Putting heater under trailer?

[jasin1]

Originally Posted by JRTJH

Looking at your photos, I have a few observations and suggestions:

1. You installed foam board around your trailer, but failed to extend that foam board up the sides of your slide. What you didn't do was help insulate the rubber seals around the slide opening and add insulation to the 1" slide sides. If I were you, I'd extend the foam boards up along the slide sides, paying attention to getting the foam next to the rubber seals, then secure the foam using tape to help seal any drafts away from the rubber seals. You can cut out the space for the windows if you prefer, but that will reduce the insulation at the single pane window locations. You can also put foam board on the roof of the slide and under the slide if you want. Those locations, like the sides, are minimally insulated and anything you do to improve the r value will help keep you warmer. Also consider that those rubber seals are located on both sides, top and bottom of the slide opening and anything you do to help reduce drafts will keep you warmer.

2. Now, my take (for what it's worth) on heat under the trailer: As air warms, it expands and increases the capacity to hold moisture. Moisture collects (condenses) on cooler surfaces pulling that moisture out of the "warmer air".... What does that mean for you??

By putting a heater under your trailer, you're going to warm some of the air and help that air to pull moisture from the ground under the trailer. That moist air will then condense on the inside of the foam, along the exposed frame rails of your trailer and the J-wrap that is not as well insulated as the underbelly. So, in short, what you'll be doing by putting a heater under your trailer is wasting electricity (it won't keep you warmer) and increasing condensation under your trailer which will reduce the r value of your fiberglass insulation in the underbelly, increase humidity and potentially enhance mold/mildew formation and create a "perfect storm" for rust/corrosion on your undercarriage.

I'd think through the "heater operation" under your trailer. It likely will make things worse rather than better.

Is it feasible to drop part of the underbelly and try and insulate and add heat tape to the waterlines under the rv? use pipe insulation and even add a bunch of batt insulation while you have it open? seems like it would be a pain but only need to do it once…could also add a second heat outlet to the underbelly if you live in a cold climate…be nice if you could create a pipe chase that all the lines went thru that would heat easily…i feel like most people look at the underbelly as some mysterious place you shouldn’t mess with…and i realize it’s a mess under there but anyone with some plumbing skills could make it a lot better

[GlasNav]

I have a friend that worked in North Dakota oil fracking. The company bought a batch of "All Season Rated" travel trailers with polar packs. The winter conditions laughed at the weak attempt, and my friend made a bunch of extra money addressing the issue to make the trailers sort of habitable in the extreme conditions. He completely boarded sealed and insulated the sides and used 110V heater tape on the exposed piping wrapping over the heater tape with insulation and a flap to access the valves. No heater under the trailers. Some of the workers even added bales of hay around the sheathing.

[JRTJH]

Originally Posted by jasin1

Is it feasible to drop part of the underbelly and try and insulate and add heat tape to the waterlines under the rv? use pipe insulation and even add a bunch of batt insulation while you have it open? seems like it would be a pain but only need to do it once…could also add a second heat outlet to the underbelly if you live in a cold climate…be nice if you could create a pipe chase that all the lines went thru that would heat easily…i feel like most people look at the underbelly as some mysterious place you shouldn’t mess with…and i realize it’s a mess under there but anyone with some plumbing skills could make it a lot better

Any trailer "underbelly" can always be improved on. That said, most trailers these days that do have a "real" (not "in name only") polar or cold weather package, have a sealed underbelly with foam enclosing the edge margins on the coroplast. If you look at coroplast, it's nothing more than a "configuration similar to corrugated cardboard" made of vinyl/plastic with lots of "square tubes arranged side by side". The "secret" to making coroplast act as insulation is to trap "dead air" in those square tubes. Keystone does that by using expanding foam on the edges as the coroplast is placed on the inverted trailer bottom and then "screwed or shot" in place so it won't move when the trailer is flipped on its axles.

Sealing the coroplast traps air in the square tubes and causes the coroplast to act more like a vacuum bottle than a thin plastic sheath. Then add that layer of "mylar coated bubble wrap" on top of the coroplast and you have a relatively functional "thermal barrier" on the trailer bottom. Then, when you add the "fiberglass insulation that's wrapped in DARCO" that actually forms the floor assembly of the trailer, there's a "dead air space" between the coroplast and the actual trailer floor with the heat ducts, electrical runs and plumbing runs. Then, most of the plumbing runs are, where feasible, above the trailer floor, along the sides/ends of the trailer, adjacent to the walls at the back of the cupboards, which is why the cupboards need to be left open in colder weather, so some cabin heat can reach the PEX tubing along the wall of the trailer, where it's usually subject to freezing is the cabinets are closed.

The "inefficiencies" come from the uninsulated steel frame rails along each side of the underbelly and the multiple holes in those rails (for slide rams, electrical and water lines to be routed, hydraulic hoses for leveling systems and the "multiple floorplans" that are built on each frame assembly. You might have several 2" holes in frame rails that would be used in one floorplan that are simply "places for cold air to get into the belly" on another floorplan. Covering or sealing those holes, making sure the edges of the coroplast are covered/sealed so they have "dead air" not "free passage for cold air" help keep the belly as warm as possible.

On most of today's trailers with a "true cold weather package", there's no exposed plumbing under the trailer and usually only the "45 degree or straight down) 3" dump for sewer connections is exposed. Where there are plumbing runs in the belly, typically there's a furnace vent duct adjacent to keep warm air near the plumbing runs.

Using a "thermostat controlled heat tape" on any city water connection, making sure the campground spigot is protected as well and then sealing/insulating the city water port on the side of the trailer helps. On trailers with a "enclosed convenience center" for those connections. Many people will use a "red rubber plunger" and unscrew the handle, put it on the shore power cord and city water hose and then push it down from the top so it completely seals the convenience center entrance hole. Others I've seen just use a big sponge or a piece of foam to push into the hole to keep cold air out of the convenience center. If it's particularly cold (like North Dakota cold) I'd hang a drop light with a 40 watt incandescent bulb inside the convenience center. REMEMBER: LED bulbs don't produce enough heat to protect the area from freezing, you'll need an incandescent bulb that gets hot to provide the freeze protection. Most people know that, but I've seen more than a few LED 800 lumen bulbs hanging next to water valves that have frozen and split, so not everyone is aware not to use LED's to provide heat......

If the gray tank valves are kept closed and only dump when the tanks are full, then completely drain any standing water out of the sewer hoses, they usually won't freeze. However, if someone leaves the gray tank valves open (for convenience) then the slow drain will allow ice (frozen gray water) to build up in the sewer hose and it will eventually freeze, blocking the gray tanks and preventing them from being dumped. That ice can "freeze vertically" and completely plug even a vertical 3" dump fitting, and once frozen, it takes a "massive effort" to thaw it, hopefully without damaging the trailer sewer dumps and valves. So, prevention is definitely superior to repairing once frozen.

There's lots of ways to improve on the winter protection afforded in any RV. The biggest hurdle, in my opinion, is many people don't take the time to analyze what is already on their trailer, determine "WHY" it was built that way and the reasons it's constructed like it is. After all these years, the engineers at Keystone and all other manufacturers don't just "wake up one morning and say, "Duh, let's build a new floorplan and see if it works". They use past experience, tricks of the trade that are completely lost on most owners and rely on what "works well for the past 30 years" with every trailer they design. Then they test them to make sure their "past successes still are effective"....

I know it doesn't seem like they know what they're doing most times, but it's usually not the engineering design that fails, it's usually the inability of workers to easily incorporate the design or more often, the interior designers who want to move plumbing 6" one way or the other, which means it's not in the right place "down below" and the "fails in practical use" issues develop.

[jasin1]

I guess i figure it wouldn’t hurt to install pipe insulation on all of the pipes under the trailer…shouldn’t be that big of a deal..In my trailer most of the water pipes are right next to the basement ….i could probably remove the wall that separated my basement and my underbelly and get to almost all of them..The kitchen island may be a bit of a stretch and the washer dryer connection may take a bit of thought.While i was at it i’d probably install shutoff valves so i could isolate all the fixtures.

Could even leave the kitchen sink shut off and the washer dryer connection shut off at the source if i was feeling really adventurous …..i could camp in much colder temps without a kitchen sink and washer…thereby taking out the remote runs from the freeze equation….but id still have a toilet and shower

this is if you treat the rv basement the same as a crawl space in a regular home, as far as insulation and freeze prevention…in a home you wouldn’t think of leaving the pipes uninsulated in colder climates….if you never camp in the cold then i guess it doesn’t matter

[JRTJH]

Originally Posted by jasin1

...

this is if you treat the rv basement the same as a crawl space in a regular home, as far as insulation and freeze prevention…in a home you wouldn’t think of leaving the pipes uninsulated in colder climates….if you never camp in the cold then i guess it doesn’t matter

Just remember that insulating plumbing in the belly of an RV is a bit different than insulating it in a crawl space of a S&B house.

In a house, the heat ducting is insulated to keep heat inside the duct runs and the crawl space is unheated and usually vented to help keep the space from collecting excess humidity.

In an RV, the heat ducting is not insulated so the radiant heat can help warm the space around it, which is where the plumbing runs are usually located. The belly is normally not intentionally vented.

In a S&B, you want to protect the pipes by insulating them from the colder air in the crawl space which is usually unheated but in an RV belly, you want to expose the pipes to the warm air in the uninsulated ducts to help prevent freezing...

Plus, in an RV, if the pipes do freeze, you want them exposed to the radiant heat to hasten thawing, so insulating them would delay recovery of the plumbing function..... Sort of the opposite way of thinking than in a S&B...

Now as for your galley island and the washer connections, putting valves on them would allow you to either use air to blow the lines clear or even allow you to add antifreeze to those parts of the plumbing. Essentially, what you'd be doing is "creating zones" to better manage the plumbing, protecting parts of the system while using other parts. That could get complex, but is workable with enough effort and understanding of the system, its layout and its limitations.

But, as a general rule, insulating RV plumbing next to a heat duct run is counterproductive as it makes recovery more difficult once it does get "too cold"....

ADDED: If you compare the two, RV's and S&B's, they use two different "processes" in cold weather management. In a S&B, the "mantra" is to conserve energy and BTU's by insulating/protecting pipes in the crawl space and only expending BTU's above the floor in the inhabited space. In an RV, the "mantra" is to expend energy and BTU's in the belly to heat it using cabin (inhabited space) heat to warm the belly. Significantly less efficient use of propane than in an S&B, but attempting to convert from one concept to the other could prove to grow more problems than it would solve.

[jasin1]

Originally Posted by JRTJH

Just remember that insulating plumbing in the belly of an RV is a bit different than insulating it in a crawl space of a S&B house.

In a house, the heat ducting is insulated to keep heat inside the duct runs and the crawl space is unheated and usually vented to help keep the space from collecting excess humidity.

In an RV, the heat ducting is not insulated so the radiant heat can help warm the space around it, which is where the plumbing runs are usually located. The belly is normally not intentionally vented.

In a S&B, you want to protect the pipes by insulating them from the colder air in the crawl space which is usually unheated but in an RV belly, you want to expose the pipes to the warm air in the uninsulated ducts to help prevent freezing...

Plus, in an RV, if the pipes do freeze, you want them exposed to the radiant heat to hasten thawing, so insulating them would delay recovery of the plumbing function..... Sort of the opposite way of thinking than in a S&B...

Now as for your galley island and the washer connections, putting valves on them would allow you to either use air to blow the lines clear or even allow you to add antifreeze to those parts of the plumbing. Essentially, what you'd be doing is "creating zones" to better manage the plumbing, protecting parts of the system while using other parts. That could get complex, but is workable with enough effort and understanding of the system, its layout and its limitations.

But, as a general rule, insulating RV plumbing next to a heat duct run is counterproductive as it makes recovery more difficult once it does get "too cold"....

ADDED: If you compare the two, RV's and S&B's, they use two different "processes" in cold weather management. In a S&B, the "mantra" is to conserve energy and BTU's by insulating/protecting pipes in the crawl space and only expending BTU's above the floor in the inhabited space. In an RV, the "mantra" is to expend energy and BTU's in the belly to heat it using cabin (inhabited space) heat to warm the belly. Significantly less efficient use of propane than in an S&B, but attempting to convert from one concept to the other could prove to grow more problems than it would solve.

All good points John….I have a hard time remembering that rvs are not the same as residential homes …gets me every time i think i have something figured out

[JRTJH]

Originally Posted by jasin1

All good points John….I have a hard time remembering that rvs are not the same as residential homes …gets me every time i think i have something figured out

Yep, that's why I said in an earlier post that it takes standing back and thinking about the WHY the engineers designed RV's the way they did. RV's and S&B's are very different.... Heck, when was the last time you saw a new house built with a furnace that was 55% efficient? Light your RV furnace and you'll get as much heat "blown out the exhaust vent" as you get blown into the ducts. A furnace with that efficiency rating would NEVER be allowed in any modern construction, yet every RV produced this year will have the same Suburban or Atwood furnace rated at 35K BTU and blowing 15K to 20K of those BTU's out the side of the trailer.... Most RV furnaces, if you think about it, have a built in "smore maker" as standard equipment. You'd never be allowed to install that kind of furnace in a S&B.....