Renovation & Design

Must I heat the cottage over the winter?

If you're not planning to heat your cottage in winter you must drain all plumbing of any water.

Question: We are thinking of running no heat in our cabin this year, first time ever. It is normally a furnace-heated cabin, two-storey, built on a crawl space. We always leave the furnace at 10 C, but we have a lot of windows and it costs us quite a bit of money for something we might use once in the winter. We are worried about the cold.

Will this harm the laminate floors, appliances, drywall, etc? What are your thoughts?

Thanks, Barb Borden


Answer: Your question is one is surely shared by many cottage owners, especially this time of year. The decision whether to spend the money and energy heating a building that may only be used a few times during the heating season is a tough one. My answers will hopefully help with your dilemma.

Leaving the heat on in a vacant cottage, even at a fairly low temperature, may create some substantial utility bills over the course of an entire winter. Even with doors closed and windows sealed, a large amount of heat loss can occur, unless it is very well-insulated. While the costs associated with this are concerning, so are the environmental consequences of wasting precious energy on an unused building for months at a time. Since you may be planning on only using your cabin only once during the long winter, shutting off the heat may be a wise decision, but there are items that will need addressing with that choice.

When "winterizing" a summer residence, the primary concern is what to do with a plumbing system that would surely freeze during sub-zero temperatures. While some of your other concerns may be valid, the main problem could be with damage to plumbing pipes and fixtures if they are not properly attended to before freeze-up. Whether you have a well, or draw your water from a nearby lake, all the water-supply pipes must be completely drained before winter. This should include disconnection and draining of the pump and pressure tank and the water heater. If the system is well-designed, and sloped properly, it may only require disconnection of the pump and draining all the other items by gravity. That situation is ideal, but rarely the case, so blowing out the water-supply pipes with an air compressor should remove almost all the residual moisture that may otherwise remain in the pipes.

Even a small amount of water in a low-lying, improperly sloped section of pipe can freeze. When that happens, the water will expand, which can cause fittings or the pipes to crack. A leak from a damaged pipe may only be discovered once the pump is reconnected and the system pressurized next spring. I'm sure there are numerous cottage owners who can tell stories of having to climb through the wet spring soil with a propane torch and solder, to repair damaged water pipes after reconnection. I can attest to the nuisance it can be to attempt minor plumbing repairs when plans are to enjoy a newly opened cottage for the season.

The next thing to address are the plumbing drains and fixtures in your summer cabin. Drains will have less chance of freezing than supply pipes, because of the size of the pipes, the open vents above the roof and the fact almost all are now ABS plastic, not metal. While this is less likely, it still can occur, especially in several areas.

The main item to address in regard to winterizing the drain pipes are the toilets and the traps below all the other fixtures. Since toilets are self-trapping, they will always have some water in their bowls, even if the supply is shut off and the tanks drained. The same goes for standard P-traps under sinks and tubs. Because of the design, it may be quite difficult to remove all the water from these areas without removal of the traps or toilets. In removing these, sewer gas can be allowed to enter the building, posing a serious health concern if these pipes are left open for a long time.

The solution to the drain issue is to manually remove as much water as possible from the toilets and traps, before completely filling these with plumbing antifreeze. This non-toxic liquid can be easily sourced at local building supply or hardware stores. Pouring in enough antifreeze to displace the water will serve two purposes. Firstly, it will prevent freezing and cracking of the pipes or fixtures. Secondly, the liquid will prevent noxious sewer gases from entering the cabin from the sewer or septic system. In fact, pouring plumbing antifreeze inside the water-supply pipes can also help prevent expansion and damage, due to any frozen water that may be difficult to remove when draining.

As far as damage to wall and ceiling coverings, flooring and appliances within the frozen building, that may depend on numerous variables. Many cottages are shut down every year and have few visible effects the following year. The main consideration may be damage due to condensation from moisture trapped within the building. Excessive air moisture due to high relative humidity, typical at most lake properties, can be a problem if it stays inside your cabin. Airing out the living space as the weather cools may help prevent this, as well as some possible winter ventilation. While leaving your furnace fan on low speed will certainly help to prevent condensation issues, the cost may be prohibitive. If you have a wood stove or fireplace, leaving the damper open, as long as you have a proper rain cap and pest screen, may allow good natural ventilation of the indoor environment.

Having drywall and manufactured products such as laminate flooring in your cabin may increase the chances of condensation and moisture-related damage in the cold winter, but taking other precautions may prevent any serious problems. Allowing the indoor environment to dry out in the fall, and leaving a natural vent such as a fireplace flue open, will help prevent damage and reinforce the benefits of turning off the heat during the freezing winter months.


Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the president of the Canadian Association of Home & Property Inspectors -- Manitoba ( Questions can be emailed to the address below. Ari can be reached at 204-291-5358, or check out his website at


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