Comments on: Attic Insulation & Radiant Barrier Work Together In Warm Climates

By: Ed

Ed — Tue, 14 Jun 2011 18:05:29 +0000

Chris,

No, Ohio is not too far north to have an effective radiant barrier; we have customers in Northern Canada! What makes a radiant barrier effective is one thing: a source of radiant heat. This source can either come from direct sunlight or from inside your home (heating unit).

About the condensation issue – it’s important that it’s clear that foil does NOT cause moisture. The meeting of two drastically different temperatures causes moisture (think of someone’s HOT breath on a COLD window – that condenses and causes moisture). Now if your ceiling (aka attic floor) is not air tight, then it is possible that warm air escaping through the ceiling into the cold attic in the wintertime can present an opportunity for moisture to occur. To combat this you need to make your ceiling airtight. The foil is perforated, which does allow small amounts of moisture to pass through it and evaporate. However, large amounts of moisture could get trapped behind the small perforations, so air sealing is a priority. For more information on sealing common culprits of air leakage, check out this page on the AtticFoil.com website: How To Install Radiant Barrier Over Can Lights

By: Chris B

Chris B — Fri, 10 Jun 2011 03:54:46 +0000

Hi. I live in Columbus, OH. I have been recommended to your site. I have been doing lots of research on whether to install insulation on the attic floor or the roof joists. I have also seen on a .gov site that it is only recommended for warm climates, not cool and that you shouldn’t install on the attic floor which is contrary to your recommendations for certain situations. I have two questions: 1. Is Columbus, OH too far north for the radiant barrier to be effective? 2. Is installing the barrier on the floor, even perforated, a likely cause for warm air to condensate under the barrier on my fiberglass insulation in the winter time?

Thanks for the information. I look forward to your response.

Chris

By: Ed

Ed — Wed, 27 Apr 2011 18:00:59 +0000

Mark, Radiant barrier should never be a substitute for regular insulation. Refer to the Department of Energy for the recommended insulation levels and follow that guide - then add a radiant barrier to the attic for optimal results. Being in a mostly warm climate, you're greatest benefit will be the heat reduction in the summer months. As far as how to approach a bonus room over the garage: if the garage door/walls catch direct sunlight, then add the radiant barrier on the garage ceiling, to make a big impact on the temperature in the room above the garage. However, if the roof area above the garage catches sunlight as well, then you should also add radiant barrier above the room, since it is probably absorbing the majority of the heat from the roof catching direct sunlight. Think of it as looking for shade from the HEAT; the foil is your shade so to speak. For more info on hot rooms, read the article I wrote: Hot rooms in my house - how to make them more comfortable.

By: Mark barrow

Mark barrow — Fri, 22 Apr 2011 18:42:53 +0000

I live in warm middle Georgia. what do you think of radiant barrier versus foam insulation for mostly warm climates? Also, what do you think would work best for cooling off a bonus room over a garage which is hotter than other upstairs rooms?

By: Ed Fritz

Ed Fritz — Tue, 08 Feb 2011 19:46:54 +0000

Eban,

You basically need an umbrella for you home. I’d use radiant barrier on the roof and then (if needed) add insulation to the attic floor later. Insulation on the roof helps, but it’s really the wrong placement of R-Value. Example: I can hold a jacket over my head and it ACTS like an umbrella – right? Why not just use an umbrella?

If you have good attic ventilation as you stated, then a radiant barrier should drop attic air temperature. However, AtticFoil® Radiant Barrier will REALLY drop the surface temperature of your ceiling. This is the heat you FEEL coming into the home. Try it, you will be very pleased.

Please send some pictures of your installation in warm Hawaii – It’s been COLD lately here in Texas.

By: Eben Stiefel

Eben Stiefel — Sat, 05 Feb 2011 08:16:15 +0000

In Hawaii, we normally insulate the attic ceiling…not the attic floor. We have good ventilation (tradewinds) and not usually moisture problems. We don’t have to worry about keeping warm air in the house because it doesn’t get cold outside. So it is usually EITHER a radiant barrier OR fiberglass. In my case I only have 2 x 4 truss top chords so can only do R13 bats and can not decide which would be a better product if I have to choose only one. Of course I could insulate the attic floor with bats AND the ceiling with foil..but not in the budget and I think overkill in our relatively temperate ‘paradise’. Uninsulated the attic easily gets over 120, even 130. but I have put R19 in 2 x 6 roof joists and that kept the attic to 90 or 95..very comfy.
Basically because I only have 2 x 4 I was wondering if foil might be better?