My garage is below a heated room, and there are heating pipes running through the garage to heat that room. In the recent incredibly cold spell in New England, one of those pipes froze and burst. I have lived in this house for 30 years, and this is the first time I've had a problem; now I have to figure out the correct solution. My plumber tells me that the pipes can't reasonably be moved anywhere better. They do have pipe insulation on them (though due to my own stupidity the insulation on the place that burst had fallen off and I hadn't replaced it.)

The garage is about 17'x17'; there is an adjoining room as well that is about 13'x12'. The house itself is heated with gas forced hot water. The garage has an old large radiator in it that is part of the basement zone; several years ago I put insulation over that radiator, as the basement zone rarely fires (it stays pretty warm down there due to the boiler itself).

In addition to better pipe insulation (which again my plumber tells me is insufficient), I see two reasonable solutions:

  1. replumb the radiator in the garage to be on its own zone and set it to some really low temperature, or
  2. purchase an electric wall-mounted heater to heat the garage, again to some low temperature.

Which of those is preferable (or is there another solution I'm missing)?

Clearly this is (at least historically) a pretty rare issue for me, so I don't need or want a high-end solution, but it was sufficiently unpleasant that I would like to address it.

  • See help centre and meta regarding product recommendations. Jan 12, 2018 at 14:18
  • 1
    And the cold will be back tomorrow or the next day, by the looks of the forecast.
    – Ecnerwal
    Jan 12, 2018 at 15:01
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    The heating pipes froze? Aren't they themselves meant to be warm/containing hot water?
    – cr0
    Jan 12, 2018 at 19:12
  • From some answers it sounds like you weren't using those heating pipes at the time. I didn't get that from your question though, since you say 'My garage is below a heated room, and there are heating pipes running through the garage to heat that room.'
    – cr0
    Jan 12, 2018 at 19:16
  • @cr0 Indeed I was using those pipes. I think the thermostat backed off and the heat went off for long enough to freeze the pipes. It was very cold.
    – rogerl
    Jan 12, 2018 at 21:34

6 Answers 6


Your plumber seems to be poorly educated if you are left without the following solutions having been mentioned.

This is pretty standard problem for folks with a boiler AND a woodstove - the woodstove keeps the house warm and the boiler pipes are subject to freezing off in the corners of the house. Not that this is your situation, but a "standard" solution to "pipes running in a cold space" exists.

The standard solution is a timer that circulates the boiler water every so often (a more sophisticated one could take input from an outside temperature sensor to influence how often) whether or not there's a call for heat. In combination with insulation, that will keep the pipes from freezing.

There are other possible solutions (that don't involve heating the garage if you don't want to heat it), the most obvious of which is to replace the heating system water with non-toxic antifreeze. Heat tape (on the pipe, under the insulation) would be another option, but is frankly fussy and can be unreliable.

A final possible influence - if you use a "setback" thermostat or you manually turn the heat down at night - don't do that in very cold weather. It makes for a long "off" time before the first call for heat after turn-down, and that's when things tend to freeze. When it turned very cold here, I set my thermostat to "hold" and left it there.

  • 2
    Or just run the ciuculator all the time in the very cold weather.
    – Paul Logan
    Jan 12, 2018 at 15:50
  • Sounds like a combination of more/better insulation, setting the basement thermostat up high in very cold weather so the garage radiator heats, and not setting back the thermostat for the offending circuit should do the trick. (BTW, my plumber says that antifreeze needs to be replaced every so often, you can't just do it once. Is that right?) Thanks for the help.
    – rogerl
    Jan 12, 2018 at 21:37

I think you answered your own question:

They do have pipe insulation on them (though due to my own stupidity the insulation on the place that burst had fallen off and I hadn't replaced it.)

The pipe insulation on the rest of the system worked as it should. The only reported failure was where there was not insulation. This suggests to me that the insulation was indeed working as it should have and the solution is to replace and maintain that insulation.


Another avenue to look at (combined with other things) is improving the insulation in the garage as much as feasible. Is the door insulated? Are the outer walls? Fix drafty windows, etc. Avoid opening the door in extreme cold if you can. All of this is good for the overall energy consumption for the house anyway.


not sure you can use it, ask a plumber, but maybe adding some anti-freeze to the water could help?

also if you consider heating the garage with electricity you might remove the pipes and heat the room above the garage with electricity instead.

  • If you do use antifreeze, use one designed for hydronic systems -- this will be a Propylene Glycol based product (i.e. non-toxic) with appropriate additives for corrosion control Jan 14, 2018 at 19:31

I like Ecnerwal's answer. I think the quick and easy fix is to go the electric heater route in the garage, which would give you independent control over that room, so if the rest of the house heat is turned down, the pipes in your garage won't freeze. Also, consider heat tape, or electric heat cable kit (home depot, etc.)


When it is very cold outside, why not run the basement zone which includes the garage and turn off the basement radiator, this way you could still heat the garage just enough to keep the heating pipes in the garage area from freezing?

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