Radiant Barrier for Attic?

[RRees]

Anybody installed or have installed a radiant barrier over their attic insulation?



If so, have you realized any energy reduction, better comfort?



Thanks.

 

[daytripper63]

Anybody installed or have installed a radiant barrier over their attic insulation?



If so, have you realized any energy reduction, better comfort?



Thanks.

Actually what you want to do is insulate the roof of you attic so that the actual attic space is insulated from radiating heat through the roof. I do Heat and A/C and the most comfortable attics I have ever been in had the underside of the roof insulated as well as the homes ceiling

 

[EricBu12]

we did do the reflective barrier in our house and I believe we did notice the furnace didn't run as often and the bills are a little lower. We also in the same time frame, replace all our windows with better dual pane ones.

The barrier is worth it

 

[Bill Stockard]

We built a new house last year. For the roof decking we used plywood with a radiant barrier attached to the panels from the factory. We wanted the radiant barrier more for restricting radiant heat load in the Texas summer. It works very well. The roof is galvalume finish concealed fastener metal which also helps reflect the radiant heat. On the hottest summer days the temperature in the attic has never been over 10 degrees ambient.



Bill

 

[RRees]

Thanks all.



My heating bill this year will be about $1113. 00 (700 gallons propane * $1. 59)



I'm hoping to save at least 1/10th of that each year. Plus the comfort level that goes along with that.



I'll try attaching more insulation to the underside also. The ceiling is pretty well insulated.

 

[daytripper63]

Thanks all.



My heating bill this year will be about $1113. 00 (700 gallons propane * $1. 59)



I'm hoping to save at least 1/10th of that each year. Plus the comfort level that goes along with that.



I'll try attaching more insulation to the underside also. The ceiling is pretty well insulated.

Do you know what efficiency your furnace is?

Anytime I install a new furnace on a home that is L. P. gas I refuse to put in anything less than a 90+ percent furnace, part of your problem could be an inefficient furnace or improperly sized.

Also

Where are your air ducts? Under the house or in the attic?

 

[I-6DZL]

Thanks all.



My heating bill this year will be about $1113. 00 (700 gallons propane * $1. 59)



I'm hoping to save at least 1/10th of that each year. Plus the comfort level that goes along with that.



I'll try attaching more insulation to the underside also. The ceiling is pretty well insulated.

Man i'd love to pay that much for a winter in MI. I spend about 3 times that much. New windows saved me ALOT! Now i need to insulate the whole house instead of having blown-in insualation. #@$%!

 

[BILLVO]

Do you know what efficiency your furnace is?

Anytime I install a new furnace on a home that is L. P. gas I refuse to put in anything less than a 90+ percent furnace, part of your problem could be an inefficient furnace or improperly sized.

Also

Where are your air ducts? Under the house or in the attic?

I have a few friends that are HVAC techs and they all agree that high effiniecy furnaces are not that reliable. They all claim that the gain you get from the efficiency will be greatly overidden by the high cost of repairs that they "WILL not may" need.

 

[Bill Stockard]

Thanks all.



My heating bill this year will be about $1113. 00 (700 gallons propane * $1. 59)



I'm hoping to save at least 1/10th of that each year. Plus the comfort level that goes along with that.



I'll try attaching more insulation to the underside also. The ceiling is pretty well insulated.

When we designed our new house about two years ago, we had a choice of either electric or LP gas as a heat source. Instead of LP gas, we built an all electric house using very high efficiency heat pumps. Fortunately in this area of Texas, the winters are realtively mild and heat pumps work very well. We designed/built the house with energy efficiency as one of our top priorities.



Since May 2006, our electric utility bill has averaged $125/month heating and cooling approximately 2800 square feet of living area at 76 degrees in the summer and 74 degrees in the winter.



Bill

 

[HoleshotHolset]

For the roof decking we used plywood with a radiant barrier attached to the panels from the factory. ... On the hottest summer days the temperature in the attic has never been over 10 degrees ambient.

What's that stuff run compared to normal 1/2" OSB?

10 degrees over ambient in your attic is UNREAL - wow!!!



Beers and cool attics,



Matt

 

[Bill Stockard]

What's that stuff run compared to normal 1/2" OSB?

10 degrees over ambient in your attic is UNREAL - wow!!!



Beers and cool attics,



Matt

I don't remember. We were paying lumber bills left and right at the time. It wasn't too more than 1/2" OSB decking or I would have remembered it. Here's a link to a supplier: Radiant Barrier – LP



Bill

 

[HoleshotHolset]

Thanks, Bill.

I found that stuff online earlier this week, but had never known anyone to use it.



I just might spec that stuff for my current garage project...



Beers,



Matt

 

[daytripper63]

:-laf

I have a few friends that are HVAC techs and they all agree that high effiniecy furnaces are not that reliable. They all claim that the gain you get from the efficiency will be greatly overidden by the high cost of repairs that they "WILL not may" need.

4-5 or more years ago I would have to agree with your friend, but today that is definetely not the case. Unless your friend is dealing with some of the cheaper Quality equipment such as "Goodman" "ICP products which is your HEIL, Comfort Maker, Snyder General, Whirlpool, Tempstar, Arco Aire" & "nordyne which is your Maytag, Westinghouse, Gibson, Frigidaire" If you stay away from these you should be fine, remember one thing the most expensive is not always the best either, there are some middle of the road brands that have no issues plus alot has to do with quality of installation... Kinda like our diesel truck parts:-laf

 

[mgoncalves]

Any hvac tech that thinks a new 90+ furnace is less reliable than an 80 % furnace, has their head in the sand.

 

[RRees]

I checked. According to the labeling.

I have a Lennox 92% efficient.



It's not a pulse type though.



Now, my debate is - Insulate under the rafters or do the reflective barrier.



It's like drinking a Leinies beer - which one is the best.

 

[Bill Lins]

Install the radiant barrier under the roof decking & insulate between the joists, not the rafters.