Ontario · Energy · checked September 28, 2026

Home energy audits in London

25 NRCan-licensed service organizations deliver EnerGuide home evaluations in London. Here's what one costs, what it tends to find in London houses, and which Ontario rebates it unlocks.

Get matched in London → What a home energy audit involves
An energy advisor’s kit on a front-hall bench: infrared camera, pressure gauge with tubing, tape measure, headlamp and a floor sketch

Licensed organizations

25

Companies NRCan licenses to do EnerGuide evaluations

Typical cost

About $500–$700

Heating degree-days

3,809

A moderate heating season

Houses built before 1991

66%

Older houses usually leak more and have less insulation

How London is built

London's houses by when they were built Ten house shapes, one for each tenth of London's 119,295 houses. Before 1961: 25%, 1961–1990: 41%, 1991–2000: 11%, 2001 or later: 24%. Older houses glow hotter.
  • Before 1961 25%
  • 1961–1990 41%
  • 1991–2000 11%
  • 2001 or later 24%
Each house stands for one in ten of London's 119,295 houses (single-detached, semi-detached, row and duplex), drawn by when it was built. The glow shows the usual pattern: older houses tend to be leakier and less insulated. More snow in the drawing means more heating degree-days: a longer, colder heating season. Sources: Statistics Canada 2021 Census (table 98-10-0233-01), NRCan HOT2000 climate data.

What an evaluation finds in London homes

Of London's 119,295 houses (single-detached, semi-detached, row houses and duplexes), 25% were built before 1961 and 66% before 1991, according to the 2021 Census. The typical London house dates from 1971–1980, and an evaluation is how you find out what that means for yours: the blower door measures air leakage, the advisor inspects the attic, walls, basement, windows and heating system, and the report ranks upgrades by what they'd save.

London gets about 3,809 heating degree-days a year, a measure of how much heating its climate needs, and its winter design temperature, the cold day heating systems are sized for, is −18.4°C. Those figures come from the climate data for London in HOT2000, the home-energy software Natural Resources Canada (NRCan) gives energy advisors. That's right around the middle of the 70 cities we cover. A moderate heating season with warm summers: fixes should cut heating bills and keep the house cool.

London summers are hot and humid, so the air sealing and insulation that cut heating bills also keep the house cooler, and a heat pump can do the cooling more efficiently than an old air conditioner.

In the London area, 73% of households heat mainly with a forced-air furnace; natural gas is the main heating energy for 61% of households and electricity for 24% (Statistics Canada, 2023). The heating system on the report shapes the recommendations: a forced-air furnace invites a ducted heat pump, electric baseboards a ductless one.

What it costs in London

Typical Ontario prices are about $500–$700 for the initial EnerGuide evaluation and $200–$450 for the follow-up, plus HST where it applies. Windfall Ecology Centre charges $500 + HST for the initial evaluation and $250 + HST for the follow-up, Reep Green Solutions charges $540 and $406 with no HST, and City-backed programs in Ottawa and London quote $500–$700 as typical for the first visit. Only assessments from the seven HRSP-approved organizations qualify for the $600 Home Renovation Savings rebate, and none of the seven publishes a price.

Most providers quote the initial (pre-upgrade) and follow-up (post-upgrade) visits separately. Rebate programs that pay on measured improvement need both, so ask for the combined price.

How a home energy assessment (EnerGuide evaluation) works

  • Initial evaluation, about 2–3 hours. The advisor measures and inspects the house and runs the blower door test.
  • Report and EnerGuide rating. You get the home's energy rating in gigajoules per year and a list of recommended upgrades with estimated savings.
  • Do the work. Most rebate programs only count upgrades done after the initial evaluation.
  • Follow-up evaluation. A second visit measures the improvement, which is what most rebates pay on.

Read the full guide to home energy audits.

Great Lakes–St. Lawrence Southern Ontario and southern Quebec

London’s climate: Great Lakes–St. Lawrence

Cold winters and hot, humid summers: seal the attic, dry the basement, plan cooling.

This region has real winters and hot, humid summers, so bills come from both heating and cooling. Natural gas heats most Ontario homes, while most Quebec homes use low-cost electricity. An EnerGuide evaluation here should cover air sealing and the attic, cooling and dehumidification, and keeping the basement dry before insulating it.

In London: London's summers are hot and humid, with about 55 days a year at a humidex of 30 or more, and lake-effect snow can pile up in winter. Plan right-sized cooling and dehumidification, plus attic air sealing to prevent ice dams.

  1. Seal air leaks and top up the attic

    Air sealing is still the first retrofit. In the snowier Ottawa–Montreal–Sherbrooke belt, a leaky, under-insulated attic also causes ice dams.

  2. Right-size cooling to control humidity

    In humid summers, an oversized air conditioner or heat pump cools quickly but shuts off before removing moisture, leaving rooms clammy. A heat pump replacing the air conditioner also covers much of the heating.

  3. Keep the basement dry before insulating

    Basements can be about 20% of heat loss, but insulating a damp basement from the inside can rot the new wall. Flash floods have hit Toronto and Montreal repeatedly.

When to book: Book the evaluation in winter (December to February) for clear thermal scans, and start a 3-month radon test in fall. Check the basement after spring thaw or heavy rain, and line up cooling work before summer.

Everything homes in London need →

Sources for this climate guide · checked October 26, 2026

NRCan-licensed service organizations serving London

A service organization is a company that Natural Resources Canada (NRCan) licenses to deliver EnerGuide evaluations; its registered energy advisors do the home visit. Every organization below is licensed by NRCan to deliver EnerGuide evaluations and lists London postal codes. Coverage is the share of London's urban postal areas each one lists.

Only assessments from the seven HRSP-approved organizations qualify for the $600 Home Renovation Savings rebate and its assessment-path upgrade rebates; each listing below says whether it's one of them.

Source: NRCan list of licensed service organizations, checked September 28, 2026. Call to confirm your street is covered and ask about wait times.

Rebates and financing an evaluation unlocks in London

Provincial · needs an evaluation Home Renovation Savings — Home Energy Assessment path Up to $10,000 per home ($5,000 if heated with Enbridge gas), including $600 back on your two assessments, for insulation, windows, air sealing and more — if the follow-up assessment is done by December 31, 2026 Open · deadline Municipal BetterHomes London loan City of London program (FCM Green Municipal Fund-supported) with a free retrofit coach: loans up to $40,000 at a 2.5% fixed rate, terms up to 20 years, repaid through property taxes, with up to 50% of approved costs paid up front. The project must cut energy use by at least 25% (typically a $20,000-$30,000 investment); at least 80% of costs must be energy efficiency. For detached, semi, townhomes, duplexes and triplexes used as a full-time primary residence. Participants usually pay for the initial energy assessment ($500-$700) before financing approval; EnerGuide assessment costs are eligible for financing. Site updated Sept 2026. Municipal BetterHomes London income-qualified incentives Grants that do not have to be repaid, deducted from the loan balance after renovations. Paid on a sliding scale by energy savings: $2,500 at 25%, $3,000 at 30%, $4,000 at 40%, $5,000 at 50%, $6,000 at 60%, $7,500 at 75%, up to $10,000 at 100%. Household income must be under $95,000 for one person or under $115,000 for two to five people. Rental properties are not eligible.

Home energy audit in London: common questions

How much does a home energy audit cost in London?

Typical Ontario prices are about $500–$700 for the initial EnerGuide evaluation and $200–$450 for the follow-up, plus HST where it applies. Windfall Ecology Centre charges $500 + HST for the initial evaluation and $250 + HST for the follow-up, Reep Green Solutions charges $540 and $406 with no HST, and City-backed programs in Ottawa and London quote $500–$700 as typical for the first visit. Only assessments from the seven HRSP-approved organizations qualify for the $600 Home Renovation Savings rebate, and none of the seven publishes a price.

How many companies do EnerGuide evaluations in London?

NRCan's list of service organizations shows 25 licensed organizations with London postal codes (checked September 25, 2026). All seven organizations approved for Home Renovation Savings assessments are among them, and only their assessments qualify for its $600 rebate.

How long does an EnerGuide evaluation take?

The initial visit usually takes two to three hours, including the blower door test. The follow-up visit after upgrades is shorter.

Does an energy audit help with summer heat in London?

Yes. The advisor's upgrade list covers air sealing, attic insulation and windows, which slow summer heat gain as well as winter heat loss, and the evaluation's measurements are the starting point for sizing a heat pump that also cools.

Which rebates need an EnerGuide evaluation in Ontario?

Currently: Home Renovation Savings — Home Energy Assessment path (Up to $10,000 per home ($5,000 if heated with Enbridge gas), including $600 back on your two assessments, for insulation, windows, air sealing and more — if the follow-up assessment is done by December 31, 2026). Check the program page for current terms before you book.

Home energy audit near London

Home energy audit in Waterloo79 kmHome energy audit in Kitchener81 kmHome energy audit in Brantford82 kmHome energy audit in Cambridge90 kmHome energy audit in Chatham-Kent98 km All 70 cities →

Sources

Checked September 28, 2026. Census figures are for the municipality (Ontario); climate data is NRCan's HOT2000 station London (10 km away).

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