On Fri, 10 Aug 2012 14:45:36 -0700 (PDT), "
wrote:

On Aug 10, 5:38*pm, Ed Pawlowski wrote:
On 10 Aug 2012 14:59:30 GMT, Han wrote:

There are obvious exceptions: For example, four bedrooms each with its
own window unit may be more expensive than the central unit. But the
main point remains: why cool the whole house when only part is
occupied?

You are forgetting important advantages of not having window units.
Firstly, the rooms are much lighter, less need for lighting. *Secondly,
if it cools a little outside, it is very easy to open the windows and get
natural cooling. *Try that with window units. *Lastly, it is generally
more comfortable and efficient for 1 whole house A/C unit than 4 or more
window units. *Of course, that presumes adequate insultion of the home.

One size certainly does not fit all. *Your points are valid, but not
deal breakers for me.

If you only have one window in a room, you are correct. *If you have
two or more, makes no difference to open them.

They may eliminate some light, but in a bedroom at night, who cares? I
have one in the dining room on the north side and there is little
light to start with and while it cools other rooms, it does not
detract from their windows at all. *Dining room gets plenty of light
from the east side window.

In my house, it is not practical to put a central unit. *There are no
ducts so installation would be more costly. *If I had hot air heat,
I'd probably go with central. *Even then, adapting later is not as
good as a primary design for it.

As for efficiency, window units are generally less efficient to
operate, but not necessarily more costly. *Depends on how they are
used. *A 6000 BTU bedroom unit uses less juice overnight than keeping
and entire house cooled by a central unit when only a single room
needs to be cooled.

If you ever decide to add central air, take a look
at the high velocity mini duct systems. They cost
more for the eqpt, but deliver air via hoses that are
maybe 2" inside diameter? Much easier to route/install
in old work. I've only seen one actually in use, but
it seemed pretty cool. Both the temp and the way
it worked.

Wouldn't they be noisy and drafty?