Bubble foil insulation on duct work in basement?

[jeff000]

My master bedroom is far away from the furnace, gotta be at least 80' of duct work. And 50' of that is in my basement. I get airflow, not the greatest, but not terrible. The air isn't nearly as hot as the air in my main floor bathroom (shortest run from the furnace).

I was thinking if I used that reflective bubble wrap insulation it might keep the air hotter.

But at the same time I am going to be using roxul safe and sound insulation for soundproofing, and while they say it is a zero r value I have a hard time seeing that. I was going to put the safe and sound above and below the ducts. So with that and being drywalled in it should insulate the ducts anyways right?

I guess what I am asking is if it's worth it to foil wrap the ducts that I can see?


PS, all the joints have that commercial paste stuff on them.

 

[volleyball]

If the basement isn't conditioned space, then it should be insulated. How big is the duct? Maybe it should be bigger or maybe add a booster fan for that room.

 

[jeff000]

If the basement isn't conditioned space, then it should be insulated. How big is the duct? Maybe it should be bigger or maybe add a booster fan for that room.

The basement is insulated. And I am in the middle of finishing the basement.

It's an 8" round duct off the main trunk. I have thought about a booster fan. But the only place I could put it and still have access after it's finished would be ~6' off the trunk line and it would still be a good 50' of duct.

 

[buddyboy]

if you haven't already done so, I would make sure the entire duct system, both supply and return for the whole house is sealed tight.

air leakage is your biggest enemy.

once you feel you have all leaks sealed and you still want more air flow out of one register, (before you get a makeup fan) try choking down some of the other ducts, this will force the air to the ducts you need. you can do this by closing down the registers or your ducts should have gates in them too.

also make sure you have a cold air return in the room you're trying to get air to.

once you get your air flow issue addressed then you can start to worry about insulating the ducts to reduce heat loss, but if you don't fix air loss first all you're doing is blowing air into insulation or unwanted areas.

good luck

 

[volleyball]

8" seems small to me, at least that's what the ho said, to run 50'. To what size room? You can add the booster at the bedroom.
Maybe putting a damper on the bathroom will help even out the flow. Another option may be to zone the house. You could do bedrooms as a zone, the basement as a zone, the living space as another. That way you can balance the house. Your original ductwork was designed for the way the house was built, which is changing.
I would fix the heat problem before you install any ceiling in the basement.

 

[jeff000]

8" seems small to me, at least that's what the ho said, to run 50'. To what size room? You can add the booster at the bedroom.
Maybe putting a damper on the bathroom will help even out the flow. Another option may be to zone the house. You could do bedrooms as a zone, the basement as a zone, the living space as another. That way you can balance the house. Your original ductwork was designed for the way the house was built, which is changing.
I would fix the heat problem before you install any ceiling in the basement.

The master is a large room, 22x17 and a 12x16 master bath.
Well it is kinda zoned, each floor has it's own main trunk. And I have the main floor bathroom blocked off.

I got a quote to properly zone the house and use a triple thermostat system with dampers, but at $12,500 it's well past what it's worth to me.
But 200 bucks to insulate isn't bad at all.

How can I add booster at the room side? I have no access to the ducts without thousands in refinish work.


I definitely don't feel like it's too cold or too hot in places of the house, but the bedroom could use some extra help for sure.

 

[volleyball]

You need a better quote. There are too many zeros in that quote. If you have trunks already, adding a multi zone valve and dampners should be easy. And for that size room, I would expect a 12" or more trunk and 8" from there to the bath and the bedroom.
With a larger duct, you won't need a booster.

 

[jeff000]

You need a better quote. There are too many zeros in that quote. If you have trunks already, adding a multi zone valve and dampners should be easy. And for that size room, I would expect a 12" or more trunk and 8" from there to the bath and the bedroom.
With a larger duct, you won't need a booster.

Right now the duct work follows the path of least resistance as I have several large beams without any penetrations. Part of the cost is that I need to change some plumbing lines and a gas line to my fireplace.

Right now I have a 10x14 main trunk And after measuring it is a 10" line off the main. That 10" line runs 20' and then feeds four 4" lines, one in the toilet part of the master bath, one under the cabinets in the master bath, one on the east side of the master window, and one on the west side of the master window. I already had the lines changed around to take out between 90 and 270 degrees worth of bends.
The only place I could put a booster in the 10" line is 4' off the main trunk.

I have a cold air return in the master, and even after having its line changed, I still can't get any air movement at that return, not enough for a piece of paper to tell anyways. Even with the door closed.
I have two other cold air returns upstairs that are a far more direct route to the main cold air return, and both those I can feel the air moving with my hand.

I'm really trying to be cost effective on my changes. Even 1000$ is really more than it's worth.


When I go to build my dream house it will be built with HVAC in mind, and not have it be such an afterthought like every other house.

 

[volleyball]

I had ductwork installed as an afterthought and it works flawlessly. I was involved in every inch of the system along with the designer.
Spending $1k for a proper system is cheap imo. I'd get a couple of guys in that design systems and tell them that performance over price is your goal. See what they say.

 

[ishiboo]

Reflective bubblewrap gets its R-value from the reflective properties of the foil. The "bubbles" themselves have almost zero R-value. Wrapped tight against a duct, it's not going to do much good.

Use fiberglass.

Sound deadening insulation alone is designed to have a high mass... having a bunch of open but isolated airspace like thermal insulation is not in its best interests. It has an R-value but it won't impress you and if they say it has "none", it's probably just not rated to have an R-value.

 

[ishiboo]

The master is a large room, 22x17 and a 12x16 master bath.
Well it is kinda zoned, each floor has it's own main trunk. And I have the main floor bathroom blocked off.

I got a quote to properly zone the house and use a triple thermostat system with dampers, but at $12,500 it's well past what it's worth to me.
But 200 bucks to insulate isn't bad at all.

How can I add booster at the room side? I have no access to the ducts without thousands in refinish work.


I definitely don't feel like it's too cold or too hot in places of the house, but the bedroom could use some extra help for sure.

8" duct is simply vastly undersized for that room. Plus it's a take-off off the main duct, unless it's on the end of the duct it's not getting the flow it needs.

If you have no access to run a new duct, you're stuck with point heating/cooling and trying to make it up with a booster fan. The more CFMs you flow, the more likely you are going to hear it, and perhaps other things... if it was designed improperly, will there be significant leakage somewhere? Will it whistle/make noise?

Try a booster fan, it's cheap. If not, you'll want a REAL professional with familiarity with a bunch of systems (including perhaps high-velocity) to come up with a solution.

 

[jeff000]

8" duct is simply vastly undersized for that room. Plus it's a take-off off the main duct, unless it's on the end of the duct it's not getting the flow it needs.

If you have no access to run a new duct, you're stuck with point heating/cooling and trying to make it up with a booster fan. The more CFMs you flow, the more likely you are going to hear it, and perhaps other things... if it was designed improperly, will there be significant leakage somewhere? Will it whistle/make noise?

Try a booster fan, it's cheap. If not, you'll want a REAL professional with familiarity with a bunch of systems (including perhaps high-velocity) to come up with a solution.

I could easily live with it how it is now. But would really like greater performance from it.
Cooling is probably the bigger issue, as just not enough AC makes it into the room.

I guess before I put an inline fan in I would need to know how much flow there is already so I can make sure I am getting a fan moving more than that air right?

A big problem here is getting someone to do the job even. No one wants to come and quote it even because it's not worth their time, they are busy with bigger higher profit jobs.
I had to call 12 places before one would come out and quote me, was 5500 for the HVAC stuff, and then 7000 for the other work to allow the ducting to be ran. Using insulated duct (with the black stuff on the inside).
I could do it for 2000, but then it would ruin my vision of what I want out of my basement. And what I want from my basement is far more important than the extra performance in a couple rooms.

Reflective bubblewrap gets its R-value from the reflective properties of the foil. The "bubbles" themselves have almost zero R-value. Wrapped tight against a duct, it's not going to do much good.

Use fiberglass.

Sound deadening insulation alone is designed to have a high mass... having a bunch of open but isolated airspace like thermal insulation is not in its best interests. It has an R-value but it won't impress you and if they say it has "none", it's probably just not rated to have an R-value.

It's roxul insulation. Probably not rated, but even crumpled up newspaper has an r value. The foil is only 3.7 R rating. Although says up to R21 depending on application.

I guess that snake wrap insulation would be better (I don't know what it's actually called, but we wrap heat traced pipes with all the time, it's like a really long bag with fiberglass insulation in it). I mean that is if insulating the pipe will even make a difference.

I had ductwork installed as an afterthought and it works flawlessly. I was involved in every inch of the system along with the designer.
Spending $1k for a proper system is cheap imo. I'd get a couple of guys in that design systems and tell them that performance over price is your goal. See what they say.

I was unfortunately not able to be involved in the construction as I bought a spec house.

I really wish I had options like there are in the states as far as cheaper labor and actually getting people that want the work. But like I mentioned it's just not easy here unfortunately.

 

[volleyball]

I took an old house with zero ductwork and now it has a lot. It can be done. You do lose some stuff. Decide what is important to you. Your place will never be nice if you don't make the structure right.
The bubblewrap insulation is the way to go, you just have to know how to install it. Not the way previously mentioned.
We don't know what size duct is right. We don't know where you live, what kind of house, what thermal values it has. You can get a designer to design you a system. Maybe it is having a pro do it off hours if the company is not interested.
Maybe a mini split for the bedroom and bathroom will solve your problem. Not the way I would go and way more expensive than doing the ductwork.
By your admission, your house is not done right. So it must be not comfortable, maybe tolerable. Mine is excellent. Not a bad spot in the entire place. Plenty of headroom in basement and I am not short.
I bet this is a good time of year in most parts of the country for you to contact people to do your job. You get them when they are not busy and you will get a response.

 

[Chevy-SS]

Following this thread closely, as I have almost identical long runs of HVAC duct in basement as OP (60' of 10" round, plus 20' of 10" square). I definitely need to do some insulating down there.....