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Cool air from attic

Ever since I had central air installed in my 1 story house with the ducts in the attic I experience alot of cold air coming back down thru the air ducts into the rooms causing a draft.
Why is this happening and how do I correct it?

P.P. The attic is well insulated with 9 inches of pink insulation and the ducts in the attic are also insulated.

Re: Cool air from attic

I have the same problem with a 2-story house. My air conditioning contractor told me to use cardboard(I used rigid insulation) where my filter is in my air return at the top of my stairs. He said warm air is going up, creating a current and pushing the cold air down. I tried it and while I'm sure I'm at least blocking warm air from leaving it didn't stop the cold air. I'm going to cover the vents somehow. I can't easily put insulation inside the vents(for the winter) because the vents are not only screwed on but glued to the ceiling.

Dolton Lewis
Re: Cool air from attic

Hot air alway rise due to having less "density" and therefore weight. Cold air will alway go down due to being heavier (more dense) and this is called natural convection. If you want to avoid draft (the main complain on all-air-system AC is to go to radiant cooling and heating with micro capillary tubes with just a small DX acting as a Dedicated Outside Air System, DOAS, for ventilation purposes only (10-15% size of an all-air-system).:)

Re: Cool air from attic

You can have a motorized damper installed in the return to close when the system is off.Of course you need a air flow proving switch so the unit won't come on unless the air is moving.
John Cannamela

Re: Cool air from attic

I solved a similar problem by removing the ceiling registers,installing a foam packing sheet, and replacing the registers. Yes, I know you said they were glued to the ceiling. They may only be stuck to the paint as mine were. I also sealed the air returns. This solved the cold draft problem coming from the registers. However, it did not solve a problem I have of condensation driping from the registers when the attic gets warm enought to melt the condensation in the duct work. Any one out there know how to solve this problem.

Re: Cool air from attic

I replied to another member earlier with a condensation problem, but our Diffusers may be able to have a positive effect for your situation as well.
Cold air entering from registers and diffusers happen in other homes and businesses across America.
We suggest you replace your diffusers and registers with HIGH QUALITY PLASTIC DIFFUSERS such as VERSATILE V-8 or VERSATILE V-10 Diffusers. These are currently available in 8"X8" AND 10"X10". 6"X6" will also be available soon thanks to consumer feedback.
The advantages of our UNITED STATES PATENTED DESIGNS are many:
1. Versatile diffusers are manufactured using ABS plastic which will NOT transfer heat like metal and ABS plastic is extremely durable. You actually can take one of our diffusers, drop it and it will not crack or dent.
2. Versatile diffusers are designed so the air exiting the diffusers and entering the room will actually flow ACROSS the ceiling and thus allowing the conditioned air to drop down the walls. This is the MOST efficient way to deliver the conditioned air. Typical registers and diffusers are designed to allow the air exiting the registers to drop straight down or at a slight angle. This does not take advantage of natural convection currents to produce even cooling within a space. If you have small children or elderly adults in your home typical registers are drafty feeling. You can place an infant’s crib directly below the VERSATILE Diffusers and they will feel absolutely NO DRAFT, but yet the room will be comfortably cool!
3. Versatile Diffusers are fully assembled for use as a 3-WAY diffuser and can easily be converted to 2-WAY with the extra baffle supplied with each diffuser. If 4-WAY air flow is desired, the factory molded baffle can be easily removed using a utility knife.
4. Versatile Diffusers can quickly and easily be closed during the colder months without the use of a ladder. We supply an adapter knob with each diffuser that can simply be attached to a wooden dowel of any length needed to reach the ceiling. A few turns on the adjustment knob and it’s closed until next cooling season! Yes, you will be able to do this while standing on the floor in EACH room. This is a positive shut off. This REDUCES HEATING BILLS! ATTIC AIR STAYS IN THE ATTIC! WHERE IT BELONGS!
5. Versatile diffusers are white to blend nicely with any ceiling.
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It is truly amazing how much ingenuity and value that is built into each Versatile Industries Inc. diffuser.
Thank you.
John Jongebloed
Sales Manager
Versatile Industries, Inc.
PO BOX 7371
Wantagh, NY 11793
(516) 785-5218
[email protected]

Re: Cool air from attic

Hi again.
I forgot to mention previously that you can block the return grille with insulation and plastic, BUT, YOU MUST turn off the electrical disconnect to the condenser (Outdoor unit)
and shut off the breaker or switch to the air handler/evaporator (Indoor unit). If you start your sytem without REMOVING the insulation, plastic, and any other blockages installed, it may result in damage to your system and/or home. It is also important to note that you open up your registers and diffusers before staring the A/C system in the Spring.

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