[Michael G.]

Wife and I attended a seminar at a home demonstration on
attic wrapping an attic with a space age vented foil laid over the insulation to keep the heat from the attic off our ceilings in the house.

Also, they talk about wrapping that same vented foil around our ventilation ducts, in the attic and water heater.

Google says ventilation ducts in Florida last 15 -20 years.

Anyone know anything about this, especially wrapping the ducts in foil?

Thanks

[villagetinker]

Sounds like snake oil. Now go to BBB and check out the company, if you cannot find them RUN away very fast. Then I would contact your local electric supplier many of them have energy audit programs and they may have some information on this stuff. I would also check with Seniors against crime to see if this is a real company and if there are any complaints. Finally if you are still considering doing this, get ALL of the documentation in advance, and have a trained expert (home inspector?) go over the claims, being made. I went to 2 of these types of seminars, and saw all kinds of holes in the presentations, so I did not bite.
Please proceed cautiously.

[retiredguy123]

Sounds bogus to me.

[DangeloInspections]

While I do not want to hurt anyone else's business, I would not recommend this for the following reasons;

1) the newer homes in The Villages have attic insulation that is an R-38. That is a good amount of insulation and there is a law of finishing return if you add more.

2) Radiant barriers stapled to the top chord of the trusses often fall down, and they lose effectiveness once they get dusty, and they will.

3) To install, the installers have to trample your existing insulation which hurts it's effectiveness.

4) None of us are young enough to see a return on investment.

While this is just my learned opinion, I have sat through hours of educational seminars on this from engineers that were much smarter than I am. I would give it a hard pass.

Hope that helps! Respectfully, Frank D.

[Toymeister]

I saw that presentation. I must say the food was very good.

The full presentation of facts was nowhere to be seen or spoken.

Your already HAVE a radiant barrier on your ducts.

The radiant barrier on the insulation that they peddle at several thousands of dollars is incredibly inexpensive the "RadiantGUARD Radiant Barrier Ultima FOIL Insulation Roll 500 sq ft | 48-inch by 125-feet | U-500-B | HEAVY DUTY Perforated Foil Radiant Barrier Attic Insulation - Blocks 97% of Heat" from Amazon is less than 20 cents a square foot. I believe the special show price was 15.00 a square foot installed for an identical product.

If you believe the presentation then buy it from Amazon and pay someone handsomely to install it any you'll save several thousands of dollars.

The main problem with the "facts" presented is you are never told how much of the home's heat gain comes from heat radiating down into the home. It's 25 to 35% if there is NO INSULATION.

Let's say that is the case, to make this example extremely favorable to radiant barrier let's say that every month is as hot as August. Since 50 to 60% of your total electric bill is HVAC let's say you have a very high electric bill of 250/month let's go even more ludicrous and say there are no fees on this bill and all of it is for electric consumption. Let's go all in and say this radiant barrier is 100% effective.

So, $250 X 60% consumption in hvac X 35% savings = $52.50 monthly savings. 630.00 annually. At the prices I was quoted it would take over 12 years to recover.

But: every month is not August and you do have insulation and a large portion of your utility bill has nothing to do with your incremental consumption.

By my calculations the radiant barrier would recover it's cost in 76 years.

I have better ideas on how to invest my money.

[thevillages2013]

In our area in Pine Hills the builder used Tech Shield roof decking. Each sheet of 4x8x7/16 roof decking (oriented strand board) OSB has a film (like aluminum foil) on the bottom of it. I can tell you that it definitely makes a difference in the attic temperature. This is not my first experience with this product. Also there was a company in Ga that coated the bottom of the roof decking and any gables with spray foam insulation. It works so well there was is no ceiling insulation needed

[Boffin]

Originally Posted by Michael G.

Wife and I attended a seminar at a home demonstration on
attic wrapping an attic with a space age vented foil laid over the insulation to keep the heat from the attic off our ceilings in the house.

Also, they talk about wrapping that same vented foil around our ventilation ducts, in the attic and water heater.

Google says ventilation ducts in Florida last 15 -20 years.

Anyone know anything about this, especially wrapping the ducts in foil?

Thanks

Radiant barriers in attics may be a viable strategy for reducing cooling loads in hot climates. However, that reduction is limited to solar gain from the attic—about 22% of a home’s cooling load. So even though research has found that radiant barriers can deflect 40% of incoming attic heat, the net savings represents about 8% to 10% of a home’s total cooling costs.

[DangeloInspections]

Originally Posted by thevillages2013

In our area in Pine Hills the builder used Tech Shield roof decking. Each sheet of 4x8x7/16 roof decking (oriented strand board) OSB has a film (like aluminum foil) on the bottom of it. I can tell you that it definitely makes a difference in the attic temperature. This is not my first experience with this product. Also there was a company in Ga that coated the bottom of the roof decking and any gables with spray foam insulation. It works so well there was is no ceiling insulation needed

Yes, they did this for a few years. Radiant barrier applied to the bottom of the roof sheathing, as yours is, is different than aftermarket radiant applications. Back then they did this and used an R-30 insulation. Folks complained about poor cell phone reception, etc., so they switched back to using regular 15/32" OSB sheathing and upgrading the insulation to an R-38. The use of spray foam on the underside of the roof sheathing is different altogether, and of course has it's own benefits and problems. Actually The Villages did build some homes with the spray foam in one neighborhood a few years ago, then returned to the use of R-38 insulation above the ceiling.

[Michael G.]

Originally Posted by Toymeister

I saw that presentation. I must say the food was very good.

The full presentation of facts was nowhere to be seen or spoken.

Your already HAVE a radiant barrier on your ducts.

The radiant barrier on the insulation that they peddle at several thousands of dollars is incredibly inexpensive the "RadiantGUARD Radiant Barrier Ultima FOIL Insulation Roll 500 sq ft | 48-inch by 125-feet | U-500-B | HEAVY DUTY Perforated Foil Radiant Barrier Attic Insulation - Blocks 97% of Heat" from Amazon is less than 20 cents a square foot. I believe the special show price was 15.00 a square foot installed for an identical product.

If you believe the presentation then buy it from Amazon and pay someone handsomely to install it any you'll save several thousands of dollars.

The main problem with the "facts" presented is you are never told how much of the home's heat gain comes from heat radiating down into the home. It's 25 to 35% if there is NO INSULATION.

Let's say that is the case, to make this example extremely favorable to radiant barrier let's say that every month is as hot as August. Since 50 to 60% of your total electric bill is HVAC let's say you have a very high electric bill of 250/month let's go even more ludicrous and say there are no fees on this bill and all of it is for electric consumption. Let's go all in and say this radiant barrier is 100% effective.

So, $250 X 60% consumption in hvac X 35% savings = $52.50 monthly savings. 630.00 annually. At the prices I was quoted it would take over 12 years to recover.

But: every month is not August and you do have insulation and a large portion of your utility bill has nothing to do with your incremental consumption.

By my calculations the radiant barrier would recover it's cost in 76 years.

I have better ideas on how to invest my money.

Is there anything that can stop the 3 second warm air infiltration coming through the ducts when my AC comes on?

Would more insulation wrapped around the ducts be the answer?

[Toymeister]

Originally Posted by Michael G.

Is there anything that can stop the 3 second warm air infiltration coming through the ducts when my AC comes on?

Would more insulation wrapped around the ducts be the answer?

No.

It is not infiltration of air into the system, it is air that is already in the ducts. Short of placing a vacuum on your ducts you will always have air that heats to the ambient attic temp when the system is off.

[retiredguy123]

Originally Posted by Michael G.

Is there anything that can stop the 3 second warm air infiltration coming through the ducts when my AC comes on?

Would more insulation wrapped around the ducts be the answer?

Adding more insulation to the ducts will not help. The only way to solve the problem is to set the supply fan to run all the time on a low setting. Note that the heating setting can be set to delay the start of the supply fan for 15 seconds or so until the air handling unit plenum heats up, so that you don't get a blast of cold air. But, I don't think the cooling setting has a delay option, and it probably wouldn't help anyway.

[thevillages2013]

Originally Posted by Boffin

Radiant barriers in attics may be a viable strategy for reducing cooling loads in hot climates. However, that reduction is limited to solar gain from the attic—about 22% of a home’s cooling load. So even though research has found that radiant barriers can deflect 40% of incoming attic heat, the net savings represents about 8% to 10% of a home’s total cooling costs.

Don’t use national statistics in Florida. We cool way more than we heat

[thevillages2013]

Originally Posted by DangeloInspections

Yes, they did this for a few years. Radiant barrier applied to the bottom of the roof sheathing, as yours is, is different than aftermarket radiant applications. Back then they did this and used an R-30 insulation. Folks complained about poor cell phone reception, etc., so they switched back to using regular 15/32" OSB sheathing and upgrading the insulation to an R-38. The use of spray foam on the underside of the roof sheathing is different altogether, and of course has it's own benefits and problems. Actually The Villages did build some homes with the spray foam in one neighborhood a few years ago, then returned to the use of R-38 insulation above the ceiling.

We had cell phone issues when we moved in this house six years ago but after inquiring about it we were switched to another tower and it helped but then the problem suddenly went away. The reason TV went away from the spray foam insulation was probably related to $$$$

[tomoscan]

Thanks, I am so impressed by the feedback given related to this topic.
As one had remarked, beware of free lunches that are really just sales bait.

[Life as I know it]

Had friends that bought that package. Results and savings are minimal. Just do your math. Figure out how many years it will take you to recoup the expense of your savings. You probably will never see the total savings. Best thing to this install a solar fan to draw out the heat.