Care & Maintenance
Humidity Control for Calgary Homes
Updated 3 min read
The short answer
Aim for around 35% relative humidity through the heating season. Calgary homes routinely sit at 15–25% in deep winter, which is dry enough to shrink wood visibly, open mitres and crack painted panel joints. Holding 35% is the single most effective thing a homeowner can do for millwork, hardwood floors and their own comfort.
Why Calgary is a special case
Calgary combines three things that are individually manageable and collectively hard on wood: a genuinely dry regional climate, a long heating season, and chinooks that swing temperature by twenty degrees or more within a day.
Heating air dramatically lowers its relative humidity. Cold outdoor air holds very little moisture, and warming it to room temperature drops the relative humidity further. In a well-sealed modern house with the furnace running, indoor levels of 15–20% are common in January.
Wood responds by giving up moisture and shrinking across the grain. Then a chinook arrives, the furnace stops, humidity rises, and it swells again. The repeated cycling is harder on joinery than a single sustained dry period would be.
What happens at each level
| Relative humidity | Effect |
|---|---|
| Below 20% | Visible shrinkage, mitres open, panel joints crack, static, dry skin |
| 20–30% | Noticeable movement in solid wood; typical unmanaged Calgary winter |
| 30–40% | Target range — wood stable, comfortable for people |
| 40–50% | Fine in summer; risks window condensation in deep winter |
| Above 50% in winter | Condensation on cold glass, potential mould at window frames |
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How to manage it
- Measure first
- An inexpensive hygrometer tells you what you are actually dealing with. Most people are surprised how low it is. Put one in the main living area.
- Whole-house humidifier
- Mounted on the furnace, feeds the whole house automatically. The most effective option and the least effort once installed.
- Portable units
- Effective in one room. Need refilling and cleaning regularly — a neglected portable humidifier becomes a hygiene problem.
- Adjust seasonally
- Turn it down as outdoor temperature drops. A setting that is fine at −5°C causes window condensation at −25°C.
- Watch the windows
- Persistent condensation on the inside of glass means the humidity is too high for the outdoor temperature. That is your feedback signal.
- Do not overcorrect
- Sustained high humidity in a Calgary winter causes its own problems at windows and in wall cavities. 35% is a target, not a minimum.
Answers
Frequently asked questions
- What humidity level should I set my humidifier to?
- Around 35% is a good target, adjusted down in very cold weather. If you see persistent condensation on the inside of your windows, it is too high for the current outdoor temperature and should be reduced.
- Will a humidifier actually stop my cabinets cracking?
- It substantially reduces the movement that causes it. It will not make solid wood behave like a stable synthetic material — nothing will. Combined with the right material choices, such as MDF panels for painted doors, it prevents most visible problems.
- Is high humidity bad for a house?
- Sustained high humidity in a cold climate is genuinely problematic — condensation on cold surfaces, potential mould at window frames, and moisture driven into wall assemblies. This is why the target is a range rather than "as much as possible".
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