Small cabinet heater? Heat tape?

[John]

Hey gang,

It is routinely getting below freezing temperatures outside and I've been relying mainly on a wood stove to heat the bus (since the local propane guys wont come around) I have a Shurflo water pump that I want to protect from freezing. It is on the interior of the bus as well as is the water supply. It is in a small cabinet under the sink.

I was thinking about either getting some 12V DC heat tape (don't know of a good brand/source) and wrapping it, or perhaps getting a thermostatically controlled electric heater to heat the cabinet under the sink (and thus the water lines, faucet, etc...) Does anyone know of a good way to heat a small cabinet area? If I can come up with a good solution I may also add some to the pantry to prevent the cans from freezing.

We've been running the wood stove and it gets nice and toasty, this is just for cold-weather emergencies to prevent any damage.

[GoneCamping]

Why heat the cabinet? Just open the door and let the room air circulate in there... that is how I got by in the winter... then again I'm in a pretty mild area, only gets into the freezing temps a few weeks off & on during the winter...

[John]

I'm currently living full time in the bus. The wood stove tends to heat the bus well, but only about 2 feet off the floor up to the ceiling. For some reason I can't seem to get the bottom two feet warm. That's even where I have most of the insulation (1-3/4" blue board in the walls (below the windows), 1" in the floor.)

I hope that the wood stove will keep everything above freezing temperatures, that's my goal. Same with propane. I am just looking for an emergency option. Something that will kick on if the bus gets cold enough, but hopefully will never kick on.

This winter I'll be facing some 20 to 30 below nights. Not all the time, but every now and then. My water heater is protected against those temperatures as long as I have propane and power to it. But my plumbing might not be.

[Redbear]

All of the ideas are good ones. The computer fans would use the least electricity, if you intend to keep the woodstove going.

When I had a cabin in the Adirondacks, I used one of those 1500 watt ceramic heaters aimed directly at the shallow well pump to keep the pump from freezing. It was located in an unheated 1/3 basement. As a side benefit, the heater kept about 2000 cubic feet of basement air in the 30's or 40's, also. Two of those would probably keep an insulated bus fairly comfortable, at least in the 50's, when it is -10°F outside. One would surely keep a cabinet warm. The downside is the electricity for 24/7 operation was about $5 per day each.

I also had the pipe from the well to the pump running above ground outdoors, protected with heat tape and foam insulation. I don't ever remember a problem with this. There had been an underground iron pipe that came up through the foundation, but it had clogged up decades before I bought the place. A previous owner just ran copper pipe out through the back wall and down through the well cover out back. I did put an old storm window frame over the pipe to keep the snow and wind off. I still had running water when it was -25°F outside.

A neighbor used the light bulb method inside a small well pit next to his house. I've seen light bulbs used for chicken incubators, too. You just have to be sure the bulb doesn't burn out.

If you do use pipe insulation as part of the solution, just remember that it not only keeps the cold out, but also 'protects' the pipes from any heat being applied to thaw them. There must be heat tape inside the foam, or the insulation should be removable, in the event thawing a freeze-up with a hair dryer is required.

One other trick used on below zero nights is to let a faucet dribble to keep the water in the pipes moving so it is less likely to freeze. This may be another way to protect the bus' pump and pipes. In a bus without hook-ups, you obviously don't want to be pumping all your fresh water into the grey tank. But a recirculator system could be designed with a return line that would allow water to cycle through the pump to a warm area like the sink and then return to the fresh tank. A valve or restrictor might allow this to occur slowly, so the pump would cycle often instead of running continuously. Keeping water moving may even help a little in preventing the water in the tank from freezing, depending on the layout.

I've seen such a circulator system for the hot water in an office building. There were three pipes: Hot, Cold, and Hot return. A pump would cycle fresh hot water into the pipes from the hot water tank when an aquastat indicated the pipes had cooled off. This sent the warm water resting in the pipes back to the tank through the return line. With this design, there was true hot water as soon as you turned on a faucet, no waiting. The plumbing for cold cycling would be similar, the reason for it would be different.

[GoneCamping]

Well, I wintered in mine last year, and had a similar problem with the cold floors. though I didn't have enough ceiling in there to put in a ceiling fan, I did set a turbo fan that tilts straight upwards on a counter about mid point in the bus, and I let it run on low facing upwards, it helped make the hot air above circulate even down to the floor. If you have enough room to mount a fan near the ceiling and have it blow downward you'd be miles ahead of the game. In the end I wound up buying a "Stanley" ceramic work site heater, kept it on low 600W setting, and propped the back end of this thing upward so that the blower would stream air down ward on my feet (or that general area) and that helped a great deal too.
Heater

As for the plumbing, I used a combination of things. On the fresh hose coming in from the tap, I had heat tape started at the bottom of the tap pipe as it came from the ground, all the way up, around the spigot, and down the hose to where it went into the bus, the heat tape was secured in place with cable ties, and I kept the heat tape on the bottom side of the run as much as possible as heat rises. I then wrapped the tap pipe, and the hose with foam pipe insulation, again securing it with cable ties. I also put a outside tap insulation cover over where the hose attached to the bus.

Under the bus inside the cargo compartment where ALL my plumbing was run, I used 2 sets of 18' rope lights (they actually work as well as heat tape), again all cable tied to the plumbing, and all of wrapped with foam insulation, and had a thing that plugged into the wall socket that turned it all on/off at around 37ºF or so. I had temps into the single digits and never froze anything up. That is cold as it gets around here, can't say what would happen at -20 or so...

[TygerCub]

A minor thing that can make a great deal of difference is to block wind from flowing under your bus. Use plywood, foam, tarp... anything to block the wind. This includes the wheel wells. That's what they do it on mobile homes. It's quick, simple and easy to do.