Electric Garage heaters

Noisy as hell. Does the job. Just use my compressor plug 220.

May not be what you need just throwing it out there.

Tom... is your office in the house, a garage, basement, in the corner of a pole barn shop?

Hanging a resistive electric heater from ceiling is a cheap and dirty... almost as cheap and dirty as pluggin in an electric cube at the wall.  They don't heat the floor well... a radiant electric will heat the floor better... but they'll both heat your wallet really well, as electric heating is the most expensive method there is.  One kw = 3400ish BTU.  To get 3400bth/hr, you have to run 1kw/hr of power.  I don't recall what our most recent Alliant bill was, but I'm gonna stab at $0.20/kwh...  a little electric brick heater running constantly will quietly grind through $5/day, which doesn't seem like much until the additional $144 shows up on the bill in your mailbox monthly.  A 7500w unit, in the same service, would run $1,080...  and it'd be putting out 25,500btu/hr. 

I don't know the size of your shop, but 25,500btu is much higher than it should require for comfort in an office.  If my wild-guess of your office space is even close, what will probably happen, is the heater will kick on, make the area in front of it ghastly hot for a very short time, then shut off, and chill you.

The problem with most any heating system, in our vicinity, is a cold floor.  A room can be 60F, and totally comfortable, but even if the room is 75F, and the floor is cold... you'll be uncomfortable. 

IF you choose the electric option, and have a concrete floor, one thing you CAN do that will help tremendously, is to lay down a 1" layer of pink foam, and then put down tongue-and-groove plywood, with carpet on top.  That'll raise your floor by 2", but isolate and insulate your feet, furniture, etc., from that slab, and make the room substantially more comfortable.  After that, bringing up the air temp with the electric can be done with a whole lot LESS power, gently, and consequently, less money.

The OTHER really great way to do it, is put down a layer of 1" foam, and a layer of inset tiles for PEX tubing, then put your T&G floor with carpet on top of that.  Connect the PEX to a tiny water heater and run a Taco 3gpm pump to circulate pink RV anti-freeze through the pex.  Floor always warm, heater will run for about 4 minutes total on a day, the electric pump will run for less than 2 hours, and it'll be cozy.

The title kinda throws me.  Why would you need to heat a garage if it is only for parking vehicles?  Just pit a remote start on the vehicle if you have to set your boody on a warm seat. 

We did not even have heat in the garage in AK.  Did have a block heater for the sub zero stuff.