Energy Retrofits Done Right

Energy efficiency retrofits can reduce your energy consumption, impact on the environment and save you money. If not done properly, however, replacing windows, adding insulation and reducing air leaks can have unintended effects on your house, indoor air quality and your family’s safety.

So before the work is started, have your house checked for pre-existing conditions that could lead to problems down the road. These problems may include high humidity, water leaks, dampness and mold. Your house may also have stale air, lingering odours, soil gas intrusion and pollutant emissions from household products. Structural sags, cracks and deflections in the walls, floors or ceilings also represent problems that may need to be addressed first. Undertaking an energy efficiency building envelope retrofit before dealing with pre-existing conditions may make the problems worse and result in loss of time and money invested in the retrofit work.

For example, sealing air leaks can improve comfort, reduce heating costs and protect walls, windows and attic because it cuts down on the amount of leaking in to and out of your house. But, this can cause the air in the house to seem stale and odours to linger longer. Odours from previously unnoticed sources such as hobbies, pets or stored items may become more noticeable.

Measuring the air leakage of the house with a blower door test before and after the retrofit work can offer an idea of how much the air leakage of the house has been reduced. If the reduction is significant, it may be a good idea to add a bathroom fan, range hood, air exchanger or better yet, a heat recovery ventilator. When properly designed and installed, mechanical ventilation is more energy efficient and effective than uncontrolled air leakage.

Reducing air leaks can also decrease the air needed for the safe and efficient operation of furnaces, water heaters and fireplaces. Adding powerful or numerous exhaust fans can further increase the risk that fuel-fired appliances will not properly vent combustion gases – a situation known as “backdrafting”.

Providing adequate combustion air for heating appliances and sufficient make-up air to balance exhaust fans may be a necessary part of a building envelope insulation retrofit project. The safest solution is to convert fuel-fired appliances to direct-vent units or sealed-combustion units. The backdrafting risk can often be assessed by a qualified energy advisor. Mechanical contractors can be consulted regarding make-up air systems as well as direct-vent and sealed-combustion appliance options for furnaces, hot water tanks and fireplaces.

Retrofitting your home to make it more energy efficient and to reduce your heating and cooling costs is always a good idea. By recognizing and addressing the potential issues associated with any retrofit project, you’ll help reduce the likelihood of problems occurring after the work is done. Consult a qualified energy advisor, building professional, home inspector or contractor before you begin your energy efficiency retrofit to better understand, and plan for, pre-existing conditions and possible unintended effects of the retrofit project. Often, corrective measures can be planned that not only prevent problems, but also add value to the overall project.

To learn more about other sustainable technologies and practices that can improve the performance of your home, visit Canada Mortgage and Housing Corporation’s website at www.cmhc.ca or call 1-800-668-2642.