If your house was built in the 1960s or 1970s, you likely have many options available to make it more energy efficient and reduce your utility costs.
Among these is to add insulation to the roof and exterior walls as well as to the basement foundation walls and floor slab. You can also consider upgrading your home’s windows and doors in addition to sealing cracks, leaks and holes. These retrofits will help reduce heat losses in winter and heat gains in summer.
A house built in the 1960s or 1970s can lose heat through air leakage. One of the most cost-effective ways of reducing heating costs is to improve airtightness of your home by sealing cracks, holes and gaps.
Common spots where air leakage occurs include electrical boxes, plumbing, wiring and ducts that run through exterior walls or into the attic, around chimneys and exhaust fans in attic spaces, and where the first floor joists rest on the foundation wall. Windows and doors with worn or missing gaskets and weather-stripping or those not well-sealed to the surrounding walls are also locations of air leaks..
The 1960s/70s house also tends to be lightly insulated compared with newer houses. In the attic, a layer of insulation was typically placed over top of the ceiling drywall. It can be easy to top up the existing insulation by layering on new batts or blowing more loose-fill insulation. Be careful not to block existing attic ventilation baffles at the eaves needed to allow air into the attic.
The above-grade walls in this type of house are typically wood frame, and there may be fibreglass batt insulation in the stud cavity. To increase insulation values in the exterior walls, the existing interior drywall and polyethylene can be removed and a new second row of wood framing installed. Insulation and a new polyethylene vapour retarder and air barrier can then be added to the new stud wall complete with new gypsum board finish.
Replace existing single- or double-glazed windows with double- or triple-glazed windows that meet or exceed Energy Star rating for your location. Energy-efficient windows often have low-e coatings, argon-gas fill and low-conductivity insulating glass edge spacers.
The below-grade walls are often concrete or concrete block, and they may either be uninsulated or have wood-frame walls with fibreglass batt insulation that were added some time after the house was built. One way you can increase the thermal resistance of the foundation walls is to install foam board insulation directly against the inside surface of the foundation wall. Be sure to insulate and air seal the area between the floor joists where they rest on the foundation wall. For the basement floor slab, if you have adequate ceiling to floor height, you may be able to install extruded polystyrene board insulation over the existing slab and then add new finished flooring.
Before you start your retrofit it’s wise to hire a qualified residential energy service adviser.
Canada Mortgage and Housing Corporation (CMHC) has a fact sheet called Energy Efficiency Building Envelope Retrofits — Interior Retrofit for 1960s and 1970s Two-Storey Houses.
Download your free copy at www.cmhc.ca.
Steve Jacques is the Ontario manager – community development, research and professional services at Canada Mortgage and Housing Corp. You can reach him at 416-218-3479 or at email@example.com.