At its most basic, your home is a big box that protects you from the weather and maintains a comfortable temperature throughout the year. Two components – the building enclosure and the heating system – are at the heart of what makes your home operate efficiently while providing maximum comfort.
You can start by conducting a basic inspection of your home’s enclosure and heating system in order to make informed decisions about Canada renewable energy efficiency upgrades. This activity better prepares you for a professional audit. A good master plan can be implemented over time with do-it-yourself tasks while leaving the more complicated tasks for a professional organization.
The first step in home energy audits is to understand where the boundary is between the heated and un-heated spaces in your home. This boundary is called the building enclosure, or shell.
The shell includes the walls, ceilings and floors between the inside and the outside, as well as those between heated and un-heated spaces, such as a garage or basement. In a simply shaped home it may include just four walls, a ceiling and floor, but most homes are more complex.
A floor that loses too much heat becomes a cold floor, or a side attic connects to a wall letting heat escape. Bay windows have tops and bottoms where heat can dissipate, and skylight wells must be insulated, too. Making a sketch identifying the specific configuration of your home will go a long way towards maximizing geothermal heating and solar energy efficiency.
We often think of insulation as the primary means to create an energy-efficient building enclosure. However, like a sweater with a windbreaker, insulation must work with an air barrier to be effective.
The air barrier prevents the movement of air between the interior and the exterior (or un-heated spaces). Where there are gaps in the air barrier, air leakage occurs. Cold air from the outside enters the home and warm air from the interior escapes. Since warm air rises, a heated home in winter acts like a big chimney. As the warm air rises and escapes through ceiling penetrations, cold air is pulled in from the basement, garage, or crawl space. The cold air can bring dust or pollutants with it, as well as make our homes more dry. This occurs when moisture escapes with the warm air and the cold air coming in lowers the humidity in the space.
Any penetration in the building shell will result in air leakage. Along with doors and windows, obvious places where cold outside air enters a home are penetrations for heating ducts, water pipes, sewer stacks, wiring, lighting fixtures, electrical switches and outlets, chimneys, ventilation fans, attic hatches, fireplaces and pet doors. Air leakage can be responsible for up to 1/3 of the heating cost, so it’s a very good investment to tighten up your home.
Identifying air leakage involves two approaches:
1. Taking a visual inventory of potential problem areas.
2. Noting actual air movement.
You will want to move around the interior of your home and look for leaks in the building enclosure, checking exterior walls, ceilings and floors. You will also investigate the unheated side of your ceilings and floors by looking in your attic and crawl space or unheated basement.
By checking the unheated side of ceilings and floors you can find problem areas not evident from the inside. Use the diagram you created of your building enclosure to help identify areas to investigate. An efficient method would be to go to each room in your house, first looking for specific problem areas and then using an incense stick to identify air movement. You can note air leakage points on your enclosure diagram and/or mark those locations with tape.
Once you’ve identified where air leakage is occurring, you’ll want to seal off these gaps. Depending on location, you can seal air leaks with caulk, sealant or spray foam. Apply caulk where you need a flexible seal at narrow joints; weather stripping is used where two surfaces move against each other, like at a window; and spray foam is an excellent choice for irregular shaped gaps because it will expand to fit any opening.
A professional home energy audit comes with a fee, but gives you the benefit of your home/building performance based on expert experience and judgment. Professional tools, including test equipment for air leakage and infrared camera scans, allow you to ‘see’ energy losses in new ways. With the cost of Hydro today we feel an energy audit in Ontario is a worthwhile investment.
Here are some examples of home performance services available:
Blower Door Test – by depressurizing the home with a large fan and then measuring airflow into the home, the overall air leakage of the entire home can be measured. The test can also be used to determine the location of leaks.
Duct Pressure Test – will identify the area and location of leaks in the duct system. A related ‘balance’ test of the heating ducts determines if the right amount of air is flowing to each room for comfort and efficiency. Other tests confirm combustion safety and ventilation fan flows.
Heat Pumps and A/C Commissioning – a set of tests that confirm the systems have the correct air flow and refrigerant charge. Equipment may have been sized using only rules of thumb, which can mean poor performance and durability.
Thermal Imaging – measures surface temperatures using infrared cameras and creates a visual image of heat loss. The cameras detect radiation in the infrared range of the electromagnetic spectrum. Typically, warmer surfaces appear brighter, and cooler surfaces appear darker. The images can reveal where walls, ceilings or floors are inadequately insulated or where windows and doors aren’t well sealed.
Payback is an estimate of how long it will take to save enough energy to pay for the cost of a conservation measure. A payback calculation will help you decide which upgrades to prioritize. Sealing up air leaks and duct-sealing are low cost measures and usually come in first place for payback. Air infiltration can be up to a third of a home’s heating load. Insulation, especially in walls or basements that have none, is an excellent investment.
We recommend doing those improvements first that cost the least and save the most energy. The following list of energy conservation measures are arranged in the order of their payback.