Lower Bay Mini Split AC size

[Darkspeed]

I am looking at a high efficiency mini split ac to cool/ heat my GM 4106.
I am planning on running it off of a 220vac inverter with solar assist like the off grid tiny house guys do.
My GM 4106 will have 3.5" of closed cell spray foam and double pane argon insulated windows / skylights.
The biggest loss will be the front windshield / driver passenger side windows.

Any one have experience on what is the minimum BTU Mini Split for a GM 4106 in Florida?

I am looking at the fuji 33 SEER 9,000 BTU with possibly a second head in the bedroom area.

http://www.fujitsugeneral.com/wallmountedRLS3.htm

[robertglines1]

As high as 33 seer. Would question that.  I use 120 volt. Key factors. Inverter type--I like Toshiba compressors. I have 2ea 9,000 and a 12,000.  Keep it simple.  My 9,000 pull 6 amp  at 120V constant. 

[Darkspeed]

33 seer > http://www.energystar.gov/index.cfm?c=most_efficient.me_cac_ashp

[Darkspeed]

As high as 33 seer. Would question that.  I use 120 volt. Key factors. Inverter type--I like Toshiba compressors. I have 2ea 9,000 and a 12,000.  Keep it simple.  My 9,000 pull 6 amp  at 120V constant.  

You are using 2 x 9,000 + 12,000 in your bus? Are these split systems? If so what efficiency?

Most of the 120v units are low efficiency is why i am asking..

[eagle19952]

i think 3/4 ton will need to run full time to maintain any tolerable condition...imo etc.

[robertglines1]

15 seer verified. The requirements of local power company says 15 or better to qualify. Further research yielded most roof tops are unrated and if they were would be under 10.  Asuli is a roof top in europe that uses inverter technology. The rest of the world has embraced the technology for 15 plus years.  I have  splits in house also. Both under 20 seer . they do a fantastic job.  I like duplicate units in case on fails.  After cooled down one 9,000 did maintain inside when it was high 90's outside in sun.  45 ft coach with tall ceilings plus 3 slides. Lots of extra insulation over the stock 2 inch Prevost foam from factory. Biggest problem people have had in  is cracked fittings mostly at flares.  I still would recommend 2 separate 9,00  units instead of one larger one. anchor the lines and units. Plus every where I could added more insulation to freon lines.  Just paid $644 for 9000 delivered to house with line kit. 1 more thing use teflon paste to flare fittings to help in leak prevention. My only failure was a cracked flare that I did when I did flare. I have a total of 5 units running now.  31,000 btu cools our home with 2625 sq ft on main level also heats it.  Bob 

[Darkspeed]

Thanks Bob - that is good information!

I will try it with one 9,000 BTU split but go ahead in build in a second line set in the bedroom incase a second 9k is needed.

The only mobile AC I have done I used flex adapters and mounted the AC on rubber mounts and so far no leaks or broken fittings > http://www.unisource-mfg.com/products/oneproduct.php?categoryid=50&productid=203

[Ace]

I'm thinking about installing a 24,000 btu mini split in our truck conversion. As a wise friend told me just recently, you can turn a large one down but you can't turn up a smaller one! Food for thought!


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[robertglines1]

Just that 208 or 220 will be required for anything over 12,000 that I have seen.If your races our like our tractor shows there is often 120 V 20 amp service available. our 24,000  208 V in house is prob 3ft Long and 16 inches high . The 9,000 is about 30 inches by 10 inches(inside unit).  Been waiting for roof shaker in toter to quit so we can put split in it.

[TedCalvert]

Too large a system may not run enough to dehumidify.  So I've been told by my HVAC tech friend.

Ted

[Scott & Heather]

Ted, this is true for most a/c units. My dad has done a/c all his life in Arizona, and he has told me this. Rule is, match your tonnage to your needs. Buuuuut, modern mini splits (Fujitsu specifically) have a "dehumidify" feature that solves that problem. So, overbuying your btus isn't as much of an issue now. That being said, unless you purchase the higher end variable compressor units that actually wind up or down depending on the cooling needs, then you may be drawing more power than necessary.


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[belfert]

What some of the heat pumps do in dehumidify mode is to alternate between heating and cooling the air.  I know that is what my Atwood RV heat pump seems to do when I have it in dry mode which is their name for dehumidifying.

[Ace]

Bob the 24,000 unit is 40.5x8.5x12.50 and it has a toshiba comp. it's powered by 220 which is ok because our races don't usually have hookups so the genset comes into play. Almost all campgrounds we go to are 50amp.


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[luvrbus]

LOL it's 108 degrees here in AZ @8PM and feels like a 102 with 11% humidity,starting Monday it's going to be 116 all week with 20% humidity.

You guys bring on the 9000 btu mini splits 2 or 3 if you don't roast like a hot dog by 2 PM I 'll jump on the mini split bandwagon.At 90 degrees I would not even worry with AC    

I am leaving town Mon am people will be ringing the phone off the hook with AC and generators problems. I have 67,500 btu's of AC and love every BTU when needed.

I had my son calculate the BTU's to cool a bus 8 ft wide,45 ft long and 6.5 high inside with normal insulation he came up with 31,470 btu per hr or 9,222 watts cooling from 90 degrees ambient temp to 75 degrees inside I checked him on a site and he is not far off    

[Ace]

that's what I was told too! The more, the better. Besides you can always add more!


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