How many BTU's do I need?

[JWG]

I have a 7x16 that I will have sprayed with closed cell foam. Walls will be sprayed with 1.25" and ceilings 2". Floor is 3/4 plywood. Might add insulation under if needed. Due to the head room where I park it, there is no room for a roof mounted AC. I plan on adding a window unit that will slide out when needed. So back to the first question, how many BTU's do I need to keep it comfortable. 90% of our use will be in the south. Thanks in advance. Jim

[aztrooper]

I'm getting the GE 6,050 BTU Window Air Conditioner with Remote Model AEL06LS from Home Depot when they come back into stock. The calculations I checked on mine, a 7X18 V nose said 5500 watts. I'm just going to mount it inside, line the "tunnel" with aluminum for the water to drain onto and down through a hose and exit the exhaust out the side that will be covered with a louvered vent cover so it will look like a refrigerator exhaust. I am going to put a vent on the roof above it so it gets lots of outside air. The vent will be the normal RV type vent with rain cover.

[DustinS]

Regarding floor insulation I recommend reading Rainer70's thread and the improvement in heat retention/reduction in run-time of a heater (same would be logical for a/c). Starts about page 4 or 5 talking about plans for floor insulation. Your mileage/desire may vary.

viewtopic.php?f=42&t=55219

[Mike S]

My trailer is the same size as yours with about the same amount of insulation. I use a 6000 BTU residential window unit mounted at the top of the drivers' side wall. I push the unit out when it's in use and pull it in for travel and storage. I did zero calculations to determine the size it needed. It was just a guess. It works okay for the summers we have here. The worst day we had last summer was 105F. The A/C was able to maintain an inside temp of around 80F which was adequate for me. I definitely wouldn't want anything smaller.

I plan to modify the set-up this summer to allow me to operate the unit without pushing it out. To do this, I'm going to create a box that's sealed from the inside and vented through the roof. The vent will provide cooling to the mechanical parts of the A/C (the part that's normally vented through the side vents). I know I could loose efficiency but I want the ability to run it without pushing it out.

Good luck with your build!

[lrrowe]

Based on other posts here and the fact I was able to buy one a 5000 BTU unit for $25 (used) for my 6 x 14 CT. 18" of the inside space will be walled off, so really I have a 6 x 12.5 unit to cool. I think that size will work for me.

[Socal Tom]

A 5000 btu is for a room of about 100 sqft. Your trailer is 112, however don't expo much more than 25 degree temp drop vs the outside air temp. I had a 5000 btu unit cooling a ford van ( under 100sqft) and it would keep temps about 30 degrees below. Worked great until it was 122 outside. And 90 inside. I would say 5k to 8k are probably in the right ball park. Window units are more efficient vs portables,.
Tom

[JWG]

I push the unit out when it's in use and pull it in for travel and storage.

I plan to modify the set-up this summer to allow me to operate the unit without pushing it out. I want the ability to run it without pushing it out.

Mike S, I am curious as to why you are changing from the slide out option to the inside mount. I might be headed the wrong direction with the slid.
Any insight you can share is appreciated. Thanks

[JWG]

I'm getting the GE 6,050 BTU Window Air Conditioner with Remote Model AEL06LS from Home Depot when they come back into stock. The calculations I checked on mine, a 7X18 V nose said 5500 watts. I'm just going to mount it inside, line the "tunnel" with aluminum for the water to drain onto and down through a hose and exit the exhaust out the side that will be covered with a louvered vent cover so it will look like a refrigerator exhaust. I am going to put a vent on the roof above it so it gets lots of outside air. The vent will be the normal RV type vent with rain cover.

AZTrooper,

Thanks for the heads up on the GE Model #AEL06LS. It looks like a good deal with positive reviews. What type of wall and roof vent are you planning to use and who are you getting them from? Thanks in advance. Jim

[aggie79]

Though they are more expensive, if I ever have the $ to do a CTC, I will probably use a "through the wall" air conditioner. A "through the wall" air conditioner has all of the condenser intake and exhaust on the back of the unit and none on the sides like a "window" unit. The "through the wall" air conditioner will allow a more compact, fixed installation than a "window" air conditioner.

[aztrooper]

JWG. Here is the type of roof vent cover that I am going to use. I'll put the regular roof vent in with out a fan and then put this roof vent cover over that.


For the big exit vent where the exhaust will come out of the side of the trailer, I will use something like this. I will get one that is sized for the exit. I have looked at Home Depot and seen a couple I like there that are made for home ceiling A/C up ducts where the filter goes.

[Mike S]

I push the unit out when it's in use and pull it in for travel and storage.

I plan to modify the set-up this summer to allow me to operate the unit without pushing it out. I want the ability to run it without pushing it out.

Mike S, I am curious as to why you are changing from the slide out option to the inside mount. I might be headed the wrong direction with the slid.
Any insight you can share is appreciated. Thanks

I just like the look and convenience of having the A/C flush mounted with the outside of the trailer. The other option would be keep it out permanently, and travel with it out, but I'm not sure that would be good for it. I might look at the "through the wall" A/C's that aggie79 talked about.

[DustinS]

I was looking at through-the-wall A/C units and the lowest BTU rating I could find was an 8,000 BTU unit. They are generally pretty expensive, the cheapest NEW unit was almost $400. The one that really caught my eye was the 8,000 BTUH unit from Comfort Aire. It runs on 115v with (per the description of specs) 15amp draw. Its size wasn't bad, at roughly 2 foot wide, a little under 2 foot depth, and just over 1 foot high. I didn't see any specs on the weight of many of them, but shouldn't be too much. Here is the unit I'm referring to: http://www.menards.com/main/appliances/ ... c-5571.htm

Now with a wall unit, you could pretty much flush mount the back to the outside or maybe have the whole unit inside and run duct/drainage out. Certainly the 300-350 sqft. cooling capacity would handle MOST ctc if one desired. They even have some models with heat.

[jwhite]

I wouldn't go lower than a 8000[album][/album], the best part is it cools down fast 15 20 minutes is all it takes in the summer, I bought a 5000 btu at walmart then went down to lowes and found the 8000 on sale for around 160.00 so I have both, last year the 8000 quit working so I put the 5000 in and I could tell it barely kept it cool.
I noticed the 8000 had a some type of plug that was switching it off so I cut it off and put a regular plug and it works fine now.
For me living in the south and using mine mostly in the summer bigger is better.

[JWG]

I spoke to an AC contractor (friend) about what I doing and he proposed another option. He suggested a "Mini Split System". The compressor would mount on the outside on the tongue and the air handled would be mounted inside. He said it would be very quiet. I going to check them out.

He suggested something like this;
https://www.acwholesalers.com/LG-Air-Co ... oCIdbw_wcB

[MtnDon]

Mini splits are wonderful, some more wonderful than others. They all are more energy efficient and because they are split into an inside and an outside unit, much quieter. They tend to start at around 9000 BTU. The really good ones can be programmed to run at lower speeds instead of just being on or off like the typical window shaker. At one time that was rare; I don't know about today. Downside is the cost is more and there is refrigerant piping between the units. Some use special fittings that allow a DIY installation. (Once connected a refrigeration technician is needed to disconnect and reconnect.)