Air Conditioner Improvements

[awwall]

Borrowed this from another forum. Some good ideas here if you are having trouble keeping your RV cool in the summer. I plan on doing the dog house insulation recommended.

"Air Conditioner Modification by Gordie Kaltz

The largest heat gain is from the front windshield, if you install the foil bubble insulation on the windshield while parked it will drop the temp by some 10 degrees, also remove the filters and look straight up and look at the cooling fins, if they are black or brown they need to be cleaned. I did make some mods to the roof a/c's that have improved the performance, anyone can e-mail me off line for the info. I currently can hold 77 degrees inside at 115 outside with direct sun, that is with the windshield blocked off. If you’re looking for maximum a/c performance you’re going to have to do your homework, the fix is not to install a larger unit(s).


Here are the modifications that I have been e-mailing off line. Let me start by saying that after I did the mods I have been happy with the 2-13.5K Duo-Therm's (low profile).

Start by taking of the fiberglass covers, you will see a foam seal between the cover and the condenser coils; replace it with a closed-cell foam seal available at Lowe's. While the covers are off clean the condenser coils with coil cleaner foam available at Lowe's.


Now, next up front of each unit you will see a galvanized steel "dog house". Remove all the screws and remove the covers - this is the evaporator dog house. It is where the unit sucks in the air from the coach and passes it across the evaporator coils to cool it. Go to Lowe’s or Home Depot and get that foil coated bubble insulation, and a can of 3m "77" spray adhesive. What I did was cover the entire evaporator "dog house" both inside and outside with the foil bubble insulation. I even covered the sides, you have to remember that all that is between the outside cover (fiberglass) and the evaporator coil was the dog house. The heat load on the cover is tremendous, and even the foil bubble insulation may not look like much, but it works! While you have everything apart, make sure you have a good seal between the discharge of the A/C and the roof duct-work entrance. I had large holes in mine - fixed that with foil tape at Lowe’s for hot water tank flue's. Cut and piece together a good solid seal between the roof opening (you may have to remove the metal control box to make sure you get a good seal to the roof ducts). Also check every roof discharge opening so that it has a good seal to the duct work that runs the length of the roof on each side.

Use the 3M “77” spray adhesive this way: cut your insulation pieces to fit each part that you want to insulate, then spray the 3M stuff on the galvanized metal and let dry. Then spray on your foil insulation; let dry, then press into place.

You may think these are small items, but they add up! I had considered replacing both units with the 15k units, but after I made the modifications, there is no need to replace them.


We live in the desert southwest and routinely camp in Vegas or Lake Havasu. Here's another item....Currently in South Texas and if I run the A/C's on low or med the roof discharge registers sweat because they get so cold, so I know the insulation on the evaporator dog house has done the trick. Also, I forgot to add to clean out the squirrel cage blower for the condenser.

Gordie Kaltz"

[SaskCampers]

Very good info. Looks like some more work to be done now.

[donanddona]

Got Pics?

[mike2wheels]

Did someone mention a cleaner they used on the A/C parts or would Simple Green work?

[Tiggerdad]

Product called "Koil Cleaner" is available at Home Depot and I believe Lowe's. Have a friend who has his own A/C business and he avoids Koil Cleaner as it has a high Ph and long tern use can damage aluminum. He uses Dawn or similar products in a pump up sprayer. By using a sprayer, it penetrates deeper into the coils that the aerosol Koil Cleaner and in his opinion cleans just as good.

[Herk7769]

Going to do this mod (the foil bubble insulation) before Gettysburg in July.

[fivecodys]

Originally Posted by herk7769

Going to do this mod (the foil bubble insulation) before Gettysburg in July.

Hi Lou,
If you do this mod, will you take pictures and post them for us?
I'm very interested in this.

Many thanks,

Bill

[Freds342]

I have the foil bubble stuff that I use when I have the MoHo parked, but I like having the open windshield when I'm parked with a view.

I have five tractor-trailer springy shades that I use in the windshield when it gets too hot at the lake in the afternoon. Easier to install and remove, and easier to store on the road.

I leave the foil/foam thingies in the bedroom windows all the time, unless I want a breeze. My wife is ill, and naps quite a bit.

[Herk7769]

Originally Posted by fivecodys

Hi Lou,
If you do this mod, will you take pictures and post them for us?
I'm very interested in this.

Many thanks,

Bill

As (almost) always! Will do.

[ryand]

To the OP....Thanks for the effort!

[checca]

Thanks for the idea, I also covered in entire a/c unit cover with foil bubble wrap on the inside. The idea is to keep as much as the suns heat load off the a/c unit.