Our air conditioner unit is almost 20 years old now. It is a Trane unit and
still works fine-SEER is 12.

The attic furnace, also a Trane, is natural gas and is about 13 years old.
It still works OK.

We haven't had problems with any of the equipment since installation. I
live in northern Texas-the summers can get pretty hot and humid.

I hear a lot of commercials recommending that I change out the old units
with new, higher efficiency air conditioners and furnaces. Many of the
commercials claim that the newer units will pay for themselves with savings
in utility costs.

My house was built in 70s and I have added insulation in the attic. It has
about 2200 sq ft living area. My highest electric bill this summer was
$350 (electric only).

Is it worth replacing the AC and/or the furnace with new units? Depending
on the costs, I would strongly consider upgrading the SEER.

Thanks.