Renovation & Design

Heat may be needed to prevent plumbing from freezing

Question: I was hoping you could suggest how to prevent a pump from freezing in winter. It is located in the crawl space at the end of the building, which is skirted with insulation panels. The water lines have heat tape, however the pump does not. We considered building on a heated area adjacent to the pump. Any ideas? Thanks, S. Sawich.

Answer: Preventing plumbing from freezing in a crawlspace in our frigid winters can be a challenge, but should be possible with proper insulation and a reliable heat source. Ensuring the area is properly insulated and sealed before installation of additional heating will be the key to prevent any problems.

Any time plumbing systems are installed in a crawlspace, especially if it is a building with occasional or seasonal use, risk of freezing is increased. Because the crawlspace is below the heated living space, it will be colder than the floor and rooms above. While the crawlspace may get some radiant heat from the building, it will still be substantially cooler. If there are areas in the crawlspace perimeter that have gaps or poorly sealed areas, cold drafts may cause unwanted freezing of plumbing fixtures and pipes, especially if you have copper supply pipes.

Unless the crawlspace has a good heat source, to warm the air and the plumbing, there is always a chance of freeze-up, especially on very cold days. Installing heat into this area may require tying into the existing ducting, if you have a forced-air system. Adding an additional duct to the furnace plenum may not be overly difficult, as long as there is proper access. If the ducts already run through the crawlspace, but have no direct duct or register for that space, it may be quite simple. Diverting heated air from another duct, or from the plenum, into the crawlspace should be straightforward for a licensed HVAC technician. If there are no ducts in the crawlspace, or if you have a different heating system, then other alternatives should be chosen.

One of the simplest methods to add a heat source to your crawlspace, regardless of your current heating system, is to add electric baseboard heaters. These inexpensive heaters may be installed by hanging them from the floor joists, or securing them to vertical columns or the perimeter walls of the crawlspace. Supplying them with power, and a crawlspace mounted thermostat, can easily be accomplished by a licensed electrician, as long as you have capacity and space in your electrical panel. If you have a 200-amp service there should be no issue, but it may also be possible with most 100 amp. panels, as long as you are not currently maxed out. Installing one heater near the pump should ensure your freezing concern is met. Adding baseboards in other strategic locations may also allow you to remove the heat trace cables from your existing plumbing pipes, as long as a couple of other provisions are taken into consideration.

Heating the crawlspace will only be completely successful if you have proper insulation and air sealing on the perimeter of entire area. Having older insulation may not be adequate to form a completely sealed area, which will withstand strong winds and bitter winter temperatures. Reinsulating this area with high density spray-on foam, or rigid extruded polystyrene, should allow you to seal it properly against the worst weather.

The dirt floor of the crawlspace should also be sealed with 6MIL poly, to further prevent moisture and air intrusion into the confined space. Upgrading these components in the crawlspace may be the most important part of the process to prevent future frozen plumbing.

The other consideration may be the reliability of the electrical supply to the building. Especially if this is a cottage or other remote property, which is only used periodically in the heating season, this concern must be addressed. If the electrical utility is subject to regular outages, electric heating in the crawlspace may be interrupted for extended periods. If this is more than a few hours, in the dead of winter, freezing pipes and pump is once again a problem. The solution would be to install some form of low temperature alarm, which would notify you if the temperature suddenly dropped in the crawlspace. This is a good idea even if you permanently occupy the home, just in case something else, like a tripped circuit breaker, happens. With modern Wi-Fi systems, this is something that could be readily installed, as long as you have an internet connection in the building.

While there may be other, simpler solutions to prevent the pipes and pump from freezing, like leaving a faucet dripping in the coldest weather, a properly heated and insulated crawlspace is the best choice. This will not only prevent a plumbing breakdown, it will also warm the floor above, making the living space more comfortable. The crawlspace does not have to be heated to the same temperature as the living space, but should be several degrees above freezing at all times. That way, you can reliably prevent frozen fixtures without a large increase in your Hydro bill.

Implementing any strategy to prevent frozen plumbing pipes, pumps, or other equipment in a crawlspace should rely on proper heating, insulation, and air sealing. Preventing cold air from getting into the area, and warming it to a reasonable temperature above freezing, will be the most reliable, long-term solution.

Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and a Registered Home Inspector (RHI)( 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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