When the right type of radiant barrier is installed and installed properly, the effects are amazing! That being said, a home should be air sealed properly as well as the ac and duct system. Ventilation of the attic too, plays a big part in the BIG PICTURE! The longer the hot or cold air stays in the attic, the more time it has to sneak its way into your home! All these systems working together properly and then adding radiant barrier, is like Icing On The Cake!
This garage was converted into a Brew Room / Storage area that was almost too hot to use. Not anymore! As per the home owner, "Garage was nice and cool today! garage definitely cooler and a nice improvement!"
I see returns like this all the time. Problem number 1.) There is no return air plenum. If you look at the Before photo, you can see its just a 2x6 frame. Problem number 2.) The top of the return frame is AC Ductboard. Whats wrong with that? Take a look at the sides of the duct board - it's fiberglass insulation which does not stop air flow. So when the unit is running, it is pulling air, dirty and unfiltered air, in through the fiberglass (look closely and you can see that it is discolored, dirty) and straight into your home!
Our solution for this was to seal everything at the base and then spray with closed cell foam.
Proper attic ventilation is important. How important? We should have between 10 and 12 fresh air exchanges per HOUR in our attic space! So what can we do to acheive this; Solar Attic Fan. With the proper installation, and the right amount of NET FREE Ventable Area, a solar attic fan can and will do the job. However, BE AWARE OF JUST ANYONE INSTALLING THESE. I go into homes where the roof has been replaced and fans were sold. The installations end up costing you more money though when a roofer or any other non-qualified individuals install them and then do not air seal or duct seal your home. Add a fan without doing this helps air you are losing to escape faster!