Radiant Barrier in Attic

[dieselscout80]

We are thinking about installing a Radiant Barrier in our attic, but we are trying to determine if it's a good thing for us in South Carolina.

Has anyone installed a Radiant Barrier product in their attic?

How effective has it been in reducing your electric bill for AC during the heat of the summer?

Has the Radiant Barrier affected your cell phone reception in your house?

Do you feel it was cost affective?

Has it adversely affected your roof/shingles?

 

[WM75Guy]

We used TechShield for the decking on our house when we built in 2009 in East Texas and cut our cooling bill way down. The attic stays cool during the summer reducing the conduction of heat thru the insulation to the ceiling. The attic is usually no more than 10 degrees above the outside temp. We heat and cool 3200 square feet all electric and the auto season thermostats are set for 68 - 72 degrees year round. Our electric bill has at the most been $350 during the hottest part of the summer. Between the house and the stables there are 3 AC heat pumps, 1 3 1/2 ton, 1 2 1/2 ton and 1 2 ton, 4 refrigerators and 3 hot water heaters. Our old house at 2200 square feet with 1 5 ton HVAC heat pump, 1 hot water heater, and 2 refrigerators and no TechShield used the same or more electricity and I could not keep the house cool. The best we could do was 78 degrees during the hottest part of the summer.

 

[ustmd]

We are thinking about installing a Radiant Barrier in our attic, but we are trying to determine if it's a good thing for us in South Carolina.

Has anyone installed a Radiant Barrier product in their attic?

How effective has it been in reducing your electric bill for AC during the heat of the summer?

Has the Radiant Barrier affected your cell phone reception in your house?

Do you feel it was cost affective?

Has it adversely affected your roof/shingles?

I used it on my shop and the tack room--I asked for it on the house, but the builder "forgot". I would highly recommend it. It is very common here and there are talking about making it part of the code for the city of Austin.

 

[DKCDKC]

My last house was built in 1974 with the then-popular all aluminum insulation - just layers of aluminum foil and brown paper. It actually worked for the summer in central Virginia, but failed miserably in the winter. And it never affected cell phones. Of course the house also had aluminum wiring. That was a blast.

My house now is mostly shaded by oaks. That works too.

 

[dieselscout80]

My last house was built in 1974 with the then-popular all aluminum insulation - just layers of aluminum foil and brown paper. It actually worked for the summer in central Virginia, but failed miserably in the winter. And it never affected cell phones. Of course the house also had aluminum wiring. That was a blast.

My house now is mostly shaded by oaks. That works too.

Thanks guys!

If you have a Radiant Barrier that is stapled to the bottom of the rafters is it solid from the bottom to the top or is there a gap at the bottom and top?

We had a nice big Oak tree that keep the morning sun off hte east facing side of the house, but it rotted from the inside and fell down in a wind storm at least it missed the house.

 

[edlegault]

Wouldn't regular insulation (batts or blown in) be a better barrier?

 

[wcampbell47]

The house we built last year has a radiant barrier on the bottom side of the roof decking. Traditional bat insulation was installed as well. In the summer months my electric bill was never over $200 so I think it helped a lot. Radiant Barrier has the potential to reduce your cell phone signal.

 

[dieselscout80]

Wouldn't regular insulation (batts or blown in) be a better barrier?

I have about 14" to 16" of insulation currently in the attic floor.

 

[SPIKER]

I believe you need to
1. insulate the inside from the outside attic space (attic floor) with or without wood flooring makes a difference. With wood insulate between drywall living space and wood floor with blown in insulation. In this case the radiant barrier can be stapled to the rafters so there is free space between the floor and radiant barrier. You need to have full length peak venting so air can come up from the eves and under the roof above radiant barrier and out the peak vent. If you have copulas or attic vents they need to pull out this heated air.

2. with NO attic Floor but lots of blown in insulation you can lay the radian barrier right on top of the insulation on the attic floor. This is a bit of a better solution but stops the attic as storage space which is needed in many homes. The roof venting is still needed in either case but a powered or solar vent in this case works much better. You can also re-insulate over blow more insulation on top of the radiant foil stuff as well later on.

It should not make a difference in cell reception unless you have the exterior walls insulated with radiant barrier as well. But I have no claim on this aspect.

Mark

 

[dieselscout80]

I believe you need to
1. insulate the inside from the outside attic space (attic floor) with or without wood flooring makes a difference. With wood insulate between drywall living space and wood floor with blown in insulation. In this case the radiant barrier can be stapled to the rafters so there is free space between the floor and radiant barrier. You need to have full length peak venting so air can come up from the eves and under the roof above radiant barrier and out the peak vent. If you have copulas or attic vents they need to pull out this heated air.

2. with NO attic Floor but lots of blown in insulation you can lay the radian barrier right on top of the insulation on the attic floor. This is a bit of a better solution but stops the attic as storage space which is needed in many homes. The roof venting is still needed in either case but a powered or solar vent in this case works much better. You can also re-insulate over blow more insulation on top of the radiant foil stuff as well later on.

It should not make a difference in cell reception unless you have the exterior walls insulated with radiant barrier as well. But I have no claim on this aspect.

Mark

We have a partially floored attic and will be flooring more of it. Our attic also has a full length ridge vent and soffit vents that are unblocked to allow air flow. I'm not sure whats under the vinyl, but I doubt there is a radiant barrier the home was built in 1989.

I'm thinking that I should start the radiant barrier about a foot above the insulation and end it about 18" or so before the ridge vent does that sound ok?