jbogs wrote:
The goal is not to go to big with a unit since that will reduce the
actual efficiencies of the unit and you will be using more fuel with
the constant starts and stops. The goal is to have the unit on the
coldest day run for 45 minutes. This is like higheway mileage vs city
stop and go.

So bigger is not better.

I don't think a car analogy is a good one. Imagine walking into a car
dealership and saying I want model X, with options Y and engine Z and
all of a sudden getting interrupted by the dealer saying, sorry, you
can't choose the engine, I will pick the engine for you that will
maximize your gas mileage and give you barely adequate performance
under your worse case load conditions (i.e., you will have to floor the
gas pedal to maintain 55 mph), I don't think many consumers would be
happy to hear that...