Natural Gas Versus Electric Garage Heater

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Forum topic by johnhaynesiv posted 10-19-2011 02:19 PM 17244 views 2 times favorited 39 replies Add to Favorites Watch
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9 posts in 1074 days

10-19-2011 02:19 PM

I recently received a quote to have a natural gas fueled heater install in my 3-car (700 SF) garage which would be a Modine Hot Dawg 75,000 BTU Garage Heater, vented with T-Stat and all electrical connections fot $1,992.00.

I’ve also noticed that I could have installed an electric 5,000 watt electric heater for about $600 (a third of that cost) depending on which model I choose (NewAir G73, Dimplex, Fahrenheat, etc.)

My question relates to cost/benefit. I’m willing to spend the extra cash and go with the natural gas unit, but I’m primarily going to be working in my shop 3 to 4 days per week. The cost of electricity here in Utah is $8.7/KWh, so it would cost me $0.43 per hour to run an electric unit. The cost for NG here is about $4.6 per decatherm, but I’m not sure about the consumption rate.

Any thoughts on the long term economic benefits of gas versus electric?

39 replies so far

#1 posted 10-19-2011 02:51 PM

I didn’t recognize the term ‘decatherm’ until I looked it up.
Approximately the equivalent of burning 1000 cubic feet of natural gas (a therm is approximately the equivalent of burning 100 cf of gas).
However the math turns out, it is good to realize the many electric power utilities burn gas to generate electricity, so in that case you would be paying the electric company to process the electricity into power that you would, in turn convert to heat. In many cases it would turn out to be inefficient.
My choice was a ceiling mounted gas furnace which draws outside air for combustion and has a power vented exhaust.
Still, I try not to run it except for important work. Social Security doesn’t provide that much for extras!

-- Will trade wife's yarn for tools.

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1852 posts in 2214 days

#2 posted 10-19-2011 03:02 PM

First off, you are not comparing apples to apples.

A 5000 watt electric heater will produce about 17,000 BTU. That might be enough to keep you warm, but would take a long time to heat the area from a cold start.

When I lived in Nebraska I had a similar sized garage workshop and I had a 12,000 BTU electric heater that would barely keep it comfortable on cold days. I used a 75,000 kerosene torpedo heater to bring it to temp, (it would only take about 5 or 10 minutes) then let the electric maintain the temp.

If it was really cold outside (5-10F) the electric couldn’t maintain the temp by itself.

So – I said that to say this. You need to have a qualified person calculate how many BTU’s you need on the coldest day you expect to use your shop.

-- Joe

View StumpyNubs's profile


6192 posts in 1453 days

#3 posted 10-19-2011 03:25 PM

I use a vent free wall mounted natural gas heater. It cost me a couple hundred bucks, I installed it myself and it keeps everything toasty warm even in the cold Michigan winters. I also have a 2 story house that I heat with a single vent free natural gas fireplace. I never use the furnace.

Why spend all that money? Go get the largest vent free wall unit you can get (It will cost less than $400). It will also cost a lot less to use because vent free is so much more efficient.

Don’t waste your money on one with a blower. It’s much better to just get a big exhaust fan and hang it from the ceiling near the heater angled toward the floor. That does a MUCH better job pulling the hot air down from the ceiling and circulating it throughout the shop. In fact, you can even build an overhead shop air filter that will double as an air circulator for heating. Just make it so it pulls air from the ceiling and exhausts it toward the floor.

It’s also well suited to your schedule. Set it on the lowest setting (buy one with a thermostat) and keep the air circulating when you’re not in the shop. It’ll keep things above freezing for next to nothing, and when you work in the shop it’ll take only a short time to warm up.

I’m telling you this from experience. You’ll be just as happy going this way and you can take all that cost savings and buy some nice tools!

-- It's the best woodworking show since the invention of wood... New episodes at:

View Pdub's profile


893 posts in 1832 days

#4 posted 10-19-2011 03:49 PM

I heat a 560 SF shop with a 5,000 watt electric heater. I live in North Dakota so it get pretty cold up here. I have 2×6 walls and blown insulation in the ceiling. My heater keeps it plenty warm in the shop, but I leave it on all of the time. I just turn it down if I won’t be working in there for awhile.

-- Paul, North Dakota, USAF Ret.

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Gene Howe

5636 posts in 2081 days

#5 posted 10-19-2011 04:13 PM

My shop is 36X28 with a 10’ ceiling. Like Sumpynubs, I use a ventless gas heater. Mine’s propane, and does have a blower, tho I’d agree, it’s not needed.
While it seldom get’s REEELY cold here, it has been -8 and the heater kept it toasty.
Our home’s well water pressure tank and pump is in the shop, so it MUST be above 30 at all times.
We are seriously considering installing one in the house, also.
Here is the one I use in the shop. ProComm

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

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Bill White

3451 posts in 2613 days

#6 posted 10-19-2011 05:22 PM

What do you do about the moisture created by the gas heaters? Don’t the unvented units generate a bunch?
I use an electric oil-filled radiator in my shop. 20’ X 20’ insulated well with dbl. paned windows. Seems to do a good job.
If it gets really cold plug up a second one.


#7 posted 10-19-2011 05:31 PM

I heat my whole 2 story house with unvented gas wall heaters. They do very well and are extremely effecicient. I have some concern for the use of them in my shop, however, because of the open flame.

In my experience with these heaters, I find that the blue flame type generates a lot of water, but the ones with the ceramic elements that generate infrared do not.


-- Will trade wife's yarn for tools.

View StumpyNubs's profile


6192 posts in 1453 days

#8 posted 10-19-2011 08:44 PM

The two issues raised about ventless heaters are, in my experience, non issues.

1. Open flame- I have a dust collection system. BUT- I don’t always use it. Sometimes there’s sawdust on the floor around machines and a thin layer of dust on everything, including the heater. The fact is, a piece of glass covers the flame. There is no way for it to jump out and set something on fire. I can leave a handful of sawdust on top of the heater (if I was so inclined) and it would never catch fire. I could even throw a handful of sawdust at the heater and most would never hit the flames. It doesn’t create sparks like a wood fireplace, so it is near to impossible for it to spread. I think it is as safe as any electrical element heater…

2. Moisture- I’ve read lots of stuff about them creating excessive moisture. But in reality I never notice a thing, not in the house or the shop. My wood doesn’t swell and my saws don’t rust. HOWEVER- as is the case with any heating system, letting it get down to below freezing and then warming it up every day will cause condensation and rust your machines. So keep it turned down but not off on those winter nights.

-- It's the best woodworking show since the invention of wood... New episodes at:

View adaughhetee's profile


103 posts in 1336 days

#9 posted 10-20-2011 12:44 AM

I have a vent-less 3 brick in my 2 car garage with a 18ft un-insulated garage door and it does fine at worst I have to leave one brick running.

View Fred Hargis's profile

Fred Hargis

1783 posts in 1146 days

#10 posted 10-29-2011 03:08 PM

To me, the math of the choice is very simple…even with your low electric rate, nat gas is going to be cheaper fairly quickly. The price of your quote strikes me as being very high. I just installed a 45K modine style in my own shop last year (this one is a Sterling Garage Guy). Doing it myself, it cost about $800 for the furnace and venting. The wiring was already setup for the thermostat and power. I plumbed the gas (LP, in my case) myself. Even if your uncomfortabel doing such work, I would think you could buy the heater, hang it yourself and then have the connections done and still save money. BTW, 75K may be too much, I use the 45K to heat a 24×32x8 shop with R19 walls and R40 ceiling….and it’s way more than adequate. I realize my winters may not be as bad as yours (NW OHIO), but it’s still something to consider.

-- Our village hasn't lost it's idiot, we sent 'em to Washington.

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Fred Hargis

1783 posts in 1146 days

#11 posted 10-29-2011 05:03 PM

I should have mentioned in my previous post: the reason my heater was as high as it was ($800) is that I ordered with the direct vent kit (bring in outside air for combustion). That was almost $300 of the cost, and amounted to little more than about $75 worth of HVAC fitting and a custom box to hold it all together. The heater itself was about $400, and the rest was for things like a thermostat, fuel piping, etc. Would have just edited that post but ran out of time….

-- Our village hasn't lost it's idiot, we sent 'em to Washington.

View CharlieM1958's profile


15696 posts in 2871 days

#12 posted 10-29-2011 05:33 PM

If you are paying eight dollars and seventy cents per kWh, as your post states, you should really go with gas. :-)

-- Charlie M. "Woodworking - patience = firewood"

View JJohnston's profile


1577 posts in 1944 days

#13 posted 10-29-2011 05:45 PM

I just realized I have my electric bill right here at my desk, and Charlie’s reply prompted me to check for myself: I pay 9 cents per KwH for the first 450, then 12 per KwH in excess of that. This is in New Mexico. If you really are paying almost 100 TIMES that much, go gas.

-- "Sorry I'm late. Somebody tampered with my brakes." "You should have been early, then."

View johnhaynesiv's profile


9 posts in 1074 days

#14 posted 10-29-2011 05:52 PM

I’m off by a decimal point… The cost of electricity here in Utah is $0.87/KWh. it would still cost me $0.43 per hour to run an 5,000 watt electric unit.

View JJohnston's profile


1577 posts in 1944 days

#15 posted 10-29-2011 08:07 PM

Still sounds like you should go gas. If what I pay is any comparison, your electric rate is still way out of proportion. You pay 46 cents per therm for gas; I pay 49 to 54 depending on the quantity, and you still pay 8 times what I pay for electricity.

-- "Sorry I'm late. Somebody tampered with my brakes." "You should have been early, then."

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