This is probably more info than you want or need but maybe not. Here's my writeup that I posted on another forum:
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We were planning on spending the Christmas break in Florida with my sister, but family matters interrupted those plans and on Monday, we left Big Bend NP for Colorado Springs. As you probably know, there is a BIG cold air mass in the central US. We had the choice of beating the cold in and getting set up or waiting a week or more and then perhaps dealing with traveling in temps in the 20s/30s. Hindsight being 20/20, we should have chosen that option.
When you are camping in really cold weather, the challenge is to have the resources to keep the coach plumbing from freezing and doing serious damage. For us, the driving factor is propane, and we don’t have the ability to attach an external tank. This was an unexpected trip and there was no time to add the connections to allow that. This is also our first experience camping in severe cold with our coach and I had no idea how much propane we would need to keep things warm.
We arrived in Pueblo, CO on Tuesday at about 1300, filled the fuel tank (anti-gel additive), water tank and propane tank and set up camp. It was about 65 degrees and blowing 30 MPH. I then started my prep for the approaching cold front. We picked Pueblo because it is usually 10+ degrees warmer than the Air Force Academy where we usually camp, and the KOA has on-site propane fill capability.
From Home Depot, I bought 3 sheets of 3/4”, foil faced building foam. Try carrying that around in the wind! I used it to make panels inside the bay doors for the wetbays and cargo bays. There was also enough to do the front windshield and the shower skylight. I used duct tape on all the edges to cut down on the little round foam bits that get shed everywhere. We also put all the DayNight shades down to conserve heat.
I had one 200W MyHeat Lasko electric heater, and that went in the PS wetbay by the water pump. I also have a second one on order that should arrive today for the DS wetbay.
I had a remote read thermometer and kept an eye on the temp in the PS wetbay. The thermometer was sitting on the floor of the bay.
Tuesday night, the lows were about 20 and we ran the propane furnace on automatic (set to 45 degrees--about 50% on/off cycle) starting at about 0300 to keep the bays warm. I think the residual heat from the fresh water tank also helped keep the bays warm.
We have strip heaters in the AC units and ran them all day on Wednesday as the temps continued to fall, and they kept us comfortable and the bays above freezing. We also went out and bought an additional remote read thermometer (about $15 at Lowes) for the DS wetbay. I set it about mid-height in the bay and consistently got readings that were 10-15 degrees warmer than the PS wetbay which I attributed to the furnace vent in the bay. It turns out it was much colder on the floor of the bay.
I bought a 750W electric heater for the cargo bay--it, along with the electronics there seem to be keeping the bay above freezing.
During the afternoon (at about 15 degrees), I started the Cummins--just to see if I could, in case I needed to get propane before it really warmed up--about the middle of next week. It started but wasn’t happy. Next time I will run the block heater even longer than the 4 hours I did this time, and also will try to wait for warmer temps if my propane supply allows.
By bedtime last night, the temp was down to about 8 degrees, and we were having to run the propane furnace about once an hour for 10-15 minutes to keep the wetbays in the high 30s.
In order to conserve propane, overnight, I set the alarm clock for every 90 minutes and got up and ran the furnace for about 15-20 minutes to pump heat into the bays. In between, we ran the strip heaters, and I tried to nap. By about 0300, the outside temp was down to 0 and I was getting up after an hour to run the furnace. It took about 45 minutes to get the temps back up from 35 degrees to 42 degrees before I shut it off and went back to bed.
I had lots of time in the middle of the night to think about how long my propane will last. It’s not going to be up to the low 20s until Saturday (then cold again) and then up to the 30s until Tuesday. I was worried about needing to try to start the Cummins before Saturday to drive to the front of the RV park to get a refill.
After doing some research on the web (isn’t wifi wonderful for filling those underutilized minutes at 0400 in the morning) and a few calculations, I think I have an answer. Under ideal conditions, a full propane (131#s) tank will run my single 35K BTU furnace for about 79 hours. We have the water heater on electric and have not been using the stove much. So I should make it until at least Saturday and may be able to stretch it until Tuesday. So far today (15 degrees), we’ve mostly run on the heat strips and have not needed to use much propane.
Today, I bought an additional 750W heater for the PS wetbay. The 200W heater was fine at 15 degrees but wasn’t cutting it at 0. I also moved the thermometer in the DS wetbay down to the floor.
If you’re going to camp in very cold weather, the FT is a great vehicle. Camping in weather above 20 degrees should be pretty easy. But at lower temps, there are a lot of single point failures that could cause you real problems. Your furnace has to work and you need propane. Also in my case, the room slide has to work and the Cummins needs to start. Hope this helps you be prepared. It’s going to be 0-10 degrees for the next 5 nights. Wish us luck!
Rich