Ontario · area guide · 21 communities · checked October 8, 2026
Home energy audits, radon and well water testing in Wellington County
The seven towns and townships on this page are home to 97,286 people (2021 Census), and 25% of their houses were built before 1961. This guide covers 21 communities, from Fergus, Elora, Mount Forest and Erin to the smallest hamlets, with the local numbers that shape an energy audit or a home health test.
Population (2021)
97,286
Communities listed
21
Houses built before 1961
25%
How Wellington County is built
- Before 1961 25%
- 1961–1990 36%
- 1991–2000 13%
- 2001 or later 25%
This page covers the seven towns and townships of the County of Wellington. Guelph is a separate city with its own pages.
Great Lakes–St. Lawrence Southern Ontario and southern Quebec
Wellington County’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.
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.
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.
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 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)
Six local guides for Wellington County
Energy audits and heat pump sizing
Wellington County at a glance
People and homes
97,286 people and 37,541 private dwellings in 2021, up 7.0% in population since 2016.
Housing
Of the 31,695 houses in Wellington County (single-detached, semi-detached, row houses, duplexes and mobile homes), 25% were built before 1961 and 61% before 1991, according to the 2021 Census. The typical house dates from 1981–1990.
Climate
Environment and Climate Change Canada's 1981–2010 climate normal at Fergus Shand Dam (13.2 km from the middle of the area) is 4,307 heating degree-days a year, with a January mean of −7.4°C. The building code's 2.5% January design temperatures for the area run from −19°C to −21°C.
Radon
In Health Canada’s 2012 survey, 10.9% of 92 homes tested in the Wellington-Dufferin-Guelph Health Unit were above the guideline. The larger 2024 Cross-Canada survey reports 13.5% (1 in 7) of houses at or above the guideline for the Guelph metro area.
Wells
Public Health Ontario tests well water for bacteria (E. coli and total coliforms). Pick up a bottle at a public health office or a participating municipal office. Samples go back to the Guelph (160 Chancellors Way), Fergus (490 Charles Allen Way) or Orangeville (180 Broadway) offices Monday to Thursday, 8:30 a.m. to 4:30 p.m., with short Friday-morning windows; to the Mel Lloyd Centre in Shelburne (Monday and Wednesday mornings); to reception at Palmerston District Hospital or Louise Marshall Hospital in Mount Forest; or to the Township of Erin office in Hillsburgh (Monday mornings).
Energy advisors
NRCan's list (checked October 8, 2026) shows 24 service organizations registered for postal codes in Fergus. Confirm they travel to your community.
Heating
Province-wide, 58% of Ontario households heat mainly with natural gas, 18% with electricity, 4% with propane and 1% each with oil and wood (Statistics Canada, 2023); there's no published breakdown for this area alone.
Every community in Wellington County
Grouped by municipality, with 2021 Census populations. Names come from Natural Resources Canada's geographical names database and Statistics Canada's population centres.
- Township of Centre Wellington 31,093Belwood, Elora, Fergus
- Township of Guelph/Eramosa 13,904Ariss, Rockwood
- Township of Wellington North 12,431Arthur, Mount Forest
- Town of Erin 11,981Ballinafad, Hillsburgh
- Township of Mapleton 10,839Drayton
- Town of Minto 9,094Harriston, Palmerston
- Township of Puslinch 7,944Arkell, Morriston
Covered on city pages
- Guelph 143,740Guelph has its own pages.
Who does the work in Wellington County
- Energy evaluations and heat loss calculations: NRCan's list (checked October 8, 2026) shows 24 registered service organizations for postal codes in Fergus. See them with phone numbers; confirm they travel to your community.
- Radon: certified measurement and mitigation professionals are listed in the C-NRPP directory ↗.
- Wood stoves and chimneys: WETT-certified professionals are listed in the WETT directory ↗; see wood-burning inspections in Wellington County.
- Well water: free bacteria tests through the local public health unit; chemistry through a licensed private lab. Details for Wellington County.
Rebates and financing for Wellington County homes
Nearby city pages and guides
Sources
- Statistics Canada — 2021 Census population and dwelling counts (table 98-10-0002-01)
- Statistics Canada — 2021 Census, households by period of construction and dwelling type (table 98-10-0233-01)
- Statistics Canada — 2021 Census population centres (table 98-10-0011-01)
- NRCan — Canadian Geographical Names Database (official place names)
- Environment and Climate Change Canada — Canadian Climate Normals 1981–2010
- National Research Council — National Building Code of Canada 2020, Appendix C, Table C-2 (climatic design data)
- Health Canada — Cross-Canada Survey of Radon Concentrations in Homes, final report (2012), Table 5
- NRCan — Service organizations for existing homes (list checked October 8, 2026)
- Land Information Ontario — municipal boundaries (lower and single tier)
- Evict Radon National Study with Health Canada — 2024 Cross-Canada Survey of Radon Exposure (report v1.1)
- Wellington-Dufferin-Guelph Public Health — private well water testing
- Statistics Canada — Households and the Environment Survey 2023, primary heating systems (table 38-10-0286-01)
Planning upgrades in Wellington County?
Tell us where you are and what you’re planning. We’ll connect you with a registered service organization for your area — no spam, no shared lead lists.