Heating a small indoor space when a specific temperature is reached
sjbair
| Posted in Green Building Techniques on
We have our well in a small room (perhaps 10 x 10 at the most) in a large outside garage that is a part of our farm. The north face of the garage is built into the side of a hill where the well is. When the temp goes below perhaps 20 degrees, we need to heat the space where the well is so it doesn’t freeze. In the past, we used a wood fired stove at those times and all worked well. Now, caring for the stove is a challenge because of age so last winter we used a small space heater. Our electric bill jumped astronomically. I would love to apply a green solution if someone might be able to suggest it to us.
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Pull out the wood stove, then seal and insulate that room just as if it were fully conditioned living space and not inside a garage. On the below-grade section only insulate against the soil down to the frost line. In many locations simply insulating and tightly air-sealing an earth coupled room would be more than sufficient for freeze protection, no heating necessary.
Where are you located (for temperature data purposes)?
Are you only trying to protect pipes from freezing, or is there more? Heat tape is the easiest way to protect pipes, heating the entire room is not needed.
Wow! Thanks for the quick responses.
I tried to be very careful about being clear about the setting. Clearly, I wasn't clear enough. The well is in an enclosed brick room inside the larger garage. That brick room is about 10 by 10 up to the ceiling maybe 15 feet. The wood stove heated the entire space not just the well area. We put the space heater right in the enclosed space.
I will get the tape later today and try that. My goal is to keep that entire enclosed smaller space above freezing at all times cost effectively.
As for location, we are central PA. Last winter had some brutal temperature stretches. This year to date has been quite mild but anything can happen when January, February and March roll around.
Again, most sincere thanks for the help.
Are all four walls of the 10x10 space inside the larger space, or is one of them against an outside wall? If it's just the four walls, insulating them, but not the floor, would be my adaptation of Dana's advice. The high ceiling doesn't help...I'd consider dropping in a lower ceiling in that 10x10 space and insulating above it. I'd still use the heat tape, and hope that the insulation means the heat tape never has to turn on.
I'd think about polyiso or mineral wool board insulation, and probably put it on the outside of the brick so that the thermal mass of the brick helps mitigate cold snaps. Best would probably be "Thermax" polyiso which, in some situations, doesn't need a fire barrier over it, unlike other foam insulation. Mineral wool board doesn't need a barrier either, but it could lead to condensation on the brick in cool weather, if the inside of the small room is kept cooler than outside.
If there's an exterior wall involved, Dana's advice on the depth of the insulation is good. But I'd add a comma:
"On the below-grade section, only insulate against the soil down to the frost line."
(That's to be clear that it's not only the below grade section that should be insulated)
I don't disagree about insulating the space, but if there's no heat source at all, and temperatures are low enough for long enough, even insulation won't keep you above freezing. I'm guessing you get some periods where it's averaging in the 10-20 degree range for a few days at a time. You could have slush in your pipes even with plenty of insulation.
Another thing you could try is a thermostatically-controlled outlet that will turn on at 35 degrees or so. They are sold at farmer's and livestock supply places for freeze-proofing water troughs. Plug a couple of 100-watt light bulbs into that and place them very near the piping and tank... that is, if you can still get a 100-watt bulb. A halogen work light would work too.
There is an exterior wall. It is to the north and is a part of the wall that is into the side of the hill. The building extends on both sides of the enclosure.
Sally,
Can you describe your well and the way that the water pipe is routed to your house?
Here in Vermont, where temperatures drop to -40°F, our wells are almost always located outdoors. Most drilled wells don't freeze because they are so deep (generally 50 feet to 400 feet deep). Well casings are equipped with pitless adapters that allow the water line that connects the well to the house to be buried in a 3-foot or 4-foot-deep trench. Nothing freezes.
So your well must be different if you are worried about freezing. Maybe all you need to do is bury your water line?
I have used heat cable [not heat tape, use the heavier duty stuff] on outside water lines with insulation over with good results
If you need to heat the room, buy a small programmable controller[I use auber instruments they are cheap and reliable] and have it come on to run whatever heatsource you choose. They are simple to program as you will be doing 'on off' so most of the settings are not used. If you are using a heater with an external thermostat you should be able to wire one in series with the heaters thermostat, since it will be always set to a lower temp.Total cost, less than 50 bucks. If you are using an[ electric] heater with an internal thermostat it is a little more complicated, you need a relay and a little wiring. Ups cost to maybe 70 bucks.
Water line is buried. Any suggestions on an inexpensive and cost effective heat source? Thanks again for all the responses.
Sally,
If your water line is buried, why are you worried about cold temperatures?
In central PA US climate zone 5/6, fully insulating the walls and ceiling of the brick well-house inside the garage would probably achieve frost protection with the garage door closed. Insulate the exterior of the brick, to make use of the thermal mass of the bricks.
Insulating the garage walls & ceiling would help too, but not as much.
Charlie's correction of my garbled 'merican regarding below-grade sections is correct. To clarify, all above grade walls need to be insulated, but below grade portions of walls up against dirt only need to be insulated down to the frost line, not lower. (If the brick walls all have air between the well house and the garage walls that comment is moot, since none of those walls would be in contact with soil, only garage air.)