AC Choices

[Newnut]

I am just beginning the conversion of My 102-A3. I am curios if there is any consensus on the best type of AC and heating system to install in a full time live-aboard.

[kyle4501]

Cheapest is usually the rooftop units, if you don't have issues with overall height of the coach or issues with the thing on the roof messing up the looks. . . .

Some have gone with a split system, but the various styles carry varying levels of difficulty (cost) depending on who is going to install or service it.

What size generator will you have? What size power cord will you have (30A@110V or 50A@220V)?

Your intended use, operating environment & budget will determine the best system for your needs.

[TomC]

I have a 40 x 102" wide transit with 2.25" of sprayed insulation, single pane Peninsula windows (big-78" x 32"- 6 of them).  I have three Coleman 13,500btu roof airs with the front one close to the driver's seat to blow directly on me powered by a 10kw Powertech Diesel generator.  The hottest I've been in is 107 degrees, and just two of them kept the interior at a comfortable 75 degrees while driving.
Roof tops have the advantage of being the cheapest in price, easiest to repair or replace, most effective in cooling (non ducted type). But are eye sores, with three, have an extra 330lbs on the roof high up, are more noisy on the interior.
Dometic or Duotherm ducted types are basically the roof top unit redesigned for basement mounting with the supply and return air ducted to the unit.  A 15,000btu is $895.00 plus thermostat of $80.00.
Then you have splits like the Cruise Air that has the condenser unit in the bay (that is designed to pull the air in from the side and blow the air down to the ground) and the blower or evaporator in the bus with the freon lines connecting the two.  These units for a 14,000btu and a single evaporator are about $1,800.00 each.
You could run home style mini splits, but the condensers are large with no ducting on them making them real space robbers in the cargo bays.  And they are not designed for the vibration of driving.
Good Luck, TomC

[Nick Badame Refrig/ACC]

Hi Newnut,

Welcome!

You have heard about your A/C choices above from Tom and Kyle.  Let's talk heating.. First, it would be nice to know what part of the country your from?

Depending on the enviroment you will be fulltiming in, will determine the type of heating needs you will require. Starting at the top. Aquahot systems are

top of the line hydronic heating/domestic hot water boilers. This type system will allow you to have choices on the distribution of heat too. Typically,

you will be able to have either in floor radient heat, hydronic to air heat exchangers, or parameter baseboard radient heat. "your choice"  This system is

diesel fired and is also capable of preheating your coach engine as well as suppling your domestic hot water.

Next would be LP. Standard RV type LP fired forced hot air heaters. This means you will need a supply of propane onboard. These are what most folks choose

for heating because it's the most bang for the buck.

If you will be only in the south, then heat pumps built into your air conditioning systems will do the job too.

Good Luck
Nick-

[BG6]

I am just beginning the conversion of My 102-A3. I am curios if there is any consensus on the best type of AC and heating system to install in a full time live-aboard.

That largely depends on what you mean by "full time live-aboard."  YOU know what you mean, but I don't. 

For instance, I fulltime because I need the ability to jump from one town to another (with work), but I am parked the vast majority of the time.  Others make miles every day.

If you are like me, then you are mostly likely going to be happiest with rooftop aircons.  They are the simplest, easiest to mount and service, and generally cheaper.  They also free up the bay where the original aircon condenser sat -- this might be a good place for your propane tanks.

For heat I just use a couple of plug-in heaters from Costco, with an infrared remote control.

[JohnEd]

My criteria is to have as much flexability and redundancy as possible.

AC....I like the thought of two minisplits of the "heat pump" persuasion.  Each should have the capacity to cool the bus alone or nearly.  If you have a failure at the worst time in AZ, you could run only one and block off part of the bus to reduce load.  I think you should be able to find some that have square condenser units but the round ones are definitely space hogs.

      I wouldn't be without Bus air driven by the engine.  Not that enormous system but one using two independent compressors with clutches.

Heat....If the pole is close you can heat with the heatpump and not burn fuel you have to tote.

      I would also have two smaller version, 20 to 30 K BTU, propane furnaces.  One at each end.

      I would run engine coolant to heat water, toe kick heaters and the heavy work at the drivers station for defrosters.

The only thing I like Hydronic water for is pre heating the engine.  From all I have heard the Hyd sys takes nearly a gallon of D per hour to keep the place warm.  The ex of the Hyd is 600 degrees and it blows strong so I guess that is where the inefficiency comes from.  God knows it is the absolute Cadillac of heating systems with its quiet operation and ability to warm floors.  You should verify my fuel consumption numbers.  ALSO....there is a Knut here that has those Wabasto Hydronic units for sale and he sets them up for 50 or 60 KBTU(I read this stuff a long time ago and they may be even stronger.  Food for thought?

Like they say....PLAN>>>>PLAN>>>>then plan some more.

My very best wishes for you,

John

I also use those little cube heaters.  Really well insulated coach and 2 cubes will cover me down to 32 degrees.  After that its propane plus cubes.  ALONG SIDE THE ROAD?  Propane will save your bacon and keep you comfy.  Dry camping/boondocking also.

[Newnut]

For clarification,

I intend to live in this bus like a home. I move from job to job at varying times. Sometimes a job may be only a couple of months and other times it can be a couple of years. I may be in any part of the country, Mexico or Canada at any time of the year. As a side note My wife is from New Orleans and is always cold. Thanks for the help and comments.

[Hartley]

For full time use you should consider all aspects of storage capacity and then consider the problems of maintaining all of the systems that you need to live with.

My suggestion is to build in the basics using the simplest to maintain items so that you and your wife can do basic upkeep. Complicated Hi-Tech heating and cooling systems will be a bane to your existence at times.

Almost any $10 an hour idiot can change out a bad roof air. Where the $100 an hour guys will be needed for a central or package system.

Hydronic heat is great but the idea of burning expensive diesel fuel for extended winter times will keep you hauling fuel all winter. The odors will get old after a while and you can't sweeten it enough. Then the pumps, reservoirs, fans and all the extra support systems will keep you busy. These will add loads to your power needs and battery systems to keep operating properly.

On the A/C systems, Having reverse cycle heat pumps with add-on electric strips would be OK for most places unless you are dealing with temps below 30 degrees on a regular basis. Then electric or propane heat may be needed.

Your best value is to Insulate everything extremely well and include thermal-pane windows wherever possible. Heavy insulated curtains for all "front & side" drivers area to help cut down heat loss or gain when needed is always a good idea. Pay attention to door seals and bay seals to keep them tight and to keep the wind out. Spray Foam is BEST in all cases. Trying to be cheap should not be a factor.

Depending on your coach, You probably will want to pull everything out from under the dash and front end and have it all spray foamed also. Floors should be insulated either in the ceiling of the bays or under the flooring. Cold gets through those places very well.

You should also consider adding heat units to the bays to keep the water tanks and plumbing from freezing. A cut on temp of about 34 degrees is a good range.

Plumbing should be done with PEX tube and fittings. It tolerates extremes better than any Copper or PVC lines and is easier to install and maintain. PEX generally won't burst when it freezes. Others will. Just thaw out the lines and you are back in business usually. Things like water filters, pumps and even sewage fittings and lines will freeze with damaging results. All really need to be kept warm enough to work.

I have recently had a few surprises about what works at 7 degrees and what doesn't.
I don't have good insulation so my winter heating needs has been a pain in the wallet trying to feed a 35k propane furnace and 2 electric heaters full time for months at a time. Those 100 lb LP Gas cylinders are horribly heavy to wrestle with.

Good Luck and if I can be of any help, Just yell !!

Dave...

[JohnEd]

EVERYTHING Dr. Dave said.

I would add that you ca get about half a bay by using roof top AC.  If you duct it it will be quiet but the capacity will be reduced.  Build in the ability to open the duct to allow the AC to dump directly into the bus and the AC will act like it just got a shot of "methamphetamine".  Great backup feature and also helps if you lose a unit and you are trying to get by with one.  If ducted you would probably install 3 units and only run 2 at any time.

Dave really hit the nail on the head with the advice to use spray foam.  And curtains.  and double pane windows.  Spray the inside roof of the compartments.

HTH and commit Dr.'s advice to memory,

John