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Roof Treatment for Summer Heat
What has anyone used for reflecting heat on Summer days?
LD 22', 1989 Custom Build. Chassis 1990 Chevy Van G30, 5.7l.
Re: Roof Treatment for Summer Heat
Reply #3 –
Nothing that I know of except trees or a 'cover' of some sort offers shade for the roof, but many people use Reflectix to insulate the windows against heat and/or cold. (Cut to shape/size of the windows)

Double Reflective Insulation | Reflectix, Inc.

Paying attention to the orientation of the rig (if possible) and using the awning as shade can also help with heat management. Try to avoid have the refrigerator compartment in direct afternoon sun (the awning may help with that).



2003 TK has a new home
Re: Roof Treatment for Summer Heat
Reply #4 –
Quote from: Mindispower  - 
What has anyone used for reflecting heat on Summer days?

Please try to resist the urge to coat the roof with some miracle product guaranteed to lower the interior temps.
Yes, there are latex coating products that will lower interior temps but the use of them will make any future roof sealing and leak detection a big problem. Once the coating starts to break loose, and it will, it is a huge mess to deal with.

My 1983 LD had such a coating, done by the previous owner, it took many hours of scraping to remove it, once it started breaking down and loosening.
It's a project you may wish to avoid.

My advice is to find a tree or a cooler climate. The use of the awning and shade canopies can help cool the side walls of the LD and the surrounding area.

Larry




Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Roof Treatment for Summer Heat
Reply #5 –
I've seen people use Reflectix, but it's a bit of a disaster.  They were basically spending the season in 1 spot, so the Reflectix didn't have to stand up to driving.  Still, even a light wind would cause problems.

I suppose some of us use solar panels....

Rich
'03 MB in NC
2003 MB
Re: Roof Treatment for Summer Heat
Reply #6 –
Quote from: rich  - 
I suppose some of us use solar panels....

Solar panels are black and absorb heat, negating any effect of shading the roof.
Only about 15% percent of the sun's energy is converted into electric power, the rest is converted into heat
I see little difference in ceiling heat, using an infrared camera, under the solar panels.
Tilted panels may have a shading effect, with more air moving around them.
This does require an east-west parking orientation to get maximum shading and power.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Roof Treatment for Summer Heat
Reply #7 –
Quote from: Larry W  - 
I see little difference in ceiling heat, using an infrared camera, under the solar panels.

That's interesting.  Conventional wisdom for houses is different:

Solar panels help shade and insulate buildings, study shows | Human World |...

My guess would be that the space between the roof and panel is larger on the house. 

Rich

2003 MB
Re: Roof Treatment for Summer Heat
Reply #8 –
"I've seen people use Reflectix, but it's a bit of a disaster.  They were basically spending the season in 1 spot, so the Reflectix didn't have to stand up to driving.  Still, even a light wind would cause problems."
---
The use of Reflectix that I'm familiar with is on the inside of the windows, so a wind of any force wouldn't affect it. The material is cut to fit the window to insulate the rig's interior against cold or heat when the rig is parked. The Reflectix is usually taken down and stored, e.g., under the couch cushions, when the rig is being driven.

Yes, quite a few owners have solar panels on the roof, but I missed why this would have any relation to 'reflecting heat'?
2003 TK has a new home
Re: Roof Treatment for Summer Heat
Reply #9 –
Quote from: Larry W  - 
Please try to resist the urge to coat the roof with some miracle product guaranteed to lower the interior temps.
Yes, there are latex coating products that will lower interior temps but the use of them will make any future roof sealing and leak detection a big problem. Once the coating starts to break loose, and it will, it is a huge mess to deal with.

My 1983 LD had such a coating, done by the previous owner, it took many hours of scraping to remove it, once it started breaking down and loosening.
It's a project you may wish to avoid.

My advice is to find a tree or a cooler climate. The use of the awning and shade canopies can help cool the side walls of the LD and the surrounding area.

Larry





Yes, let's face it RVs are just "tin" boxes that get beastly hot in direct sun. Orienting the LD lengthwise, following the path of the sun helps a little. Our bedroom is in the rear so I let it get the late sun. It cools off by bedtime here in the non-desert West.

Chris
Formerly: 2002 30' IB
Re: Roof Treatment for Summer Heat
Reply #10 –
My solutions are all common-sense stuff. I park in the shade if possible. I orient north-south if possible. (If oriented east-west, the sun would shine broadside on the south side of the rig for most of the day.)

If shade is limited or unavailable, I use Reflectix that's cut to fit inside the sun-exposed windows. If the cab is exposed to sun, I use a thick comforter to block it off from the rest of the coach. Of course I open as many windows as I can and turn on exhaust vent fans to suck out hot air from the ceiling.

If I'm parked in shade, my roof solar panels are shaded, so I use solar panels laid on the ground in the sun at the end of a 30' cable. "Solar suitcases" are convenient, but cost twice as much per watt as plain panels. I just set out a couple of Renogy 100 W panels, connected in series to minimize voltage drop in the cable.
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Roof Treatment for Summer Heat
Reply #11 –
Quote from: Mindispower  - 
What has anyone used for reflecting heat on Summer days?
The best method is to remove heat that manages to get in, and the best solution is ceiling vent fans, Fantastic Fan or others.

Steve
2004 FL
2013 Honda Fit
Re: Roof Treatment for Summer Heat
Reply #12 –
This is a image of the inside clock.   Yes it was 114 outside.    We were at Big Bend National Park.   We tried dry camping but the heat drove us to camp with power.    With the AC at 100% we were able to get the temp inside to the 80s.   In my opinion that proved the LD was well insulated.   We put a thick blanket across the cab area to cut out the heat from the front large windows.

personal fine art photo stuff
TF Mack | Flickr
It's all good .......
2014 Twin King
Re: Roof Treatment for Summer Heat
Reply #13 –
Quote from: colddog  - 
This is a image of the inside clock.  Yes it was 114 outside.    We were at Big Bend National Park.  We tried dry camping but the heat drove us to camp with power.    With the AC at 100% we were able to get the temp inside to the 80s.  In my opinion that proved the LD was well insulated.  We put a thick blanket across the cab area to cut out the heat from the front large windows.


A 31 degree temperature drop is the maximum drop I have seen with the roof A/C and this is in a short LD, with less interior footage than the longer models. Larger models should expect less temperature drop.

Note to self, stay out of Big Bend NP during the warm season.
Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Roof Treatment for Summer Heat
Reply #14 –
Quote from: Andy Baird  - 
My solutions are all common-sense stuff. I park in the shade if possible. I orient north-south if possible. (If oriented east-west, the sun would shine broadside on the south side of the rig most of the day.)

If shade is limited or unavailable, I use Reflectix that's cut to fit inside the sun-exposed windows. If the cab is exposed to sun, I use a thick comforter to block it off from the rest of the coach. Of course I open as many windows as I can and turn on exhaust vent fans to suck out hot air from the ceiling.

If I'm parked in shade, my roof solar panels are shaded, so I use solar panels laid on the ground in the sun at the end of a 30' cable. "Solar suitcases" are convenient, but cost twice as much per watt as plain panels. I just set out a couple of Renogy 100 W panels, connected in series to minimize voltage drop in the cable.
 "I orient north-south if possible. (If oriented east-west, the sun would shine broadside on the south side of the rig most of the day.)"

I use the awning for the S side when oriented e-w.

Chris

Formerly: 2002 30' IB
 
Re: Roof Treatment for Summer Heat
Reply #15 –
Quote from: Mindispower  - 
Yes. Obviously the first step is finding shade. But beyond that?
The principle is that of putting aluminum shade covers on the dash when parked. Is there a paintable product for the roof?
LD 22', 1989 Custom Build. Chassis 1990 Chevy Van G30, 5.7l.
Re: Roof Treatment for Summer Heat
Reply #17 –
"I use the awning for the S side when oriented e-w."

Of course, I should have mentioned the awning. I tend to forget about it because I've never used mine much--first because of fear of wind gusts, and second because in three RVs I've broken three awnings in tree encounters. (It seems I cut my turns too tight, a bad habit that I still haven't entirely cured.) But yes, by all means use the awning for shade.

"Is there a paintable product for the roof?"

Your roof is already painted white, and contrary to what common sense would suggest, white reflects more heat than silver. (Touch your chrome bumper on a sunny day if you don't believe this.) That's why even  Airstream, whose all-silver trailers are iconic, switched to painting their roofs white: it's cooler that way.

Take Larry's advice: using a roof coating on a Lazy Daze invites a world of hurt later on.
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Roof Treatment for Summer Heat
Reply #18 –
Quote from: Mindispower  - 
The principle is that of putting aluminum shade covers on the dash when parked. Is there a paintable product for the roof?

No product to recommend, but a VERY STRONG warning about snake oil products, since there are many out there on the market targeting unsuspecting RVers.

There are a number of roof coating products out there that make claims of increasing R-value.  Talk of NASA and other governmental agencies doing the research, etc.  Excuse the phrase, but "horse hockey".  The only way to truly increase real R-value is thickness.  None of these materials is applied in any thickness that it would significantly affect R-value.

What these coatings do is reflect light, because they are white.  The studies references for US Navy uses, etc., were for pipes painted dark colors vs. a white coating.  It's the white color that increases effective R-value over non-white surfaces.  The REAL R-value remains virtually the same.  Your LD roof is already white.  Material used by NASA?  Many inches thick, not several mils thick, for the reported improvement.

Most of these coatings are too fragile to withstand being walked on or scratched by a tree branch.  Most are not as durable as good old clean white paint (with sand/glass beads for traction).

If this stuff were really that good, every house in the southern US would have their roofs coated with it.  There are, in fact, lawsuits against some companies for their fraudulent, misleading claims.

Keep your roof clean, keep it white, and park in the shade.
Re: Roof Treatment for Summer Heat
Reply #19 –
Quote from: Michelle C  - 
No product to recommend, but a VERY STRONG warning about snake oil products, since there are many out there on the market targeting unsuspecting RVers.

There are a number of roof coating products out there that make claims of increasing R-value.  Talk of NASA and other governmental agencies doing the research, etc.  Excuse the phrase, but "horse hockey".  The only way to truly increase real R-value is thickness.  None of these materials is applied in any thickness that it would significantly affect R-value.

What these coatings do is reflect light, because they are white.  The studies references for US Navy uses, etc., were for pipes painted dark colors vs. a white coating.  It's the white color that increases effective R-value over non-white surfaces.  The REAL R-value remains virtually the same.  Your LD roof is already white.  Material used by NASA?  Many inches thick, not several mils thick, for the reported improvement.

Most of these coatings are too fragile to withstand being walked on or scratched by a tree branch.  Most are not as durable as good old clean white paint (with sand/glass beads for traction).

If this stuff were really that good, every house in the southern US would have their roofs coated with it.  There are, in fact, lawsuits against some companies for their fraudulent, misleading claims.

Keep your roof clean, keep it white, and park in the shade.
Thanks a lot.
LD 22', 1989 Custom Build. Chassis 1990 Chevy Van G30, 5.7l.
Re: Roof Treatment for Summer Heat
Reply #20 –
On solar panels and shading...  A solar panel placed in direct contact with the roof, or with ventilation underneath blocked, is likely to add heat from conduction.  As Larry said, the panels are dark and get quite hot.  A panel with a few inches of air space between the panel back and the roof will shade the roof to some extent.  The function is similar to a heat shield.  The underside may be quite warm but the radiant heat transfer is less than that from sunlight.

I have to say that most of the heat I get in my rig on a hot summer day comes from sunlight coming in the windows.  If I remember to pull the shades, open two windows and run one of the ceiling fans, the inside temperature will sit within a few degrees of the outside temperature.  If I leave the shades up, the interior gets hot fast.  That being said, I have not been to Big Bend in the summer, nor do I want to experience it!

Ken F in NM
'08 MB
Re: Roof Treatment for Summer Heat
Reply #21 –
I was amazed last summer at how much cooler my midbath stayed after I put reflectix in the bathroom skylight. Maybe because of its location, but the entire house cooked down.
Susie
2007 MB
Re: Roof Treatment for Summer Heat
Reply #22 –
Quote from: sdever2000  - 
I was amazed last summer at how much cooler my midbath stayed after I put reflectix in the bathroom skylight. Maybe because of its location, but the entire house cooked down.
Susie
I did the same thing after a remote thermometer read 115.   It really helped.
Joel
Joel & Terry Wiley
dog Zeke
2013  31 IB   Orwan   / 2011 CRV Tow'd LWEROVE