Managing Humidity in Homes

  • Check for evidence of moisture such as musty smells. condensation on windows, staining on floors, walls or ceilings, peeling paint or wallpaper in bathrooms, black staining in shower stalls and bathtubs, and general water damage.
  • If you suspect that you have mould, then you should physically remove it. Use a mixture of one part chlorine bleach, two parts water and a little detergent to clean mouldy surfaces. Leave cleaned surfaces to dry for 15 minutes and then rinse well. Use gloves and protective glasses and remember to ventilate well. Badly mildewed carpets, furnishings and books will probably need to be thrown out. (Those suffering from asthma and allergies should have someone else do the clean-up for them).
  • Monitor moisture levels in the home with a hygrometer. Generally, the range should be between 35 per cent and 55 per cent.
  • To prevent a build-up of moisture in the home avoid line-drying clothes indoors; vent dryers to the outside; slope surrounding soil away from house foundations; patch any foundation leaks; don't dry firewood indoors; always operate bathroom exhaust fans during a bath or shower; make sure fans are vented to the outdoors; add insulation to cold surfaces and use a range hood when cooking.
  • An air conditioner or dehumidifier (and sometimes both) is a must for controlling humidity in the summer and an ultraviolet air purifier has been found to be effective in killing moulds that become airborne.
  • Equipment such as a Heat Recovery Ventilator (HRV) can be effective at helping to solve humidity problems in a home. An HRV increases the amount of fresh oxygen in a home by providing continuous ventilation without wasting a lot of energy. HRVs work by first extracting the heat from indoor air before it is exhausted outside. This heat is then used to warm up the fresh incoming air.
  • If indoor humidity levels are high and moisture sources can't be reduced any further, then professional help from a qualified HVAC contractor who has experience with indoor air quality problems will probably be required. Such a contractor will assess the indoor environment for moisture problems taking into account the type and conditions of current heating, cooling and air quality equipment.