What Should Your Humidity Be Indoors?

We get a lot of questions about humidity. What should indoor humidity be? What is good Humidity? What is bad humidity? What is the right indoor relative humidity setting for good indoor air quality? etc.

Here are some of the basics.

Proper temperature and relative humidity levels are important in maintaining good air quality and occupant comfort. Improper relative humidity settings can create a variety of problems for any building such as bacteria, viruses, dust mites and mould growth.

Elevated humidity levels indoors can be an indicator of poor ventilation or exchange between the building and outdoors. Poorly vented bathrooms, laundry facilities, cooking facilities or improper use of humidifiers can cause the relative humidity to rise leading to condensation and a mould and bacteria problem.

Low humidity levels are usually the result of low outdoor levels experienced in Canadian winters when the outdoor humidity levels can reach the low teens.

Humidity levels should be managed throughout the year at appropriate levels for the season. In general ANSI/ASHRAE Standard 62.1-2019 for Indoor Air Quality states the following:

Winter:

Maintain RH levels in winter between 30 to 40% and temperatures between 19-23 degrees Celsius. If windows show excessive condensation then the RH% levels will need to be closer to 30%. Never exceed 45% in winter.

Summer:

In warmer seasons keep the relative humidity between 50 to 55% with the temperature around 23-26 degrees Celsius. Outdoor humidity levels may temporarily increase these levels.

Be careful. Surface mould can grow at 65% RH or higher.

Health Effects

Relative humidity settings that are too low may cause respiratory infections, allergic rhinitis, and asthma. Relative humidity that is too high may cause health effects due to mould growth, dust mite infestation as well as certain bacteria and viruses.

Top 10 Ways To Control Indoor Humidity:

Know your RH level. Buy a hygrometer and monitor your relative humidity indoorsUse a dehumidifier if needed according to the season to manage the right RH% levelUse a humidifier if the RH% is too low. Be careful not to go too highEnsure proper ventilation and air flow through a ventilation device such as an HRV or ERV.Make sure there are no water leaks like plumbing leaks or water penetrationDon't dry clothes indoors unless you have good ventilationMake sure the dryer vents outsideMake sure all bathroom exhaust men outsideMake sure you cook top vents outsideDon't cook without using the vent.

Indoor relative humidity management is actually quite easy once you know the right RH setting for good indoor air quality.

If you are unsure of your indoor relative humidity setting call us for an in home air quality test.