Talk of The Villages Florida - View Single Post - Is an attic exhaust fan worth the cost ?
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Old 04-03-2022, 04:59 AM
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Short answer: no it's not worth it, solar fans are 1,000 no it's not worth it.

Here's why.
I had a 110 volt attic fan and a whole house electricity monitor which checked the mains 10,000 times a second and used machine learning to identify individual consumers of electricity. I had two years worth of data on the fan (because it operated on 110) and the HVAC. I had this data on my first home.

Solar fans economy is easiest to debunk. The fan was thermostatically operated. During the hot months the fan would come on between 11 am and 2 pm and run to 11pm to 2 am. Clearly, the sun isn't around when the attic is hot. I won't get into the math of why the claimed cubic feet per minute ratings of solar fans are a stretch of marketing. Let's just leave it as the they don't remove much hot air.

The 110 fans vary in consumption of power depending on the motor type. The types that are sold at home improvement stores are affordable but energy hogs, they simply cost more in kilowatts than they save. The more efficient fans have, potentially, a very slight savings but they cost more to purchase and install then they save over ten years.

What does have a decent RoI (return on investment)? Additional static, non fan, roof vents if you install them yourself. I did this on my current home.

The vents on your home meet the state's minimum attic ventilation requirements. In my opinion, minimum is not good enough. I added an additional 80% more ventilation for 75.00.