If you are going to do anything in your attic, I would spray the attic roof with foam insulation. It might cost you $20,000 but we’ll worth it. We built a custom 5500sq ft home in GA using all spray foam insulation, walls and attic. When you walk in the attic, it looked like an igloo, but the attic was 70 degrees all year round, and that’s with 100 degree humid days or 15 degree nights. It is also a sealed attic meaning no vents for builders gap that allow bugs in. It was cheaper to heat and cool this house (5500 sq ft, 3 heat pumps) than our current TV house

$20,000? That would be my entire electric bill for 15 years.

Hope you got a very nice dinner out of this. Notice that they only want older people who are more gullible for these free meals.

Me too. I just learned a lot from this thread! Thanks!!

Just not cost effective. If it saved 10% of cooling bill (doubtful) , that would be less than $15 a month. It would take 15 years to break even. Scam that is sold by snake oil salesman.

Really
 

One of the all time not smart post. Spend $500 to wrap more insulation around already insulated ducts. All for 3 seconds of air!! Gotta a bridge that you would be smarter investing your money in.

You would need eight inches or more of spray insulation under your sheathing to match the blown in fiberglass that comes with the house. I like spray foam, but it is much more expensive than fiberglass. If you had spray insulation under your sheathing so you wouldn’t need fiberglass on your ceiling, you would have a large insulated but uncooled space, unless you cooled the attic as well. If you did, you might need a larger air conditioner, and you would pay to cool the attic as well.

You are talking about a totally different house design. Your description indicates that you are actually cooling the attic space with your HVAC system. I have seen this done once in NC but the home used geothermal wells to supply water as the heating/cooling heat resource for their heat pumps. This is more efficient since the groundwater is typically 55 to 65 F year round and makes heat pumps use less energy than using ambient air. However, geothermal wells need to be permitted and cost money. In TV with our small lots, geothermal wells may not be practical.

In the case I mentioned they had an entire room dedicated to the HVAC condensers and geothermal water heat exchangers etc. Perhaps in Florida the equipment could be located outside since winterization is less of an issue, but you may need some equipment covers etc. that may need ARC approval.

None-the-less, spending 20,000$ for spray foam plus some more for geothermal wells and geothermal HVAC takes a very long time to recover your investment.

If your previous house used geothermal wells as the heat source/ heat rejection pool, I suspect that your lower heating/cooling costs are due to the geothermal water temperatures and not to the spray insulation.

Your hard ducts are made of a fiberglass and glue product with foil on the outside. Adding another thin layer of foil wouldn’t help at all. These inch-thick hard ducts don’t insulate very much, but they insulate far more than the metal ducts used in past decades. You could add insulation by attaching foam board to them somehow, but I don’t know how much it would save you.

Attic insulation around here has often been trampled down by workers and isn’t working at its peak, so that R-38 may actually be R-15 in many places. Probably the most effective way of cutting your cooling costs would be to have another foot of fiberglass blown in. This is fast and not too expensive. It would also cover up most of the soft ducts (two layers of plastic bag material with a little bit of fiberglass and a coil spring in between). Then those ducts would have, say R-20 insulation around them instead of R-1. I wouldn’t be surprised if this cut your electric bill by $500 a year.

BTW, the home that we went to covered their complete attic with this super duper space age vented foil, added a solar fan on the floor, bought some added lubricate for their AC, for over $10,000.

Had radient barrier installed when house built 20 yrs ago. Glad we did. House cooler in summer and get to use the attic as it’s not too hot. Would recommend it. Researched it ourselves before building. Saves money over time and home more comfortable immediately.

If you are responding to my thread, no, we didn’t cool the attic. Our builder only used the spray foam that was over 10” thick on the attic roof. There are 2 kinds of this insulation: closed cell and open cell. We had friends that retrofitted their attics with the open cell spray foam at a cost of $8000 for a 2400 sq ft, and their attic in the middle of a GA summer was also 70 degrees. There is no magic to this. The other benefit to this in GA is your furnace lasts longer because they are located in the attic. A furnace running in a room at 70 degrees will last longer than a furnace running in an attic at 140 degrees

Wonder if heavy duty Reynolds wrap would do the same as this super duper foil for a bit less money.

I attended the same seminar and even had the speaker come to my home. He went into the attic and took pictures. Sure enough, I was losing energy and things were "a mess" up there - the pictures "confirmed" this. he was a great salesperson and I seriously considered this $10,000 "improvement." While I was thinking about it he went to my neighbor's house and guess what? She had exactly the same issues I had and the pictures he showed her were identical to the ones he showed me. My advise? Run don't walk away from this scam!

We went to that presentation as well. The assumptions presented were ludicrous. I agree with many saying the payback period is ridiculously long, if it ever happens at all. Btw - I am an engineer and this “investment” wouldn’t pass muster in any business. Save your money.