This article will discuss techniques, equipment and how to’s for maximizing our roof top AC, cooling the inside of our 1987 32 foot Avion when we attended a rally at an open field fairground in TN in late June.
**we did have 30 amp shore power! We have installed a EasyStart system on our AC which does enable us to run our AC off of our 2200 Honda generator if no shore power is available. Kevin converted our generator to run on LP as we do not want to carry gerry jugs of gas and we have two 40lb LP tanks on front always anyway.
Temps ranged from 90 to 98° all week with 75 to 95% humidity! Using these techniques our AC functioned well WITHOUT AN AIR CONDITIONER FREEZE UP and we kept comfortable.
Note: Your situation is going to depend on the type and BTU of rooftop AC you have and length AND floorplan of your Avion. We have a front kitchen, mid bath and rear bedroom. We have all the original spray foam insulation and insulated layer of our original flooring too which we feel is outstanding and helps a lot!!
Our AC Unit is a 1500 Dometic brand. It is approximately 4.5 to 5 years old. We clean the fins and filters annually as part of our spring shake down. Wr clean the inside filter and cover routinely as needed which on our trip had been 3 weeks in it needed it. If you are in a high wind/sand/dirt location you will need to do the exterior and interior AC cleaning more frequently. We have the supplies we use on our Amazon list on our Resources page on this website.
We found to avoid a freeze up of your AC in extreme temps and/or prolonged use needs that you should keep all four directional vent slots inside on your ceiling open. This allows proper air circulation and helps air flow around the condenser to allow proper cycling on and off.
****IF you do get a freeze up and your AC stops working (but you have power and its just not blowing, the compressor is not coming in) .you peobably have a freeze up. Turn the swtich to FAN and temp dial to off or warm. So you are just using the fan mode, let it thaw. It could take an hour or more. You may want to put a bucket underneath to protect flooring or carpet should it drain inside. (It may drain inside if you are not completely level or if any of the weep holes on the AC roof cover are blocked)
AC SETTINGS: this will depend on temps outside. As an example the best you can hope for is to maintain the inside of your rig at 20° below the outside temp. Believe me it will feel great! So when the temp outside was 98° with 90% humidity we ran our AC on coolest setting but low fan during the day when we were out and about doing seminars, social events etc when at the rally.
*it is important to try to NOT let your rig heat up during the day and expect to cool it off starting the AC at 5 pm for a cool night sleep. Keep your rig cool all the time and the system will run more efficiently and work less hard.
TIP: We found by closing our bedroom privacy curtain we could keep the main part of the coach cooler with lower temp setting on the AC so it did not have to work so hard. We did this during the day and opened the curtain to get air back into our rear bedroom beginning around 5 pm.
When our day away from the rig was done and we were in for the night we could lower the temp dial a little as the sun went down and things cooled down a bit to the 80s to high 70s. While in the rig we kept the fan mode on high fan dial on high for all night.
Reflectix in Windows: On our way to TN we purchased 2 rolls of 45 ” reflectix. Hindsight, one 50 ft roll would have probably been enough. However, Later on as time permits and in cooler temps to work on projects I will be lining the interior outside walls of our cabinets with Reflectix sheet panels too. I noticed the interiors of our cabinets, especially the uppers were warm. We have seen Airstreamers mention this lining of cabinets works well. Again, if you are lucky to have shade on the rig this may not be totally necessary. We were in an open field and surrounded by huge 5th Wheels and Class A’s so we only got breeze when there was any from front to back.
TIP: measure your windows with a fabric tape measure so you get true interior dimensions of inside tracks of windows without screens. Cut your piece at least a 1/2″ to 1″ larger so you can crease and fold the edges for a super great fit on those stationary windows. Use velcro, painters temporary tape to secure panels that go over screened windows as you will not have those deep tracks like the fixed windows do and it’s basically a flush mount.
Auxiliary Fans: we always carry 2 small electric powdered fans with us. They are about 9″ low profile and very quiet. In hot temps we use them on the floor in hall to push cold air towards bedroom at night. In winter temps we may use one to even better circulate warm air from furnace if needed to one area.
Dehumidifier: after doing research we bought a dehumidifier to keep the humidity at between 30 and 40%. Again this helps the air conditioner by transferring the moisture out of the AC and thereby run more efficiently with less effort. A good video pu lished by the RV School staff in TX on the rationale for this is saved in our YouTube Library for you to view. Good info! We had little options on sizes buying on the road and needing quick. We bought a 25 pints at Lowes. Overkill on the size and we will get a smaller one to take up less space once we get home. If you camp in cooler temps and run your furnace you will need a dehumidifier anyway. So we always like things that have dual purpose when space is so tight! We will get an 8 or 10 pint table top version after doing more review research.
Blinds & Curtains: keep them both closed all the time when running your AC. Yes between the Reflectix and shades down you will feel like you live in a cave…but caves are 😎 right?!!
Vent Fan Covers: we have Fantastik Fans and roof top MaxAir Covers. Our roof covers are the grey smokey color which helps to reduce sunlight and heat into the rig. Putting either Reflectix or some sort of cover on your ceiling fan opening to cover the ambient heat that comes thru these is a very good idea.
Exterior Window Awnings: we highly recommend getting window awnings installed if you do not have them. We can lower the inside temp of our Avion by 10 degrees just by deploying our 2 streetside awnings (also really helps the streetside refrig stay cooler and work properly without excess strain when in the shade), the rear window awning and bedroom awning. We leave them deployed all day even if away from the rig unless a storm or high winds are expected. They can take a lot more wind, rain etc than the main patio awning due to their size.
Speaking of the Patio Awning.…when you are physically at your Avion by all means deploy your patio awning to give shade to that side of your rig. We recommend rolling it up and storing when you are not within a “run to the rig!!!!!” quick proximity. Replacing a torn patio awning or worse, broken hardware arms etc can cost you $1000’s of $$$$!
Hughes Auto Transformer: this is a new piece of equipment for us. Kevin bought it just before our trip to the Escapee Rally because he knew we were going to be sharing power pedestals at a County Fairgrounds. The transformer basically takes your 30 amps and if you get a low voltage reading it boosts it up back to a safe zone to run your sensitive equipment like your AC. This will keep your voltage up even if there is a brown out or a neighbor is sucking more than their share of power. This is not a straight surge peotector but it does also work like that. A surge protector will simply shut down if there is a low or high spike from your shore power.
We hope these tips have given you some good tools to use to survive a heat wave.
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TRAVEL SAFE…enjoy the open road!
Luise and Kevin
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