Author Topic: Building a small house. ERV (energy-recovery ventilator) necessary?  (Read 2071 times)

RavensBrew

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Hi guys! Me and my SO are building a house that will be just under 700 sq ft. It has an open floor plan on the main with a vaulted ceiling and a single bedroom upstairs. It will be heated/cooled by 2 minisplits. I don't know much about ERVs except for what I've read online and there are varying opinions about it. Our contractor can install a Panasonic (the same unit he has in his small house) unit for around 800 dollars. I asked him if it would save us money and he said probably not much, but it is good for comfort. But when I read the wiki page (which sounds like it might have been written by a salesman) it says a couple of interesting things: "demonstrated an effective means of reducing energy cost and heating and cooling loads" and "a way to reduce global energy consumption and give better indoor air quality." This sounds appealing. Anyone have an opinion on these? The idea that will be a power drain 24 hrs a day I dislike but if it lets us use let energy heating and cooling I'm all for it.

Thank you!

slugsworth

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Re: Building a small house. ERV (energy-recovery ventilator) necessary?
« Reply #1 on: April 18, 2016, 10:12:31 AM »
I'm not an engineer - so take this with a grain of salt. ERV's/HRV's and mechanical ventilation in general should be looked at as a way to get your air exchanges. Window trickle vents work too. . .I think your climate and how tight you are building your house are major factors in this decision.  For $800 I think I would do it, especially if I did have a super efficient envelope.

Big thumbs up for building such a modest sqft house!

RavensBrew

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Re: Building a small house. ERV (energy-recovery ventilator) necessary?
« Reply #2 on: April 18, 2016, 10:17:29 AM »
Thank you slugworth. We're leaning towards going for it after reading many first hand accounts. It's a bit of a rabbit hole too as people then start worrying about humidifiers and dehumidifiers and so on but considering the ERV helps with humidity and I live in an area (Portland) where it's not much of an issue I think we're just going to stick with the erv. I'm actually excited about it in the sense that it will basically act like a silent bathroom fan except for the entire house.

And yes! Our house is 1800 sq ft, three bedroom with an office. It's HUGE for 2 people! We bought it when we still had the mindset that bigger is better, not for space but for investment purposes. I don't have regrets though because in our market it has appreciated greatly AND we have enough lot for a second house. When we tell our friends we're living in the small house they look confused haha.

Telecaster

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Re: Building a small house. ERV (energy-recovery ventilator) necessary?
« Reply #3 on: April 18, 2016, 10:46:25 AM »
The answer, like a lot of things, is it depends.    There is a two-fanged problem.  First fang is that you want your house air tight for energy efficiency purposes.  Second fang is you need fresh air for the health of the occupants and the health of the building, so the house shouldn't be too tight.  Fresh air is a good thing.  Hence the need for trickle vents that slugworth mentioned.   

One potential problem is that air can, and often does, enter the house through spaces like the crawlspace, basement, or attic, in which case the air is stale.  So the wiki is correct, an ERV can improve air quality because you are drawing in fresh air from the outside as well as conserving some of the energy.   

Since you are building your house, I would aim to make it as well-insulated and energy efficient as possible and install the ERV.   On older homes that are presumably leakier it becomes kind of a crap shoot.