How does your home handle extreme cold?

When temperatures drop to extreme lows, houses face greater challenges. Condensation and ice on windows, icicles and other signs mean your house may be losing heat, potentially causing damage to insulation and structures.

Icicles are an indication of heat loss, which can cause damage to insulation
Icicles are an indication of heat loss, which can cause damage to insulation and roof structures © Wikipedia

Extremely low temperatures can test your home in many ways, causing condensation on windows, ice on windows, condensation inside walls and damage to insulation. Not to mention significant heat loss and wasted energy, which you pay for. Even brand new homes built to code can see failures of their building envelopes, windows, doors and ventilation systems.

Most of the problems that a home will face during a deep freeze are moisture related. Extreme differences in temperature from indoor to out makes indoor humidity a big concern.

Warm moist indoor air will condense on any cold surface it can find, as well as find any path to the outside, depositing condensation inside your walls in the process. Keeping moisture levels down (40% relative humidity or lower) will help mitigate some of these issues. 

Drafts around windows, doors and other openings: This can often be fixed with a tube of caulking. Air leaks are easiest to find when it's cold and windy outside, so take advantage of that time to do some troubleshooting. Be sure to get the right caulking for the surfaces you are attempting to seal - be it wood, plastic, metal or stone. Different products bond to different surfaces.

Note: The natural convection of air as it meets a cold surface can at times create the sensation of a draft when in reality there is none. Feel to see if it's just cold air falling after coming in contact with the window before you try to seal non-existent leaks. Lighting a match near a suspected leak may help you determine if there is any air movement.

Condenstaion causing ice on windows
condensation causing ice on windows © energetechs

Frosted windows: Warm humid air meeting a cold surface will leave condensation, and in some cases turn to ice. This is particularly noticeable during periods of extreme cold, in conditions of high indoor humidity or if you have lower quality windows. Solutions: You can buy a hygrometer (to measure indoor humidity) for $20 or so, to first see if that is the problem. If your relative humidity is low (20-40% RH), then the problem lies more with your windows. A temporary seasonal solution would be to cover them with plastic which will prevent heat loss, potential damage, and you'll be able to see outside.

Poorly performing windows also means cold will emanate from windows, making rooms less comfortable, so covering your windows will likely mean you can keep your thermostat a little lower and feel the same level of comfort.

Door freezing shut: If there is ice buildup on your door or weather stripping, try scraping it off carefully so that the door will close properly. In a long cold spell, ice will continue to buildup, and if you don't remove it you may find your door won't close properly, or you may have trouble opening it.

Frozen door locks: Airtight homes are great for keeping heat in, but that leaves all the indoor air pressure aiming for any hole, no matter how small. In some cases (particularly well-sealed bungalows due to the stack effect*) interior warm air is forced out through door locks, and they can freeze up. 

*The stack effect is the natural and unavoidable exchange of air that happens in any building. As warm air exerts pressure at the higher levels of your home it leaks out, and cold air is drawn in at lower levels to replace it. It is the moisture in the warm air leaking out that condenses and freezes.

Solutions: Again, lower indoor humidity will help alleviate this. Aside from that, graphite powder works well as a lubricant and is available at most hardware stores. With minimal skills and a screw driver you can in most cases take the handle off and lubricate it in only a few minutes. You could also try sticking a mitt over the outside door handle to help keep it a bit warmer.

Condensation forming on the inside of exterior walls: This can be caused by thermal bridges in the original framing, poorly installed insulation, or even the complete absence of insulation in some spots. Some insulation materials may settle; in other cases it may be that builders did a poor job or took short cuts, leaving future homeowners paying the price. 

Depending on the severity of the problem you may want to re-insulate one way or another. It is best to speak to a professional about this to come up with solutions that don’t hamper the performance of any existing vapour barrier. Some home inspectors have thermal imaging cameras which give you an accurate idea of where problem areas are in your wall, and they may also have some solutions to offer.

Icicles hanging from your roof: Big icicles means big heat loss. So many houses have them that we have grown accustomed to seeing them and can think nothing of them. As pretty and picturesque as they may seem, they are indicators of an imperfect roof structure, and really just the tip of the iceberg. An airtight and well-insulated building envelope will have no icicles whatsoever.

The bigger the icicles, the bigger the problem but they are also dependent on the amount of snow fall, so no icicles does not necessarily mean you have no problem.

Icicles can be caused by insufficient insulation, or insulation that was poorly installed without proper venting. Have a look in your attic (or hire someone to) and see if it is properly vented, and if there is enough insulation. 

Water 'leaking' in on a warm sunny day: This is more likely caused by air leakage than a leaking roof. As warm air finds its way through ceilings, it can condense and freeze. It may stay frozen for some time before thawing, offering you what *looks* like a leak when temperatures rise and there isn't a cloud in the sky.

Solutions: stopping air leakage, which is not always be an easy task. If there is no obvious leak, again you may be best to consult a professional to find the best way to fix the problem. We just cannot stress enough the importance of a good air barrier.