AC duct not sealed

[Lisa Bloemer]

Hi,

I am new to HI industry. Just completed an inspection in Pensecola Florida. There were two 2 ton (all electric) units in a new three story -duplex.
In the attic, the plenum had a A/C duct with a louver. The louver wasn't sealed all the way, and cold air was discharging into the attic. It seemed to me,that this should have been sealed (capped) off. Can anyone explain if this is common? Thanks.

[Joe Funderburk, CMI]

Picture?

[Gerry Beaumont]

Originally Posted by Lisa Bloemer

Hi,

I am new to HI industry. Just completed an inspection in Pensecola Florida. There were two 2 ton (all electric) units in a new three story -duplex.
In the attic, the plenum had a A/C duct with a louver. The louver wasn't sealed all the way, and cold air was discharging into the attic. It seemed to me,that this should have been sealed (capped) off. Can anyone explain if this is common? Thanks.

Was this a sealed or vented attic?

Regards

Gerry

[Lisa Bloemer]

Here are two photos of the opened duct. The attic had foam insulation throughout it extending to the soffit. No space for soffit air circulation. Is this considered okay? I thought insulation should never be over soffit vent area.

[David A. Andersen]

That is a balancing damper and the duct to it is missing!

Any air leak (regardless of size)results in the same volume of unconditioned air being drawn into the conditioned house.

First you loose the conditioned air, then you replace it with unconditioned air that loads the system (beyond capacity in many cases).

Also the building goes into a negative atmospheric pressure that draws all kinds of potential natural pollutants (radon, mold spores).

[Mark Nahrgang]

Since they sprayed the roof, could it be that they converted the attic to "conditioned space"? Instead of the traditional vented unconditioned. You mentioned that they insulated over the vents...

[Mark Thorman]

Did you check air flow to all the resisters and was there a register in every room?

www.mauihomeinspections.com

[Brian A. MacNeish]

Originally Posted by mnahrgang

Since they sprayed the roof, could it be that they converted the attic to "conditioned space"? Instead of the traditional vented unconditioned. You mentioned that they insulated over the vents...

Looks and sounds like they did indeed create (or try to create) a conditioned attic. This duct take off should be sealed but being unsealed is not as big a problem as some may think.

[cbottger]

Originally Posted by Brian A. MacNeish

Looks and sounds like they did indeed create (or try to create) a conditioned attic. This duct take off should be sealed but being unsealed is not as big a problem as some may think.

I don't necessarily agree but I will bite your take please---)))

[David A. Andersen]

I'm waiting also!

To start with, you don't put a supply into a closed space without a return or it will pressurize the space forcing air through the walls/roof to the exterior which is an efficiency concern.
If you blow conditioned air into the attic where does the displaced air go?

Two HVAC systems for three floors, and now they're going to air condition the attic in Florida? Yeah, right!

How many CFM are you getting through that closed four-inch takeoff? Not enough to cool the attic, that's for sure. The result is you still have hot air in the attic and you're forcing it around the ceiling penetrations and into the walls of the house. That sounds like good planning and design.

These new energy standards are really screwing things up.

By the way, I'm not directing this at you Lisa.

[Brian A. MacNeish]

Originally Posted by dandersen

I'm waiting also!

To start with, you don't put a supply into a closed space without a return or it will pressurize the space forcing air through the walls/roof to the exterior which is an efficiency concern.
If you blow conditioned air into the attic where does the displaced air go?

Two HVAC systems for three floors, and now they're going to air condition the attic in Florida? Yeah, right!

How many CFM are you getting through that closed four-inch takeoff? Not enough to cool the attic, that's for sure. The result is you still have hot air in the attic and you're forcing it around the ceiling penetrations and into the walls of the house. That sounds like good planning and design.

These new energy standards are really screwing things up.

By the way, I'm not directing this at you Lisa.

This is a conditioned attic, sealed off from the exterior by spray foam. The amount of air leaking around this small closed damper may be what...8-10-15 CFM in a system of 1000-2000 CFM......not a big deal and it is into a conditioned space. Jeez, a 4" duct is only rated to carry 40 CFM in good designs.

Residential duct systems are usually unsealed and not even close to good spec'd work seen in commercial, etc. I have seen studies from Home Energy magazine and others that claim that 20-40% of the air moving through the air handler does not come from or get to the intended grills/diffusers.....the ducts are generally so leaky!!!!! So to me this is not a big flaw but still should be sealed.....I just wouldn't hang a big, red flag on it!

As to pressurizing the attic......I wonder if you could even measure the effect with a micromanometer that this small a leak would have!!(unless it was a quite small space) Since the attic is sealed, any pressure would send air into the house through ceiling penetrations.......conditioned air from above....sounds familiar!!! Other items such as poor duct design (no returns in bedrooms with 2-3 supplies), other duct leaks, wind pressures and stack effect will cause much larger pressure imbalances/variations than this small amount of leakage.

Unlike other duct leakage in unconditioned attics, this air is lost to or returned from the conditioned space. How much efficiency would be gained if this were sealed?

[cbottger]

Originally Posted by Brian A. MacNeish

This is a conditioned attic, sealed off from the exterior by spray foam. The amount of air leaking around this small closed damper may be what...8-10-15 CFM in a system of 1000-2000 CFM......not a big deal and it is into a conditioned space. Jeez, a 4" duct is only rated to carry 40 CFM in good designs.

Residential duct systems are usually unsealed and not even close to good spec'd work seen in commercial, etc. I have seen studies from Home Energy magazine and others that claim that 20-40% of the air moving through the air handler does not come from or get to the intended grills/diffusers.....the ducts are generally so leaky!!!!! So to me this is not a big flaw but still should be sealed.....I just wouldn't hang a big, red flag on it!

As to pressurizing the attic......I wonder if you could even measure the effect with a micromanometer that this small a leak would have!!(unless it was a quite small space) Since the attic is sealed, any pressure would send air into the house through ceiling penetrations.......conditioned air from above....sounds familiar!!! Other items such as poor duct design (no returns in bedrooms with 2-3 supplies), other duct leaks, wind pressures and stack effect will cause much larger pressure imbalances/variations than this small amount of leakage.

Unlike other duct leakage in unconditioned attics, this air is lost to or returned from the conditioned space. How much efficiency would be gained if this were sealed?

The original poster never really stated that it was a conditioned attic everyone is just assuming that it was because of the spray foam sounds to me that someone had good intentions gone bad as one can see those balancing dampers are not a positive shut off and do have a good amount of air blowing bye not just 10 or 15 cfm
No the world is not going to come to an end because of it I would handle it just as any other item in need of repair

[Lisa Bloemer]

Thanks for all your help. This is the first time I've posted and glad to see the support. Especially so quickly.. I will definately bookmark this as open favorite tab.

No, don't think it's a conditioned attic. I think someone left the seal off this return. I haven't seen this before with louver not capped.

Unlikely they built return for adding attitional living space in attic for later time. This is a duplex condo.. Not much space for adding. Living areas had 14 - 20' ceilings.. so attic was chopped /divided.

Yes, they did have adequate registers in every room and house was very cold and air flow was good throughout.

The attic was large, unfinished and not cool at all. I was dripping wet while up there.. It did appear to be lost energy at most.

Still not sure why they foamed entire overhang. Yes, There are soffit vents on the outside.. But they were four stories high... so I wasn't able to see inside if foam covered them or not. Should I assume they were..and write it up as suspcious for proper ventilation. There was no other area where air flow could escape the attic... am I missing something?

The place is brand new.. had many many problems with missing significant caulking throughout in everybath/kitchen countertops.. several cracked tiles on floor and marble in shower areas.. damaged spa intake, master sink cracked, shower shelf broken and not secure on wall, torn screens, carpet unattached on top step, several cosmetic marks, stains, damages on sheetrock throughout every room, missing caulking exterior siding on ground and floor levels, Two GFCI's didn't operate... actually very surprised the amount issues for a new "Move In Ready" condo. Is this normal for new construction?

Also had a vent connection going from Water Heater/AC closet extending through roof. Can figure out what that is for either.. All electric appliances.. No fuel at all going to building.. Can you comment on that as well? See photos attached.

The Realtor / Condo Assoc Rep said "He" checked everything and it was all working fine and ready to go.. Owner (my friend) wanted someone to walk through with them as safeguard to what Realtor said. Realtor is pushing for quick sale.. Buyers are wanting repairs before signing on line..
Lisa

[David A. Andersen]

They plan for gas but use electric instead because of the increased cost of fuel.

That's what's happening around here anyway.

[Mark Reusch]

Originally Posted by mnahrgang

Since they sprayed the roof, could it be that they converted the attic to "conditioned space"? Instead of the traditional vented unconditioned. You mentioned that they insulated over the vents...

I was under the impression if an attic was sprayed that the rafters should be covered as well. Seems to me the to fully seal an attic space the trusses or refters would have to be sealed as well. If I am wrong or confused about this does anyone have some information about this ?