Top-Rated Insulation Installers in London, ON
9 local companies ranked by 715 Google reviews. Free to compare, no sign-up.
Short answer: The top-rated insulation installers in London are Koala Insulation of London (5.0★, 63 reviews), Net Zero Insulation (4.9★, 161 reviews), Great Northern Insulation (4.7★, 369 reviews).
Insulation installers in London, ranked
- 5.0 (63 Google reviews)2179 Flying Club Rd, London, ON N5V 3Z9
- 4.9 (161 Google reviews)45 Pacific Ct Unit 11, London, ON N5V 3N4
- Great Northern InsulationMost reviews4.7 (369 Google reviews)2485 Innovation Drive, London, ON N6M 0C8
- 5.0 (13 Google reviews)71 Dreaney Ave, London, ON N5Z 1W7
- 4.7 (15 Google reviews)6746 Wellington Rd S, London, ON N6L 1M5
- 4.6 (57 Google reviews)611 Wonderland Rd N #381, London, ON N6H 4V6
- 4.7 (10 Google reviews)3657 Woodhull Rd, London, ON N6P 1P2
- 4.2 (12 Google reviews)560 Admiral Ct, London, ON N5V 4L3
- Polar Energy Systems - Insulation ServicesAlso installs batteries4.2 (15 Google reviews)79 Bessemer Rd #23, London, ON N6E 1P9
Together these 9 companies average 4.8★ across 715 reviews. Great Northern Insulation has the most reviews (369).
Ranked by Google rating weighted by review count, collected September 2026. Rankings are not paid for. How we rank and how we make money.
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What a insulation costs in London
Price depends on which areas you insulate (attic, walls, basement) and how much air sealing is needed. Ask each company for a price per area and the R-value you end up with, so quotes are easy to compare.
That could cut your cost by up to $7,700 if you qualify. Most rebates have rules (income, your current heating, a registered contractor, approval before work starts).
Rebates: our verified program data, checked monthly. Always confirm the exact amount for your home.
Talk to a registered energy advisor first. Some rebates need an evaluation or heat load calculation before any work starts. See the top-rated registered energy advisors in London. Read when to call an energy advisor.
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Why insulation matters in London
In London, the average January low is -8°C, colder than 71% of the 123 cities we track. Sealing air leaks and topping up the attic usually pays back fastest here. Basement walls and rim joists are often the next biggest heat loss in older homes.
Most rebate programs pay only after an energy assessment, and some need one before the work too. Book it first.
Source: Open-Meteo historical weather data, 2015-2024.
Before you hire an insulation installer
- Ask whether they will air-seal before insulating, and what they will seal (attic hatch, pot lights, pipes, top plates).
- Ask for the R-value before and after for each area, and the material and depth they will install.
- Ask whether your rebate needs an energy assessment before and after the work, and who books it.
- Ask how they handle ventilation and any old insulation that could contain vermiculite (asbestos risk).
Questions about insulation installers in London
Who is the best insulation installer in London?
Based on Google reviews, the top-rated insulation installers in London are Koala Insulation of London (5.0★, 63 reviews), Net Zero Insulation (4.9★, 161 reviews), Great Northern Insulation (4.7★, 369 reviews). We rank by a review-weighted score, so companies with many strong reviews rank above those with only a few.
How are the insulation installers in London ranked?
We list 9 insulation companies in London, ranked by Google rating weighted by review count. Together they have 715 Google reviews and average 4.8 stars, collected September 2026. Great Northern Insulation has the most reviews (369). No company pays to be listed or ranked.
How much does insulation cost in London?
Insulation prices depend on which areas you insulate (attic, walls, basement) and how much air sealing is needed. Ask each company for a price per area and the R-value you end up with, so quotes are easy to compare.
Are there rebates for insulation in London?
Yes. Our verified program data shows insulation rebates up to $7,700 open in London. Most rebates have rules, such as income, your current heating, a registered contractor, or approval before work starts, so check the rebate page before you sign.
Is insulation worth it in London?
In London, the average January low is -8°C, colder than 71% of the 123 cities we track. Sealing air leaks and topping up the attic usually pays back fastest here. Basement walls and rim joists are often the next biggest heat loss in older homes. Most rebate programs pay only after an energy assessment, and some need one before the work too. Book it first.
What should I ask an insulation installer before I hire?
Ask whether they will air-seal before insulating, and what they will seal (attic hatch, pot lights, pipes, top plates). Ask for the R-value before and after for each area, and the material and depth they will install. Ask whether your rebate needs an energy assessment before and after the work, and who books it.
Before you call anyone, check what insulation rebates you can get in London. Many programs require approval or a registered contractor before work starts.
Planning more upgrades? See the top-rated heat pump installers, solar installers, home battery installers, energy advisors in London.
How to read these results
- Open the profile.How a installer describes its own work tells you a lot. Look for jobs like yours.
- Read the Google reviews.Stars and counts come from Google Maps. Click through and read what past customers wrote, good and bad.
- Check for program badges.A green registered-contractor badge means the company is on the program's own list, which some rebates require.
- Compare three.Do not stop at the first good installer. Three quotes show you the real range in price, equipment and plan.
Not ready to talk to a contractor yet?
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