Adding Heat to Underbelly

[HeyBooBoo]

We just purchased a new Rockwood 2104s and love it. However, our unit did not come with heated holding tanks. I asked how much it would be to add them and got a staggering price of $900! We want to camp year round,and we have to keep it winterized, but I was hoping to use the gray/black for weekend trips.

Is there a more affordable way to provide heat to the underbelly so that we can at least use the gray/black tanks without fear of freezing?

Thanks for any advice!

[jd50i]

If you have an enclosed underbelly, probably the cheapest way would be to add a duct from your furnace to heat the area.


Adding electric heat is also another option.
https://www.amazon.com/gp/product/B0...YHOQFM2H&psc=1


https://www.amazon.com/gp/product/B0...YHOQFM2H&psc=1


https://www.amazon.com/gp/product/B0...YHOQFM2H&psc=1

[dward51]

Do you have an enclosed underbelly? The Rockwood Mini-Lite info says an enclosed underbelly is standard along with radiant insulation in the floor. Check your furnace and see if there is a furnace duct that runs into the underbelly. If there is, you have a heated underbelly. If not, and you have a spare port on the furnace body where the ports are located, you might be able to run one. On my Freedom Express the underbelly duct is smaller than the other heat ducts. It is the only small one and is middle of the trailer right between the black & grey tank in my enclosed underbelly.

The term heated underbelly is generally from the furnace, but tank heaters are an additional level of protection. They are not hard to install, but accessing the bottom of the tanks to install them and run the wiring is the hard part. Other than that you just need a spare fuse spot on the DC distribution panel to run the wiring from. It goes from there to a switch (or two if you want to split them) and then to the heater panels which stick to the underside of the tanks. You man also need to protect your dump valves if they are exposed. Some models also have optional 110v in addition to the 12v. The heat panels should have a built in thermostat that turns them on at a set point, but you MUST have some liquid in the tanks when using them. That's the short version.

[01tundra]

Originally Posted by HeyBooBoo

We just purchased a new Rockwood 2104s and love it. However, our unit did not come with heated holding tanks. I asked how much it would be to add them and got a staggering price of $900! We want to camp year round,and we have to keep it winterized, but I was hoping to use the gray/black for weekend trips.

Is there a more affordable way to provide heat to the underbelly so that we can at least use the gray/black tanks without fear of freezing?

Thanks for any advice!

We camp all year and fully winterized during the cold months. No tank heaters.

Use the toilet for liquids only (personal choice, but could be used for all), pour about 1/2 gallon of antifreeze in the black tank prior to leaving the house, flush with a water bottle filled with water. Been doing this for over four years down to single digits and have never had a single issue. That's approximately $1 per trip for antifreeze, so $900 would cover us for about the next 180 years or so.

[5picker]

Keep in mind... even those R/Vs touted as 4 seasons units are susceptible to cold weather conditions/issues.

I'm not trying to change anyone's mind about cold weather camping but MANY folks believe if they have tank heaters and/or heated underbelly all you need to do is turn them on and go camping in frigid weather and all will be fine! There is more to it than that.

Just sayin'.

[TitanMike]

Originally Posted by HeyBooBoo

We just purchased a new Rockwood 2104s and love it. However, our unit did not come with heated holding tanks. I asked how much it would be to add them and got a staggering price of $900! We want to camp year round,and we have to keep it winterized, but I was hoping to use the gray/black for weekend trips.

Is there a more affordable way to provide heat to the underbelly so that we can at least use the gray/black tanks without fear of freezing?

Thanks for any advice!

An easy way to do the job more affordably is to do it yourself.

Pads, wiring, switch are all available on Amazon:

https://www.amazon.com/s?k=rv+tank+h...nb_sb_ss_i_3_9

A pair of pads for holding tank will run around $75, A Fresh water tank pad, around $45. "Elbow Heater Pads" to heat the discharge elbows from the holding tanks another $45 or so. Parts should run less than $200.

The hard work will be accessing the bottom of the tanks if there is a corrugated plastic cover. These are usually "nailed" on but a 6-point socket in a cordless drill will remove them and when time to replace just use TEK screws (self drill.tap) from Home Depot or Lowes .

Pads have adhesive on the back so they are "peel and stick".

If your power panel is a WFCO there are usually a couple of open fuse spaces at the bottom that are "High Current" for things like tank heaters. Connect all Red wires together (+), connect all black wires together (-) ,Insert positive wire in empty terminal/lug, connect negative wire to negative 12V bus, insert fuse and done. For $700 in savings I'd be more than willing to spend some time under my trailer on a creeper.

Note: I've found the best wiring for my TT add on projects (12volt) is "Marine Type" which has two wires paired and covered with a heavier insulation. Wire is stronger than the "zip cord" one can buy at a big box store and flexible so it doesn't break when flexed as vehicle runs down road. I get mine from a local Marine Supply Store. Also, it's easier to run a single piece that carries both positive and negative than to mess with pulling two separate wires.

On my trailer I have three tank heater pads and two elbow heater pads. Fuse size is 30 amp and #10 wire runs from fuse block to switch and pads.

[TitanMike]

Originally Posted by dward51

Do you have an enclosed underbelly? The Rockwood Mini-Lite info says an enclosed underbelly is standard along with radiant insulation in the floor. Check your furnace and see if there is a furnace duct that runs into the underbelly. If there is, you have a heated underbelly. If not, and you have a spare port on the furnace body where the ports are located, you might be able to run one. On my Freedom Express the underbelly duct is smaller than the other heat ducts. It is the only small one and is middle of the trailer right between the black & grey tank in my enclosed underbelly.

The term heated underbelly is generally from the furnace, but tank heaters are an additional level of protection. They are not hard to install, but accessing the bottom of the tanks to install them and run the wiring is the hard part. Other than that you just need a spare fuse spot on the DC distribution panel to run the wiring from. It goes from there to a switch (or two if you want to split them) and then to the heater panels which stick to the underside of the tanks. You man also need to protect your dump valves if they are exposed. Some models also have optional 110v in addition to the 12v. The heat panels should have a built in thermostat that turns them on at a set point, but you MUST have some liquid in the tanks when using them. That's the short version.

Depends on manufacturer. Some are now advertising that liquid in tank is not required. 60 degree shutoff temp is well below the point that the tank would be harmed if no liquid present.

[HeyBooBoo]

Thanks everyone for your help.

[aeblank]

I used self regulating 110v heat tape. I think it's 3 watts per foot. 3 each of different lengths. Traced it with the plumbing and with eternabond to the tank bottoms. It's yet unproven, but I expect it to work (or I wouldn't have done it). I don't even have pictures yet, as I did it in the dark and cold by headlamp. Being busy sucks.

[McCormickJim]

HeyBooBoo, so you want to camp year round?

I'm out in weather that is 0-5 degrees F. What temperatures will you be seeing in your Winter camping?

[NJKris]

I never got heated tanks, but if I do down the road, I priced it out, probably about 200 bucks for 3 tanks and wire/switches. IF you are handy enough to do it yourself and are willing to take down that underbelly to do it. I don't have an underbelly. Well, that's not quite true. Ugh. aging sucks.

[HeyBooBoo]

We are in Georgia but will be traveling, so I would like to be able to safely travel in the low 20s. Not sure if the whole concept is worthy - keep wondering if the pipes will freeze while the tanks warm (so is it really worth the expense/trouble to heat them?)

[NJKris]

The only time my trailer is usually below freezing is at night here in NJ. Ex: Its 25 now, and my remote sensor is showing it's 30 in the trailer, which is covered up in the driveway. I'm not sure how cold it would be if I were towing it. During the day it normally rises above freezing here. My opinion, being without heated tanks, is the first thing to worry about is exposed water lines. My FW tank to trailer line is about 5 feet, and I freeze proofed it with heat cable and insulated tape. However, that wouldn't do me much good if I had to tow it during the day in sub-freezing weather, because it plugs into A/C power from outside. When we were in one place (not towing) a couple weeks ago, it got down to below freezing in the early evening, and it got down to 17. With my pipe heater wrap and a small heater in the water filter bay, we had no freezing problems using water from an almost full 30g fresh water tank.

[5picker]

Originally Posted by NJKris

The only time my trailer is usually below freezing is at night here in NJ. Ex: Its 25 now, and my remote sensor is showing it's 30 in the trailer, which is covered up in the driveway. I'm not sure how cold it would be if I were towing it. During the day it normally rises above freezing here. My opinion, being without heated tanks, is the first thing to worry about is exposed water lines. My FW tank to trailer line is about 5 feet, and I freeze proofed it with heat cable and insulated tape. However, that wouldn't do me much good if I had to tow it during the day in sub-freezing weather, because it plugs into A/C power from outside. When we were in one place (not towing) a couple weeks ago, it got down to below freezing in the early evening, and it got down to 17. With my pipe heater wrap and a small heater in the water filter bay, we had no freezing problems using water from an almost full 30g fresh water tank.

Your trailer will only be as cold towing it as whatever the ambient temperature is.

So if it is 30° outside, the temperature of the R/V won't be any colder towing.

Wind chill only pertains to the evaporative skin of living things.

Now, a trailer that its mass is at 35° will cool to ambient temperature quicker with wind blowing over it but it will never be below ambient temperature.

[NJKris]

Now, a trailer that its mass is at 35° will cool to ambient temperature quicker with wind blowing over it but it will never be below ambient temperature.

That is what I was getting at. If I was towing it in 25 degree temps, the wind blowing over it will likely bring the inside temp down inside to the same temp pretty quickly, as opposed to parked. I don't intend to tow it or wet the plumbing when day time temps stay below freezing.