Ontario · Energy · checked September 28, 2026

Heat loss calculations in Markham

The heat loss calculation is how a heat pump or furnace gets sized for your house, and the key input is the design temperature: −19.8°C for Markham, from NRCan's HOT2000 climate data for Toronto Buttonville.

Get matched in Markham → The CSA F280 heat-loss calculation
A kitchen table with a house floor plan, a laser measure, a tape measure and a laptop showing the plan

Design temperature

−19.8°C

Heating degree-days

3,863

Standard

CSA F280-12

Typical cost

$150–$400 standalone

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. Snowfall scales with heating degree-days. Sources: Statistics Canada 2021 Census (table 98-10-0233-01), NRCan HOT2000 climate data.

Why the design temperature matters in Markham

−19.8°C is the 34th-coldest design temperature of the 70 cities we cover. The F280 calculation works out how much heat each room loses on that design day, from the house's actual walls, windows, air leakage and ceiling insulation.

At −19.8°C, a cold-climate heat pump sized to the calculation can carry most of the season, and the number shows how much backup heat the coldest days need.

In the Toronto area, 59% of households heat mainly with a forced-air furnace, 8% with a boiler and radiators, 5% with electric baseboards and 4% with a heat pump; natural gas is the main heating energy for 52% of households and electricity for 18% (Statistics Canada, 2023).

What CSA F280-12 asks for

The National Building Code 2020 requires the heating capacity for a house to be worked out with CSA F280, and its list of referenced documents names the 2012 edition, CSA F280-12. Provincial codes can name their own edition and climate values, so ask your designer which ones the calculation uses.

Why skipping it costs money

Contractors who size by square footage routinely oversize. An oversized heat pump costs more to buy, cycles on and off, dehumidifies poorly in summer and wears faster. An undersized one leans on backup heat. The F280 report is the evidence either way, and it's worth having before you compare quotes.

What it costs

About $150–$400 as a standalone calculation (a September 2026 planning range; quotes vary). Many energy advisors bundle it with an EnerGuide evaluation, which also gives the calculation measured air-leakage data instead of an assumption.

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: Heat loss calculation in York Region (Newmarket, Aurora, Stouffville, Georgina and more).

NRCan-licensed service organizations serving Markham

Many energy advisors also do room-by-room CSA F280 calculations for an extra fee; HVAC designers do them too. Ask for the F280 report itself, not just an equipment recommendation.

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.

Heat pump 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

Heat loss calculation in Markham: common questions

What design temperature is used for heat pump sizing in Markham?

NRCan's HOT2000 climate data gives −19.8°C for Toronto Buttonville. Your designer may use the building code's design value for Markham, which can differ slightly; ask which one the calculation uses.

What is CSA F280-12?

The 2012 edition of CSA F280, Determining the required capacity of residential space heating and cooling appliances. The National Building Code 2020 requires heating capacity for a house to be determined with it.

How much does a heat loss calculation cost?

About $150–$400 standalone as a planning range; often less when bundled with an EnerGuide evaluation.

Who does F280 calculations in Markham?

Many of the 28 NRCan-licensed organizations serving Markham offer them, as do HVAC designers. Ask for the F280 report itself.

Do rebate programs require a heat loss calculation?

Requirements vary by program and change often. Even where it isn't required, it is the best protection against an oversized or undersized system.

Heat loss calculation near Markham

Heat loss calculation in Richmond Hill10 kmHeat loss calculation in Pickering15 kmHeat loss calculation in Vaughan18 kmHeat loss calculation in Toronto19 kmHeat loss calculation 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).

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