We are building anICF house in Missouri (so, moderate climate.) One of the things that I’m running across is that tight, modern builds like this require whole house ventilation systems, to bring in outdoor air and exhaust stale air from the interior of the home. These systems can be fairly complex and expensive. And I don’t get it.
Windows, anyone? If I desire fresh, un heated/cooled outside air in a room, why would I not just open a window? Every room in the house has an operable window, most have several.
In reading an explanation, one comment that stood out was that in modern homes, windows are rarely, if ever, opened. That can’t possibly be true, can it? Our house is wide open whenever possible. Unless it’s very cold or very hot, windows are open. Are we just very odd people, or am I missing something? Why are windows not considered valid forms of ventilation anymore?
(Code isn’t an issue, we’re way in the country and no one cares what we build.)
I’m thinking, there are times when you can’t just fling your windows open, like the middle of winter. If you spend 2 weeks with the house shut up tight, only getting ventilation when you open and close the front door, the air will be mighty stale.
I do think it’s a bit sad that so many folks live with windows shut all year long, but they do, and if you don’t take into account that someone will own your house after you do, you set yourself up for a disappointment down the road.
In your case the house doesn’t breathe in the way that stick built homes will. You could get an an accumulation of moisture in the house that won’t eventually work it’s way out because the material are not porous. Opening windows will work fine during nice weather. You may want additional fresh air intake during the summer or winter when the windows are all closed for AC or heating.
But all these systems do is bring in air from the outside. It will be the same cold/hot air that would come in via open windows, right? If it’s feeling stuffy in the house, why wouldn’t just opening a couple of windows do the same thing?
Here is one option, that does not require dedicated duct work. You put one in each room. They’re $800. It appears to basically be a pipe going through the wall with a fan in it. How is this better than cracking a window?
heat recovery ventilation systems work to provide desired air exchanges without the cooling or heating of interior air, which is done at considerable cost.
that system also functions as bathroom fans, where you would place an exhaust dust, so you don’t need to install bath fans. exhaust duct also in the kitchen where there is much moisture.
Windows would work… when you’re home or awake to open them.
Part of avoiding Sick Building Syndrome or other stuff like that, is to change the air out somewhat regularly. Normal homes are leaky enough that this happens on its own, as the climate control systems cycle. Your home may be sealed up pretty tight, and without something complicated to explicitly exchange outside air with inside air automatically, you could run into problems.
You need a constant airflow to prevent excess interior humidity among other problems. This is why you can’t just “open a window” : you might forget. Also, “opening a window” is inefficient : it lets unheated/uncooled outside air directly into your home, defeating the whole purpose of extremely well sealed and efficient houses.
So you just need an energy recovery ventilator. That’s just a box with a fan and a heat exchanger. They are not that expensive. Inside air goes out, outside air goes in, and the two air streams exchange energy with each other to reduce the efficiency loss.
Ok, I’m convinced this would be good for winter, at least, so we will install one.
The idea of forgetting to open the windows is foreign to me, like suggesting that I might forget to put on shoes before going outside. If the weather is at all reasonable, all the windows are open. The house is designed for excellent air flow between windows. We don’t close them at night or when we leave the house, either.
But there are a few weeks in the winter and summer where we don’t want the house wide open, and the no bathroom fans thing is appealing.
By the way, most bathroom fans make a terrible racket. There’s another way. You can use inline turbine fans, mounted on a rafter several feet away and connected by flexible hose. They’re much quieter, and they move a lot more air than those LOUD little Nutones. If you’re switching over, the flexy hose slips right over the outlet of the Nutone housing. All you’ll hear is a slight rushing of air.
Interesting. I hate bathroom fan noise, which makes me not use them as much as I should. That’s pretty much the best selling point for these whole house systems: no noisy bathroom fans. Good tip, thanks.
I have a whole house ventilation system, and I’m in Missouri in my icf foundation, SIP walled house.
The system passes incoming/exhaust air over an enthalmic (spelling) core.
In summer warm air from outside is cooled and dehumidified by the exhausted air. In winter cold outside air is warmed and humidifier by outgoing air.