electric heater power/wattage recommendations for my garage?

Hi, can anybody guide me here?

Garage is 19 x 19 ft with 8 ft ceilings, partially insulated. I've been forced to get into an electric space heater after weighing many options.

Narrowed it down to three options,

a 5000w/17000btu unit,

another at 7500w/25000 btu and finally 10000w/34 000btu

Cold winters here.

Trying to save on electric with the smallest of the three, plan on running it only during play time a couple hours daily plus the requisite time the unit takes to heat up the space.

thanks in advance
 

buckshotshoey

AzB Silver Member
Silver Member
Sometimes an electric heater that is too small will cost you more to run. You work it harder. If you go to Lowe's, SOMETIMES you can get somebody that knows what they're talking about. Or talk to a HVAC guy in your area.

You didnt mention voltage, but you are going to need 220. It will run fewer amps and would be more efficient per btu produced.
 
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DaveK

Still crazy after all these years
Silver Member
Hi, can anybody guide me here?

Garage is 19 x 19 ft with 8 ft ceilings, partially insulated. I've been forced to get into an electric space heater after weighing many options.

Narrowed it down to three options,

a 5000w/17000btu unit,

another at 7500w/25000 btu and finally 10000w/34 000btu

Cold winters here.

Trying to save on electric with the smallest of the three, plan on running it only during play time a couple hours daily plus the requisite time the unit takes to heat up the space.

thanks in advance
Victoria BC or Winnipeg MB ? As you know winters vary (I am in Saskatoon).

The wattage of the heater won't matter much to your bill. You pay for kilowatt-hours not kilowatts. The bigger units will heat it up quicker and run less often once "warm", but overall your electrical consumption should be the same with any of the sizes. Of course another consideration is the plug you need. A standard 15A 110V plug will only run a 1500w unit. The heaters you mention will need 220v outlets, 30A for the 5000w unit, 40a for the 7500w, and 50a for the 10000w ... but check with you local electrician to be sure (you know the quality of Internet advice :oops:).

Hope it works out well for you.

Dave
 

rexus31

AzB Silver Member
Silver Member
Yeah I would definitely talk to your HVAC guys. A mini-split heat pump AC unit might be much better. I have that in my garage and it’s super efficient and pretty much keeps the garage a comfortable temp and humidity all year round.
Agreed. Mini-split is the way to go. Much more affordable to run. My buddy and I installed a DIY MrCool 12,000 BTU unit in my garage in a couple hours. Works great and no need to hire an AC tech to install it. 100% DIY. It has a 22 SEER rating so it is very affordable to run.
 

DaveK

Still crazy after all these years
Silver Member
Yeah I would definitely talk to your HVAC guys. A mini-split heat pump AC unit might be much better. I have that in my garage and it’s super efficient and pretty much keeps the garage a comfortable temp and humidity all year round.
That would be a good option for Victoria BC or Toronto ... they are mostly useless in the cold cold prairies. What part of the world are you in Lawnboy (we discussed this a while back but I forget).

Dave
 

Lawnboy77

AzB Silver Member
Silver Member
That would be a good option for Victoria BC or Toronto ... they are mostly useless in the cold cold prairies. What part of the world are you in Lawnboy (we discussed this a while back but I forget).

Dave
West Texas, but we get extreme cold as well, just not as frequent as you guys. When our temps were below zero for 4 straight days, and when we had electricity our mini split heat pump was still kicking out good heat, much better than our two low efficiency conventional heat pumps.

If it doesn’t work like you want during the extreme cold you can always go to backup heat.
 

budonahog

AzB Silver Member
Silver Member
Depending on brand of mini splits, some will run to 14 below zero. That is the way to go. There might also be rebates available from your electric company.
 

One Pocket John

AzB Silver Member
Silver Member
Hi, can anybody guide me here?

Garage is 19 x 19 ft with 8 ft ceilings, partially insulated. I've been forced to get into an electric space heater after weighing many options.

Narrowed it down to three options,

a 5000w/17000btu unit,

another at 7500w/25000 btu and finally 10000w/34 000btu

Cold winters here.

Trying to save on electric with the smallest of the three, plan on running it only during play time a couple hours daily plus the requisite time the unit takes to heat up the space.

thanks in advance
As a rule of thumb, you can figure 1KW of heat for every square foot. 19x19=361sf.
Based on your square footage you would need a unit that delivers enough heat to heat 361sf.

A small window unit that delivers both cooling and heating would be ideal. Or you may want to look at a Mini-Slip system.

For your information 1KW of electric heat = 3412 BTU's.

One other choice to look at is electric baseboard heating units. These can be purchased
at any home improvement store.

John
 
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buckshotshoey

AzB Silver Member
Silver Member
Hi, can anybody guide me here?

Garage is 19 x 19 ft with 8 ft ceilings, partially insulated. I've been forced to get into an electric space heater after weighing many options.

Narrowed it down to three options,

a 5000w/17000btu unit,

another at 7500w/25000 btu and finally 10000w/34 000btu

Cold winters here.

Trying to save on electric with the smallest of the three, plan on running it only during play time a couple hours daily plus the requisite time the unit takes to heat up the space.

thanks in advance
Out of curiosity, why are you forced to use electric? Wouldn't gas be a viable, cheaper option? In my area, heating with electric is 4 times the cost of gas. (Toledo Edison)
 

Keith E.

AzB Silver Member
Silver Member
One method of calculating shows a requirement of 1kw of heat per every 494 cubic feet.

Your space of 19'x19' with 8' ceilings comes in at 2,888 cubic feet.

Dividing your space of 2,888 cubic feet by 494 shows a need for 5.8461538462kw of heat. That could vary due to several factors including but not limited to building envelope leakage, insulation, weather, sunlight, etc.

Another method is 10 watts per square foot for 3.61kw of heating capacity if using baseboard heat.

Wishing you the best of luck with your venture.

Keith
 

Lawnboy77

AzB Silver Member
Silver Member
Depending on brand of mini splits, some will run to 14 below zero. That is the way to go. There might also be rebates available from your electric company.
Yes sir! I wish that they had been more prevalent here in Texas this past February when our power grid went down. When 10 million households have to go emergency strip heat at temps below 10 degrees because of inefficient heat pumps it tends to take down the power grid. It probably doesn't help that our population is growing at a crazy rate either.
 

cueman

AzB Gold Member
Gold Member
Silver Member
If you just want heat and not air look at the ceiling mounted electric units from Greater Northern.
 

Nick B

This is gonna hurt
Silver Member
I did the math 5000W is MORE than enough (even in the Artic Circle). Don't do bigger.
 

fastone371

Certifiable
Silver Member
I have propane forced air in my garage (shop) at home. It was much more difficult to warm it it up if I turned the heat off for a day or 3. Even though the air temp rose quickly it cooled down very fast because of the mass out there that was still cold. We actually used less propane turning it down to 45 degrees when Im not out there then turning it up when I go out to work. Besides, I have a lot of steel equipment and supplies that I did not want to have rust, it sweats when it freezes and then warms up.

I would also think that it would take a long time to heat up the slate. Even though our table is in the house its probably close to 5 degrees cooler in the basement, I have a small electric heater that I often put under the table for an hour or so before I play to warm up the table a little.
 

realkingcobra

Well-known member
Silver Member
I have propane forced air in my garage (shop) at home. It was much more difficult to warm it it up if I turned the heat off for a day or 3. Even though the air temp rose quickly it cooled down very fast because of the mass out there that was still cold. We actually used less propane turning it down to 45 degrees when Im not out there then turning it up when I go out to work. Besides, I have a lot of steel equipment and supplies that I did not want to have rust, it sweats when it freezes and then warms up.

I would also think that it would take a long time to heat up the slate. Even though our table is in the house its probably close to 5 degrees cooler in the basement, I have a small electric heater that I often put under the table for an hour or so before I play to warm up the table a little.
Throw an electric blanket over the table, turn it up all the way, slate will be nice and warm, and uses less electricity too.
 

buckshotshoey

AzB Silver Member
Silver Member
I have propane forced air in my garage (shop) at home. It was much more difficult to warm it it up if I turned the heat off for a day or 3. Even though the air temp rose quickly it cooled down very fast because of the mass out there that was still cold. We actually used less propane turning it down to 45 degrees when Im not out there then turning it up when I go out to work. Besides, I have a lot of steel equipment and supplies that I did not want to have rust, it sweats when it freezes and then warms up.

I would also think that it would take a long time to heat up the slate. Even though our table is in the house its probably close to 5 degrees cooler in the basement, I have a small electric heater that I often put under the table for an hour or so before I play to warm up the table a little.
For new construction, wouldn't it be best to install radiant floor heating tubes in the floor? That would definitely keep the slate warm, and from what I understand, reasonable to operate. Downside.... high initial cost.
 

Rocket354

AzB Silver Member
Silver Member
I have a two-car garage, sounds like slightly bigger than yours. I have a 1000W heater. It works, but is a bit slow. Since it's only my gym in my garage, and I'm therefore heating myself up while I'm out there, it's fine. I imagine 5000W will be plenty sufficient.

One thing I wanted to bring up is that you mentioned your space is "partially insulated." The best temperature-control improvement you can make to the space is to make it fully insulated, especially since cost appears to be a big consideration.
 
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