Adding Air conditioner to 2003 27/20

Tee-roy · 02-14-2019, 11:11 AM

My 2002 27/20 SL didn't come with A/C, I want to add it.
I'll be camping in Michigan this Summer.

I'm looking at two options:
A portable household A/C unit, around 15000 btu , I could use it to cool an upstairs room in my house when I'm not camping. Anyone have any luck using one?
Adding a roof-top RV A/c unit around 15000 btu. I've found threads covering replacing an existing unit but not adding A/C to a camper that didn't come with it.

All ideas are welcome and appreciated!

**Bill** · 02-14-2019, 12:25 PM

Tee-Roy -

There is a third option. Up until 2001 or so, TMs were equipped with a standard household window air conditioner. It was mounted on the floor in one of the kitchen cabinets, and the back of the unit poked out just slightly through a rectangular opening cut in the sidewall of the TM. The front of the air conditioner blew cold air into the hallway, and many owners set a portable fan in front of it to blow cold air around the trailer. Advantage: much cheaper and easier to install than a rooftop unit. Disadvantage: you lose some kitchen drawer space. The project is do-able by a home handyman, and there is lots of discussion about how to do it, here on the forum.

Taking your two options in reverse order:

A rooftop A/C is heavy. At very least, you will have to change out the torsion bars that lift the front shell - two (and probably four) bars. These bars are available from the TM factory, and probably nowhere else, and they are undoubtedly expensive. The replacement process is not fun, either. If I were going to do this, I would probably arrange to have the factory do it while you are in the Midwest.

If you decide to go with a household roll-around unit, you will find that most of the cheaper units have a single hose. You need to find a unit with two hoses. The reason is kind of techie, but goes like this. As part of its operation, an air conditioner generates a lot of internal heat, and it has to get rid of that heat. To do so, the A/C blows air over an internal radiator, the air picks up the heat, and the heated air is exhausted to the outdoors through a hose. All good so far. But the question is, when the A/C blows air to the outside, it has to replace that air. Where does the replacement air come from? A two-hose unit uses the second hose to bring outdoor air to the radiator, where it absorbs the heat and is blown back outdoors. This is exactly the way a rooftop A/C operates, as does a household window air conditioner or a household central air system. Outdoor air is brought into the unit, warmed, and blown back outdoors, while indoor air is cooled and blown back indoors.

A one-hose design has no way to bring outdoor air to the radiator, so it uses indoor air to cool that radiator - which is air that it just finished cooling! So although the unit is theoretically capable of producing 15,000 BTUs of cooling, you get only part of that capability. The rest is wasted by cooling that radiator, after which it is blown outdoors.

Hope this made sense. Technical stuff is sometimes not easy to explain. If you do a Google search on "portable air conditioner one hose two hoses", you will get a lot of hits explaining the same thing. Just to confuse things, most of those sites use the term "exhaust hoses" for both of the hoses in a two-hose unit, even though one is actually an intake hose and the other is an exhaust hose.

Bill

Tee-roy · 02-14-2019, 01:27 PM

Hi Bill,

Thanks for your reply.
I didn't realize adding a rooftop A/C would cause torsion bar issues. That probably makes it a non-starter.
The two hose portable A/C unit sounds like my best choice. I've heard that all older TM's had an outlet for the cabinet mounted A/C even if it wasn't installed. I haven't found it in mine.
I wonder if the electrical system can handle the portable unit?

bheisser · 02-14-2019, 02:20 PM

just run a separate extension cord to the site post, all the one I have seen have a standard wall plug in addition to a 30/ or 50 amp

Tee-roy · 02-14-2019, 04:04 PM

Quote:

Originally Posted by bheisser

just run a separate extension cord to the site post, all the one I have seen have a standard wall plug in addition to a 30/ or 50 amp

Yep, I figured if I tripped the circuit breaker that's what I'd do.

BrucePerens · 02-14-2019, 06:11 PM

To simplify Bill's explanation: One-hose air conditioners are available and probably the most common ones you will find in stores. They are substantially less efficient than the two-hose ones, as they work by exhausting already-cooled air from the room through the condenser and heating it.

While you can probably find a two-hose unit, what you will more often find is a split unit with the condenser outdoors and the cooler indoors, and mounting these would be problematical.

It might be a consideration that window air conditioners, one and two hose units, and split units are meant to be stationary. Shaking them around and then using them without allowing the refrigerant to settle could result in very hard starts or even a locked compressor and a burn-out. You will notice that many of them specify in the manual for the user to allow them to settle overnight after shipment. This will allow the unit to have refrigerant gas where it expects gas, and liquid refrigerant where that belongs, rather than a froth of gas bubbles and liquid. Transporting the two-hose unit on its back rather than upright is liable to cause trouble.

Air conditioners sold for RVs are designed to deal with movement, but even they often specify that they be allowed to settle after they are mounted. They may also want to be level, like the condenser refrigerator.

Tee-roy · 02-20-2019, 11:44 AM

The best I can do is carry the portable A/C unit upright in the Truck with the wife & dog.

tentcamper · 02-20-2019, 02:05 PM

Also, if the camper came without the rooftop AC. Does it have the raised section for the AC, or is the roof flat where the AC go's?? TM rises the roof where the AC unit sits by about 3 inches for head to AC unit clearance. I know I would be hitting my head on the AC without that rise?

Not sure if TM uses different torsion bars as mentioned. It makes sense they would and most likely do. I think I would check to make sure. I think I would check with TM or other owners with the same model as to their torsion bars diameters on the front shell.