Controlling temperature and humidity levels in your home

Temperature and humidity variations: what are they?

Room temperature and relative humidity in the home are greatly influenced by the weather outside. They vary naturally with the changing seasons and depending on whether we leave doors and windows open; significant, constant disruptions are not advisable, however.

What are the right temperature and humidity levels in a home?

It’s very difficult to say what the “right” temperature for a home is, because it varies from one person to the next. We feel comfortable when the environmental conditions allow our bodies to maintain their normal temperature (i.e., about 37°C). Put more simply, the ideal temperature for you is when you aren’t aware of the temperature!

That said, the thermostat setting in a home should generally be in the 20 to 22°C range—and up to 24 degrees for older people. Lowering the temperature to 19 or even 18°C, however, will not inconvenience a person in normal health.

Besides the actual temperature of the air in a house, the temperature perceived by a home’s occupants varies depending on:

• the relative humidity;

• whether there are cold-air drafts;

• the radiating effect of cold or hot surfaces (walls, floors, ceilings, window glass, etc.);  

• factors like age, clothing, level of physical activity, state of health, degree of fatigue, etc. 

The relative humidity, meanwhile, plays a determining role in the quality of your indoor air. Health Canada recommends keeping the humidity above 30% in winter and making sure it doesn’t exceed 55% in summer (ideally, it should be somewhere between those percent values at all times).

How can temperature and humidity variations affect my health?

1 - Temperature

To date, few scientific studies in Quebec have investigated the impact of temperature level on the health of a home’s occupants. We do know, however, that temperatures below the 20 to 22°C range can result in physical stress, such as higher blood pressure in elderly people and those living with chronic health issues. 

Some viruses, including the flu virus, survive more easily in drier, colder air. That’s another reason why you should keep the temperature above 20°C.

2 - Humidity

Excessively high humidity in the home creates a favourable environment for mould and dust mites —powerful allergens and irritants that can lead to respiratory problems like asthma. 

Conversely, if the relative humidity is below 30%, the air is too dry:

• This can cause irritation of the mucous membranes of the nose and throat, and breathing difficulties in at-risk individuals (e.g., people with asthma).

• Dry air is also harmful to people with skin or eye conditions.

There are many ways to control the temperature and humidity in a house: using the range hood and bathroom fan(s) every day, for example. Other appliances and equipment can also come in very handy depending on the situation and the season: 

• In summer, turn on an air conditioner or fans to lower the perceived temperature and dehumidify the air. If necessary, use a portable dehumidifer in the basement or in any room that needs it. Set it for a relative humidity level of 50 to 55%.

• Improve the building’s airtightness or thermal insulation to counter infiltrations air leakage and in turn ensure easier temperature control indoors. 

• If the humidity gets too high during the winter, you need to ensure better air circulation. To achieve this without cooling the rooms too much, use an air exchanger: a heat recovery ventilator (HRV) or energy recovery ventilator (ERV).

• Conversely, if the humidity is too low, a portable humidifier or one connected to a central forced-air heating system is an effective solution.