Recommended HRV Brands
AHTTAR
| Posted in General Questions on
Ok next questions for folks with experience. I had no idea there were so many brands for dedicated HRV. I’ve priced Fantech, Panasonic and Zehnder systems. Basically goes from 2k to 8500. Is Zehnder worth the money? Any other brands? GBA doesn’t seem to put brands in any of the articles, just trying to save myself some research time since I’m ordering my entire house 6 months in advance.
Second, how much power should I expect these things to use on cold winter days? The thought of constantly heating outside air has always given me pause.
Thanks
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Take a look at Renewaire.
However, my love affair with ERV's has waned. Depending on your climate, there appears to be a substantial risk of mold developing in the cores. A colleague and friend in Climate Zone 5 related NEVER testing an ERV core where mold was not found.
Interesting thanks. I was leaning towards an HRV.....same story?
How would you go about tackling ventilation if you don't do HRV/erv?
I'm doing makeup air, bath fans, radiant heat, mini split cooling/secondary heat.
In my climate, zone 4 - mixed humid, we are thinking ventilation air being introduced into a whole house dehumidifier such as a Sante Fe, Ultra Air. With the myopic focus on efficiency, most AC/HP units just don't remove enough moisture to maintain healthy indoor humidity (55 degree F dew point). So the dehumidifier is a must anyway. It's not a perfect solution. No one likes 20 degree ventilation air in the winter. Mixing it with house air does temper it some. And you can alway use a preheater. Summer heat doesn't seem to be as big an issue.
It's interesting to me that in all the discussions about ERV's, I don't see anyone talking about the savings between an ERV versus supply ventilation. The numbers I have crunched only show $40 to $60 per year savings.
The truth is, we don't know as much about the ventilation topic as we pretend.
The cost of exhaust only ventillation is easy to calculate.
For example, in Zone 4, you are looking at around 4000 heating degree days.
The energy required for say 100 cfm of ventillation is:
4000 HDD * 24h * 1.08 BUT/CFM * 100 CFM = 103 Therms.
This number is on the low side as the HDD is base 65F whereas you are heating the outdoor air to 70F.
Even if you heat with cheap gas ($1/therm), that adds up.
Move away from Zone 4 to colder say Zone 6 and you are spending some very real dollars on ventilation if you don't have any energy recovery.
The question was the savings from ERV versus supply only ventilation. I did a simulation modeling a Renewaire EV90, with efficiency generate by cores calculation. Then I repeated the calc using supply only ventilation. The house was about 3,000 ft2 CFA and 4 people. ASHRAE 62.2-2010 rate at 60 CFM. Variable speed heat pump with ECM blower. The ERV saved less than $50 per year.
I thought that number was way too low. So I called Rick Karg with Residential Energy Dynamics who confirmed the estimate was realistic.
You've got to compare apples to apples. Are the quotes from 2k to 8.5k all for just the ERV? I bought a Zehnder ERV and it wasn't anywhere near 8.5k.
One brand probably in the top 5 is vanEE/Venmar/Broan (all the same items with different branding).
Complete with ducting. Pretty much apples being compared. No labor either.
If you're comparing a complete system, include everything. If you're comparing ERVs, then that's all that should be compared.
Zehnder ducting is very expensive, but you don't have to use it. It offers some advantages over conventional ducting, one of which is ease of installation, so leaving out labor makes the comparison even less fair.
What was your Zehnder price?
8800
$2650 in 2018 (for CA350 ERV)
$2200 for CA350 HRV
Believe me I'm the first one to complain about these idiots causing inflation but that still doesn't sound right. We must not be comparing apples to apples. House size, unit CFM, unit model, etc.
That was for a CA350, which is 218cfm. You listed Panasonic, which doesn't even have a model bigger than 200cfm, so I guessed that was the ballpark.
In regards to your question, can you clarify what you mean by "use"? Electrical power draw will be somewhere between 30-100W, depending on flow setting. The fact you mentioned winter makes me think you're talking about how much of a heating load it will present. That depends on your frame of reference. Compared to no ventilation, it's a pretty big load. But no ventilation is not really an option. Compared to non heat recovered ventilation, it will reduce heat loss by quite a lot. How much it costs or saves depends highly on outdoor temperature and flow rate. You could approximate this using heat capacity of air, flow rate and temperature differential. I once did this for my groud loop preheater and I think the number was somewhere around 1kW equivalent at 80cfm and a 68degF temperature difference. But my memory could be off.
Yes exactly, heating cold fresh air. Zehnder is good down to 5F but I would of course have to install a preheater that would kick on if its colder than that. Must be wired thermostatically somehow.
Zehnder has an optional built-in preheater, which is automatically controlled. I can't recall what that option costs. Other brands employ different frost prevention strategies, most typically recirculation. While this may seem like a good idea, I don't think it is. By recirculating, you're reducing the fresh air being delivered. If you've set up your system to deliver just enough fresh air, then this reduction will become significant in very short order.
It does but only down to 5F
All I know about my Zehnder Combo air 200 is that it's been running for almost 7 years without any issues. I replace the filters twice a year and that's it. Cost around $5k in 2015. Installation was simple, according to my electrician.
All I know about my Zehnder Comfo air 200 is that it's been running for almost 7 years without any issues. I replace the filters twice a year and that's it. Cost around $5k in 2015. Installation was simple, according to my electrician. This is in Maine.
I appreciate that. The CA 200 is what they quoted me as well. With all the ducting and everything its about 7500 without commissioning cost. They will send the balancing cone for each head though so easy enough to save the 750 cost to turn it on. Of course this is with free labor, me.
Most of the cost of the Zahnder unit is not the actual ERV/HRV but all the accesories. You can use a Zehnder with standard ducting. I would go for the auto balance unit (q300) and plumb to the air handler and save the extra 5k in ducting.
You can search through here for ERV/HRVs:
https://www.hvi.org/hvi-certified-products-directory/section-iii-hrv-erv-directory-listing/
Sort by efficiency to see the better units. In colder climate an more efficient unit is generally worth the cost.
Most domestic units will operate bellow -20F without any extra hardware, no need for pre-heat. You do loose a bit of ventilation as the unit will spend some time in defrost. For example the Broan B160H65RT will go to 25min supply 10min defrost bellow -17F, so you get 70% of your setpoint fresh air supply.
Sine the heating of the incoming air is from a passive heat exchanger there is no extra cost to heating the air. All your operating cost for an HRV/ERV is running the fans which are in the order 40W to 100W.
Great info, thank. you once again.