These questions are asked very often by HO that are about to make a purchase
Try going to your states Department of consumer affairs web site : there you can find info on brands they have tested , you can find info about the company or contractor you choose to work with
for energy saving systems , try the energy star website
The Department of consumer affairs has tested and given ratings to every kind of product you can imagine anbd since most people dont seem to trust that their contractor is being hoinest with them, they can get an unbiased opinion
from the state
This is a post I had some time back along those same lines,
It has a link that is from consumers report about furnaces.
Theres only 2 brands that fall outside the lines.
as far as the margine of error go.
If you try to fail, and succeed.
Which have you done ?