On Wed, 23 Jan 2013 07:59:51 -0600, "HeyBub"
wrote:

andyeverett wrote:
A manufactured home has a compact oil fired forced air furnace in one
corner oc a 40x28 manufactured home. A large central duct runs down
the middle of an unfinished basement and perpendicular ducts run in
the joist spaces. The joist spaces in the basement are insulated with
faced fiberglass. The home is in south eastern PA. Seemed like a lot
of heat was wasted because the central duct was not insulated. The
owner of the home complained of cold and one heating contractor
installed a larger central duct (slows down flow further increasing
heat loss?)

Should the duct work be insulated and if so roughly how many years to
payback?

Thank you for any help!

Irrespective of whether the problem is connected to lack of insulation,
almost ALL duct-work should be insulated (excepting that which is in an
interior wall). Doing so will at least save on energy bills.

If you can easily reach the duct-work in question, the cost of insulating it
should be only a few dollars and a couple hours of time. Duct-work
insulation can be had at the box stores.

Payback should be in the neighorhood of one or two months of reduced energy
bills.

Wouldn't change my heat bill at all - I'd just have to open the
registers in the basement farther to heat the finished basement.