"Jim Redelfs" wrote in message
...
Imagine all the added elbow room if the adjoining water heater was GONE
during
a furnace retrofit. Well, that's what I'm going to be doing (See Downsize
Water Heater ) in
a
little less than two weeks.

My contractor wants to DOWNSIZE to 75k from the 100k size of my
14-year-old,
conventional (spec) gas furnace. Of course, this will be done with a "90"
(or
better) model. He claims that the improved efficiency of the new furnace
will
compensate for the difference. Do you agree?

Unless the contractor provided the manual calculations or you have added a
bunch of insulation improvements since the orginal install, I would be
concerned.
Do you heat more than cool?
Efficiency is not BTU's, efficiency might help the consumption but not the
heating load back to BTU's again.



He also mentioned, after taking measurements TWICE, that I need an
18-inch-frame unit and that a bigger unit would require a reducing "boot",
which he represents as a compromise. What's with that?

The boot may be changing the duct from one size to another. I call it a
transition. Very common and I can not see the installation. A good
sheetmetal man can make a round funnel with a square hole.

Then there's the PVC vent(s) outside. He claims that it is legit to use
only
ONE - an exhaust line - that the furnace uses INTERIOR air for combustion.
He
represents this as a DESIRABLE way to EXCHANGE interior air with fresh.

The UPC, or uniform plumbing code in my area does reconize using inside air
for combustion. But since your heating why would you do that. All of the
combustion air is heated and must be replaced by,,,,,,,,,,,, cold air.
Most new gas appliances have charts for the combustion air sizes.
Sounds lazy to me.,,,,,,, again I can not see the installation.



I am old enough that this furnace may well be part a big part of the
resale
value of our home. He wants to install a "Weathermaker" furnace and a
Rheem
ac condensing unit outside. He says that the Weathermaker FURNACE is
virtually the same unit as a Rheem so this would be an up-front
cost-saving
issue ONLY, assuming he's right. What about resale then?

Resale is what the buyer will pay. Sheetmetal and a pretty sticker are just
that. Most buyers are just begining to think about operting costs. Higher
effency, and higher SEER may help the resale, New installs after 1 Jan 2006
are to be SEER 13 min. SEER is a cooling rating and has not a damn thing to
do with heating. Heating is a COP number.


He further says that the condensing units are different and therefore,
recommends a Rheem unit outside.

I have not a clue what you or he means by this.

Like the others have said, more contractors, more quotes before you decide.


JR