Duct insulation question

JMphotoDecember 15, 2011

We just finished building a new home and have an air source heat pump in eastern PA. Our basement is framed and insulated, but not drywalled yet. Our basement is partially underground with a walkout door. Most of the hvac supplies in the basement ceiling are uninsulated. Is this something I should think about insulating? See photos below. The floor is concrete and as I mentioned the walls are framed and insulated, but not drywalled ye, that is something I plan on starting this spring. The basement is not really cold, but it does get into the 50's.


Thank you for reporting this comment. Undo

You mean you installed duct work without insulation? An HVAC job should automatically include insulation on the ductwork. I can't see the pics but either you don't know what you are talking about or you got ripped off.

    Bookmark   December 15, 2011 at 10:51AM
Thank you for reporting this comment. Undo

I didn't install them, the HVAC sub who did the job installed the duct work. So you are sating I got ripped off and should insulate them? I don't know, I am not an HVAC expert, I am just a homeowner, but when I questioned the builder he said it does not need it since the basement is insulated??

    Bookmark   December 15, 2011 at 11:12AM
Thank you for reporting this comment. Undo

The argument against insulating the ducts is that any heat lost will find its way (up) into the living area.

In my case, I had an oversized beast which blasted the heat, but at very high blower speed. The basement didn't seem to get much heat as the hot air didn't linger that much.

Switching to a smaller sized modulating furnace, which runs much of the time at low blower speed, resulted in the basement gaining a lot of heat.

I could feel the heat pouring off of my main trunk and the basement was noticeably hotter. After insulating the trunk, i can put my hand a couple of inches away and feel little or no heat coming off. That heat is now being applied to distant areas which previously had suffered.


    Bookmark   December 15, 2011 at 12:37PM
Thank you for reporting this comment. Undo

insulate insulate insulate.

    Bookmark   December 15, 2011 at 1:29PM
Thank you for reporting this comment. Undo

I always wonder about that in basements..
not that we have them here. but for my $$
I'd mastic seal and insulate ducts and dedicate ducts
to basement for heating.
(maybe its a good thing I don't do basements!??)

    Bookmark   December 15, 2011 at 6:18PM
Thank you for reporting this comment. Undo

In NC, it is code to insulate ductwork in a basement that is unfinished even if insulated. It is probably okay but less than ideal. Your basement may be insulated but I bet it isn't really done if it is unfinished. I had an unfinished basement but it was insulated. But it was not well air sealed. There were large leaks that I gradually plugged that would have been a lot less noticable if drywall was installed (but still an issue).

    Bookmark   December 15, 2011 at 6:59PM
Thank you for reporting this comment. Undo

How are you planning on heating the basement?

Insulating the ducts against heat loss, only to then need an actual vent in the basement is not always productive.

    Bookmark   December 15, 2011 at 7:35PM
Thank you for reporting this comment. Undo

Our heating unit is a 4 ton unit and eventually we will have them add needed supply and return to heat the basement.

    Bookmark   December 16, 2011 at 8:25AM
Thank you for reporting this comment. Undo

until then.. the heat that escapes through
uninsulated and unsealed metal ductwork is
hot basement is heated?

easier to modify while under construction than
when build is finished.

best of luck

    Bookmark   December 17, 2011 at 9:54AM
Thank you for reporting this comment. Undo

"we will have them add needed supply and return to heat the basement."

And how are you planning on heating the basement until then?

All the first level floors will be cold if you do not have at least some heat in the basement.

Heat 'lost' from ducts into conditioned space is NOT really lost.
It may not be where you want it sometimes, but there are plenty of times where it is just fine to let the ducts radiate some heat into a space.

    Bookmark   December 17, 2011 at 4:06PM
Thank you for reporting this comment. Undo
CJ Mechanical of North jersey llc.

heat runs should be added to the basement then the duct does not need to be insulated however weather the basement is heated or not insulate to improve overall performance.basement typiucally do not need much heat BUT add a low return

    Bookmark   December 17, 2011 at 10:42PM
Thank you for reporting this comment. Undo

Energy in equals energy out. Any space inside the exterior building instillation envelope does not necessarily need to be insulated unless required in local,state or national code. If the work was properly permitted and inspected the building official would have not allowed a final certificate of occupancy if not to that code. If the space in the basement contains any apparatus that contains water or is subject to freezing the basement temperature must be maintained above freezing. So to insulate the ducts then provide heat to the space would be redundant, unless the system is also used for cooling then it would be quite necessarily to individually insulate the ducts to avoid condensation from forming on the cold duct pipes. Joe M Corbett Mechanical Contractor

Here is a link that might be useful: Corbett Cooling

    Bookmark   December 18, 2011 at 3:53PM
Thank you for reporting this comment. Undo

I only have two runs insulated that are along the far north side of the house and it did make a significant duct air temp difference in those two rooms. I did seal and foam where the plumbing and electrical go to the main floor so any heat that radiates off the sealed ductwork doesn't radiate right up towards the attic through holes in the floor.

    Bookmark   December 18, 2011 at 3:55PM
Sign Up to comment
More Discussions
furnace condensation freezing up
A non-profit club that I belong to has a furnace that...
Manual J -> S ->D
JSHR: 0.81 MJ8 Tons: 3.03 SqFt/Ton: 1667 CFM/SqFt:...
Brian S
Insulating floor on my raised home in Louisiana.
We recently installed solar panels on our home. We...
ERV Systems
Hello: Is it really safe to forego bathroom exhaust...
Dona Dinkler
New Mini Split Designs for 2015
I, and I am sure others, would love to hear what is...
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™