Radiant Barrier vs. Attic Exhaust Fans
I keep getting conflicting information and opinions about this (as well as whole house fans).
Between HVAC contractors and attic insulation contractors, some seem to swear by radiant barriers and slam attic fans as useless whereas others don’t think radiant barriers work very well at all but strongly advise using attic fans. Not sure what to make of it.
I figure with attic fans, the placement matters and makes a difference. In our case, we are west-facing and very slightly south-oriented. I think the prevailing winds are from the west here (I’m located in South Orange County, Southern California). The attic/gable vents for our house though (and there are three of them) are oriented more north-south so I don’t think you get too much of a natural breeze or airflow going through. In this case, it seems like an attic fan would help – I’m just not sure whether to position it on the north-side/north-facing vent or on one of the south-side/south-facing vents (see attachement)
As far as radiant barriers, I just haven’t seen or heard of this being a super popular thing down here. But maybe I just don’t know because it’s not like I’m going into my neighbors’ attics 🙂
As a sidenote: that’s a Spanish clay tile roof and we will be having solar installed on the frontside in a couple weeks. Insulation in the attic is R19 currently so I’m also considering replacing or supplementing (as well as rodent proofing). There were signs of rodents up there (droppings, etc) but I don’t think there has been any current activity in a while (trees surrounding the home have been removed since we moved in and the droppings appear to be older).
Another thing to note: Some HVAC contractors I’ve spoken with swear by things like whole house fans where others (like my current contractor) strongly advise against and say they can cause negative pressurization as well as expose an opening in the insulation (where the fan intake is) and allowing conditioned air to escape.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part