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Garage heating systems
We recommend a ceiling-mounted, gas-fired,
forced-air unit heater. Some
installers recommend infrared heaters
because they heat objects instead of air.
You’ll be warmed and so will the floor
(if it’s free of vehicles). But you won’t
be happy with the cold tools inside
your tool chest. Infrared heaters are no
more energy efficient than forced-air
heaters, and they cost about twice as
The least expensive alternative is a
portable kerosene or propane heater.
But they’re a poor choice. They require
ventilation (think “open door”) and
pump gallons of water vapor into your
garage. That means working with a
constant cold draft and putting up with
smelly exhaust and burning eyes. Then
there’s the issue of rust on your tools
from all that humidity. Kerosene and
propane heaters just aren’t a good solution
if you work in the garage regularly.
So bite the bullet and buy a ceiling-mounted,
forced-air unit heater that’s
rated for residential use (building
inspectors won’t OK an industrial unit
in a residential garage). Plan to spend
$500 to $650, plus the cost of professional
installation. Advanced DIYers
can install a unit heater, which
involves gas lines, venting and electrical
work. But don’t skip the permits
and inspections. An improper installation
can kill you. Check with the
inspector to see if it’s even legal in your
area to perform your own gas hookups.
If you’ll be working on wood projects
or using spray finishes, choose a heater
with a separate combustion chamber.
They burn fresh outside air instead of the
dust or paint-laden air inside a garage. There’s a slight fire danger using a
conventional heater, and the dust and
paint particles will cause burner problems
that require service calls.
Some unit heaters are more compact
than others and can be mounted
within 1 in. of the ceiling. So review
the dimensions of the heater and calculate
the installed height to ensure
To help size the heater and estimate
monthly energy costs, consult
manufacturers and dealers. Most residential
garages require heaters with a capacity
of 30,000 or 45,000 Btu. Your
heater size depends on the garage’s
square footage, ceiling height and
insulation, so don’t guess. And don’t
oversize your heater—especially if
you intend to leave it on (even at a
reduced temperature) all winter. An
oversize unit heater cycles too often
and wastes energy.
If you have an attached garage,
mount the thermostat on the common
wall between the garage and the
house and away from the heated airflow.
In a detached garage, mount it
on the wall below the heater.