Hello America,

In this extreme cold, many are having frozen pipes even though the boiler is running and the wood stove is keeping them warm, but the heating pipes are on the outside walls. Many people think of frozen pipes only as a part of their plumbing system, sinks, toilets and drains. However, some folks forget about their hot water heating systems. This could become a homeowner’s nightmare. The following is a true story that took place in a quaint coastal Cape Cod town, Eastham, Massachusetts.

It was an extremely cold and blustery, snowy night. The temperatures were in the single digits with wind chill well below zero. Its was just a coastal storm, not a Nor’easter.  The depth of the snow prevented me from driving into the driveway, which was significant in length. The owner of the house was a wonderful lady with an optimism that gushed from her, like the drifts of snow that I had to walk through.


The owner explained that she had no heat in the living room and she was cold when she went into that room. After a few moments to diagnose the source of the problem, I located the problem. The boiler was running and up to temperature at about 180º, but the heating pipe coming up from the basement, to the baseboard heat, was frozen. Not only frozen solid but the pipes and baseboard were split in several locations. Even though only a short time passed, we could hear the loud thud in other areas of the room where the pipe was bursting under the strain. The temperature read 46º in the living room, on an inside wall.

In another area of the home, she had a wood stove going with a pot of water on top to add humidity to the air. The temperature in the kitchen, 79º. The thermostat in the hall read 65º but set for 63º, because, she said, burning wood was less expensive.  The point is,  even though the thermostat was in a different area of the home, the wood stove kept the boiler from coming on, by satisfying the set point on the thermostat. The exterior walls are the coldest walls, and the wind will find every crack and crevice and work its way in. The blowing wind combined with the cold found one elbow and started to freeze it. As the heating system did not call for heat because the thermostat was satisfied, the freezing continued and followed the perimeter of the room. The cost of the repairs alone far outweighed the savings she may have gained.

If you have a hot water heating system (hydronic forced hot water, or gravity hot water), and use a supplemental heating system such as a coal, wood or pellet burning stove, you could run into frozen pipes. In an icicle, here is why:

a) the heat from the wood burning stove, pellet or coal stove will satisfy the thermostat
b) the thermostat,when satisfied, will not allow the heating system to run
c) cold drafts from cracks in the walls, slightly open windows and doors, and/or lack of insulation will cause baseboard and piping (normally run along exterior walls) to freeze because the water is standing still.
  • Know where the water shut off to your boiler is,  hang a tag on it for future reference. You just might save yourself extensive and expensive repairs, and still keep the water trickling throughout the rest of the house, preventing further damage.
  • If you have an electronic thermostat, similar to the one pictured, remember to replace the battery. If the battery fails, the thermostat will not send a signal to your heating system to tell it to come on.

We recommend, when temperatures are extremely cold, to rely on the heating system to heat the home. Yes, it is more expensive to run, but the alternative may be to repair frozen pipes, walls, floors, ceilings and potential flooding when the pipes thaw. The extra cost, just could be worth it.