Will it heat a two-car garage?

Not evenly. It is a forced-air spot heater, so it warms the area in front of it. A large garage stays cold at the far end unless it is well insulated and closed off.

Does it need a special outlet?

No. It draws 12.5 amps at 1500 watts, so it runs on a standard 15-amp household circuit. Avoid sharing that circuit with power tools or other heavy loads.

How is it different from a milkhouse heater?

It is the same basic idea: a metal box with a fan and a thermostat. The H-3013 adds a tip-over switch and a full-size cabinet, and it is aimed at garages and job sites rather than bathrooms.

Does the thermostat cycle the heater on and off?

Yes. Set the dial and the heater switches itself to hold roughly that temperature, rather than running flat out until you unplug it.

Can it be used outdoors?

No. It is rated for indoor use only, in garages, basements, workshops and similar enclosed spaces.

What safety features does it have?

Overheat protection, a tip-over switch and automatic shut-off. It still gets hot on the outside, so keep it clear of clutter and away from children and pets.