home sales requiring the following would be huge leaps in the right direction:

    a) Building performance data: 12 months of water and energy use data goes a long way to having homeowners suddenly care about the efficiency of a house they are buying. They require energy use data in MD for sales, so I've seen this happen.

    b) Home owners manual: that is required to pass from current to future owners. A copy should be required to remain at the mechanical closet and one should be given to the homeowner for their records. This manual should literally list all the equipment in the house and the specifications. It should cover all maintenance required by the manufacturer.

    c) Maintenance records: These should be required. If a homeowner doesn't provide them, guess what, the house will be worth less to a potential buyer due to the risk of the unknown.

    These are things that are totally within our grasp to make requirements...but there is little financial incentive to drive this market shift, hence it's the perfect candidate for state (or national?) legislation under the need for consumer protection.

    As a Realtor I cannot tell you the number of times I've been involved in transactions where the house ends up being a total lemon. There is no lemon law for houses like there is for cars. There is literally no recourse for someone who buys a home, goes through the normal inspection process where a few things get addressed but nothing major and then within the year the HVAC blows out or after living in the place they find the HVAC doesn't reach the 2nd floor at all. This is a travesty that we all just accept as part of life and being homeowners, and it is just plain wrong.

    Having people spend money to maintain things they don't understand and that they may not see an obvious benefit from (as in ERV's) is a tough sell. Having people spend money to maintain things to that when they go to resell they will get top dollar is an easier sell (for many). As our houses have become more reliant on equipment, our laws should keep pace with our needs for consumer protection in real estate.

    I'm off my soap box...but I have to admit, i could really go on and on about this.

  35. user-426670 | | #35

    I know a guy who installs solar panels. He warrantees his work, and his contracts contain conditions under which the warranties are void. He also offers clients a service contract to inspect and maintain his installations.

    This business model allows him to check up on, and improve, his past work, maintain a relationship with his clients, and have a small revenue stream from that "maintenance" work. Consequently, a lot of his business is through word of mouth.

    Most solar panels are designed to last a long time -- certainly longer than most production cars and, some might argue, longer than many of today's production homes. If the solar industry and the auto industry can sell warranties and maintenance contracts, why not the building industry?

    Granted, this suggestion goes further toward addressing the problem of system failures going unnoticed than it does toward addressing the question of whether mechanical ventilation is needed in the first place, but both are legitimate issues. As for the latter, it brings to mind an analogy about smoking. Most people exposed to tobacco smoke will not die from any single exposure, but a statistically predictable portion of those exposed will have grave health consequences, with some people more vulnerable than others.

    I don't mean to argue that mechanical ventilation is absolutely necessary, only that we shouldn't just build for healthy people with good genetics. Indoor air quality is a legitimate issue that needs more resources and research to address. Having verified the truth of Murphy's Law, my inclination is to find methods that ensure buildings remain healthy and comfortable and have the least number of failure modes (especially catastrophic ones!)

    Of couse, this may require that the industry have more Hondas and fewer Orange County Choppers, so it might not be worth it.

  36. wjrobinson | | #36

    Huge house, two people, tiny
    Huge house, two people, tiny fan off, headaches. Fan on, no headache. What is in this house?

    I don't build homes or have never lived in a home that would give me a headache from the air in it.

    There are homes that give headaches from air quality? I would move out, sell, or find out what is wrong.

    Some people seem to say they have a headache, others never have a headache. Could there be a human factor?

    Thinking more, many of us build homes for a lifetime inches from new OSB, and paints, wood. Over all the years I have found really only one serious health issue and scare, and that was the time I sanded a Teak threshold about to be installed, inside, no dust protection. That dust instantly closed my throat. Very careful now with Sanding wood.

    I hope to never build a home that gives headaches if a fan happens to not be running. Martin, Apple pie, now that is one aid problem this guy loves. May have to find a piece today at lunch!

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