Ontario · Energy · area guide · checked October 8, 2026

Heat loss calculations in York Region

A heat loss calculation is how a heat pump or furnace gets sized, and its key input is the design temperature. In York Region, the National Building Code's 2.5% January design temperatures run from −20°C at Vaughan to −22°C at Newmarket, so a calculation for a house near Newmarket starts from a colder number than one near Vaughan. Here's what that means for Newmarket, Aurora and Stouffville and the rest of the area.

Get matched in York Region → 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

−20°C to −22°C

NBC 2020, January 2.5%

Heating degree-days

4,243

King Smoke Tree

Standard

CSA F280-12

Registered organizations

27

many offer F280 reports

How York Region is built

York Region's houses by when they were built Ten house shapes, one for each tenth of York Region's 96,970 houses. Before 1961: 11%, 1961–1990: 34%, 1991–2000: 15%, 2001 or later: 40%. Older houses glow hotter.
  • Before 1961 11%
  • 1961–1990 34%
  • 1991–2000 15%
  • 2001 or later 40%
Each house stands for one in ten of York Region's 96,970 houses (single-detached, semi-detached, row, duplex and mobile homes), 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), Environment and Climate Change Canada 1981–2010 climate normals (King Smoke Tree) and the National Building Code 2020 January design temperature for Newmarket.

This page covers the York Region towns and townships we don't have separate city pages for: King, East Gwillimbury, Georgina, Whitchurch-Stouffville, Newmarket and Aurora. Vaughan, Markham and Richmond Hill have their own pages, which also cover their hamlets.

Design temperatures across York Region

The National Building Code of Canada 2020 says the 2.5% January design temperature is the value ordinarily used to design heating systems. Its climate table lists these Ontario locations in or next to York Region:

Location in the code’s tableJanuary 2.5% design temperatureHeating degree-days
Newmarket−22°C4,260
Aurora−21°C4,210
Richmond Hill−21°C4,000
Markham−21°C4,000
Vaughan−20°C4,100

Environment and Climate Change Canada's 1981–2010 climate normal at King Smoke Tree (11.9 km from the middle of the area) is 4,243 heating degree-days a year, with a January mean of −7.4°C.

What CSA F280-12 asks for

The code requires the heating capacity for a house to be worked out with CSA F280, using the code's own design temperatures, and its list of referenced documents names the 2012 edition, CSA F280-12. The calculation works out how much heat each room loses on the design day, from the house's actual walls, windows, ceiling insulation and air leakage.

At −20°C to −22°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.

What the calculation needs from your house

Of the 96,970 houses in York Region (single-detached, semi-detached, row houses, duplexes and mobile homes), 11% were built before 1961 and 45% before 1991, according to the 2021 Census. In an older or renovated house, the walls, windows and air leakage rarely match the original plans, so ask the designer to measure rather than assume. Have this ready:

  • Room dimensions and ceiling heights, or a floor plan.
  • Window and door sizes and types, room by room.
  • Insulation levels in the attic, walls, basement and any floor over an unheated space.
  • A blower door result from an EnerGuide evaluation, if you've had one.
  • Where the ducts, radiators or baseboards run, so the heat can be delivered room by room.

What it costs

There's no standard published price for a standalone F280 calculation, so ask two or three providers for a written quote that names the deliverable: the room-by-room F280 report, not just an equipment size. Many energy advisors bundle it with an EnerGuide evaluation, which also gives the calculation measured air-leakage data instead of an assumption. Ask whether a rural travel fee applies. The CSA F280 heat-loss calculation explains the method and typical cost bands.

Communities we cover in York Region

Every town, village and hamlet below is part of this page, grouped by municipality (2021 Census population).

  • Town of Newmarket 87,942
  • Town of Aurora 62,057
  • Town of Whitchurch-Stouffville 49,864Ballantrae, Gormley, Stouffville
  • Town of Georgina 47,642Elmhurst Beach, Jacksons Point, Keswick, Pefferlaw, Sutton
  • Town of East Gwillimbury 34,637Holland Landing, Mount Albert, Queensville, River Drive Park
  • Township of King 27,333King City, Nobleton, Schomberg

Covered on city pages: Vaughan (Concord, Kleinburg, Maple, Woodbridge); Markham (Locust Hill, Unionville); Richmond Hill.

NRCan-registered service organizations serving York Region

NRCan's list of service organizations (checked October 8, 2026) shows 27 organizations registered for postal codes in Newmarket, Aurora, Stouffville, Keswick, Holland Landing and King City (L3X, L3Y, L4G, L4A, L4P, L9N, L7B). Registration means an organization lists those postal areas, not that it has an advisor in town: confirm they travel to your community, and ask about wait times and travel fees.

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 service organizations, checked October 8, 2026, matched by forward sortation area (L3X, L3Y, L4G, L4A, L4P, L9N, L7B). Call to confirm your road is covered.

Heat pump programs in York Region

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 calculations in York Region: common questions

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

The National Building Code 2020's climate table gives −22°C for Newmarket, −21°C for Aurora, −21°C for Richmond Hill, −21°C for Markham and −20°C for Vaughan. Provincial codes can use their own climate tables, so ask which value 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?

There is no standard published price. Ask two or three providers for a written quote for the F280 report, and ask whether it costs less bundled with an EnerGuide evaluation and whether a travel fee applies.

Who does F280 calculations in York Region?

Many of the 27 NRCan-registered organizations that list Newmarket, Aurora and Stouffville postal codes offer them, as do HVAC designers. Ask for the F280 report itself, not just an equipment size.

Sources

Checked October 8, 2026. Census figures are 2021 totals for the municipalities listed; the climate normal is Environment and Climate Change Canada's station King Smoke Tree (11.9 km from the area's centre point).

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