Home ventilation involves removing stale, moist indoor air and replacing it with fresh outside air in a controlled manner. This process is necessary to create a healthy indoor living environment. Proper ventilation also ensures air is circulating through the home and that adequate humidity levels are maintained.
If you have a metal exhaust chimney (when a natural gas water heater, or mid or standard efficiency furnace is in use), warm, moist air continuously exits your house through it. This draws cold, dry air into the house through cracks in walls and around the windows and doors, providing uncontrolled ventilation. This uncontrolled and continuous chimney ventilation helps to dehumidify homes in winter, but may consume excessive heating energy. A high efficiency natural gas or electric furnace may minimize or eliminate this uncontrolled ventilation.
Reducing or eliminating this chimney ventilation will save energy, but may also increase humidity levels, reduce air quality and change the way that air leaks into and out of your home. Homes usually become slightly more positively pressurized.
An increase in humidity and air pressure could cause doors and locks to freeze up, increase condensation/icing on interior surfaces of well-sealed windows, and frost build-up between the panes of poorly sealed windows. To make your home more comfortable:
- improve the weather stripping and caulking around your windows and doors (but not on storm doors);
- cover your windows using a window insulator kit (clear heat-shrink plastic over the inside of windows and frames) in the winter;
- install a ventilation system that may consist of exhaust fan(s), a fresh air intake, a heat recovery ventilator, dehumidistat and/or timer controls;
- run an exhaust fan for a couple of hours each day; or
- replace old, poorly sealed windows with modern, energy efficient windows (preferably triple pane).
Types of Ventilation Systems
- Heat Recovery Ventilation (HRV) - The purpose of a
HRV system is to exchange the air in your house on a regular basis, thereby ensuring that the interior air is fresh and healthy for your family. It removes stale, polluted, humid air from the kitchen and bathrooms, directs it through the
HRV unit in the basement and then exhausts this air outside. The
HRV unit simultaneously brings in an equal amount of fresh air from the outside to replace the exhausted air. As the cold and warm air streams pass in the core of the
HRV, the outgoing household air gives off heat to preheat the incoming cold air. The fresh air then passes from the
HRV into the return air duct of the furnace where it is filtered, heated to room temperature and distributed throughout the entire house. To help air distribution, the furnace fan runs on low speed mode whenever the
HRV is in operation.
- Ventilating Fans - Ventilating fans or mechanical fans can be mounted in the wall or ceiling (bathroom fans, range hood fans and utility room fans) and are used to remove stale, polluted, or humid air from inside the home. Ventilating fans are individually controlled by a switch or a timer and are manually turned on by the occupant when ventilation in a specific area of the home is required (i.e. in the kitchen or bathroom).
- Central Exhaust System - these systems are similar to a ventilating fan in that their primary purpose is to remove stale, polluted, or humid air from inside the home. However, a central exhaust system draws the contaminated air from multiple locations in the home via one central exhaust fan rather than multiple fans throughout the home. Central exhaust systems can be controlled by a standard switch, dehumidistat (a control that measures indoor humidity levels and when they become too high turns the switch on), or timer.
Ask your furnace contractor if an HRV or other changes to your ventilation system may improve the indoor air quality of your home. Finance ventilation improvements through our Power Smart Residential Loan.
Read our how-to booklet on air quality and ventilation.