AC installation (hidden)

[ericw]

After a hot summer where even in a small bed in our Scamp my wife and I didn't touch each other for 3 nights, we agreed to install AC. Our Scamp did not allow for a roof installation. We were ok with a closet installation because we liked the lower cost, but we are going to miss the storage. I wanted the installation somewhat hidden because I like the look of the lines of the fiberglass trailers and don't like to have lots of cutouts in the side of the trailer. I went with an 12V/120V fridge for the same reason. I decided to put it under the front couch. It added a little weight to the hitch, but was easier to vent. My wife was also more willing to give up that closet space.

The (almost) finished installation from inside. The switch to the left turns on the fan and switches power on to the AC.

A picture of the box made to go behind the AC. Note the 4" blower fan from a boat that will push the air out.

The closet where the AC will go. Air comes in the left and goes out the right. The drip pan is the silver thing on the bottom.

The same closet with the box with the fan that will push the hot air out. A vinyl dryer house connects the fan to the air outlet. The AC will sit right in front of that box.

The air inlet/outlet from the outside.

The air inlet/outlet with a cover

What it looks like outside. The arrow is pointing to the cover seen above.


I owe many thanks to a variety of people on this forum for ideas that went into this. I have more details if anyone is interested.

[Donna D.]

I love it when a plan comes together

[Tim Wood]

Great looking job.

[djtriceflt]

Mr. Eric,
I really like your design utilizing the aux. blower, the way you have ducted it down below and saved your Scamp's appearance!

Nice job and thanks for sharing the pics!!!

[Cricket]

I will want one of those I think. I don't want a roof mount cuz then it won't go into my garage.....

[cpaharley2008]

Where does this unit obtain fresh air? I always though fresh air was introduced on the sides of window units with exhaust out the back and conditioned out the front.

[ericw]

Originally Posted by cpaharley2008

Where does this unit obtain fresh air? I always though fresh air was introduced on the sides of window units with exhaust out the back and conditioned out the front.

Jim, I believe you are correct with your description of the air flow for this AC. I brought the fresh air in from the 4" hole on the left. The fresh air just fills the entire closet including around the AC except behind the AC. The box behind the AC with the fan captures the hot exhaust going out the back and pushes it out the hole on the right.

If I had to do it again, I would have use a smaller fan - perhaps the 3" instead of the 4". This fan is closer to my leaf blower than a fan that has to move a little hot air. But I do like to be on the safe side and it is designed for having some water around in a marine environment which was another consideration. I actually lowered the voltage to it slightly to slow it down.

Let me know if I was not clear. Questions are welcome.

Eric

[ericw]

Originally Posted by eggless

I will want one of those I think. I don't want a roof mount cuz then it won't go into my garage.....

The garage was a consideration for me to. If you decide to do it similar to mine, let me know and I'll share more details. I'm not a professional so despite some planning I have some lessons learned such as my cheap bits did not do so well drilling a 4" hole in metal. I also have the list of materials and a rough design with dimensions.

[Cricket]

Thanks eric....that would be awesome!

[ericw]

I'll post more details in a series of these posts since I don't have time to sit down and give you everything at once.

Cutting the 4" holes in the front closet under the coach was more time consuming than I expected. It would have been easier to put the holes in the bottom through wood, but more visible and more vulnerable to the covers of the holes getting knocked off. Therefore I went through the sides which meant cutting through the metal. You have to make sure the hole is high enough to get past the wood floor and leave yourself a little room to attach the 4" flexible hose on the inside. However, don't go too high because you are already drilling at an upwards angle. Front to back isn't too critical. You also have to leave room for the covers to mount nicely. I measured and designed it, but in reality held all the parts up in the end to where they would go to make sure it would work and I did adjust it some. I drilled a pilot hole without issue. I tried a cheap 4" hole saw first and only made a little progress. I went with a Milwaukee bi-metal 4" hole saw and that worked a lot better. A little oil or WD40 to keep the heat down a little helps. I still would drill for several minutes and then take a break to let the drill and hole saw cool down. I also ruined my 20 year old drill due to overheating I think when using the first hole saw. I found a new one with a lifetime warranty. After getting the two holes done, a good cleaning with Dawn dish soap cleaned up all the oil I had used to keep things somewhat cool.

[ericw]

In the 4" holes I put dryer vent flap valves. Make sure you put them in right side up and in the correct orientation to let air in and out correctly. I sealed these to the metal so nothing could get around them. I also took fiberglass screen material and used electrical tape to hold the screen to the housing of the flap valve. You have to be careful that the screen material still allows the flap itself to fully move back and forth and that the flap doesn't get stuck on the screen.

I covered the flap valves with clamshell covers meant for boats. I used the Nicro ventilation 3" high covers. They are technically too wide, but I squeezed them together to fit and it made the opening higher which was what I wanted to let more air out. They are also soft so they will take some beating without cracking like a harder plastic would with rocks being hurtled at it as I go down the road.

Both the flap valve and clamshell covers are held on by stainless steel metal screws.

Note that all exposed metal and wood that I cut into was first painted for longevity.

[LRS30]

Love the install, I plan on doing the ac install real soon. Is your blower 12 volt? And do you plan on installing a drain thru the floor? Here in KY. the humidity is a killer in the summers so I am pretty sure I will need to install a drain thru the floor. Last question what btu did you use? Thanks

[honda03842]

Our installation is a thru floor job with an exhaust fan on the output. We do have a drain thru the floor but have never had anything come out of it,at least that I've seen.. Our unit is 5000 btus but have never run it at night.

[LRS30]

Around here it seems window units just pour out the water! Our humidity in the summer months can stay in the high 80 to mid 90% . There are days where I would love to have "DRY HEAT". It gets so humid here that you drip sweat just walking to the mail box lol!

[LRS30]

Of course some A/C units have a built in evaporator pan, and they claim that they don't need a drain. I'm sceptical about this though. I plan on putting a 5000 btu in my hanging closet and ducting thru the floor if possible. My brothers is ducted thru the side. I'm gonna do som investigating and see which way is gonna work for me. Id rather go thru the floor than the side. I'm thinking fewer chance of leaks buy going thru the floor.

[LRS30]

Eric I really like how you did yours. I may steal some of your ideas.

[ericw]

Originally Posted by LRS30

Love the install, I plan on doing the ac install real soon. Is your blower 12 volt? And do you plan on installing a drain thru the floor? Here in KY. the humidity is a killer in the summers so I am pretty sure I will need to install a drain thru the floor. Last question what btu did you use? Thanks

Ryan, My blower is 12V. I think it is over designed. I used a 12V marine blower. I probably could have gotten by with a 3" or used something more similar to what Norm used. As for many of us, Norm was the inspiration for this modification. Given that it moves all the air in through one 4" hole and out through another, a little extra airflow is probably good. I used a Rule 4" blower. Picture below.

I did install a drain. The silver "pan" in the picture is meant to catch the water from the AC and then a hole in that pan drains it through the floor. We also have humidity and I ran the AC outside to give it plenty of humid air and test the draining system. The condensation was plentiful in that situation. The pan is just a lid of a 9x13 pan that was no longer used by my wife .

Given the size of the trailer I just went with a small 5000 BTU unit from Frigidaire. I have not used it in the worst heat of the year, but reports on this forum say it will be sufficient for me.

[honda03842]

I monitor the temperature in the exhaust area and it gets pretty warm even though I have 2 12VDC fans exhausting hot air. It maybe that all things considered that there's enough evaporation to prevent the drain from seeing any moisture.

Also I have the Air Conditioner tipped towards the drain. As to the effectiveness of 5000 BTUs, it seems it almost instantly gives the feeling of relief.

We place a small fan on the floor and blow cool air towards the rear of the trailer. Our most frequent use of the AC is when cooking on a hot day.

I must also say we never see extreme heat. In general our RV goal is to avoid extreme weather though we've been in 90 degree weather, but never where the evenings are uncomfortably hot.

[ericw]

My AC sits flat, but I tipped the drip pan to the back. If you look carefully you can see the hole in the center back of the silver drip pan.

We went a year without any AC. It was fine in the desert out West. However, in the parts of the country that have 80-90 degree humid nights, the AC is nice.

Make sure you post pictures of what you do so we can all learn and steal from your experiences also. If you have any questions, feel free to ask.

[LRS30]

Thanks guys for all the tips! I hope to get the A/c this Sunday, and maybe start on it then also.. It always seems that something pops up that keeps me from starting, continuing,or finishing projects around here. Such is life when you have 2 teenagers under roof!