should i insulate any of the furnace duct work?

Question

i have insulated my water pipes and water heater. should i insulate any of the furnace duct work?

Answer 1

if the duct work has been internally insulated, then no, that is if it is a/c&heating. If there is no insulation inside of the duck work, then yes you should insulate it.

if it is just heating duct work, then no.

Answer 2

If the duct work is inside the insulation of the house - no.
If the duct work is in the attic or crawl space where it gets noticibly cooler or hotter than room temp, then insulating will reduce the heat loss (winter) or gain (summer) and deliver more to the house.

Answer 3

Why wouldn't one do so?

As the whole point of insulation is the retention of desired temperature (hot or cold) for delivery at desired aperture, any transit loss is undesired.Any loss would need to be compensated for with greater production of required thermal volume at increased cost.

Exceptions may occur when insulation is prohibitively expensive to install (such as inaccessible wall or ceiling/floor spaces) comparative to extra generation cost. Even if accessible some areas may benefit by non-insulation: radiant heat preventing cavity condensation formation or cooling to prevent cavity "hot-spotting".

In installation ensure that access to other facilities like conduits is not compromised, and fire and electrical hazards are not created.
Many products from fibrous lagging, to fibreglass/silver tar-papers and chemical expansive foams are readily available and installed without tradesman help usually. Don't over-install: too firmly packed areas may prevent duct movement and create noises; over-doing expansive foams may pop wall sheeting off support fixtures or "bubble" flat contours.
Many products may also include fire and/or moisture resistance qualities should this be desired.

Insulative thermal effectiveness ratings for desired products are usually readily found from trade outlets, The Net or Eco-aware agencies.

Pleasant living!

Answer 4

most houses built after the 60's have duct work that is insulated on the inside.

we glue the insulation the the duct before we fold it.

the easy way to tell if your ducts are insulated is to see if it feels warm to the touch in the winter.

Possum HVAC guy

Answer 5

Shouldn't be necessary, You are not losing much, if any, heat or cooling from the duct work. Put some duct tape over any leaks you may find, but most duct work is usually tight.

Answer 6

If it is traveling through an unheated area, like a crawl space,attic or garage, you should. Otherwise, it should be fine.

Here is a good article which adresses your question:
http://www.bhg.com/bhg/story.jsp?storyid=/templatedata/bhg/step-by-step/data/hie_insulatingducts_03212002.xml