We are often told about the perks of having solar attic fans and how they can keep our energy bills down by keeping our attics cooler.
There is no doubt that they probably keep the attic cooler just as this article states and sources a UF study.
But do these solar attic fans actually work the way they are intended? In this blog, we will break down the estimated savings, true savings, and total costs of the solar attic fan.
Solar Attic Fans – How They Work
Solar attic fans work by pulling in the cold air from the soffits and pushing out the hot air that has accumulated at the top of the attic.
This is basically how air naturally moves: cold air is at the bottom, and warm air is at the top. The attic fan just helps the air move more which adds cooler air circulation.
Attic Fan Savings Claims
Finding monthly savings claims was actually VERY difficult. It seems nobody can really tell you what the average expected savings are. This is most likely due to the variance in HVAC efficiencies, insulation effectiveness, home location, etc.
HOWEVER, I was able to find one resource that was particularly interesting. This is the Attic Breeze Energy Savings Calculator! Based on the averages I put in (see my screenshot), it will take 4-7 years for me to theoretically make the return on investment of an attic breeze solar attic fan.
Their solar attic fans cost around $500, not including installation costs. So you can probably expect your total expenditures to be around $700-$800 for a full install.
By the way, if you are curious about where I received my averages for the calculator entries, I got them from the EIA report for average Florida energy consumptions, and my expertise as a home inspector in Florida.
So based on the calculations… the average person, in Florida, will save $131.36/year. (Based on total costs of $750 it would take 5.5 years to recoup the costs). This is about on par with what Matt Risinger states in his video on solar attic fans (linked below).
Other Arguments for Solar Attic Fans
I have found other points that solar attic fans help keep attics cooler and therefore extend the life of your roofing shingles. However, there is no statistical evidence of this being true.
Arguments Against Solar Attic Fans
Now there are many articles that are against solar attic fans, for many different reasons. Let’s talk about them and see if they hold true.
Attic Fans Can Pull Air From Inside the Home
This claim is most definitely true. This states that your ceilings (although covered with insulation) have tiny cracks and holes that allow your cool air to be released into the attic. Therefore, adding an attic fan would just end up sucking more of your conditioned air into the attic which causes your A/C to run more frequently.
Check out this video from Matt Risinger that shows how conditioned air is lost through the ceiling.
Basically, Matt and his friend partnered with a Flir (thermography) camera, show how conditioned air is lost through the ceilings.
So, how do you stop this?
In order for you to stop this from happening, you basically need to re-insulate and seal those tiny cracks just like how Matt tells us in the video. The unfortunate part is that older homes tend to be the least energy efficient. So, theoretically, you can cause a bad insulation/sealing problem worse by adding in an attic fan!
Solar Attic Fans Are Just Another Leak Waiting to Happen
Again, this claim is true. Penetrations in a roof is not a matter of if it will leak, it is a matter of when.
In most cases, homeowners install attic fans and then forget about them. However, this could not be further from what is actually needed: a roof needs continuous maintenance.
If a roof is left unmaintained year after year… you will end up seeing more costs from roof leak repairs than you would see savings from energy bills.
Older Homes Have Blocked Soffits
Again, many older homes have poor energy efficiency to start with. And with that, they are missing baffles near soffits.
Baffles are pieces of cardboard that basically prohibit insulation movement over certain areas. This will protect the soffits from getting clogged with insulation so soffits can properly breathe.
You can check out this article from EnergyStar.Gov that explains the importance of baffles with attic fans.
So again, we are missing a greater picture that older homes have energy efficiency issues to begin with. A solar attic fan seems like patch rather than a proper repair at this point.
So What Are the True Savings of Solar Attic Fans?
Honestly, you tell me. I have not found any resource available online that shows true cost savings from solar attic fans. On the other hand, I found many people and reviews that state their home/attic feels cooler.
Feeling cooler and actually causing monthly savings in a cost effective manner are two different things. Furthermore, I would be happy to report about their roof leak from the attic fan penetration once they go to sell their home.
Concluding on Solar Attic Fans
Solar attic fans are not needed in brand new construction homes. Their energy efficiency is already extraordinary.
So, is it truly worth it to add a solar attic fan on an older home? Or, is it better to abide by proven methods of insulating a home and increasing attic ventilation through soffits, ridge vents, or offset ridge vents?
My belief, is solar attic fans are not worth it. There are too many different ways you can better insulate your home to avoid energy loss. Also, adding more penetrations to your roof is cause for more roof maintenance and potential roof leaks.
In my mind, attic fans seem like a great idea and have a great pitch, but in reality, you would be better off spending your money in other places.
If you don’t believe it from me, watch this video from Matt that explains why.