Insulation R-Value Question

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
My door is better made than roadking's, with fiberglass insulation packed inside, but it's still almost half glass (dual pane, but still a major heat sink). Another major heat loss/gain area is the windshield on a motorhome, but there isn't much to be done about that.
 
The Driver's door and the entry door on ours has zero insulation.  ::)  I agree that they should put something inside these things!  Winnebago should also use a "wrap" around the walls before the luan and fiberglass exterior for minimal weight gain and extra R-Value.

We take our unit to Breckenridge in a couple of weeks, and will be using electric heaters in both water bays, and electric heaters, the furnace and our "fake" fireplace inside.....and still will have cold air circulating in the cockpit area.  ::)

Where we live, R-Values (and air conditioning capacity) are going to be a much more important factor on our next motorhome purchase! 
 
Every little addition of insulation you can add helps.  The windshield is a major problem, but in our old Class A I carried 2 pieces of R- 4.76 foam cut to fit the inside of windshield.  Many times just before bed on cold nights I slipped them in and they made a noticeable difference.  I carried them in the back of the closet.  A friend added 1" of foam insulation in the back of all the cabinets, both uppers and lowers.  It made a big difference in winter and the cabinets stayed cooler in the summer.  Another friend went another step by adding insulation to the inside of the front cap over the cabinets.  Our old MH had none there and the new is the same.  I plan to spend part of my winter down south adding insulation to ours.  I'm still thinking the rear cap would be a easy way to add foam type insulation to and would add next to nothing weight wise.  It might even help cut down on the outside noise.  One thought was to seal the bottom shut, then make an access hole to blow foam pellets into the opening.  It might settle a little at the top over time, but again any thing added is a help.  I sure would like to hear others thoughts on ways to add some insulation, it's very low cost project for the good it may do.
 
Interesting idea adding foam to the back of cupboards.  Makes sense.

I'd be a bit concerned about flammability or toxic gases in the event of a fire.  OTOH you should be evacutating fairly rapidly.
 
Tony_Alberta said:
Interesting idea adding foam to the back of cupboards.  Makes sense.

I'd be a bit concerned about flammability or toxic gases in the event of a fire.  OTOH you should be evacutating fairly rapidly.
Click to expand...

I can understand the concern.  I watched the local fire department at a training session try to extinguish a interior RV fire.  After seeing how fast fire spreads through an RV I think the heat might get you before the toxic gases do.  It's just unreal how fast they burn.  It's like one second there was a little fire and smoke and the next second the whole interior was on fire. 
 
Dad was telling me of the building the milk distributor put in the early 1960s in Thompson, Manitoba where it gets real cold in winters.  It was a metal structure and one of the first to ever use a spray on foam.  Dad told me of how a fire started in the back.  The guy near the fire was running to the exit at the front of the building and the flames and smoke almost got to him.  Now I'm sure building codes are much stricter.

Of course what about all the plastics and foam already in your RV?  Such as chair and couch cushions or bed?

Tony
 
We are in San Benito TX. and last night it was about 45. The 2 slide out bedroom windows are a bad source of heat loss. I personally would not want them in the bedroom. I can feel the cold while my head is near them. Without the windows it might be a little darker in the bedroom which would be OK with me as I could enjoy my 3 p:m nap! 
  The gas heater is in the back under the bed. When it cycles on there is no way we can sleep. You folks who have the gas heater in the middle of the coach as I have seen on other floor plans mounted in the side should have a quieter bedroom.
 
 
Naturally, there is some value in added insulation in walls, etc but.. if there is not air leaks in the walls, windows, doors, etc, I've always been told that approx. 90% of heat loss in homes, MH, your body, etc is through the roof, ceiling, head ....  heat always rises.... Believe if the unit is relatively well sealed, added insulation in the top is 9X more effective than the total of the side and bottom exteriors.
Home in northern WI has R64 in ceiling / attic and somewhere around R19-R27 in walls....
 
It's a common misconception that heat rises. It does not. Heat flows from warm  to cold. Try sleeping on a cold water bed. It'll suck the heat right out of you.

Of course hot air does rise. This can make insulating a roof/ceiling more important as the warmer air at the top of a room wants to get to the cooler outside even more (greater delta temperature). It also makes sealing holes important as hot air rising out a leaky vent sucks cold air in somewhere else.
 
WhiteEagle said:
Naturally, there is some value in added insulation in walls, etc but.. if there is not air leaks in the walls, windows, doors, etc, I've always been told that approx. 90% of heat loss in homes, MH, your body, etc is through the roof, ceiling, head ....  heat always rises.... Believe if the unit is relatively well sealed, added insulation in the top is 9X more effective than the total of the side and bottom exteriors.
Home in northern WI has R64 in ceiling / attic and somewhere around R19-R27 in walls....
Click to expand...

Agree. That's why I use the thermo balance method. With my sleeping area in the rear of the coach..before retiring at night, I lower the front jacks about 1/2 bubble..this pockets the warm air in the rear of the coach. In the morning relevel the coach.  ::)
 
The roof is typically the best insulated part of any RV, though nowhere near residential standards.  But you still have the several skylights, vents, and a/c openings that leak a lot of heat both ways.

Another issue in RVs is that just about every vertical surface is an outside wall and you are never far from a window either. That means you are physically more aware of the heat/cold that emanates from those high heat transfer areas. We think of them as drafts. Residences, especially older ones, have cool walls & windows too, but much more of the interior space is far enough away to mitigate the effect.

The slide outs are just plain poorly insulated. Usually the slide walls, ceiling and floors are only about 1" thick, leaving almost no dead air space to insulate. It's a tradeoff of space vs comfort, and probably a poor one when viewed objectively, but the appearance of spaciousness in the interior is a big selling point so every inch counts.
 
You must log in or register to reply here.

Latest posts

Members online

Total: 779 (members: 26, guests: 753)

Forum statistics

Threads
132,147
Posts
1,391,002
Members
137,864
Latest member
Tim Dunn
Back
Top Bottom