Propane useage math

[JSK76]

I went through a 30# tank way to fast and did some checking and came up with a 20,000 input furnace could run 32 hours straight on a 30# tank. Doesn't seem right, so someone check my math!

30# tank 80% full is 640,500 btu (roughly 7 gallons, 91,502 btu per gallon)

20,000 btu input heater

640,500/20,000= 32.025

I just can't see a 30# tank running that size heater for 32 hours non stop.

I don't think I even had the thermostat on for 32 hours total and it doesn't run non stop after it gets to temp. Starting to think I have a gas leak. The house is new to me and I always thought it smelt funny, not like propane egg smell but like a dirty diaper smell. Propane detector hasn't gone off and it doesn't stink outside of house.

[BigFish1]

I don't disagree with your math but I get around 30 hours or so on a thirty pound tank ice fishing. That would also include using the oven and stove top. I have a 14ft house with a 3 ft v for a total of 17ft.

[minndonn]

Did you weigh the tank to be sure it was empty? How cold was it while you used it? If it is very cold the tank will not create enough pressure as the gas level goes down. I have had tanks quit at 25 to 30 left because it can't absorb enough heat to vaporize.

[Lip_Ripper Guy]

With my 25,000btu Suburban I get about 3 full days out of a 30#. If it is real cold, after about 2 1/2 days I can hear the burner in my furnace 'pulsate', and I'll switch over to my 2nd tank.

Even though I have an auto changeover regulator, I always keep my 2nd tank shut off. This helps monitor propane usage and will keep me from having any surprise shortages in the middle of the night.

[JakeJ_Mn]

I have an 8x20 wheelhouse with an Empire DV215(15,000BTU) direct vent along with a 20,000BTU Suburban furnace, 3 burner stove with oven in my house. I run the Empire 24/7 on a thermostat set at 70( the few days I wasn't at the house I turned the heat down to 50) and normally only run the furnace occasionally. I have 40# tanks and average 5 1/2 to 6 days when it's really cold and up to 9 when the temps are 20 or above per tank.

I turned the heat on in the house last Thanksgiving and shut it off today. My average for the winter has been 7 1/2 days per 40# with an average cost of $32 per fill.

My house has thermo windows, 2 inches of spray in the walls, 3 inches in the ceiling, and the floor has 1 inch pink foam sandwiched.

I have an insulated box built around my propane tanks which seems to help burning all the propane in the tanks.

[river rat316]

30# tank holds 30# of propane first of all, the tank its self could hold 36# so the expansion is built into the tank. Either your tank wasn't full or it is not emptying all the way, cold could be one reason, or a faulty valve or condensation, the new style valves are POS imho.

[magicstix]

Isn't 10-12K per 1-lb of fuel a ballpark figure? If so I think your math sounds about right.