In my Compact Jr., I wanted to install air conditioning
. I cannot do roof air because the center of the roof pops up; besides, it juuuussst fits through my garage door at its current height. I am (as we speak) beginning to install a window unit in the camper. I find visible window units on campers to be really distasteful, but I want A/C! My solution is to bury the window unit in one of the storage areas under the booth seating.
I purchased the smallest window unit I could find, both in size and current draw. I required one without digital controls of any kind (explained later). I found a 5000 btu, 4.8 amp unit. I am setting it in the compartment on rubber to isolate the vibration. I'll separate the A/C portion of the storage are from the remaining area with plywood. For moisture control, I'll lay new fiberglass in the A/C chamber on the floor and a couple of inches up each side. The "inside" face of the unit will not be visible, either. It will be up against the footwell portion of the bench. I will cut out sufficient venting in the footwell board for the airflow. The openings will be covered by a cold air return grate used on the wall in household applications.
For exhaust air, I will cut out 4-5 round holes in the FLOOR of the camper near the rear of the A/C unit, through the newly laid fiberglass. This way, there will be no exterior clues to the existence of the unit, and no unsightly grates on the side of the camper. The holes through the floor will be covered from the outside with a smaller cold air return grate, with household window screen material inside to repel insects while allowing exhaust air and condensate to pass through.
Back inside the enclosure, I will use foam to separate the front of the A/C unit from the rear (essential), and will use sound deadener on the front (where able), sides, back, and under the seat board to keep sound down. The unit will be firmly mounted using 1x1" angle running across the top of the unit from left to right side, with holes on each end just beyond the edge of the unit. Through these holes I will run all-thread down and through the floor, where it will be bolted from underneath the camper with washers. The angle will sit on a strip of rubber to further isolate the camper from the unit's vibration. The seat top board with sound deadener backing will be screwed down to the bench with thin weatherstripping rubber finishing the enclosure seal.
Now I will have successfully created a stealth enclosure, but how do I access it to turn it on/off or adjust it? I won't!!! The unit will be controlled by a standard household thermostat. It can turn it on/off, of course, with the switch, but will also turn it on/off as interior temperature dictates. Mounting the thermostat on a convenient wall location, I will power it with a 24V transformer. When the thermostat kicks on, it sends that 24V to a relay with 24V coil voltage. The relay will have 120VAC input on one side, and 120VAC output to the window unit on the other. When the thermostat energizes/deenergizes the coil, the relay will send/cut power to the A/C unit, turning it on and off. This on/off power situation is why I cannot use a digitally controlled unit.
One more thing.....my A/C unit clearly warns to let it sit three minutes after turning it off before turning it back on. Actual necessity?? I don't know. But just to be sure, I'm using a 20 amp programmable timer relay for power control (about $30.00 if you shop around). It will be programmed to wait three minutes from receipt of 24V from thermostat before closing the 120VAC circuit. It will be programmed to shut off immediately upon loss of 24VAC. When first using the unit, I'll leave the front cold air return grille off, so I can set the unit for most desired performance (fan hi/med/lo and temperature selection dials). My goal is to adjust it so that it is quiet and comfortable, but has no problem keeping the inside at 65 degrees when it's 100 outside (if I choose), and also adjust it so it doesn't kick out ice cold air in a short spurt and then shut off for a long time, causing perceptible temperature and comfort flunctuations. Once adjusted, I'll screw the grille back up and forget about it.
The same system would work in a bottom cabinet. Simply replace the cabinet door insert with attractive grating material. Also, this way one could simply open the cabinet door to adjust the unit, negating the need for the thermostat and relay; though, personally I would still do the thermostat solution because it's coooool (oops, pun!)!
The exhaust airflow may be a little less than optimally efficient, because I'll only cut a few (4 or 5) holes about 2.5" in diameter. I don't want to cut out a large rectangle through the bottom fiberglass and risk weakening it too much. Besides, even the smallest unit will be MORE than enough for my 13' camper.
With this A/C solution there are several benefits:
--center of gravity is low.
--overall height of camper is not changed.
--no unsightly roof air or window unit is visible; stealthy.
--space lost is only about the size of a small/med. microwave
--can be mounted in any bottom storage area or cabinet. Choose the one that is the biggest pain to access, anyway!
--If you're less than honorable, in campgrounds that have different rates for units with A/C, you could be an evil, deceitful, sniveling scrooge!
--It's way cheaper than standard camper A/C solutions.
--No chance of roof leaks
from A/C cutout.
--easily accessible/removable for service/cleaning/etc.
--camper use is not compromised when unit is removed.
--no loss of headroom in center aisle.
I plan on having this installed in time for the July 4th weekend. Wish me luck!