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Well-known member
Feb 22, 2006
new castle pa.
This is part of an old question that i had. I have wrote about my air conditioner not cooling my mh. You have given me many great answers. So help me with this. I just checked my air conditioner using a thermometer. outside temp. is 75 with low humidity. When I put the thermometer right on the air conditioner it says 48 That is after 15 min. Can my 89 mh  be that hard to cool off ?That is with the sun right on it [ no shade ] I would say my air is working. Any other ideas
thanks jiggs

Outside air temperature AND relative humidity determine how cool you can expect your a/c outlet temperature to be, but this alone doesn't tell you how cool you can expect your coach to be. Even with a reading of 48 degrees at the a/c outlet, that doesn't mean there is enough air flow at that temperature to make up for all the heat that's coming inside. Outside temp and humidity does not take into account the heat load of direct sunlight on exposed surfaces like the outside of your MH. If it were painted white, or better yet silver, it would reflect much of the sun's rays and help the air conditioner maintain a comfortable inside temperature.  A dark colored surface absorbs a lot of heat from the sun, and sometimes one or even two a/c's can't keep up with the heat load. Some suggestions are awnings, window tinting, parking under trees, covering skylights and vents with insulating material, etc. I'm sure others will have suggestions as well.
Back in the "good old days" insulation in RVs was a joke and few rigs had dual pane (thermal) glass either. I would say it is quite likely it will be rather hard to cool your motorhome, especially once it gets thoroughly warm inside. Cabinets, appliances, etc. hold a lot of warm air and stored heat, so it is best in such rigs to never let it get too warm to start with. If a hot day is expected, turn the a'c on while the inside temp is still down where you would like it to be - don't wait until it is already hot inside.

As Karl says, you may not have a lot of cold air flow, even though it is 48 degree air. Is your a/c a ducted unit with outlets spaced around the mh or does it exhaust all the cold air direct from the underside of the unit itself?  Ducted systems distribute the air better and give the interior a more uniform temperature.
Update...... I just got back from camping.  The air conditioner worked great. The temp got to mid 80's - 90's . Inside i could cool the mh down to 65 degrees. I was able to park in the shade at this new campground. I believe the poor insulation. single pain windows and sitting in the direct sun was too much for the one air to cool it off. Thanks for all your help and ideas jiggs
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