reflector in attic

Where

would you be attaching it? I've heard of Folks in Texas putting foil in under the roof to reflect back the infra red waves from the sun to cut cooling costs. I also heard it cut the life of their roof shingles in half as they got a double dose of infra red waves coming and going. Wehre would you install it to help with heating? WW

Somewhere in the Holohan archives...

Dan had a story about a house that was built way back when, that had nothing but shiny aluminum reflectors built into the walls. As I remember, the theory was that very little radiant energy would be needed to support the house and maintain good comfort conditions. As I remember, it failed miserably, as have many other attempts.



Bubble Foil Bubble is another fine example of this misapplied theory.



There is more to heat transfer than just conductive energy transfer, and there is more to maintaining human comfort than just providing heat.



ME

Reflectors:

The first house I built was in 1964. It still has the same paper shingle roof on it. There is no insulation in the rafters. Just between the collar ties.

I now see houses with 10 to 15 year old roofs failing. Excessive heat.

If you have AC and you are in Taxas, or anywhere for that matter, put a big fan in the attic and a thermostat to run it. If it is a open attic space, heavily insulate the floor and install fans. Heat flows to cold and dampness flows to dryness. If it is 100 degrees outside and you are trying to maintain 70 degrees inside, that is a 40 degree differential. If your attic space goes to 140 degrees, which isn't all that difficult, you now have a 80 degree differential. A fan, circulating 100 degree outside air will drop the differential back to 100 degrees. It will cost you less to cool your house with 40 degree differential ceilings that 80 degree. You should understand that.

Aluminum foil is a scam. By someone either well meaning or trying to seperate you from your hard earned cash.

In New England,, most old houses had roof scuttles. So you could get on the roof and clean the chimneys. And to open in the summer to let air curculate through the house. I call it "Third World Air Conditioning". I have a customer who wanted to put AC in their old house. It was a verfy complicated house to do it in. They got a price of over $60,000 to do just part of the house. They were going to try window air conditioners. I told them to put window box fans in the attic windows and open the windows downstairs. To put a box fan in their bedroom and have the air blowing on their bed. That at night, the air was cooler and that the cooler. dryer air would cause evaporation and that was the basis of cooling. They finally did. For less than $100.00, they cooled their house. With third world AC. In their house in Maryland, they definately need AC. But if you want to cut your cost and not wreck your roof, put in some attic fans. Get a big one. WW. Grainger sells some nice ones.

I use the same principle on getting rid of excessive dampness in crawl spaces. Blow the cool, damp air out and it will be replaced by warm dry air.

Radiant barrier

untill you have lived in the south, in an area with 300 predominately sunny days with temps that hit a 100 often, you won't understand what radiant barrier can do for you.



Perhaps the OP misunderstood where the reflective goes, never in Or on the insulation.



I can enter my attic on a 90 degree, sunny day and it won't be over 100, with no fans.



Liked it so much, I added it to a 3.5 car attached garage making the area tolerable in the summer with fans.