The temperature of an attic can skyrocket in summer and plummet in winter. In summer, you incur higher electricity costs because the air conditioners will combat the heat and run for more extended periods. In winter, the cooler air in the attic meets the heated air from the living areas below, resulting in excessive moisture, dampness, and the associated danger of wood rot. Electric fans are one of the touted methods to control this. Is a more modern solar fan an appropriate replacement?
Both solar and electric attic fans have pros and cons, and there is no clear winner in this debate; solar-powered attic fans have advantages in areas with constant sunshine. The sun’s energy is free; brushless solar motors are silent and durable. Electric fans run 24 hours a day are cheaper and more potent.
An attic fan’s function is to circulate the air to keep the temperature as close to the outside air as possible. If you have an enclosed attic and need to cool it in summer and create a drier winter environment, you might consider an attic fan. The question is whether you use the secure electricity supply from the utility or opt for a solar-powered attic fan.
There are several potentially more effective solutions than attic fans to manage the temperature in your attic or loft space. These include:
- Making the attic airtight, so the hot air doesn’t escape into the living spaces.
- Installing high levels of insulation to prevent heat transfer through the ceilings.
- Installing a reflective light-covered roof.
- Installing air vents to release the hot air.
If these options are not viable, or you want to install a complementary system, an attic fan may be the most realistic solution.
The opinions on the effectiveness of attic fans are varied. Some commentators report that their attic fans achieved no temperature differential, while proponents claim that the improvement achieved is up to an effective 200 f.
The Florida Solar Energy Centre’s research reported that gable-end models are the most effective type of attic fan. They work the best because they move considerably more air than roof-mounted mushroom top units.
We recommend you research the manufacturer and the most effective system of the attic fan and its potential power source.
Solar Attic Fans Pros And Cons
Deciding between the two fans systems is not a simple either/or decision.
The Pros Of Solar Attic Fans
- The lowest long-term solution. The sun is essentially an unlimited source of free energy. While electric fans are heavy energy consumers, which will drive up your monthly utility bill after the cost of purchase and installation, solar attic fans have no recurring running costs. In summer, when the sun is the most intense and the attic is the hottest, in theory, solar fans work at their peak efficiency.
- Using brushless motor technology, they are both quiet and durable.
- Solar attic fans have a lower power rating and run slower than electric ones. As a result, the air pressure remains more even in the attic; this results in fewer low-pressure areas, and cool air is less likely to be drawn from the living areas to the attic. The air-conditioned air in the living areas is not leaked to the attic.
- Most solar fans come with a very long warranty period, in some cases up to 25 years.
The Cons Of Solar Attic Fans
- A solar attic fan only works when the sun is out; this is a problem when trying to reduce moisture build-up in winter.
- Unless it has a battery backup, a solar attic fan only operates at peak efficiency when the sun is brightest; this is a five-to-six-hour window each day. The attic will reach the hottest temperature at the end of the day when the solar fan will start slowing down and becoming less effective.
- A solar attic fan will only work on the correct facing roof (south in the northern hemisphere and north in the southern); this makes the installation inflexible and may result in the positioning not being optimized.
- Solar attic fans cost four to five times more than electric fans.
- Solar attic fans operate slower than electric fans, so more may need to be installed than an electric attic fan.
The Pros And Cons Of Electric Attic Fans
Electric attic fans also have strengths and weaknesses.
The Pros Of An Electric Attic Fan
- Electric attic fans cost about 25% of the cost of a solar attic fan.
- Electric attic fans are considerably more potent than solar attic fans. They are more effective, and fewer may need to be installed.
- Electric attic fans don’t need the sun to make an appearance and can continue to work even when the weather is overcast or at night.
- Some electric attic fans are equipped with a thermostat. By setting this to 1300f, you will save on electricity costs.
The Cons Of An Electric Fan
- An average-sized electric attic fan will increase your electricity bill by +-USD 40.00 per annum.
- If the electric attic fan lowers the temperature in the attic, it may result in the air conditioners in the living areas consuming less electricity. You could just be transferring the electrical cost to the attic instead of achieving a real saving for the whole house.
- A DIYer could install a solar attic fan with decent woodworking skills, while a qualified person with the correct certifications must install an electric attic fan.
- Electric fans tend to have a much smaller warranty period – 1 year is quite normal.
- Some commentators report that electric fans are more prone to starting house fires. Although it may be true that electric fans may have started some house fires, we don’t believe this is a significant factor.
Deciding on whether to install a Solar Vs. Electric Attic Fan is not a simple process.
The overall effectiveness of attic fans creates some controversy. Proponents claim substantial temperature differentials, while those opposed claim no significant improvement.
Likewise, the discussion continues whether solar attic fans or electric attic fans are more effective. Solar attic fans are cheaper to run (free). They are quieter and more durable than electric attic fans. In contrast, proponents of electric attic fans claim that their ability to run 24 hours a day may make them superior and worth the monthly running cost.
The final decision is yours and will depend on your circumstances, the cost of electricity in your area, the average temperatures, and the reliability of the sun in your state.