What is the best way to heat a detached garage in Ontario?

Electric unit heaters and natural gas garage heaters are both common; the right choice depends on whether gas service is available and how much you use the space in winter.

Do I need a permit to insulate and heat my existing garage?

Minor insulation and a plug-in heater usually do not need a permit, but adding gas lines or a new electrical circuit typically does and should be done by a licensed trade.

Can I insulate a garage myself and just hire someone for the heater?

Some homeowners do split the work this way, though a contractor doing both together can make sure the insulation and heat source are sized correctly for each other.

Heated garage & insulation upgrade for an existing garage

This covers upgrading a garage you already have, insulating the walls and ceiling, adding a heat source, and finishing the interior, without changing its use to living space or adding square footage. It sits apart from a full garage addition or conversion because the footprint and function (still a garage) stay the same.

Wall and ceiling insulation added to an existing unheated garage
Installing a garage heater (electric, gas-fired, or in-floor)
Drywall, epoxy flooring, or other finish work over the existing structure
Sealing and weatherproofing doors and windows to hold heat

Common for homeowners turning a garage into a proper workshop, gym, or year-round vehicle bay without touching zoning or permit-heavy change-of-use rules.

What it costs

Cost depends on the heating method chosen (electric unit heater versus gas versus in-floor radiant), how much insulation upgrade is needed, and whether flooring or drywall finishing is included. A garage that already has electrical service in place is usually cheaper to heat than one needing a new circuit run.

Top 3 by our score

Ranked from our published scoring of public Google reviews for custom finishes & heated garages.

1. Oakville Home Renovation Contractors by Gracia Makeovers
5.0★ · 185 reviews

94
2. Summit - Sheds and Structures
5.0★ · 184 reviews

90
3. Magnolia Design & Build
4.8★ · 125 reviews

89

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FAQ

What is the best way to heat a detached garage in Ontario?: Electric unit heaters and natural gas garage heaters are both common; the right choice depends on whether gas service is available and how much you use the space in winter.
Do I need a permit to insulate and heat my existing garage?: Minor insulation and a plug-in heater usually do not need a permit, but adding gas lines or a new electrical circuit typically does and should be done by a licensed trade.
Can I insulate a garage myself and just hire someone for the heater?: Some homeowners do split the work this way, though a contractor doing both together can make sure the insulation and heat source are sized correctly for each other.

When you submit a quote or contact form here, your enquiry may go to partner providers who can do the work, and we may earn a referral fee. Our rankings and scores come from our published scoring method only, never influenced by referral fees.