This is about attic spray-on reflective insulating paint. Is it worth it to spend around 55-cents per sqft?

Question

The reflective paint is to be applied by paint sprayer to the joists and to the underside of the roof's plywood sheets, where the asphalt singles are nailed down. The theory behind it was that most infra-red heat waves that penetrate the roof and heat up the attic air space are redirected or reflected back to outside of the attic.

Answer 1

I have to express my opinion on this one, because I'm not familiar with the product.

This sounds like some kind of scam. Please, read my reasoning before you make a decision. The heat that penetrates into your attic, through the roof is not infra red. Sunlight heats the roof tiles, and the tiles CONDUCT heat to the plywood, and the plywood conducts heat into the attic space. A reflective surface on TOP of the roof might work, but I dont see how it works underneath.

Heat is transfered three ways: 1. Radiation, such as a heat lamp. This is the infra red you speak of. 2. Conduction, where one hot thing transfers and heats up another. Stick one end of a piece of iron into the coals, and eventually, the heat moves up to the other end. 3. Convection, as when air is heated, and the warm air rises and heats up more air. An oven bakes food this way, from heat in the bottom of the oven moving up and heating up the entire inside.

Unless the spray material provides some kind of insulating properties, I just don't understand how it would work.

I look forward to reading more responses. Maybe it does work.