Second guessing ERV/HRV install
Planning for new construction in the Finger lakes region this year. Both our architect (recommends ERV) and a local insulation contractor (recommends HRV) are advising us to install a stand alone ventilation system as we will not have an HVAC/duct work. After reading some of the articles on this site; I’m not sure how necessary it is to take on that expense.
The house will be approximately 2200 sq ft / open floor plan with loft / clerestory / one bedroom and bathroom on the main floor and one bedroom and bath upstairs. I am wondering if we install a quality exhaust fan the downstairs bathroom (Panasonic Whisper), and quality kitchen exhaust system over range, and a Panasonic spot ERV in the upstairs bathroom if that will be sufficient, as we will us windows in the spring/summer/fall. Both bathrooms are on the north side of the house, have exterior wall access, and the upper floor bathroom is directly over the downstairs bathroom; not sure if this matters.
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BTW, both are recommending the system be put into the attic, which bothers me as these units need regular filter maintenance. To me attic installation is just asking for the system to get neglected. We are pretty good at maintaining our home systems, but in 20 years when I am 60 and my husband is 70, we do not want to be climbing into the attic every month.
Nina:
If you are building a well-insulated house, you will be better served by a ducted ventilation system. (The Panasonic FV-04 will fail if installed in a humid environment, BTW.) Here are a couple of articles you should read before making any decisions.
Designing a Good Ventilation System (https://www.greenbuildingadvisor.com/blogs/dept/musings/designing-good-ventilation-system)
HRV or ERV (https://www.greenbuildingadvisor.com/blogs/dept/musings/hrv-or-erv)
Steve, I have read both of those, twice. Then I also read "Are HRVs Cost-Effective?" and another article on this site regarding a study on cost savings over time, but I cannot find it now. The cost savings article did seem to be controversial from the comments made after the article was posted. It can be somewhat humid up here at times in the spring and summer, but in winter it is dry. Of course I am comparing that to Columbus, GA, which is where I lived for 9 years before moving up here; definitely no as humid as it was there.
Renewaire got a ERV payback calculator at http://www.ervcalc.renewaire.com/
Nina,
You are correct that it's a bad idea to install an ERV or an HRV in an attic -- especially if the attic is outside the home's thermal envelope. (Even if the attic is inside the home's thermal envelope, putting equipment in an attic makes maintenance awkward.) So if you decide to install an ERV or an HRV, try to find a better location -- perhaps a mechanical room.
In your climate zone -- the Finger Lakes region of New York -- the climate is cold enough that it makes sense to consider installing an HRV or an ERV. That said, not everyone can afford to install a balanced ventilation system. If your budget is tight, the alternative you suggest (exhaust ventilation) would work, with one adjustment: skip the Panasonic ERV.
Panasonic does not recommend the use of their spot ERV in cold climates. In your climate, the unit would only work from April through November -- it wouldn't work from December to March. (See the Panasonic map below.)
So an exhaust fan in the upstairs bathroom makes more sense than a Panasonic ERV.
-- Martin Holladay
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Thank you. Somehow I missed that important detail about the Panasonic ERV. I have not given up yet on the decision to incorporate an ERV or HRV. Just last night I was thinking about the fact that we have 3 cats and have an oil lamps n almost every room that we use more often than the average person; two aspects of our lifestyle that probably cause me to lean for one. I think we can fit into the budget, I was just having a hard time agreeing to having it put in the attic; for the money we would pay, I would want to ensure the system was maintained.
There may be an advantage to an HRV when you have cats, depending on where you place the ductwork pulling stale air out of the home.
We have two cats each has its own litter box. One litter box sits in the soaking tub in the master bath (like many people we generally only use the shower). That cat sometimes "forgets" to cover up. The constant HRV exhaust from that room limits odor to just that space.
Nina,
You should not use the lamps. Battery-powered LEDs are a better source of emergency lighting. If you are using the lamps for aesthetic reasons, be aware that they can significantly degrade indoor air quality (especially in a tight house). Here is an excerpt from an National Institute of Health report on the negative effects of combustion on indoor air quality:
"Of the 4.3 million people who die every year because of household air pollution, 60% die because of cardiovascular diseases and 40% die because of pulmonary diseases 1 ( Figure 5). Short-term effects of exposure to household air pollutants confer an increased risk for deaths because of cardiovascular as well as respiratory causes. A 10 µg/m 3 increase in indoor particulate matter (PM) has been shown to increase cardiovascular mortality by 0.36% and respiratory mortality by 0.42%. Similarly, a 10 µg/m 3 increase in indoor PM 2.5 has been shown to increase cardiovascular mortality by 0.63% and respiratory mortality by 0.75%. In the long term, every 10 µg/m 3 increase of household PM increases the risk of mortality by 23% to 67%."
The entire report is here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5089137/. The report focuses on the developing world, but I think the data helps to explain why breathing in particulate matter is a bad idea.
We framed a little enclosure in our mechanical room for the litter box. It's about 3' wide, 2' deep and 2' high. It has it's own HRV exhaust port. Above the space is a space for drawers that is in the adjacent room.