Electric heater questions

[BrokeEF]

Hey guys, I have a 20' X 20' garage with ~8' ceilings, and I live just west of Chicago. As you can imagine it can get pretty cold out here, and I am sick of using a kerosene torpedo heater for many reasons. I am wanting to add a ceiling mounted heater for next winter, and am starting to look at options.

This spring I am going to tear down all of the drywall, insulate everything, and put up new drywall (existing is all beat to ****). The door is a newer insulated aluminum door. One full wall is an interior wall, and maybe half of another is as well. Above the garage is open attic.

I was looking at electric just because it seems very easy to install, and less money than a gas heater. The garage is pretty small, and I won't be heating it unless I am doing some work out there. My question is will a 5,000 watt take forever to warm it up? They are about 17,000 BTU, which I am sure is enough to maintain temp once I have it all insulated, but I am worried about that warm up time.

Anything else you guys have to say about options for me, I am all ears.


Thanks,
Sean

 

[Davefr]

What garage temp are you looking to get up to?

Do you want that temp to be uniform throughout the entire garage or are you OK with being comfortable in one portion of the garage? (ex workbench/shop area?)

You really need to do a load calc. for BTU loss but my gut feel says you'll be OK if you're happy close to 60 degrees in a portion of the garage close to the heater. (assuming it's well insulated.)

 

[BrokeEF]

What garage temp are you looking to get up to?

Do you want that temp to be uniform throughout the entire garage or are you OK with being comfortable in one portion of the garage? (ex workbench/shop area?)

You really need to do a load calc. for BTU loss but my gut feel says you'll be OK if you're happy close to 60 degrees in a portion of the garage close to the heater. (assuming it's well insulated.)

I would like it somewhat uniform, but not sure I have ever worked in a space that was evenly heated I am usually hot, so in the winter I am good around 60 max I would say. Probably even cooler than that, but it depends what I am doing.

I am not planning on going nuts with the insulation, but I will stuff all the walls and ceiling with R11 or R13, and probably put up 5/8" drywall on top of that. All of the electrical will be surface mounted, so I shouldn't have too many air leaks to worry about (other than the big door). I will foam around the few places that punch though the outside as well, like the carriage lights, gas line, etc. The attic above the garage is set up for storage, so that wont be as insulated as a normal attic above a house. Right now it has nothing but drywall though, so should help quite a bit.

Here is a quick shot of the attic to give you an idea. This was before the new lighting.

So what do I need to do a load calc?


Sean

 

[mm08822]

Electric is usually the cheapest to install but has very high operating costs.
I would compare the purchase prices, installation costs, and energy costs to see how long it takes for you to break even between NG and electric.

Doing a BTU loss calculation with your new insulated values is needed to size the unit properly. With the drywall down, you can properly insulate all walls and draft proof many areas that you otherwise could not with drywall in place. Even consider extra insulation on the garage door panels.

 

[BrokeEF]

We did calculate it a bit, but it depends on the heater of course. If I get an electric heater for ~$200 that is 5000 watts, running that for 40 hours a month (just guessed a number) it would add around $20 to our electric. If that is correct, it will take quite a long time to get to the cost of a natural gas heater. I am seeing about $400 for the heater, plus b-vent, gas line, etc. I would say another $200 to be safe on install materials. So the difference is about $400, and if I am $20 a month to run it that is 20 months. Say I use it 4 months a year, that would be 5 years to cover the initial cost of a gas unit.

This house is not our "forever home" as people like to say. Nothing is set in stone for how long we will be here, but we want more land and the ability to put up a shop at least. In the meantime, it is what we have so I want to make it more serviceable for our needs. That is why I am spending the time and money to put a sub panel in the garage, insulation and drywall, new lighting, new electric, etc. I am all for a gas heater, and have helped some friends install them, but they all have bigger spaces and plan on sticking around. With my garage being pretty small it almost seems like overkill, and if the cost difference works out like I said above it is hard to justify the upfront cost. UNLESS I have to spend $400 or so to get a heater that will work for my space, or the 5000 watt will never shut off trying to get to temp.

Sean

 

[Falcon67]

If you insulate the ceiling at 8' it'll work good. If you leave the ceiling open, not so much IMHO. Mine has no problem warming a 28x24x8' insulated area in about 30 minutes or so to mid 60s with it being in the 20s outside. (starting close to 50F). My old 20x24x8 R13 insulated shop that heater could keep the area at about 68~70, taking about 30~45 minute from dead cold to that temp, then cycled for a total of about 15 min/hr of run time to maintain temp.

 

[BrokeEF]

If you insulate the ceiling at 8' it'll work good. If you leave the ceiling open, not so much IMHO. Mine has no problem warming a 28x24x8' insulated area in about 30 minutes or so to mid 60s with it being in the 20s outside. (starting close to 50F). My old 20x24x8 R13 insulated shop that heater could keep the area at about 68~70, taking about 30~45 minute from dead cold to that temp, then cycled for a total of about 15 min/hr of run time to maintain temp.

Your shop came up when I was trying to do some research actually. Your shop is also stand alone right, so all outside walls? I cant say I have paid too much attention, but I know my garage is quite a bit warmer than outside air temps. I have seen it in the high 30's during the coldest days (single digits or lower), but normally its in the upper 40's. This is all according to the thermometer that is on the garage door opener, so take it with a grain of salt.

I think if it is insulated well I should be OK. If it takes 30 minutes or so to warm up, that is fine. My space is smaller than yours, and I don't want it as warm as you have it. I only keep my house at 65 MAX in the winter, so I don't see bringing the garage to 70

I should still run a load clac so I have a more clear idea of what I need.


Sean

 

[finn]

I lived in Naperville for almost 40 years and had a similar, albeit slightly larger Garage. I insulated the walls and installled 6" of fiberglass in the ceilings.

I started out attempting to heat the space with portable electric space heaters, to no avail.

I switched to a used direct vent natural gas heater of unknown capacity, which heated the garage great, even at ambient temperatures below zero.

Unfortunately, after a couple of years, it developed a crack in the heat exchanger and spewed carbon monoxide in the room. Lesson learned...no more used heating equipment for me.

I replaced it with a new Empire direct vent natural gas heater rated at 18000 btu. It was fine at temperatures down to the twenties, but inadequate below that. Simply took too long to heat up the air and cold soaked cars and tools.

So, in my opinion, the electric heater you are looking at will probably leave you a little short of satisfied.

 

[Falcon67]

>Your shop is also stand alone right, so all outside walls?

Yes, both the old and new ones are all 4 sides to the wind. When we've been in the 20s for a day or two, I have seen high 40s in the building but not anything lower. It's have to be some kind of long hard freeze spell before I'd worry about any container of water in the shop LOL. The box race trailer is metal with no insulation - it's always within a few degrees of ambient.

I think if it is insulated well I should be OK. If it takes 30 minutes or so to warm up, that is fine. My space is smaller than yours, and I don't want it as warm as you have it. I only keep my house at 65 MAX in the winter, so I don't see bringing the garage to 70

If the house gets above 67 in the winter, the wife want's to know WTF. I have a 12x24 work room in the new shop, I'll run it at a balmy 72 when I'm working out there.

 

[Davefr]

I should still run a load clac so I have a more clear idea of what I need.


Sean

Yes, there are some online calculators out there that'll help you size a unit.

My garage is about 800 sq. ft. and I have a 4000 watt electric Cadet Hot One along with a Mr. Heater Big Buddy plumbed to an external 20 lb tank.

The garage is insulated except for 24' of uninsulated overhead doors.

If it's in the high 20's outside, the Cadet heater will bring the garage from the low 40's up to around 60 in about an hour. However 60 will be in the work area closest to the heater. I'm sure there's a temp gradient across the entire garage but I haven't measured it. Now if I supplement the Cadet with the Mr. Heater the temp rise is much quicker. (about 15 minutes)

IMHO propane heat is much nicer then electric. It's radiant + convection and feels much warmer.

The Cadet electric heater only creates a 40 degree temp rise but moves a lot of air. The air movement alone tends to create a chill.

 

[cgall]

Installed 5000W Farenheat unit last month in attached 3-car with 11' ceiling, took about 2 hours to get up to 60°, left it on all month and just got my bill. It used about 580 kWh more than average at a cost of $15. Granted this winter has been very mild, even if it had been $30 I would be happy with all the time I have spent out there.

This is a 240v unit, I paid an electrician $300 to pull the wire and install a 30a breaker in the panel in my basement.

 

[BrokeEF]

Well this seems to be pretty split down the middle! I think I am still leaning toward the electric. The cost upfront is nice, and our electric is pretty cheap around here it seems. I think the garage will be pretty well insulated, and tight (for a garage) when I am done as well. I think if I do it and discover that it just doesn't do what I need I won't be all that upset about taking it out and putting in a gas heater later. I am guessing that I will just learn to deal with it instead


Sean

 

[bottom feeder]

My attached garage is a similar size to yours at about 25' x 27', 10' ceilings. The three outside walls are not insulated but are drywalled. The garage door (8' x 18') is insulated with rigid insulation, and there is blown-in insulation in the ceiling. I run a Fahrenheat 5000 watt heater when I want to work out there in the winter. I move the cars out unless I'm going to be working on one; more room that way and the garage heats up more quickly as well.

Typically I'll turn the heater on about 1/2 hour to an hour before I plan to go out there. I rarely have it go much beyond 60 degrees or so, but it can do it if you let it run. 60-65 degrees in the wintertime feels a lot warmer than it does in the summer and I can work out there without a jacket. Since I only use it when I plan to work out there and not run it constantly the extra cost on my electric bill is pretty trivial. My advice would be to put some insulation in your ceiling/attic floor if at all possible.

 

[TractorJeff]

Put in a 240 volt heater!
Worse comes, comes to worse, use the Torpedo to initially heat it.
Turn it on before you go out there to work, when out there, turn it off and turn on the electric. Also insulate the ceiling as most of the heat rises!
Then when you move on, leave it for the next guy!

 

[Marctrees]

Consider roll up 6 mil poly curtains, to seperate your are you want to heat and the balance of garage.

Just 6 mil poly rolled up on 2x2's, like a Roman Shade.

Raise or lower in 5 minutes.

YaYA, I know all about poly has no R value.

It will work great for what it's supposed to do.


Heater idea - http://www.garagejournal.com/forum/showthread.php?t=347448


Marc

 

[Marctrees]

Put in a 240 volt heater!
Worse comes, comes to worse, use the Torpedo to initially heat it.
Turn it on before you go out there to work, when out there, turn it off and turn on the electric. Also insulate the ceiling as most of the heat rises!
Then when you move on, leave it for the next guy!

I like that idea. Marc

 

[Marctrees]

cgall - Your #11 post - What is your estimate of the temp in garage BEFORE you turned on the heat??

Sorry, "mild" does not help us.

And, what temp range has the garage been last few days?
How cold was everything?

And, it has not been heated long for a day or more?

You understand what I'm asking, it will tell so much more if you can help w that info.

Thank you, Marc

 

[p_mori7]

I have a 16x30, 10' walls. Detached. Walls are insulated R13. Ceiling insulated R28. My 5000w heater keeps it a 60 no problem with the dial set on "2". I also have a separate fan circulating air throughout the garage all the time. If I put the heater at max setting, it heats the garage to 85deg+.

Using a fan to circulate the air is key.

If I let the garage go cold, it will bring the temp from slightly below freezing to 50 in about 1.5 hours.

 

[racerex]

I have a detached 18x24, 9'6" ceiling height, R15 in the walls, R30 in the ceiling, 5/8 drywall, a single insulated garage door and my Dayton G73 (208/240v) 5000w heater heats the garage up in no time. I only use it when I'm in there. I want to say that I keep the place at around 60 when Working in the garage and the heater cycles on and off to maintain that temp. I'm very happy with it.

 

[mahefccyqjj]

Good Example Through Image.

 

[yeldogt]

My current space is very well insulated .. I can't keep it up to a suitable temp running the heater for 1.3 hours per day.

An empty garage is easier to heat -- if you have tools and other items they stay cold.

The example above -- 580 KW and they only get charged $15 ! that's .025kw.

I pay .20 -- so the same 580 would be $116. I can easily spend $200 when it's cold keeping my studio to temp on the coldest month in PA. It's bigger vs yours

 

[martyre]

nice example on the image

 

[lakeroadster]

An empty garage is easier to heat -- if you have tools and other items they stay cold.

Excellent point. And it is much more difficult heating up a garage that has cold vehicle, or vehicles, in it. The bigger the vehicle, the bigger the difficulty.

My last garage had a fully insulated maintenance bay with a 2 post lift. The bay measured 18' x 22' with 14 foot ceiling.

I had one 5000 watt 240 Volt heater. It worked well when the bay was empty. Didn't work well at all when there was a freezing cold vehicle in the bay.

After a couple years I ended up installing a second 5000 watt heater.

I also learned that if I was going to work on a vehicle, that taking it out for a drive and getting it up to temperature was a big help in keeping the shop warm too.

 

[bzinsky]

My current space is very well insulated .. I can't keep it up to a suitable temp running the heater for 1.3 hours per day.

An empty garage is easier to heat -- if you have tools and other items they stay cold.

The example above -- 580 KW and they only get charged $15 ! that's .025kw.

I pay .20 -- so the same 580 would be $116. I can easily spend $200 when it's cold keeping my studio to temp on the coldest month in PA. It's bigger vs yours

there is no place in the united states that 580kwh will cost $15, doubtful in the entire world, his math is wrong

Most electric companies have a charge for supply and distribution, electric is pretty cheap here in NJ, and if it's 12 cents a kwh for supply, then there's also a distribution cost on top of that.

I usually use 18 cents per kwh when I'm calculating cost

 

[BrokeEF]

Hey guys, thanks for all the replies! First up, I am not positive without reading back though but you may have been talking about my math. There is a VERY high likely hood that I did the math wrong. I actually want to work out the math though, so here it goes.

I am mainly concerned with a good estimated run time. Lets say its an hour to get to temp. I am sure there will be times it will be more, and times it will be less. I think 1 hour sounds good from what I have heard in here so far. Once its warmed up, lets assume 15 minutes out of each hour will be running. So now lets say I am busting *** and work for 10 hours a day Saturday and Sunday every weekend. That comes out to 8 hours of warm up, and 20 hours of run time for a month. I guess we can just round that up to 30 hours just because.

So now we can use the 18 cents per hour that was mentioned above and we come out to $27 a month, even going to 20 cents per hour its $45 a month. If I am honest, I wont use it THAT much. If I really get after it and use it that much, I would would still take probably 2 winters of use to start to even out with a gas heater. That is also assuming I spend about $200 on a electric heater, but I am liking those $70-80 heaters linked in here.

I still have some time to think it all though. I am going to start tearing down the drywall and doing electric in the coming weeks. Probably wont get to a heater until late summer. Plenty of time to flip back and forth


Sean

 

[yeldogt]

there is no place in the united states that 580kwh will cost $15, doubtful in the entire world, his math is wrong

Most electric companies have a charge for supply and distribution, electric is pretty cheap here in NJ, and if it's 12 cents a kwh for supply, then there's also a distribution cost on top of that.

I usually use 18 cents per kwh when I'm calculating cost

Where is electric cheap in NJ ? and .18 KW is not cheap.

 

[yeldogt]

Hey guys, thanks for all the replies! First up, I am not positive without reading back though but you may have been talking about my math. There is a VERY high likely hood that I did the math wrong. I actually want to work out the math though, so here it goes.

I am mainly concerned with a good estimated run time. Lets say its an hour to get to temp. I am sure there will be times it will be more, and times it will be less. I think 1 hour sounds good from what I have heard in here so far. Once its warmed up, lets assume 15 minutes out of each hour will be running. So now lets say I am busting *** and work for 10 hours a day Saturday and Sunday every weekend. That comes out to 8 hours of warm up, and 20 hours of run time for a month. I guess we can just round that up to 30 hours just because.

So now we can use the 18 cents per hour that was mentioned above and we come out to $27 a month, even going to 20 cents per hour its $45 a month. If I am honest, I wont use it THAT much. If I really get after it and use it that much, I would would still take probably 2 winters of use to start to even out with a gas heater. That is also assuming I spend about $200 on a electric heater, but I am liking those $70-80 heaters linked in here.

I still have some time to think it all though. I am going to start tearing down the drywall and doing electric in the coming weeks. Probably wont get to a heater until late summer. Plenty of time to flip back and forth


Sean

It all depends on how you work and conditions you like to work ,, some guys work outside for a living -- so working in a 50 degree shop fully clothed is nothing. They are moving around all the time. ME -- I'm a light weight ... I want a warm quiet space where I can think and be away from it all .. work on my cars -- do my woodworking. I may have a light sweatshirt on .. don't want all my tools cold as ice.