Latest Discussions : HVAC


02:51PM | 09/14/03
Member Since: 09/12/03
4 lifetime posts
As a Professional Engineer I was interested in testing all the claims for Radiant Barriers and Paintable Radiant Barriers, before I installed one in my own home. I tested the following 4 products, 3 paintable radiant barriers and 1 foil barrier over the course of about a year. The foil worked well for the equivalent of the first 2 years on an accelerated testing program. This involved adding dust over the course of 3 months. Effectiveness dropped to 46% for a 5 year period.
The next test was a paintable radiant barrier "Radiance," according to the product MSDS sheet the formulation contains "Formaldehyde" the product tested well but I would not subject my family or employees to this chemical. I also found some of the graphs and charts on their website useless and full of discrepancies.
Next product test was "Heatshield" the website is full of a tremendous amount of misinformation. According to their MSDS the product has a 300 psi crush strength but claim it can be sprayed. We tested using a Graco 795 airless sprayer, with an average operating pressure of 2,571 psi at the tip. A density test was performed, it showed 58% of the glass bubbles were crushed at this pressure. The product worked well when applied by roller, but rated very low when sprayed.
The last product tested was Radiosity 3000, the website is a true presentation of the product (no unsubstantiated space age claims). According to the MSDS the product has a crush strength of 3,000 as the name implies. Same testing was performed as above, using the same Graco airless at an average operating pressure of 2,579 psi at the tip. Doing the same density test 3.2% of the bubbles were crushed. I had a contractor apply Radiosity in my attic this past spring. My summer A/C bills have been 31% lower than the same 4 months last year.
My interior and exterior will be painted next year, after seeing the results I've seen with this product I will have it mixed in with both interior and exterior paint.

William Bonnell Ph.D. PE


10:48AM | 10/13/03
Member Since: 10/12/03
4 lifetime posts
I found this action by the FTC against a company marketing insulative ceramic paint products... makes me wonder whether this stuff is all hype:


09:58AM | 05/04/14
I have been investigating Radiant Barrier for my home in the SW and find the demonstrations impressive, yet, I hope someone, (other than a person who sells this stuff), can answer my questions. First the plan was to tack this to the roof deck a few inches short of the peak and a few inches short of the ceiling level to allow air to pass upward from the attic and bird board holes. Next having a vent on the side of the attic peak to allow air to pass through. Now the important question. If this reflects such potentially damaging rays and heat, does the 4" air space between the foil and my plywood and shingles provide enough protection to not damage my roof and shingles? and I heard the effectiveness drops in 5 years by 46% due to dust, is that true, and finally what is the expected effectiveness? I have hear up to 30% reduction of strain on the A/C not necessarily reflective in your bill. I am mainly after a cooler home without the A/C running too much during the worst months. Last, does your house have a harder time heating in winter due to this foil.

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