Specifications

Heartland Owners Forum http://manuals.heartlandowners.org
Heating and Cooling Guide V1.pdf Page | 18 Version: 1, March 15, 2013
Propane characteristics in cold weather
As outside temperatures fall below freezing, propane pressure from your tanks may fall below what’s
necessary for reliable furnace operation. Propane gas pressure at 0 degrees (F) is about ½ the pressure
from the same tank at 50 degrees (F).
For example, if you have a 30 pound tank that’s 40% full, and a 42,000 BTU furnace, at +20 (F), the
propane pressure will be slightly under what’s needed to reliably operate the furnace.
In very cold weather, an external tank may be necessary.
How Long Will a Tank of Propane Last?
This is a little like asking “how long is a piece of string?” It depends on how cold it is, how well the RV is
insulated, what kind of windows you have, size of the tanks, size of the furnace, furnace efficiency, and
perhaps other factors.
That said, a 30 pound tank contains enough propane to supply 646,440 BTU of heat. If the furnace
consumes 42,000 BTU per hour of operation, that would give you about 15.4 hours of furnace
operation. Of course you don’t normally have the furnace running continuously. So if it runs for 10
minutes of every 30 at night, and 5 minutes of 30 during the day, the tank might give you about 2.5 days
of operation.
Because propane vapor pressure drops as temperature drops, the efficiency of the furnace may
decrease as outside temperatures drop. This may result in a drop in the temperature of the hot air
coming out of the registers.
Also, as temperatures drop, the trailer loses heat faster and the thermostat will call for heat more
frequently to keep the trailer warm. So you may get far less than 2.5 days from a 30 pound tank if
temperatures drop to zero (F) overnight.