Propane leak?

Smell? Wouldn't one be able to smell a propane leak?

I would start with spraying soapy water (1/2 dishwasher liquid; 1/2 water) on all exposed propane connections. You might get lucky and find it.

35,000 Btu ..........furnace burner rating means it consumes 35,000 BTUs per hour of operation

1 gallon of propane is 91,000 btus....about 2.6 hours of furnace run time

30# propane cylinder...7.2 gallons------655,200 BTUs total.
Roughly 18.72 total hours of furnace run time

5 hrs of run time per 24 hours you would run out of propane in 1 cylinder on 4th day.

50*F during day....what are night time temps gong down to?

mbrooks43 wrote:
It is about 50 degrees out. 35,000btu furnace. It runs once in a while but not that often.

Furnace output rating means little, it's the input rating (as listed in the appliance manual) that determines just how much gas this furnace uses. Since a pound of propane is worth about 22,000 BTU you can then easily calculate based on the furnace input rating just how much run time you'll get out of a 30 lb tank ... but if you want to determine if that's what you're getting or whether some of your propane gas supply is leaking off you'll have to be more precise about tracking the furnace run time than just "once in a while".

Yes that seems like a lot of propane. Leak test with a sniffer or soapy water.
I am thinking it is outside and maybe the regulator.

It is about 50 degrees out. 35,000btu furnace. It runs once in a while but not that often.

25 gallons of gas a week is not unreasonable in cold weather.

We started using electric space heaters when we realized how quickly the furnace eats up propane.

mbrooks43 wrote:
I have a '16 Montana 3710FL. It has two 30# / 7gal tanks but after about 3-4 days a tank is empty. The furnace runs on propane as well as the stove when used. The fridge ran on it for about 12hrs but electricity since then. Does that sound reasonable? Furnace is set at 65 during the day and 63 at night.

You haven't provided any information about your furnace but let's say a pound of propane provides you with an hour of furnace run time, in which case you'd obviously deplete a 30 lb tank in just 30 hrs of total run time on the furnace alone. Obviously any other gas use such as the stove, oven, fridge, water heater, etc, would reduce what's available for the furnace. Since you haven't told us how cold it was outside or how frequently the furnace was runnning it's impossible to say whether this gas usage is excessive or not.

running the heater it sounds normal to me