A/C/heating ducts-question?

[babylonsister]

Our air conditioning & heating ducts are in the attic. They are resting above the ceiling insulation. Should they also be covered with insulation? Our electric bills were atrocious last summer so we're trying to figure out what we're doing wrong/what more we can do. We live in hot Texas. Thanks!

[Berserker]

1. Yes you do need

to insulate the air conditioning and heating ducts in the attic. Johns Manville makes a product called DuctWrap. It is foil-faced so it will reflect radiant heat from the sun that penetrates the roof. It gets very hot in the attic in the summer and in the winter your attic should be the same temp it is outside. Also make sure your attic is ventilated properly. You will notice the savings.

[Jersey Devil]

2. Yes, my duct work was installed with insulation on it

Also make sure you have an attic ventilating fan connected to a thermostat so that the attic temperature can be kept down.

[babylonsister]

3. Thanks for the advice! nt

[arkie dem]

4. Most definitely

Like an earlier poster said you can buy duct wrap from an HVACR wholesaler and do it yourself. The instructions are on the package to figure how to measure the wrap. You will also need an outward clinch stapler and 3 or 4 rolls of scrim tape.
It's quite a job to wrap duct in an attic. You might find an HVAC installer willing to moonlight. If it were me I would pay big bucks to hire someone to wrap it. I really hate wrapping duct. I use flex duct as much as the building codes allow in attics, it saves time and money.

Also have your A/c serviced before summer. Clean coils will definitely save you money and unneccesary wear on your equipment.

[FloridaPat]

5. You can also install sheets of aluminum foil - I forget what it's called -

it reflects heat away from the house. You can put it on top of the ducts. They still need insulation, but this will help a lot. You can actually tell the difference if you do half the house.

[FloridaPat]

6. Radient Barrier! This is the aluminum foil you use to lower power

bills. It is great.

[babylonsister]

7. Is this the stuff that's used in roofing?

Had a completely new roof put in last spring; the guys anchored down a reflective surface before putting the shingles on.

[Berserker]

8. No

A Radiant Barrier that is used in roofing is made differently and has a different purpose. The duct wrap is and insulation and a radiant barrier. The foil that is used on the exterior of the duct wrap will have dust accumulation on the reflective faces in the attic over time reducing its radiant barrier effectiveness. But it will retain the insulation value that the heating and air conditioning ducts need.

There are a variety of installation options for radiant barrier applications for roofing: There are rolled foil types, roof sheathing that has a radiant barrier laminated to it. There is even aluminum foil "chips" mixed with blown-in cellulose insulation.
It is recommended that a Radiant Barrier only be applicated in Hot climates.

It is NOT recommended in cold climates. It will trap the warm moist air that leaks into the attic in the winter and condense on the underside of the barrier causing the roof sheathing to support mold and rot.