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December 17, 2007
Preventing heat loss
We have a 3.5 story house with a 1-story, 12 foot rear extension on the garden level. The extension is new masonry wall construction with insulation in the walls and roof.
This part of the house loses heat much faster than the rest of the house. We have a one-zone old fashioned steam heat system that is functioning well. Although the rooms in the extension heat up fine when the heat is on, matching the thermostat temperature, they cool off much faster, uncomforatbly so, while the rest of the house retains its temperature. Therefore, as it stands, the only way to keep these rooms warm is to overheat the rest of the house.
Short of ripping open the walls and putting in heavier duty insulation, any thoughts on ways to contain the heat in this part of the house?
Comments
Irrespecive of the insulation you have in the extension, if the extension is exposed on 4 sides, it won't hold heat like the part of your house insulated by party walls. Assuming your windows are already good quality, you might try putting an insulating window film on them. You'd be surprised how much heat is lost from windows. Same thing for skylights. I know it is annoying to have these micro-climates, but there may not be a lot to be done.
Posted by: guest at December 17, 2007 2:45 PM
I always recommend a separate heating zone, with its own thermostat, be included in the design and construction of a building extension for this very reason.
The heat loss of the extension is likely to be very different than that of the existing structure and so control with a common thermostat often provides varying degrees of bad results.
Also, was a new boiler installed along with the extension or was the old one found to be large enough to handle the additional load?
Posted by: Master Plvmber at December 17, 2007 3:38 PM
Thanks for the comments.
MP -- We stuck with the old boiler becasue it was (and is) working fine (knock on wood). I don't think this is a boiler capacity issue because the extension heats up fine when the boiler is on. That is, the temperature rises to the level at which the thermostat is set more or less at the same rate as the house as a whole. The problem seems to be that while the room where the thermostat is located retains heat quite well, the extension loses it fast. Perhaps we should have considered an additional source for the extension, but I don't think that is feasible now.
2:45, I will look into the insulating window film. It may not cover the whole problem, but every degree helps.
Any other thoughts?
Posted by: slopefarm at December 17, 2007 4:31 PM
Just use an electric heater for supplemental heat, like a Vornado heat fan or one of those portable radiators (oil-filled, I believe). You can even buy a plu-in baseboard heater. My spouse recently started working at home. We haven't changed the thermostat so the house really cools off during the day. But rather than heat up the whole building, she stays snug in her study using a Vornado.
Posted by: guest at December 17, 2007 4:43 PM
How much insulation did you install. US DoE recommends R39 under the roof and R13 in the walls. That means some 9-12 inches overhead and 2-3 inches rigid batts in the exposed walls. A little late now.
Perhaps you can look at outsulation(EFS glued to the outside masonry with thin coat of cement stucco over that, then painted). I see it being done here in Brooklyn. Check out 518-530 Meeker Ave, under the highway.
Posted by: guest at December 17, 2007 5:21 PM
Check the electrical boxes for drafts--it's possible to remove the device and shoot foam behind the boxes.
Posted by: bugleg at December 17, 2007 7:41 PM
Thanks again, everyone. There are several good suggestions to follow up on, and we will see how far it takes us. I believe we did use R-13 in the walls but I don't remember about the ceiling.
Posted by: slopefarm at December 17, 2007 10:17 PM
Move things like bookcases and furniture toward the outside walls. Those provide a small measure of insulation too (books are not good conductors of heat). Make sure you have thick silk/ velvet/ wool drapes that you can close at night. The idea of a supplemental heat source sounds good too. If the room recieves direct sunlight, try painting the walls a darker color so they retain the heat and not reflect it. If the extension is small how about a small green roof on top of it. Although they would help more in the summer when the extension heats up (I'm sure that happens too), the green roof media also prevent heat escaping, sort of like adding isulation. Gaia soil is one such medium for green roofs that is made of recycled styrofoam peanuts, which has insulating properties. The plants themselves also form an insulating blanket, much like dead leaves heaped up around tree/ shrub roots in the winter to prevent the soil around the roots from repeated freeze-thaw cycles that could uproot them.
How about a little electric fireplace?
And you could blow-in additional insulation, although that might be difficult to do if there is pre-existing insulation in the walls/ ceiling.
The above are all small measures, but they could add up to make you feel comfortable. It's amazing how much just adding drapes to windows can do to prevent body heat being radiated to the cold window glass, which can make you feel cold even when it is a comfortable 69 degrees inside.
Posted by: ohiise at December 19, 2007 11:36 AM
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