Three Season Trailer to Four Season Trailer

Insulation and enclosing are good but adding furnace ducting with the other two is better.

I don't have a 4 seasons trailer, but if that was a requirement for me I would do my research very carefully. There are a few manufacturers who have actually taken the time, effort, and money to fully test their designs using a cold testing facility, but the vast, vast majority just add a sealed underbelly and a pipe off the furnace and throw a 4 seasons label on the trailer.

Agreed, tbh, i would never consider a trailer for 4 seasons, unless winter was in the south.

There is a lot more to consider for a 4 season trailer than just dealing with the underbelly.

I was FT for 2 Alberta winters in my 3 season TT, and although an enclosed heated underbelly would have helped, there were a lot of other issues too.

In the minus 30s C, I literally had frost building up on the inside walls in some places. I had to throw a lot of heat at it to keep it liveable. I went through a lot of 30 pounders. Gets expensive.

Water lines that run inside the trailer are typically in the back of closed cabinets. It was a full time fight to keep my water running.
I had to leave cabinet doors open and run electric heaters aimed inside to thaw frozen pipes.

Dump time was no picnic either. I had to leave a radiant heater under my dump pipes for hours just so I could pull the gate valves and empty the tanks.

Another consideration was my propane tanks. In minus 30 temps the furnace ran a lot and the flow would reduce to a slow trickle. A heating pad between the tanks helped a lot.

The windows were caked with ice. Had to block various outside hatches from cold air entering. Had to cover a few windows with foam to try to keep heat in.

The fridge packed it in, too cold, and after many little fixes like a light bulb in the back (Thanks Don for that one) I wound up buying a small bar fridge to hold me over until spring when I pulled the fridge and got it going again.

But!! It was a blast! I enjoyed the challenge of being FT in freezing Alberta winters! Great memories! And a few stories to go with it... :B

We have a 2007 NUWA 5th wheel that is rated as 4 season
We FTd in it for 7 yrs.
Waste tanks/fresh water tank are enclosed, underbelly is insulated and it does have a Furnace Heat duct down into the tank/valve/piping area

We also have 3 Attic Vents ....front/mid/rear roof areas

We have spent time in Very Cold Temps (-19*F) , Snow (2+ feet overnight) Ice/Sleet ---stayed roasty toasty and NO freezing issues with tanks/lines

Have spent time in High Temps.....110*F+ and stayed nice and cool

Yes some MFGs use '4 Season' as a marketing ploy.
Some actually are 4 season


Need to 'insulate' the tanks/valves/piping and not with Batt Insulation
Need to provide a heat source----duct from furnace works especially when you also have return air ducting back to furnace (airflow circulation)
Enclosed Underbelly...fully sealed ---cracks/crooks/nannies

Upgrade you propane cylinders to dual 30# cylinders

Then it is up to how well the walls/ceiling/floor and slideouts have been insulated

If you're going to be stationary for the winter where it's actually cold see if you can get the propane company to rent/give you a 120 gallon tank, in most jurisdictions that's the largest that can be placed right near a dwelling, so while it's only 2x dual 30s it's easier and cheaper for them to refill so you'll still likely come out ahead.

I have similar trailer with exposed tanks etc. Added heat pads to the water tanks and heat tape to the waste plumbing. Had a fresh water freeze up so I added a hot water circulating system. Furnace had poor air flow so I added two additional ducts for superior performance. Single pane windows still sweat and it goes through a lot of propane but does fine to at least -10F. For this I really need an electric power connection. Just go and keep adding what you find you need.

Thanks, everyone, for your input. Lots of food for thought.
Mike

WE bought a 18 month old used 27' 5th wheel to live in one winter while the house was being built. It had two grey and a black tank with exposed under belly. The dealer installed heat blankets on the bottom of each tank and the encapsulated each tank with expanding foam. Then sprayed the outside of the foam with a rubberized texture. The blanket wiring were tied to one thermostat. No issues down to 6 below and 40 mph winds all winter. Fresh water tank was inside the trailer.

Thanks to Bob'sYOur Uncle.