What things would the ideal air quality home have?
I’m planning on doing a new build or reno where I focus on energy efficiency and indoor air quality. Forgive me if I go off the rails, I’m just brainstorming.
As a starting point, let’s assume we’re constantly bringing contaminants into the home via consumer products and electronics and clothes and whatever.
My ideas on air quality are as follows:
– I honestly think regular old hot water heating (maybe powered by a heat pump) is the best for air quality. Both mini splits and furnaces are not designed with indoor air quality in mind. They accumulate dust and other contaminants and the heat makes it easier to distribute these around the house in gas form. Radiant heat in the floorboards or something might lead to offgassing via nearby glues or coatings.
– High volume particle filtration is needed to collect dust, which contains contaminants. Maybe there could be a ductwork system for air conditioning only with a whole house HEPA installed in the ductwork, with a properly sized blower running continuously.
I’m not sure if running duct fans 24/7 is energy efficient though. Is there a better way? Individual air purifiers suck as a rule.
– Fresh air is needed to keep down CO2 and VOC levels. I’m partial to HRVs over ERVs because ERV cores allow VOCs to penetrate, but this requires careful humidity management.
– Electronics should be segregated. The stuff they put in electronics these days, if you do your research, are nasty. And they tend to release these chemicals as they heat up. So all electronics should ideally be put into one office room, possibly with an exhaust running? In the winter, this would be highly inefficient, there’s gotta be a better way to do it.
Those are my ideas, any thoughts welcome. I know I’m really going all in on air quality here, but it’s just an exercise to know what the ideal is. I’d then take a more realistic approach when doing the build
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NOT AN EXPERT or even qualified to respond honestly. But I am designing my own house right now and have been obsessed with perfecting the indoor air quality. First thing that needs to be done is the house needs to be insanely airtight. This will allow for more and more control of the air. The more you can control the air the cleaner you can keep it.
-Hot water heat- I am using a central ducted heat pump to heat and cool. I found this was the best option because it means that air will be flowing (generally) the same places at all times of the year no matter if I am heating or cooling. This means the air is more predictable which means I can control it better. Make sure not to put the supply vents on the floor as this will allow dust to fall into them when they are not running then blast the dust into the room when they come on.
-Air filtration imo should be a separate duct system. Just a fan running constantly, or can be hooked to monitors that sense when air quality is dropping and automatically run. The benefit is that you can add HEPA filtration without having to increase the stress put on the already very expensive fan in the indoor unit. This would not need to be a big fan or even move much air so it will not be using much electric at all.
-ERV- A must. I live in climate 4A so I am using an ERV. My house is in the middle of a 200 acre field so I am not too concerned with VOCs because not all VOCs are bad but a charcoal filter could be added if that is a concern. To maximize the effeteness of the ERV put the returns in the bathrooms, laundry, around pets the idea is to catch all of the dirty air before it has a chance to get to your face. When you bring the air back into the house the recommendation is to dust it into the return side of the heating/cooling system so that it can get double filtered before it enters the living space.
-Electronics- Also have concerning levels of radiation emitted from them but that does not effect air quality. If you want to collect all of the bad stuff that they put into the air just put them into one room and have a return for the ERV/HRV in there imo that would catch anything that is in there. If you are worried that 20cfm is not enough than add a boost switch so that it can suck out more air when you want it to.
The single most important addition to a home to improve IAQ is kitchen exhaust. I am designing my kitchen to have a range hood larger then the cooktop with sides to use geometry to help catch all cooking fumes and also making sure to put the oven under the kitchen exhaust as well. Also. indoor trim finishes have a huge impact on IAQ. Real 100% wood floor or tile floor are the best options. There is so much that plays into IAQ and I am fascinated with it. If you want to learn more I really like the youtube channel "Home Performance"
Interesting stuff Mick, thanks. A couple of questions. Where is the heating element in a full heating/cooling heat pump? Is there separate heating coil in the ductwork? My concern with this kind of setup is that dust from the house (which will contain contaminants from carpet, furniture, electronics, etc which all contain VOCs and flame retardants and other nasty stuff) could be sucked into the ductwork and might settle on coils. Heat + crud = gas which re-releases all those chems back into the house. Unless there's a MERV 13 filter or higher on the return air.
On the separate ducting for filtration, could a single duct line work? Like having a return in the living room with a straight line to somewhere else.
I agree about the extra ventilation in the office, the range hood, and definitely agree about wood or tiles for floors. I prefer tiles since they can be non permeable and thus easier to clean fully.
Been thinking lately that a voc filter would be nice in addition to the hepa filtration