Garage Heater Installation in Woodstock, IL and Chicagoland — Modine Hot Dawg, Reznor & More

GSHA Services installs natural-gas and propane garage heaters from $2,400, with most 2- and 3-car garages in McHenry, Lake, Kane, Cook and DuPage counties landing between $2,800 and $4,500 installed — heater, gas line, venting, thermostat, electrical, permit and start-up. We hang Modine Hot Dawg® and Reznor unit heaters most often, plus Mr. Heater Big Maxx, Sterling and electric heaters for garages without gas, and we size every heater for a -20°F northern-Illinois night so your workshop, gym or car barn is warm when you walk in.

At a glance
Installed priceFrom $2,400 · typical 2-car garage $2,800 – $3,800 · 3-car / long gas run / separated combustion $3,500 – $4,500+
Heaters we installModine Hot Dawg HD/HDB (30–125k BTU), Modine HDS/HDC separated combustion, Reznor UDX/UDAP, Mr. Heater Big Maxx, Sterling, electric (King, Fahrenheat, Modine HER)
FuelNatural gas (Nicor / North Shore / Peoples), propane (LP conversion), or 240V electric
Sizing1-car 30–45k BTU · 2-car 45–60k · 3-car 60–80k · uninsulated: add 25–50%
TimelineFree estimate → most installs done in half a day → permit & inspection by GSHA
IncludedCeiling mount, gas piping from your meter or existing line, power venting through wall or roof, 120V outlet or hard-wire, thermostat, CO/gas safety check
AlsoElectrical panel upgrades, EV chargers and garage lighting by our licensed electricians on the same visit
Want a warm garage this winter?
Free estimate for gas or electric garage heaters. Serving Woodstock, Crystal Lake, McHenry, Huntley, Lake Bluff, Barrington and beyond.

Which garage heater is right for you?

TypeExamplesInstalledBest for
Power-vented gas unit heaterModine Hot Dawg HD45 / HD60 / HD75, Reznor UDX, Mr. Heater Big Maxx$2,400 – $3,800The standard for attached and detached garages: fast warm-up, compact, quiet, vents through 3–4 inch pipe
Separated-combustion gas heaterModine HDS45 / HDS75, HDC, Reznor UDAS$3,200 – $4,800Woodshops, paint booths, dusty or humid garages — draws combustion air from outside so sawdust and fumes never reach the burner
Infrared tube heaterModine Effinity / PTS, Reznor, Re-Verber-Ray$3,500 – $6,000Tall or drafty garages and shops: heats the floor, cars and people directly instead of the air; comfortable with the door open
Electric garage heater (240V)King, Fahrenheat, Dr. Infrared, Modine HER$900 – $2,200No gas at the garage, occasional use; higher running cost, no venting needed
Ductless mini-split heat pumpCarrier / Bosch cold-climate mini-split$4,500 – $7,500Insulated garage gyms and offices you also want to cool in summer

How big a garage heater do you need in northern Illinois?

Our design temperature is about -20°F, colder than most sizing charts assume. For a garage kept at 50–60°F and warmed to 65°F when you are working, we use these starting points, then adjust for ceiling height, insulation and how much of the year you want to use the space:

GarageSizeInsulatedUninsulatedTypical heater
1-car240–300 sq ft30,000 BTU/h45,000 BTU/hHot Dawg HD30 / HD45
2-car400–500 sq ft45,000 BTU/h60,000 BTU/hHot Dawg HD45 / HD60
3-car600–800 sq ft60,000 BTU/h75,000–100,000 BTU/hHot Dawg HD60 / HD75 / HD100
Shop / barn1,000+ sq ft or 12 ft+ ceilings75,000–125,000 BTU/hTwo heaters or infraredHD100 / HD125, infrared tube

Modine Hot Dawg® heaters are 80% efficient, come in 30/45/60/75/100/125k BTU sizes, ship for natural gas with an LP kit available, and include a Braeburn thermostat and mounting brackets on sizes up to 75k. A properly sized heater brings a 2-car garage from 20°F to 60°F in roughly 30–45 minutes.

What a GSHA garage heater installation includes

  • Site visit and sizing — square footage, ceiling height, insulation, door type, how the space is used, where the gas meter and panel are.
  • Gas piping — black iron or CSST from the meter or an existing line, sized for the heater plus your other appliances, with a shut-off and drip leg at the heater; propane regulator and conversion where needed.
  • Mounting — heater hung from the ceiling joists or trusses with the manufacturer’s brackets at the required clearances from walls, doors and stored items.
  • Venting — power-vent exhaust through the side wall or roof with the correct pipe, termination and clearances from windows, doors and property lines; separated-combustion intake where specified.
  • Electrical — a dedicated 120V circuit or outlet by our licensed electricians, thermostat wiring, and optional Wi-Fi thermostat so you can pre-heat the garage from your phone.
  • Permit and inspection — mechanical permit and gas piping inspection in your village or county, pulled and attended by GSHA.
  • Start-up — gas pressure, combustion check, CO test and a walkthrough of thermostat settings and filter/maintenance.

What affects the price

  • Gas line length and routing — the biggest variable. A heater near the meter with an existing line is the low end; a detached garage 40–80 feet from the house needs trenched underground gas piping and can add $1,000–$2,500.
  • Heater size and type — separated-combustion and infrared cost more than a standard power-vented Hot Dawg.
  • Venting path — a straight side-wall vent is simplest; roof penetrations and long runs cost more.
  • Electrical — if the garage has no power or the panel is full, we add a circuit or sub-panel.
  • Extras — Wi-Fi thermostat, ceiling fan for tall spaces, insulation upgrades.

Every quote is written and includes the permit. Financing through Synchrony and Service Finance Company is available on garage heater installations. Financing details.

Safety, codes and permits for gas garage heaters

  • Gas unit heaters must be installed by a licensed contractor with a mechanical permit and gas piping inspection in every municipality we serve; the heater must be listed for residential garage use (Modine Hot Dawg and Reznor unit heaters are).
  • Heaters in garages are mounted with the burner at least 18 inches above the floor (typically 7–8 feet at the ceiling), clear of vehicle paths and the door travel, and outside the garage door’s swing.
  • Never use an unvented propane or kerosene heater, a “torpedo” heater, or a home furnace not rated for the garage as permanent garage heat — carbon monoxide, moisture and fume ignition are real risks. We install a CO alarm in the garage on request.
  • Detached garages get a shut-off at the building and, when the line runs underground, tracer wire and a riser.

More than a heater

GSHA is an HVAC and electrical contractor. While we are installing your garage heater we can add a 240V outlet for a welder or compressor, an EV charger, LED shop lighting, a sub-panel or a standby generator — one crew, one permit set.

Garage heater service and repair

We repair and maintain garage heaters too: ignitors, flame sensors, fan motors, gas valves, thermostats and venting on Modine, Reznor, Mr. Heater, Sterling, Dayton and others. A garage heater can be added to your GSHA PROTECT plan for an annual check with your furnace tune-up.

Frequently asked questions

How much does it cost to install a garage heater in the Chicago suburbs?
GSHA installs gas garage heaters from $2,400. A typical 2-car garage with a Modine Hot Dawg HD45 or HD60, gas line from an existing line, side-wall venting, thermostat and permit runs $2,800–$3,800. Three-car garages, separated-combustion heaters and detached garages that need underground gas piping run $3,500–$4,500 or more. Electric heaters are $900–$2,200 installed.
What size garage heater do I need for a 2-car garage?
In northern Illinois, an insulated 2-car garage (400–500 sq ft, 8–10 ft ceiling) needs about 45,000 BTU/h; an uninsulated garage needs 60,000 BTU/h. Add capacity for 12-foot ceilings, large windows, or if you want the space at 65°F all winter. We confirm the size on the free estimate.
Is a Modine Hot Dawg a good garage heater?
Yes — it is the most popular residential garage heater in the Midwest for a reason: compact, quiet, 80% efficient, power-vented through small-diameter pipe, listed for residential use and available from 30,000 to 125,000 BTU/h. The HDS separated-combustion version is the right choice for woodshops and dusty spaces. Reznor UDX and Mr. Heater Big Maxx are solid alternatives.
Do I need a permit for a garage heater in Illinois?
Yes. Every village and county in our service area requires a mechanical permit and a gas piping inspection for a gas unit heater. GSHA pulls the permit and meets the inspector. Electric heaters on a new circuit require an electrical permit.
Can you install a heater in a detached garage?
Yes. We run underground gas piping from the house or meter to the detached garage, install a shut-off at the building, and vent the heater through the wall or roof. Underground runs add cost depending on distance; propane is an option where natural gas is not available.
How much does a garage heater cost to run?
A 45,000 BTU/h gas heater uses about 0.45 therms per hour on high fire. At Nicor’s 2026 residential rates, keeping an insulated 2-car garage at 50°F and heating to 65°F for weekend use typically costs $20–$45 a month; a comparable electric heater costs two to three times more to run.
Gas or electric garage heater?
Gas if you have natural gas at the house and will use the garage regularly — faster heat, far lower running cost. Electric if there is no gas nearby, you only need occasional heat, or the garage is very small. A cold-climate mini-split is the choice if you also want air conditioning in a garage gym or office.
Can a garage heater be installed with a Wi-Fi thermostat?
Yes. We install Wi-Fi thermostats compatible with unit heaters so you can raise the garage temperature from your phone before you head out to work in it, then drop it back to 45–50°F freeze protection.
Get a garage heater quote
Call (224) 220-3660 or book online. Gas, propane and electric options. Serving Illinois & Wisconsin.

Last updated September 16, 2026 by the GSHA Services team. Prices are “installed from” for a standard installation including current discounts; your written quote reflects your garage, gas line and venting.