Attic Fans and Solar—What You Need To Know.

Updated: Jan 20, 2021


Summer heat can be brutal, especially in places like Texas, California, Nevada or Arizona.  Attic fans have been widely promoted as an effective way to minimize energy consumption by lowering attic heat and thereby save money on electricity costs.  


Market claims over the internet suggest improved attic ventilation may result in a significant reduction in energy consumption and thereby put less stress on air conditioning units.  To this point, Solar Consultants may feel tempted to recommend or even add a power assisted venting system to somewhat increase solar energy offset. But, is it true?  Some people swear it’s not.  Let’s take a closer look at this controversy and see if we can figure this out.  


What is an Attic Fan and How Exactly Will it Help Reduce Heat from the Attic? 


Attic fans are often confused with whole house fans—another type of fan. Whole house fans or whole house ventilation grants an opportunity for homeowners to bring cooler outdoor climate through windows and into the home. That’s not the type of fan where talking about here—although it could work well in almost any type of climate alongside proper attic ventilation.


On this article we’re going to focus on attic fans for the purpose of helping lower energy consumption and claims that such will increase solar energy offset and pay back in net metering credits.


The main goal of investing in attic fans is to remove the solar heat from the attic during hot weather and remove moisture vapor during cool weather.  Two things need to be considered in order to achieve proper attic temperatures, ventilation and insulation. 


To achieve proper ventilation, airflow throughout the attic must be consistent at all times.  However, too much ventilation can also cause mold and moisture problems. 


How Natural Convection Works


Natural convection refers to a way to ventilate using natural airflow, by allowing cool air into the attic through the soffit vents below and out through the ridge vents above.  Heat rises in the attic and is pushed out through the ridge vents by cooler air flowing in through the bottom soffit.


Power convection is ventilation assisted by a fan powered roof vent—commonly known as attic fan.  Attic fans are to be installed high on the roof by the ridge to help extract rising heat inside the attic. The amount of attic fans needed to properly cool an attic depends on its size, construction and insulation.  


Will Attic Fans Improve Solar Energy Offset?


It depends... The efficiency and speed by which the attic fan can remove the hot air from the attic will determine if the investment is worth it or not. However, we must keep in mind that power assisted ventilation could also pose an array of issues if not used in the right setting. An Expert Solar Advisor must be aware that in the same way that not all homes qualify for a solar system, not all homes can benefit from power assisted attic fans. 


Attic ventilation fans could certainly be effective, but ONLY if your home has:

  • Attic insulation that is LESS than R-19 —because a well insulated attic has no need for an attic fan. 

  • An attic floor that is thoroughly air sealed—cool air from inside the home could be sucked into the attic putting more pressure on your A/C system.

  • Bountiful eave soffit ventilation space—increased air flow in the attic.

  • HVAC equipment in the attic that is well insulated and sealed so it doesn’t heat the air coming in through the soffit vents.

Most homes will have deficiencies in sealing off the attic and it is highly recommended to insure proper insulation to avoid air leakage from inside the house.


Two Types of Attic Fans.



There are two main types of attic fans you may consider to do the job, electric fans and solar fans—there are pros and cons for both. Electric Attic fans have a higher capacity and can cover more space than solar fans.  They can also be strategically positioned to maximize air flow and ventilation. The draw back is that it uses the same electricity your trying to save and requires professional installation by a certified electrician.

On the opposite side, solar attic fans are easy to install and will not require but enough sun power to operate. The problems posed by this option is that they must be installed by the ridge facing south to maximize efficiency and the lower capacity demands more units per cubic feet than it’s counterpart.  Moreover, they will cease to operate if covered by a cloud, shadow and/or at night, thereby undermining the investment and purpose of it.


Conclusion


A professional and highly ethical Solar Consultant must put the customer first at all times and as such should advise and recommend supporting systems accordingly—never misrepresent the solar offset or output to close a sale.  In the end, results surface and will be a determining factor to scale your business through referrals and word of mouth. Keep your business clean and it will pay off for years to come. 


MANOLO BARDEGUEZ - Welcome to my Blog. I hope the articles on this site inspire you and I encourage you to discover the benefits of going solar for yourself by clicking Go Solar. By clicking Join you can also learn how you can join our movement to connect the world to sustainable technologies and get paid handsomely by the fastest growing solar company in America. If you have any questions, contact me directly at ManoloBard@SunbrightNet.com or call me by clicking the phone icon above.

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