Home Depot – Reflective Insulation Radiant Barrier Roll

It’s summer and my place is heating up.  I am always on the lookout for ways to better insulate my home.

I was looking at insulation on the Home Depot website and noticed this product.  Reflective Insulation Radiant Barrier Roll  At 5mm thick was the perfect thickness to place outside my hottest window.

It was stiff and fit perfectly between my screen and the outside of the glass.

The radiant barrier insulation appears to be 3 times as thick as the aluminum window insulation I purchased from amazon.com but the reflectivity seems lower.  I decided to try using them together.  I added a layer of aluminum window insulation on the outside and the radiant barrier on the inside.

In the summer the sun shines on the window the longest and the angle is straight on so the room is exposed from around 12pm – 7pm and it has always been the hottest room in my townhouse.

I took temperature readings at 6pm which is around when that room gets the hottest.  On the left side of the window it’s just glass and all the insulation is on the inside.  The insulation for the left side of the window:

165F layer 1 low-E 3 glass
113F layer 2 a layer of aluminum window insulation on the outside and the radiant barrier on the inside.
107F layer 3  1″ thick foam insulation
95F layer 4 1″ thick foam insulation
85F layer 5 1″ thick foam insulation

On the right side of the window I have the radiant barrier insulation and aluminum window insulation on the outside of the glass.

95F layer 1 a layer of aluminum window insulation on the outside and the radiant barrier on the inside.
85F layer 2 low-E 3 glass

Patio 84F
Bedroom 80F

From my test results I have proven that insulation is much better at keeping the heat out when placed outside the glass and the radiant barrier insulation with aluminum window insulation work great. together.

I was surprised to find the left window glass got up to 165F.  This is due to it getting hit by a double dose of solar radiation.  Normally it would just get hit by the sun once but the reflective insulation on the inside of the glass reflects the sun against it a 2nd time.

Another interesting test result is I get about a 10F temperature reduction with each 1″ layer of foam insulation.  If the summer gets hotter I can make them room cooler by adding 1″ foam insulation to the right side window.  Sadly there isn’t any more room on the left side for more foam insulation.

You can read about my other insulation projects below.