Cheap Heat electric add-on
I'm just curious if anyone has had the Cheap Heat electric heat by Comfort Systems added to their coach? I am thinking about having one added to my coach but would love to get some feed back from peop...
Forum Discussion
Hi Lady Fitzgerald.
Please read more carefully. The folks who were visiting were from Tx. The Montana is in KY.
Here are the numbers:
He was running 3000 watts of heaters that's 10236 btu's. He went through 45 pounds of propane, but we don't know the time frame other than it was Thanksgiving. Let's guess it was a week?
Propane does 21499 btu's per pound. Lets say his furnace was only 70% efficient? (it is probably 80). 21499 X 0.7 =~ 15000 btu's (rounding down for worst case?)
15000 x 45 = 675000 btu's
675000 / 7 days = 96428 btu's per day from the furnace.
10236 x 24 = 245664 btu's from the two electric heaters
So his heat requirements are 342092 btu's per day.
The smallest cheap heat is 16 amps or about 1920 watts which is 6551 btu, assuming zero voltage drop.
6551 x 24 = 157224
That means the smallest cheap heat is in a deficit position and can't possibly work. But that is no surprize.
The largest cheap heat is 42 amps or about 5040 watts. That works out to 17197 btu's
17197 x 24 = 412728 btu's
This is more than enough and the unit would cycle on and off.
The medium If I remember correctly (they have removed the web page, so I can't go back and check) is 32 amps
32 x 120 = 3840 watts or 13102 btu's (again with zero voltage drop)
13102 x 24 = 314448 btu's. So it might not be enough at night.
Also I maximized the possible output of the cheap heat and minimized the propane furnace. If I redid it with the propane at 80% efficiency and a voltage drop of 10% the medium size probably won't "cut the mustard". Certainly it would be constantly be on during the night, if not 24 hours. Since by design the cheap heat is "either or" the propane furnace would have to carry the entire load at night when the temperatures are the lowest. Too sad, too bad.
If the visit were only 4 days then even the largest 42 amp unit would be being pushed to its limits.
We also don't know if it was 45 lbs of propane--it might be more--or it might be less.
I hope I did not make any errors. This is a "back of an envelope" calculation, so only one step up from a "guess".
I'm sure you have more expertize than I do in this area lady fitz. Please knock the stuffing out of this email so I can learn from you.
Please read more carefully. The folks who were visiting were from Tx. The Montana is in KY.
Here are the numbers:
He was running 3000 watts of heaters that's 10236 btu's. He went through 45 pounds of propane, but we don't know the time frame other than it was Thanksgiving. Let's guess it was a week?
Propane does 21499 btu's per pound. Lets say his furnace was only 70% efficient? (it is probably 80). 21499 X 0.7 =~ 15000 btu's (rounding down for worst case?)
15000 x 45 = 675000 btu's
675000 / 7 days = 96428 btu's per day from the furnace.
10236 x 24 = 245664 btu's from the two electric heaters
So his heat requirements are 342092 btu's per day.
The smallest cheap heat is 16 amps or about 1920 watts which is 6551 btu, assuming zero voltage drop.
6551 x 24 = 157224
That means the smallest cheap heat is in a deficit position and can't possibly work. But that is no surprize.
The largest cheap heat is 42 amps or about 5040 watts. That works out to 17197 btu's
17197 x 24 = 412728 btu's
This is more than enough and the unit would cycle on and off.
The medium If I remember correctly (they have removed the web page, so I can't go back and check) is 32 amps
32 x 120 = 3840 watts or 13102 btu's (again with zero voltage drop)
13102 x 24 = 314448 btu's. So it might not be enough at night.
Also I maximized the possible output of the cheap heat and minimized the propane furnace. If I redid it with the propane at 80% efficiency and a voltage drop of 10% the medium size probably won't "cut the mustard". Certainly it would be constantly be on during the night, if not 24 hours. Since by design the cheap heat is "either or" the propane furnace would have to carry the entire load at night when the temperatures are the lowest. Too sad, too bad.
If the visit were only 4 days then even the largest 42 amp unit would be being pushed to its limits.
We also don't know if it was 45 lbs of propane--it might be more--or it might be less.
I hope I did not make any errors. This is a "back of an envelope" calculation, so only one step up from a "guess".
I'm sure you have more expertize than I do in this area lady fitz. Please knock the stuffing out of this email so I can learn from you.
