Question on electric garage heater

Rot 911 · 11-25-2013, 07:10 AM

Well now that I have my garage extended and as well insulated as I can get it, I want to install an electric garage heater. I don't have a gas line to the garage and I have tried the kerosene heaters and don't like the smell. So 240 volt electric it is. Not a huge space, around 500 square feet with 9 foot ceiling. Anyone have something they use and like? I won't heat it all of the time, just when I am working out in the garage.

stomachmonkey · 11-25-2013, 07:20 AM

If you feel like spending a couple of hours on a side project you can build an aluminum can solar heater to augment.

Could be a fun father / daughter project.

matt f · 11-25-2013, 07:30 AM

Check out the ceiling fans with heater incorporated.
My garage is approx. 2x the size of yours, I have 2 mounted.
With outdoor temps even near 0, the units will get garage to 60 in 45 mins.
Available at Lowes.

Matt

Seahawk · 11-25-2013, 07:32 AM

We did this two places on the farm, the difference is we bought dual units, air conditioner and heater.

The shop unit is 240 and heats and cools about 650sf...the ceiling is about 13 feet.

It works great. I augment with fans in the summer. The unit is pictured below. I used to use propane heaters but didn't like the smell.

At the stable, we have a window unit that we framed in. It cools and heats about 300sf perfectly and runs on normal power.

I admittedly hate the humidity in Maryland so the cooling aspect is as important as the heat. Both units work very well and are only turned on when needed. I couldn't be happier.

gacook · gacook's Garage

A buddy of mine recently bought one of those electric "fire places" (basically it's a heater that looks pretty). He's got a 2.5 stall garage and it takes the nip out of it pretty damn well.

GH85Carrera · GH85Carrera's Garage

I bought a 220 heater that I hun on the wall. It works great. It will warm up the work area in short order. I love the thing. I rebuilt my 911 suspension working in jeans and a t-shirt and total comfort during a full fledged blizzard. It cycles on when it needs to but I just turn it off when I am not out there. It did not cost that much but I will have to look up the brand. I have had it for several years.

Rot 911 · 11-25-2013, 07:52 AM

Quote:

Originally Posted by Seahawk

We did this two places on the farm, the difference is we bought dual units, air conditioner and heater.

The shop unit is 240 and heats and cools about 650sf...the ceiling is about 13 feet.

Paul I saw that picture in the BMW motorcycle thread. How does the heat work when it gets below freezing? I thought they worked like heat pumps so the colder it gets the less ability to heat.

Seahawk · 11-25-2013, 07:58 AM

Quote:

Originally Posted by Rot 911

Paul I saw that picture in the BMW motorcycle thread. How does the heat work when it gets below freezing? I thought they worked like heat pumps so the colder it gets the less ability to heat.

It works well, even with the high ceilings. Sunday it was 29 degrees and I set the heater to 60 degrees.

I insulated to only around R30 but the barn is well sealed

No issues at all, very comfortable. It is the a/c that I love!!!

jpk · 11-25-2013, 08:22 AM

With electric resistance heaters, they are all the same as far as efficiency; you get out the amount of heat that's pretty much 100% equivalent to the amount of electrical energy input. You get about 1000 btu's/hour per 300 watts of electric heat (293 watts actually, but 300 is a nicer number to work with).

With 120v heaters, you're limited to about 1500watts per unit since that's just under 15 amps - the limit of most circuits in the house. That means you can get 1500/300 or 5,000 btu's/hour out of one 120v heater.

With 220-240 volts, you typically install a dedicated circuit which can go much higher and you can size the heater to the need and the circuit to the heater.

The next question is how much heat do you need? guidelines say about 1000 btu's per 30-35 square feet. Based on that, you need 15,000 to 18,000 btu's for you garage. But, that's based on normal living space in a Northern climate. You might not need quite so much if you don't need to get the garage up to 72 degrees or if it's 35 degrees outside vs -20.

You might get by just fine with a single 1500 watt 120v heater. Since there's no efficiency difference between the different types (oil filled, ceramic, Amish craftsman built fireplace etc...) I'd suggest trying a $25 milkhouse heater. If that works, then you're golden. If it's not quite enough, you could get a second, just realize you'll have to plug it into a different circuit or you'll just blow the breaker. Even if you had to run a separate circuit back to the panel it might be more cost effective to use 2 (or 3) 120v heaters than buying and installing a dedicated 240v unit.

GH85Carrera · GH85Carrera's Garage

I went through the design phase of how much heat would be needed. I quickly discovered that if I am working much at all I generate a lot of heat internally. Comfortable temperature while working on a car is a LOT different than sitting inside watching TV. I started off with a cheap 110 volt free standing space heater. It did OK but it did not have a fan to push the heat away from the unit. My forced air electric unit is just right. It only runs a few minutes and the area is warm.

Rot 911 · 11-25-2013, 10:23 AM

Glen and Paul, could you guys look up the brand and model of what you are using? Thanks!

GH85Carrera · GH85Carrera's Garage

I will do that when I get home today.

Seahawk · 11-25-2013, 11:17 AM

I'll do the same.

Rusty Heap · Rusty Heap's Garage

Insulation is just as important as a heat source, and time of heating.............24/7, or just a couple hours while you're out there.

Personally, I love my wood stove, but I gots lots of wood to burn for free........also a big Propane IR units can be portable for spot heating, but I've also got a 3000 sq ft shop and don't really heat half of it due to scale.

I agree with above posters, watts in = watts out, regardless of 120/240 (mo' is betta)

As an electrical engineer, I'd REALLY love to see some info backing up of BTUS / Watts. of thermal energy/electrical energy.

Another cheap heating idea, is find someone parting out or scraping an old mobile home. As I used to have a triple-wide mobile, Coleman makes kickasss big 240VAC electric furnaces for manufactured homes...

40,000 btu and a big squirrel cage fan in a shop corner sure wouldn't suck too bad......new they're $500, but used off of Craigslist, I dunno $100?

Coleman Mobile Modular Home Electric Furnace EB12 EB12C | eBay

Seahawk · 11-25-2013, 12:08 PM

Quote:

Originally Posted by Seahawk

I'll do the same.

Here is a photo of the manual for the barn shop heater:

It has a remote and you can dial in the temp:

It has been about four years without issues.

This Kenmore unit is in the stable. It is nearly nine years old and still works great. The only issue is that there are two only setting for both heat and cool. Hard to dial in. I think I paid around $400.

It does have oscillating vents side to side. I have no idea what model it is.

If I didn't need 220, (I ran 220 into the barn shop for other reasons) the Kenmore would have been fine. I'd have bought two for the shop and been done. Sorry for the dust and grime, but we really use both spaces!

Chocaholic · 11-25-2013, 12:15 PM

I use an Amana heat and AC unit like the ones you see in hotel rooms. My garage is 30 x 44 with a 10' ceiling and it heats and cools it with ease. I use it all the time since my office is in one corner. Have used it almost constantly since 2005 without a hiccup.

jpk · 11-25-2013, 12:19 PM

Quote:

Originally Posted by Rusty Heap

As an electrical engineer, I'd REALLY love to see some info backing up of BTUS / Watts. of thermal energy/electrical energy.[/url]

I got the 293 number from wikipedia, but watts as heat power are everywhere in thermodynamics (boiler rating, steam engine etc...)
The key is that the units are BTU/hour -> watt

rfuerst911sc · 11-25-2013, 01:41 PM

I have been kicking around the idea of what to do for heat/AC in my detached garage. I currently have a PTAC unit in our sunroom, it is an Amana and as I'm typing this it's set at 69 degrees and pouring the heat out. It's about 40 degrees out but the wind is whipping. The PTAC units can be a heat pump only or a heat pump with a heat strip. Mine has the heat strip and has no problems when the temp's get in the 20's. The only thing I don't like about them is the size of the hole you have to cut to install the installation sleeve. So one of the ideas I'm kicking around is a window AC or two and somewhat permanent installation and just a separate electric heater. Unlike a northern state I don't need heat that much but I do need AC. I'm still in the planning stage so these posts are very helpful to see what others are doing.