Crawlspace heating
Swaysan
| Posted in General Questions on
Our crawlspace was recently sprayfoamed, with an updated vapour barrier. We’d like to add a baseboard heater or two, but only want to heat about a third of the 1000 sq ft. Can I partition a space off with plastic or canvas to keep the heat concentrated, or will this impede airflow?
Moisture is not an issue; humidity is reasonably low year-round.
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Replies
There's usually no need to directly heat a crawlspace if that's what you're asking about. Usually all that you need to do is allow for some airflow between the crawlspace and the living space to 'connect' the two air spaces together. The crawlspace will typically run a bit cooler, but it will be plenty warm enough to avoid freeze issues.
Bill
I'm not concerned about freezing but would like my floors in the living area to be warmer. Our crawlspace contractor advised that heating the crawlspace would make a big difference on the main level.
I am sorry to inform you there is no free lunch. (Like you did not know this)
If you want to avoid mold and rot you will need to condition the air in your crawlspace to more or less the same temp and humidity as the rest of your conditioned spaces.
The game you are playing is Russian Roulette with rot. Some people do win at this game but not everyone. The question becomes what is the dewpoint of the air in your crawlspace and will the temp of your walls fall below the dew point often enough for long enough for enough water to condense and will mold and rot destroy your house. Do you feel lucky?
Walta
I generally agree that there's no free lunch. However, the heat loss of a structure isn't determined by its floor area or volume, it's determined by its external surface area and insulation level. Heating the crawlspace doesn't change either of those so it doesn't really change the building heat loss. Yes, there is some increase in heat loss because the interior temperature is higher. But keep in mind that the whole point of heating -- beyond the point where your pipes freeze -- is comfort.
I'd go the other way and say there's no point in heating only part of the crawlspace. Almost all the heat you put into there is that much less heat you have to put into the first floor.