Excellent write-up Robert! Thanks! I have a few additional suggestions gleaned from previous posts here on this forum and from personal experience during late fall and early spring living in southern Canada or northern US.
1. A remote thermometer in the water bay is very useful to monitor the temperature down there. They are inexpensive (less than $20 at Walmart
or Home Depot
) and give great peace of mind. I keep my thermometer display on my bedside shelf and sleep better for it.
2. Like Robert, I also use a small ceramic heater (like these from Lowes
, Home Depot
) in the water bay and a heated hose, both of which I plug into the engine block heater outlet or directly into the pedestal if there's a 20A plug available there. My 12V water bay heater died in 2011 during our first year of full-timing and I simply replaced it with a 120V ceramic heater - hung on the same bracket as the 12V heater - and run it on low power using it's own thermostat. The remote thermometer allows me to monitor the situation and I've never had a problem with freezing or overheating in the water bay.
3. I have a macerator and as long as the temperature doesn't get much below 20 deg F, I leave the 1" diameter dump hose out but insulate it with pipe insulation (looks like gray pool noodles). I use double insulation: one layer of smaller diameter (~1" ID) insulation around the hose and one layer of larger diameter insulation (~3" ID) around the first layer. I learned this through experience as my uninsulated macerator hose froze once during an unexpected overnight snap freeze in Albuquerque and it split everywhere when I tried to break up the ice (er... frozen gray water) in the morning to put it away. Luckily I found a new hose online at a clearance price because they can be pricey.
4. Many Monaco coaches have bedside outlets that are powered separately, i.e. not through the inverter. My coach is this way, so we use the closest of the bedside outlets for the ceramic heater that we use for heat in the bathroom, to save on propane when outside temperatures are too low for the heat pumps. We prefer using free-to-us electricity rather than not-free-to-us propane when we can.
5. Inspired by several write-ups here on iRV2, I installed a separate circuit with two plugs in the kitchen (one near the floor and one near the counter) and one in the bathroom. The circuit ends in the power bay with a 20A extension cord that I can plug directly into the pedestal. We use this primarily when we're running on a 30A pedestal, but it's also useful on 50A when we want to run the front ceramic heater, the kettle, the toaster or the hair dryer at the same time. More than two of those appliances through the regular 20A "RV outlet" inverter circuit will trip the breaker at the inverter, but by running one or two of the those appliances through the separate circuit, it allows us to run two others on the inverter circuit. (My coach has a 30A input circuit for the inverter, with a 20A output circuit for the microwave and a 20A output circuit for all the outlets in the coach - except the outlets for the fridge, water heater, block heater, washer/dryer and, as already mentioned, the two bedside ones).
6. I always leave the storage bay 12V lights on when it gets close to freezing or below. It's not much additional heat, but combined with the factory insulation it's enough to prevent the contents of the basement bays from freezing, especially in my (smaller) tool bay where all my expensive cleaning, caulking and lube cans/tubes live. I only added an extra 120V light bulb in that bay once, when it was to go down to 5 deg F overnight, and I've never had anything in there freeze (knock on wood).
7. Finally, if it will get much below freezing and I'm not going to run the propane heaters overnight I always leave the doors open on the bottom kitchen and bathroom cupboards so the water lines and and drain pipes at the bottom of those cabinets get heat from the room, and I leave the bedroom closet sliding doors open so the washer water lines and drain pipe at the bottom of the closet will get heat from the bedroom.
Hope this and Robert's write-up help those planning on living in the cold.
Written sitting in the Phoenix sunshine...