Winter, Humidity and your Household
As the outside air becomes cold and dry during the winter season, so does the air inside your homes.
The levels of humidity in the air can affect the comfort of your home. According to the comfort zone diagrams of the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE), Thermal Environmental Conditions for Human Occupancy standard, there is no recommended lower level of humidity limits for achieving thermal comfort, however dry conditions can lead to dry skin, irritation of mucus membranes, dryness of the eyes and static electricity generation.
Drying out mucous membranes can make you and your family members more susceptible to infection and aggravate allergies and asthma. These are some of many effects of very low humidity levels.
So how do we achieve a more comfortable environment? By improving our home’s humidity! Ensuring that you have the right level of humidity in your house can make the cold winter months a lot more comfortable and enjoyable for you and your family.
Acceptable operative temperature
The acceptable ranges of operative temperature for relative humidity levels of 30% and 60% during winter and summer are demonstrated in the table below based on comfort zone diagrams in ASHRAE Standard-55-2004. Occupants vary their clothing with the seasons, so recommendations for summer and winter are given, to reflect the amount of “clothing insulation” (clo) that clothes provide.
Improper levels of humidity during the dry season can not only affect your health but can also possible damage your home.
Here are some of the ways low humidity can affect your home:
Damage to wood products – wood needs a certain amount of moisture to maintain its form and function; too little moisture causes the wood to dry, which can lead to cracking and splintering. The result is creaky floors, doors that don’t close properly, separation along the trim, window sills or crown molding, or gaps appearing between counter tops and walls.
Electric shocks - When air is dry, the possibility of getting “shocks” at home are higher.
Cold air feeling – humidity holds heat; when there isn’t enough moisture in your home’s indoor air, the heat generated by your heating system isn’t held long enough to make you feel comfortable. As a result, you’ll feel cold and will likely push your thermostat up which can subsequently cause an increase in your heating bills. The best ways to reduce the effects of low humidity is with the installation of a humidifier. If you opt to install a whole-home humidifier, make sure you hire professionals you can count on.
Benefits of Proper Humidity Levels
Here are a few reasons why your health and your home would benefit from having the proper humidity level:
Reduces risk of possible infection(s)
Softer glowing skin
Reduces stuff nose
Reduces dry throat
Reduces condensation on windows
In general, low humidity level makes people feel uncomfortable. High humidity level can cause condensation, mold, mildew, and rot in homes as the warm moist air hits cool surfaces. Managing the humidity in your home during all seasons can make the time you spend in your home much more enjoyable.
A rule of thumb!
To prevent window condensation during the heating season, the recommended indoor RH is 30% to 50%. When it is below -10°C outdoors, recommended indoor RH is 30%.
Humidity levels in your home can be too high or too low. In either case, problems can result. An accurate hygrometer can provide the information you need to determine whether you have a humidity problem.
Ref: ASHRAE. ANSI/ASHRAE Standard-55-2004: Thermal environmental conditions for human occupancy, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Atlanta, 2004.
CMHC/SCHL. About your house, Measuring humidity in your home