Need help choosing heater for 24x30 garage

[DanWheeler]

I'm in Western Washington and in the process of building a detached garage 24x30 which is 720 sq foot. I'm trying to decide between

propane:
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200316365_200316365

or

Electric:
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200316377_200316377

my goals are cheap, easy and comfortable. It doesn't really get that cold here and i'm not opposed to wearing a few extra layers, i just want to keep the garage above 60 degrees or so. I am planning on insulating heavily. I probably spend 1-2 nights/week in the garage for 4-5 hours per night.

I'm leaning towards the electric heater despite the expected costs just because I dont want to deal with keeping a propane tank filled. I was just wondering if anyone had any experience with a heater like this in a 700sq ft garage or similar.

- will it actually do a decent job of heating 700sq ft?
- is it going to jack up my electric bill? (already very high due to lots of computers and lighting in the house)

if I were to go with propane, what would be my tank and fill options? I know nothing about propane. I guess I wouldn't be opposed to taking a big tank down to the gas station every once and a while and getting it filled as long as the tank could fit in my trailer and i could move it by myself.

thanks,
dan

 

[DanWheeler]

also considering the Dayton G73 but airnwater.com says it can only heat a 500 sq ft garage. The G73 is rated at 17,000 BTU

for a little bit more money I could get 2 of the QMark portables which are rated at 19,000 BTUs each. I'm not sure why AirNWater.com tout the G73 which costs $299 and only puts out 17,000 BTU while the QMark is $169 and puts out 19,000 BTUs. Am I overlooking something?

QMark:
http://www.air-n-water.com/product/BRH562.html

 

[timgr]

I have 2 of the Daytons in my 360 sqft garage. Above freezing, it keeps the garage very comfortable with one heater. This seems pretty good, since the roof is not insulated yet.

Note that the Dayton is 5000W, and runs from a 30A 240V single phase circuit. It can be wired with 10-2 Romex, which is easily sourced at the big box stores. I'd suggest you place an on/off switch on the wall below the heater - you can buy a 30A 240V switch for about $10-15, though they are not as easy to source as the wire (I bought mine from MSC, but you should be able to get them at an electrician's supply).

The IGC site has a calculator that lets you estimate the number of BTUs you need to heat the structure. http://www.igcusa.com/non-greenhouse-btu-calculator.html The two Daytons was overkill for me, but it was clear that a single unit could not have heated my garage to shirt-sleeve temps on the coldest days, so I went with two. IGC seems to have the lowest price on the Dayton.

The Quellet unit http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200307927_200307927 makes as much heat as the Dayton, and is somewhat cheaper.

What's the difference between the Dayton and QMark? The Dayton is meant to be ceiling mounted, and the QMark is a portable. The Qmark unit is plug-in, where the Dayton must be hard wired. You'll need to buy a whip to connect the Dayton to the wall, but there's a cheap whip available at HD for $10. The Dayton has a mounting bracket and air deflectors, the QMark doesn't. The Dayton can be configured for the capacity of the circuit it's connected to, and it looks like the QMark cannot. Depends on what you want. I would not pay too much attention to the description - that's usually advertising copy provided by the manufacturer.

hth!

(more) The initial cost of electric heat will be lower, and it's clean and convenient. Over time, it will be more expensive than gas, but by how much depends on the rates in your area. You can make a guess using the rates on your electric bill. The cost of electricity will be listed in Kw-hr. The Ouellet is 10kW, so make a guess at the duty cycle (on v. off time) and add up how many hours it will be on in a month. Multiply that times your rate times 10 and walla, that's the cost.

 

[JCByrd24]

Just my 2 cents. Check the prices of electricity and propane in your area. Here in Maine the electricity is expensive and even at our rate, the turning point $$ wise is around $3.20/gallon per propane, which we are fast approaching, not to mention the convenience factor of electricity.

Here is how you figure it out.

92000 (BTU/gal of propane) x efficiency of burner x your cost per kwHr / 3412 (BTU/kWhr) = turning point cost of propane

Thus if you have an 80% efficient propane burner and pay $0.12/kWhr the turning point is:

92000*.8*.12/3412= $2.59 /gal

 

[DanWheeler]

Thanks very much for the replies guys. I checked my electric bill and AFTER taxes, fees and even paying for 100% green energy (extra .0125/KWh) my avg cost per Kwh is .11. Otherwise, base rate is .07 up to 600 KWHS and .09 after that. (I use over 1000/mo)

so my turning point is about $2.37 but i'll have to find out how much a gallon of propane costs around here. anyone know for the Seattle area?

Tim, that calculator says I'm going to need about 30,000 BTUs if it's 30 degrees out to get the garage up to 60 degrees. The Oulette is rated at 34,000 BTUs so I would only need one of those if thats true. Since it's 10,000watts and my final rate is .11 does that mean i'd be paying $1.10 for every hour that heater is on?

 

[DanWheeler]

Is there any advantage to running 2 heaters instead of a single? I may be able to get my required BTUs cheaper going with 2 heaters. (as opposed to the big Oulette which is over $500)

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200316377_200316377

 

[timgr]

Is there any advantage to running 2 heaters instead of a single? I may be able to get my required BTUs cheaper going with 2 heaters. (as opposed to the big Oulette which is over $500)

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200316377_200316377

Don't know that there's any advantage, except possibly more even heating. The smaller units are ... smaller, and you'd have a little more headroom. I can think of a possible disadvantage - with two thermostats, they could have different set points, and one heater will run all the time and the other won't run at all. I don't think that will happen, if you keep them set to close the same setting. Don't have enough experience with them to say this for sure yet. With one heater, the heater will cycle on and off even in a cold garage. The air around the heater heats up and it takes a few minutes for the heat to diffuse throughout the garage, so the heaters (at least, my Daytons) won't run constantly regardless of the temperature.

 

[timgr]

Just a comment about the fan cycling on my Dayton heaters.

Seems that the fan will only run when the element is hot enough to heat the moving air effectively. The fan moves more air than the element can keep up with, so the fan cools the element and then the fan shuts off. The heater really can provide 17K BTU continuously.

I'd think that if you put the two heaters in opposite corners of the structure, their temperatures would be sufficiently decoupled that it won't matter that they operate on different thermostats.

 

[timgr]

Since it's 10,000watts and my final rate is .11 does that mean i'd be paying $1.10 for every hour that heater is on?

Yes, at 100% duty cycle. Hopefully you won't be running 100% all the time.