Christian Fox wrote:
Hi,

I'm planning on getting a high-efficiency natural gas-fired furnace
to replace our current 15-year old standard-efficiency furnace within
the next year or so.

I've heard that the high-efficiency furnaces require different
ducting, and use a vent on the side of the house rather than a
chimney as an exhaust.

Our current furnace has two insulated ducts going to the side of the
house, and the chimney running to the roof. If I get a new
high-efficiency furnace, is it likely that the ducts to the wall will
need to be changed?

The reason I ask is that I'm considering finishing my basement, and
if I do the ducts won't be easily accessible. If the ductwork will
need to get changed or replaced, I'd rather do that before finishing
the basement ceiling.

Thanks in advance for your help!

Christian Fox

There is no specific reason you would need different distribution
ducting. However you may want to have what you have inspected and evaluated
as many homes have a poorly sized and designed duct system. You can do that
anytime. If you are adding A/C then you are likely to need some adjustment.
A good duct design can make any system perform better giving you more
efficiency and comfort.

It is likely you will need a new intake-exhaust for the new furnace.
That depends on what you get. Generally they are easy to install and should
not pose a problem. If you are doing work now, you might want to plan. The
problem is who knows for sure what you will need for next year's equipment?

If it were me, I would have a pro take a good look at the existing duct
system and offer you suggestions about what you may want to do now.
Consider zoning as well. Now is the time to consider that.


--
Joseph Meehan

Dia duit