Electric Garage Heater Options?

Hi,

I have a detached garage powered by a 12/3 w/G feeder that is wired to two 20 amp breakers (adjacent) in the main panel of the house. The feeder goes to an old style fuse box in the garage. The garage outlets and lights are 120v on 15 amp fuses. Given this setup, what are my options for electric heater? I figure I can't go over 3000watts? Any suggestions on products and recommended wiring? All the 240v heaters I see are higher wattage like 5000W or so.

 

Welcome to the forums.

You could safely connect up to 3850 watts on that 20A 240v line.

How much heat are you looking for ?
What will you be doing ?

An electric heater of any decent size will pretty much use up the entire circuit leaving nothing for lights when the heat is running. A basic 1500w could be used on the second 120v circuit.

 

Well I just need the heater to run for a short period of time while using nothing else except a few LED shop lights that only draw 50Watts. Once the garage heats up I will shut it off. I currently do this with a oil heater, but was hoping to upgrade to something effective.

 

Okiedokey:
Approximately how far is the detached garage from the panel in the house (in feet). Just need to know if voltage drop needs to be taken into consideration.

 

Depending on the oil heater's efficiency, I am guessing that it will b noticeably to considerably cheaper to run compared with ordinary (resistance) electric heat.

The 120 volt circuit tied into the fuse box receiving the 12/3 feed cannot be used for much once the new 3800 or so watt electric heater is switched on.

I would suggest a new 6 gauge 50 amp 120/240 volt underground feed out to the garage. The old feed would have to be discontinued because today's code allows just one feed going to any one outbuilding. (Available amperage would be less if the run to the house main panel is more than about 150 feet.)

 

What is the current BTU rating of the system?

If I remember correctly electric recommendation is 10 watts per square foot with an 8 foot ceiling.
My experience has been that this is OK for maintaining a temperature but should be double for a decent warm up time.

It is the warm up time that may be a defining spec here.

As far as finding an electric heater if you cannot find a garage space heater at the watts you need take a look at in wall forced air heaters. They come in many wattages.

 

Take a look at the propane heaters, you can get a 40K BTU for around $100 and remember, 3K watt heater is the equivalent to two hair dryers, not going to heat up much with that!

 

Garage is 50ft from main panel, conservatively 75ft of cable run given the route it takes. I am not going to invest the time or money at this point to run any new wiring. Just not worth it to me at the moment.

I did think about the propane option, but honestly wasn't sure of the cost efficiency / comparison to electric and also dony want to work in the fumes. I will look more into that option.

 

Propane ones are super efficient and no fumes unlike the kerosene heaters!