Propane or electric heta?

Users who are viewing this thread

DarylF08

Mec. Elect. Engineer
Messages
19
Reaction score
0
Points
0
Location
St. Louis Missouri
I have a 800 sq. ft garage. I wan to heat and keep around 45 to 50 at all times except when I am working, 60 to 65. Garage is insulated.
I have a Comfortaire 2 stage furnace that runs off a 60 and a 30 amp breaker.
My ? is, would it be cheaper to run a Propane furnace instead.
I was looking at a used 25000 btu and a 80000 btu.
Any advice would be greatly appreciated.
Thanks Daryl
 

Bob NH

In the Trades
Messages
3,310
Reaction score
9
Points
0
Location
New Hampshire
Propane has about 92,000 BTU per gallon and electricity has 3413 BTU per kWHr.

The following applies if your electric furnace is a resistance heater. If it is a heat pump then it should cost a lot less.

Assume 75% efficiency for a small propane furnace, and 100% for electricity.

92,000 x 0.75 = 69,000 BTU of available heat.

69,000 BTU / 3413 BTU/kWHr = 20.2

For the assumed efficiency it will require 20.2 kWHr of electricity to produce the same heat a 1 gallon of propane.

Look at your electric bill and propane bill. If 1 gallon of propane costs less than 20 times the cost of 1 kWHr of electricity, then propane will be less expensive.

Electricity where I live is about $0.15 per kWHr, so if propane costs less than $3.00 per gallon then propane would be cheaper.

I estimate that your total of 90 amps electrical is probably connected to about 15 to 20 kW of electric heat, or about 60,000 BTU per hour.

Assuming that the ratings you provided are OUTPUT and not INPUT; a 25,000 BTU gas burner would probably be large enough for all but the coldest days and 80,000 BTU per hour is probably more than the electric heat provides. You can judge by how well your existing electric system keeps you warm.
 

DarylF08

Mec. Elect. Engineer
Messages
19
Reaction score
0
Points
0
Location
St. Louis Missouri
Here are the rates from Ameren UE
Propane is around 3.25 per gal.

Summer Rate (Applicable during 4 monthly billing
periods of June through September)
Customer Charge - per month $7.25
Energy Charge - per kWh 7.92¢
Winter Rate (Applicable during 8 monthly billing
periods of October through May)
Customer Charge - per month $7.25
Energy Charge - per kWh
First 750 kWh 5.62¢
Over 750 kWh 3.78¢
Optional Time-of-Day Rate
Customer Charge - per month $15.00
Energy Charge - per kWh (1)
Summer (June-September billing
periods)
All On Peak kWh 11.51¢
All Off Peak kWh 4.72¢
Winter (October-May billing periods)
All On Peak kWh 6.79¢
All Off Peak kWh 3.36¢
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks