How Dufferin County is built
- Before 1961 16%
- 1961–1990 38%
- 1991–2000 16%
- 2001 or later 30%
This page covers the eight towns and townships of the County of Dufferin, from Orangeville and Mono north to Shelburne, Melancthon and Mulmur.
Design temperatures across Dufferin County
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 Dufferin County:
| Location in the code’s table | January 2.5% design temperature | Heating degree-days |
|---|---|---|
| Orangeville | −21°C | 4,450 |
| Shelburne | −22°C | 4,700 |
Environment and Climate Change Canada's 1981–2010 climate normal at Orangeville MOE (14.1 km from the middle of the area) is 4,421 heating degree-days a year, with a January mean of −7.5°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 −21°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 20,775 houses in Dufferin County (single-detached, semi-detached, row houses, duplexes and mobile homes), 16% were built before 1961 and 54% 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.
Great Lakes–St. Lawrence Southern Ontario and southern Quebec
What this means in Dufferin County’s climate
Cold winters and hot, humid summers: seal the attic, dry the basement, plan cooling.
Why it matters here: Prevents oversized equipment that short-cycles and dehumidifies poorly, and is needed to choose the right heat pump.
Best timing: Before replacing an air conditioner or furnace, based on the house after planned upgrades.
- 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. Ask: Ask for a room-by-room heat-loss calculation and a duct and airflow check before replacing your air conditioner or furnace.
What else homes in Guelph need →
Sources for this climate guide · checked October 26, 2026
- National Building Code of Canada 2020, climate data (NRC)
- Canadian Climate Normals 1991–2020 (ECCC)
- Keeping the Heat In (NRCan)
- Air-Source Heat Pump Sizing and Selection Guide (NRCan)
- Heating and Cooling With a Heat Pump (NRCan)
- Heat pump basics (NRCan)
- Gas and heat pump hybrid systems (NRCan)
- Primary heating systems by household, Table 38-10-0286-01 (Statistics Canada)
- Electricity price comparison, April 2025 (Hydro-Québec)
- Canada's top weather stories of 2018 (ECCC)
- Canada's top weather stories of 2022 (ECCC)
- Canada's top weather stories of 2023 (ECCC)
- Canada's most impactful weather stories of 2024 (ECCC)
- Canada's top weather stories of 2025 (ECCC)
- 2024 Cross-Canada Survey of Radon Exposure
- Guide for Radon Measurements in Homes (Health Canada)
- Conditions for thermal scans, ASTM C1060 summary (Cx Associates)
Communities we cover in Dufferin County
Every town, village and hamlet below is part of this page, grouped by municipality (2021 Census population).
- Town of Orangeville 30,167
- Town of Mono 9,421
- Town of Shelburne 8,994
- Township of Amaranth 4,327
- Town of Grand Valley 3,851
- Township of Mulmur 3,571Mansfield
- Township of Melancthon 3,132
- Township of East Garafraxa 2,794Orton
NRCan-registered service organizations serving Dufferin County
NRCan's list of service organizations (checked October 8, 2026) shows 22 organizations registered for postal codes in Orangeville (L9V, L9W). 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.
- Acacia Engineering HRSP-approved: No
- Air Barrier Canada HRSP-approved: No
- All Season Inspection HRSP-approved: No Profile
- AmeriSpec HRSP-approved: Yes Profile
- CoEfficient Building Science HRSP-approved: No
- EcoLogic Energy Advisors HRSP-approved: No
- Ecostep Energy Services HRSP-approved: No
- Energy Werx HRSP-approved: Yes Profile
- Enerhold Engineering Solutions HRSP-approved: No
- EnerQuality HRSP-approved: No
- EnerSolution HRSP-approved: No Profile
- Engreen Home HRSP-approved: No
- ER Energy Solutions HRSP-approved: No
- GETS Energy HRSP-approved: No
- Green Canada Home Advisors HRSP-approved: No Profile
- Greenbrain HRSP-approved: Yes Profile
- Sensible Home Inspections HRSP-approved: No
- The Energuy HRSP-approved: Yes Profile
- Verdatech Energy Management and Consulting HRSP-approved: No
Heat pump programs in Dufferin County
Heat loss calculations in Dufferin County: common questions
What design temperature is used for heat pump sizing in Orangeville?
The National Building Code 2020's climate table gives −21°C for Orangeville and −22°C for Shelburne. 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 Dufferin County?
Many of the 22 NRCan-registered organizations that list Orangeville postal codes offer them, as do HVAC designers. Ask for the F280 report itself, not just an equipment size.