Is this ok?

First time I have seen this. Flexible dryer vent type duct being used for the branch lines to the floor registers. Modular home built in 2003. Obviously needs replacing, my question is: Is this an approved material to be used as heat supply duct? Thanks for your input…Rick

(This is in a crawlspace and was originally installed between the floor and the insulation that has been removed, so I don’t think insulated duct is an issue.)

This duct is not allowed for use in concealed spaces. It’s a fire hazard and should be replaced with smooth-walled steel.

It looks like duct for a clothes dryer. Am I right? If so, it’s certainly not made for use as distribution duct for the HVAC.

Thats what I was thinking Jeff. This is a Manufacured home and this is what they used to come off of the Main trunk line to feed the floor registers.


I’m seeing more and more of these cheap un-insulated flexible aluminum foil ducts on homes that are being flipped by investors. Most of the aluminum ducts I see, are on the return side.

I tell my clients that the material is very cheap, uninsulated will not last more than a year. I always report this installation as “Recommend HVAC technician upgrade heating ducts to a more rigid material”.

The professional insulated flex duct is a more professional approach.

Thanks David. Thats pretty much what I put in the report. It’s hard to believe some of the short cuts and “crap” materials they use in some of these homes.

Didn’t find exactly what I was looking for in my search but found this link. Good info!

That does not look like dryer vent to me it appears to be regular flex A/C type duct with the outer insulation missing as in gone.

That looks like some of the work from one of the local contractors here???

I have never been a fan of any kind of flex duct period for A/C.

Especially within a crawl space.

I always make the client aware of what is in use and when expected replacement is going to be required.

That is not a dryer flex duct, it is just missing the insulation.

That’s all they’re using here in new construction in Massachusetts.

Nothing but insulated Flex duct.

They use a lot of it here too David; but pay me now or pay me later

I see a 1/2 million dollar home with flex duct makes no sense to me???

Flex duct connectors are acceptable in michigan, but the insulation should be intact. No more than 14 ft. in length, supported less than every 5 ft. with a strap of a minimum of 1.5 in.Matt.