Find out where your home loses energy and how air sealing, insulation, ventilation and smart upgrades cut bills and improve comfort.
Canada's long, cold winters make heating the biggest energy expense in most homes. Drafty rooms, cold floors, ice dams and high bills are all signs that a home is losing heat it paid to produce. The good news is that many of the most effective fixes are affordable, and some are simple enough to do yourself.
Energy efficiency is often called the first fuel: the cleanest and cheapest energy is the energy you don't need to use. A more efficient home is also more comfortable, quieter and more resilient during outages, and it makes later upgrades like heat pumps or solar smaller and less expensive.
This course explains where your home's energy goes, what a professional energy evaluation involves, and how to plan upgrades in the right order. You'll learn about air sealing, insulation, windows, ventilation, heating and hot water, plus practical tips for renters and for paying for retrofits. Sundamentals is an independent non-profit, and we don't sell products or services.
The course is free, self-paced and takes about an hour. It has three modules with short knowledge checks and a 10-question final exam. Score 80% or higher to download your PDF certificate of completion.
In a typical Canadian home, space heating is by far the largest use of energy, often accounting for more than half of the total. Heating water is usually the next largest use. Lighting, appliances, electronics and air conditioning make up the rest. The exact split depends on your climate, the age and size of the home, and how you heat it.
Heat escapes a home in two main ways. It conducts through the building envelope, which is the roof, walls, windows, doors and foundation that separate inside from outside. It also leaks out with air, as warm indoor air escapes through gaps and cracks and cold outdoor air is drawn in to replace it. In many older homes, air leakage is responsible for a large share of heat loss.
That is why the biggest savings opportunities usually involve the envelope and the heating system, not light bulbs. LED lighting and efficient appliances are still worthwhile and easy, but if your goal is to make a real dent in your energy bill and improve winter comfort, focus first on keeping heat in.
Your utility bills are a good place to start. Compare winter and summer usage to see how much goes to heating and cooling. Many utilities also offer online tools that show hourly or daily usage and compare your home with similar homes nearby.
Your own habits play a role as well. Thermostat settings, how long showers run, how often you do laundry in hot water, and whether doors and windows are left open all affect energy use. Simple changes in habits cost nothing, and they help you get the most from any upgrades you make later.
A home energy evaluation, sometimes called an energy audit, is the best way to understand your specific home. In Canada, evaluations under the EnerGuide program are carried out by registered energy advisors working with service organizations licensed by Natural Resources Canada. The evaluation produces an EnerGuide rating and label for your home.
During the visit, the advisor inspects the attic, walls, basement, windows, heating and ventilation equipment, and water heater. They take measurements and perform a blower door test. A powerful fan is fitted into an exterior door to depressurize the house, which measures how airtight the home is and makes leaks easier to find, sometimes with the help of a thermal camera.
You'll receive a report with your home's EnerGuide rating, which estimates the home's annual energy use under standard operating conditions, along with a list of recommended upgrades and their estimated impact. Because the rating uses standard assumptions about occupants and thermostat settings, it allows homes to be compared fairly.
Many incentive programs have required an evaluation before and after upgrades, so check program rules before starting work. Even when it is not required, an evaluation helps you avoid spending money on upgrades that won't make much difference in your home.
To prepare for an evaluation, make sure the advisor can access the attic hatch, basement walls, furnace and water heater, and have recent utility bills on hand. Close windows and fireplace dampers before the blower door test. Write down any comfort problems you have noticed, such as cold rooms, condensation or ice dams, so the advisor can investigate them while on site.
A house is a system of connected parts: the envelope, the heating and cooling equipment, the ventilation, and the people living in it. Changing one part affects the others. Tightening a leaky house changes how moisture and indoor air quality behave. Adding insulation reduces the size of the heating system the home needs.
This leads to a sensible order of operations for most retrofits. First, understand the home through an evaluation. Second, reduce the load by air sealing and insulating. Third, make sure there is proper ventilation. Fourth, right-size and upgrade heating, cooling and water heating equipment. Finally, consider adding renewable energy such as solar.
Doing things in this order saves money. A heat pump sized for a home after air sealing and insulation can be smaller and cheaper than one sized for the leaky original. A solar system can also be smaller if the home uses less electricity.
Life rarely follows a perfect sequence. If your furnace fails in January, you will need to replace it right away. In that case, ask your contractor to account for any envelope upgrades you plan to make soon, and keep the bigger plan in mind. A simple written retrofit plan helps you make good decisions when equipment needs replacing unexpectedly.
The house-as-a-system approach also helps you avoid problems. For example, adding attic insulation without first sealing air leaks can trap moisture and lead to frost and mould in the attic. Adding a powerful kitchen exhaust fan to a very tight house without makeup air can draw exhaust gases back down a chimney. Thinking about how changes interact keeps your home safe and healthy.
Air sealing is often one of the most cost-effective upgrades you can make. Warm air rises and escapes through gaps in the upper parts of the home, while cold air is pulled in through gaps lower down. This stack effect drives drafts and heat loss, especially in cold weather.
Some of the biggest leaks are hidden. Common culprits include gaps where the attic meets the walls and ceiling, around plumbing stacks, chimneys and light fixtures, attic hatches, and the rim joist area where the house framing sits on the foundation. Leaks around windows, doors, electrical outlets on exterior walls and baseboards add up too.
Many sealing jobs are suitable for a handy homeowner: caulking around trim and window frames, weatherstripping doors and attic hatches, installing foam gaskets behind outlet covers on exterior walls, and sealing basement rim joists with appropriate materials. Larger attic sealing is often best done by a contractor, ideally before new attic insulation is added.
Safety comes first. Fuel-burning appliances such as older furnaces, water heaters and fireplaces need air to operate and vent properly. Significantly tightening a home can affect their venting. Make sure you have working carbon monoxide alarms, and ask a professional to check combustion appliances after major air sealing. This is another reason to plan for ventilation, covered in Module 3.
A simple way to find drafts yourself is to wait for a cold, windy day and slowly move a lit incense stick around windows, doors, outlets and baseboards, watching for the smoke to waver. You can also feel for cold air with the back of your hand. Keep a list of what you find, then tackle the biggest and easiest leaks first.
Insulation slows the flow of heat through the envelope. Its effectiveness is measured by R-value, or RSI in metric units, and higher values mean better resistance to heat flow. Building codes set minimum levels for new construction, but many older Canadian homes have far less insulation than today's standards.
The attic is often the easiest and most cost-effective place to add insulation, because there is usually room to add more on top of what is there. Basements are another big opportunity, since an uninsulated foundation wall loses a lot of heat. Exterior walls are harder to upgrade, often requiring insulation to be blown into wall cavities or added during a siding replacement.
Moisture management is critical. Insulating the wrong way can trap moisture and lead to mould or rot, especially in basements and in attics with poor ventilation. Follow building code requirements, use appropriate vapour and air barriers, and get professional advice for basements and walls. Ice dams on the roof are often a sign of heat escaping into the attic through air leaks and weak insulation.
Before disturbing older insulation, be aware of hazards. Some older homes contain vermiculite insulation that may contain asbestos. If you see a loose, pebble-like, grey-brown or silvery material in your attic, don't disturb it; have it tested and, if necessary, handled by qualified professionals.
Some insulation jobs suit a confident do-it-yourselfer, such as adding batts in an accessible attic or insulating hot water pipes. Others, such as spray foam, blown-in wall insulation and most basement projects, are best left to professionals with the right equipment and knowledge of code requirements. Whoever does the work, wear proper protective equipment and ensure the area is well ventilated.
Windows are often the first upgrade people think of, but they are frequently not the most cost-effective one. Replacing windows is expensive, and the energy savings are usually smaller than those from air sealing and insulation. That said, windows strongly affect comfort, condensation and noise, and replacement can make sense when existing windows are failing.
If you are replacing windows, look for ENERGY STAR certified products rated for your climate zone. Key features include double or triple glazing, low-emissivity coatings that reflect heat back into the room, insulating gas fill between panes and insulated frames. Triple-glazed windows are increasingly common in colder parts of Canada.
Installation quality is as important as the window itself. The gap between the window frame and the wall must be properly sealed and insulated, or the new window will leak air like the old one.
If replacement isn't in the budget, there are cheaper ways to improve existing windows and doors: replace worn weatherstripping, caulk gaps around trim, add interior window insulation film in winter, and use insulated cellular blinds or heavy curtains at night. An insulated exterior door with good weatherstripping can also make a noticeable difference in an entryway.
Condensation on the inside of windows in winter can be a clue worth investigating. Some condensation on very cold days is normal, especially on older windows, but persistent heavy condensation can point to high indoor humidity, poor ventilation or failing window seals. Fixing the cause, whether through ventilation or better windows, protects window frames and walls from moisture damage.
Build tight, ventilate right is a common saying among building experts. As homes become more airtight, they need a controlled way to bring in fresh air and remove stale, humid air. Bathroom and kitchen exhaust fans that vent outside are the basics. Many tighter homes also use a heat recovery ventilator (HRV) or energy recovery ventilator (ERV), which exchange indoor and outdoor air while recovering much of the heat from the outgoing air.
Once the envelope is improved, it is time to look at heating and cooling equipment. Heat pumps, covered in detail in our heat pump course, are an efficient option for many homes, and a tighter, better-insulated home makes them work even better. If you keep a fuel-burning furnace or boiler, a high-efficiency model and properly sealed ducts can still reduce energy use.
Water heating deserves attention because it is often the second-largest energy use. Options include heat pump water heaters, which use the same heat-moving principle as heat pumps for space heating; high-efficiency gas units; and simple measures such as low-flow showerheads, insulating hot water pipes, and fixing dripping taps. Drain water heat recovery units can capture heat from shower drain water.
Smaller upgrades add up too. A programmable or smart thermostat, LED lighting, ENERGY STAR appliances and turning off devices that draw standby power are easy wins.
A good retrofit plan lists the upgrades you intend to make, in a sensible order, with rough costs and timing. Many households complete their plan in stages over several years, often timing big upgrades to coincide with other work, such as adding wall insulation during a siding replacement or upgrading the furnace when the old one reaches the end of its life.
Federal support has changed. The Canada Greener Homes Grant closed to new applicants in 2024, and the related Canada Greener Homes Loan is also closed. In 2026, the federal government began rolling out the Canada Greener Homes Affordability Program, aimed at low- and median-income households, including renters, and delivered through provincial and utility partners in participating provinces. Provinces, municipalities and utilities also run their own rebates, loans and free upgrade programs.
Because programs open, close and change, use the Sundamentals rebate finder to see what is currently available where you live. Read each program's rules carefully before you start work, since some require pre-approval or an energy evaluation first, and keep all receipts and documents.
Renters can make a difference too. Use removable weatherstripping and window film, LED bulbs, smart power bars and efficient habits, and talk to your landlord about larger upgrades, sharing information about available programs. A warmer, more efficient home benefits everyone, whoever owns it.
Be cautious with door-to-door or phone offers that claim to be part of a government program. Legitimate programs will have clear information on official government or utility websites, and you should never feel pressured to sign on the spot. Verify any claim independently, get multiple quotes, and ask contractors whether they are registered or approved for the specific program they mention.
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