Ontario · Energy · checked September 28, 2026

Attic insulation inspections in Markham

The attic is usually the cheapest big energy fix in a house, and the inspection decides how to do it: how much insulation is there, where air leaks through the ceiling, and whether anything up there must not be disturbed.

Get matched in Markham → What an attic inspection checks
Loose-fill insulation between attic joists, a yellow ruler showing its depth and frost on the roofing nails above

Cost

Included in an evaluation

Houses built before 1991

40%

Older houses usually leak more and have less insulation

Heating degree-days

3,863

A moderate heating season

Common finding

R-10–20 vs R-50–60 target

Higher R-value means more insulation

How Markham is built

Markham's houses by when they were built Ten house shapes, one for each tenth of Markham's 91,305 houses. Before 1961: 3%, 1961–1990: 38%, 1991–2000: 17%, 2001 or later: 43%. Older houses glow hotter.
  • Before 1961 3%
  • 1961–1990 38%
  • 1991–2000 17%
  • 2001 or later 43%
Each house stands for one in ten of Markham's 91,305 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 inspections find in Markham attics

Of Markham's 91,305 houses (single-detached, semi-detached, row houses and duplexes), 3% were built before 1961 and 40% before 1991, according to the 2021 Census. Attics in older houses commonly have a fraction of today's recommended insulation, and top-ups done over the years often buried air leaks instead of sealing them first.

Markham gets about 3,863 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 −19.8°C. Those figures come from the climate data for Toronto Buttonville 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. The colder the climate, the faster added attic insulation pays for itself, and in a hot summer the same insulation keeps attic heat out of the bedrooms below.

Vermiculite. Loose, pebbly, grey-brown or silver-gold insulation may contain asbestos. Health Canada's advice is not to disturb it; have it sampled before any attic work. Asbestos and vermiculite testing in Markham

The right order for the work

  • Seal the air leaks first: top plates, pot lights, plumbing stacks, the hatch.
  • Fix ventilation baffles so new insulation doesn't block soffit vents.
  • Then top up the insulation. Burying unsealed leaks under new insulation wastes much of the benefit.

What an attic inspection checks.

Great Lakes–St. Lawrence Southern Ontario and southern Quebec

What this means in Markham’s climate

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.

  • 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. Ask: Ask for a blower door test and attic inspection, and whether old vermiculite insulation needs testing before any attic work.

What else homes in Markham need →

Sources for this climate guide · checked October 26, 2026

Communities served

Markham's page covers the whole City of Markham, including Locust Hill and Unionville.

The organizations and professionals listed for Markham may or may not travel to every community, so ask when you call.

Area guide for the surrounding region, with every town and hamlet listed: York Region area guide (Newmarket, Aurora, Stouffville, Georgina and more).

NRCan-licensed service organizations serving Markham

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 EnerGuide evaluation includes an attic inspection: insulation depth, air leaks and red flags such as vermiculite or knob-and-tube wiring.

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.

Insulation programs in Markham

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 Provincial Home Renovation Savings — direct rebates (no assessment) Heat pumps up to $7,500 ($12,000 ground-source), solar with battery up to $10,000, plus attic, thermostat and appliance rebates — no assessment needed Open Federal National Heat Pump Rebate Announced October 8, 2026 and opening early 2027: up to $10,000 below the median income, $2,000 for other eligible homeowners Announced · opens 2027 Federal CMHC Eco Improvement premium refund A 25% energy-efficiency rebate on your CMHC mortgage insurance premium after $20,000 of energy renovations Open

Attic insulation inspection in Markham: common questions

How much attic insulation should a Markham house have?

Advisors commonly target around R-50 to R-60 in attics. Your EnerGuide report gives the recommendation for your house.

Can I top up the insulation myself?

Only after the air leaks are sealed and you've confirmed there is no vermiculite. The inspection tells you both.

Will more insulation stop ice dams?

Insulation helps, but ice dams are mostly caused by warm air leaking into the attic. Air sealing is the bigger fix.

Attic insulation inspection near Markham

Attic insulation inspection in Richmond Hill10 kmAttic insulation inspection in Pickering15 kmAttic insulation inspection in Vaughan18 kmAttic insulation inspection in Toronto19 kmAttic insulation inspection in Ajax22 km All 70 cities →

Sources

Checked September 28, 2026. Census figures are for the municipality (Ontario); climate data is NRCan's HOT2000 station Toronto Buttonville (6 km away).

Get matched with a registered advisor in Markham

Tell us your postal code and what you’re planning. We’ll connect you with one licensed service organization serving your area. No spam, no shared lead lists.

By submitting you agree we may share your request with one registered service organization serving your area. Participating advisors pay us a referral fee — you pay nothing, and it never affects the directory. See our privacy note.