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chuckb · Dec 12, 2007, 01:49 PM

So, my wife wants to add a/c to a 400 s.f. room in our home, so I'm thinking something I can do with a split - condenser hung under rafters of our one story ranch home, and the fan/thermostat unit in the area she wants cooled.

I looked at a mitsubishi, but it required 220vac 20amp (?could be wrong) - that is much more power than I can add to my existing service.

Besides upgrading the service, any recommendations out there? The window unit will not suit her aesthetics requirements.

Thanks, and enjoy,
chuckb.

hvac1000 · Dec 12, 2007, 02:56 PM

400 sq ft is just about3/4 of a ton load. That is about 9000 BTU of A/C needed.
You will spend some big bucks over a window/wall unit if you go for a split.

A 1 ton unit may be to large for the space. If to large it will cool but will not pull the moisture out of the air. Then you will feel cold and clammy. Stick with 9000 BTU.
You never mentioned the area where you live? Or how many windows and do the windows face north,south,east,or west.

chuckb · Dec 12, 2007, 05:07 PM

4 windows and one half glass door facing mostly E, with some SE exposure. Zip 94556.
Other walls surrounded by interior space. Interior space tends to be some 20 degrees F cooler than outside temps in summertime - with maybe one week of 100 degree weather, 10 weeks of 80, 20 weeks in 70, rest down to a week in freezing, 3 weeks in 30s, rest in 40/60 in winter months, I'd guess:

Average Weather for Moraga, CA - Temperature and Precipitation

I think it's a waste of $$, but there would be other costs for not complying to the wishes of the one who must be obeyed.

chuckb

hvac1000 · Dec 12, 2007, 05:33 PM

9000 BTU will do just fine.
Make sure when you mount the outside unit it is outside in fresh air not hanging from rafters under the roof because the condensing units are not designed for that. Now if you are going to hang it on the rafter tails outside that would work but one word of caution. Make sure the unit is in a easy place to service it from. Working from a ladder is a real pain and make sure there is a power disconnect within easy reach for disconnect when servicing.

I also have one of those SHE's who must be obeyed units here. I learnd long ago just to roll with the punches. LOL