What is a solar exhaust fan? Is it worth the cost?

What is a solar exhaust fan? Is it worth the cost?

The worth of the solar exhaust fan has been a very debatable topic on the solar field over the years. Some strongly stated that solar exhaust fans as a waste of money and the time when others praise it as a good investment.

The point is you cannot simply answer that question. The worth of the solar panel depends mainly on what you expect from it. Then there are many other factors too. To understand all these things you should have basic knowledge of solar exhaust fans.

What is a solar exhaust fan?

Solar exhaust fans are used to improve the air circulation inside an enclosed space. It can be used for attic, bathroom, greenhouse, dog house, garage, shed, etc.

Mainly there are two types of solar exhaust fans, gable mounted and roof-mounted. The gable-mounted solar exhaust fans move a considerable amount of air than the roof-mounted solar exhaust fans.

How does a solar exhaust fan work?

Solar exhaust fan consists of a fan and solar panels to generate power. When solar panels are exposed to the sunlight, they will generate the electricity the fan needs to work.

When the outside temperature is high, the temperature of the inside spaces like the attic, bathroom, garage, etc will go up. So the solar exhaust fan will push out this hot and humid air out and improve the circulation in these enclosed spaces.

So these solar exhaust fans will help to stop the overheating of the space during summer or when the outside temperature is high.

Also, in winter solar exhaust fans help to stop excessive moisture. This is very important for attic spaces as excessive moisture can form molds and damage your roof.

Is a solar exhaust fan worth the cost?

The answer depends on what you expect from your solar exhaust fan.

Solar exhaust fan is designed to improve the air circulation, by doing so they can decrease the overheat. But some brands falsely advertise that solar exhaust fans will cool your space like air conditioning units. But it is not possible.

Some try to install solar exhaust fans to reduce the electricity bills as grid-powered exhaust fans consume more power and that will increase the electricity bill and the power usage. But if you are installing a solar exhaust fan just to decrease the electricity bill it is not a good idea. The reason is you have to pay more for installing solar exhaust fans than installing grid-powered exhaust fans. It will take about five-ten years to cover all the money you had to pay for installations, just buy the decrease in electricity bill.

So as we suggest this solar exhaust fan is mostly worth it for the people who like to increase their green energy usage and people who live off-grid, not for people who try to find ways to decrease their electricity bills.

Advantages of solar exhaust fan;

  • You do not have to worry about power outages.
  • Best for off-grid living.
  • You can install them anywhere you want without worrying about having outlets near. This can be very useful when installing them in attics, greenhouses, dog houses, etc.
  • Can use these in rural areas.
  • No electricity bill.
  • Increase the use of green energy – using grid-powered energy causes environmental pollution as grid power production uses so many fossil fuels. So by using solar-powered devices you can decrease pollution.

Disadvantages of solar exhaust fans;

  • High initial cost.
  • Do not work without sunlight, if there is no backup battery.
  • The installation has to be done carefully as you need to put holes on your roof to install solar panels. If installers are not properly installed the panels, or if they do not use proper flashing methods, or if they are not careful on the roof it can ruin your roof. (Read more – Do solar panels ruin your roof?)
  • When you are installing solar exhaust fans on the attic you have to make sure that your attic is properly sealed and air circulated. If your ceiling has any cracks or holes and you have air conditioning running to cool your house, then it can increase the workload for your AC unit as the solar exhaust fan push the inside air out.

 

How to increase the efficiency of solar exhaust fans?

  • Proper placement of solar panels – if you are lining in the northern hemisphere, by placing your panels facing south you can increase its efficiency. If you are living in the southern hemisphere, facing your panels to the north will increase its efficiency. Also, make sure to tilt your panels 20 – 30 degrees.
  • Make sure that your panels are not shaded.
  • Proper maintenance – makes sure that your panels and the fan are clean and dust-free. Also, makes sure that there is not anything stuck between the blades of the fan.
  • If you have a backup battery you have to make sure that it is also in good condition.

 

What is the lifetime of a solar exhaust fan?

The average lifetime of a solar exhaust fan is about 15 years.

If you have purchased your solar exhaust fan from a qualified manufacturer it can last for about 15 years.  But you need to properly maintain it. If you are using a backup battery the average lifetime of the backup battery is about 3 – 5 years.

How to choose the right solar exhaust fan for you?

  • Type – there are different types of solar exhaust fans available in the market (mainly gable mounted and roof-mounted). For the attic, gable mounted solar exhaust fans suitable more.
  • CFM value – CFM value means Cubic Feet of air per Minute. This value will indicate how much air the solar exhaust fan pushes out per minute (the capacity of the fan). More the value better.
  • Square feet value –most solar exhaust fan providers will mention how many square feet their fan can cover. So you can choose which solar fan is most suitable for your need and decide how many fans you need. Sometimes this value is not mentioned, but you can use CFM value to decide the fan you want.
  • Watt value of the solar panel – the Watt value of a solar panel will indicate how much power it will generate per second under optimal conditions. More the value better.
  • Manufacturer –you should make sure to purchase your product from well-known high-quality manufacture.
  • Durability –as we have to fix the panels outside your product should be durable for adverse weather conditions.
  • Warranty

How to determine the size of the solar exhaust fan, you need for your space?

To determine the size or the capacity (CFM) of your solar exhaust fan, first, you have to find the square footage of your space.

For that, you have to multiply the length by the width.

For example, let’s say your space is fifteen feet long and ten feet wide. Then the square footage of your space is 15*10 = 150 sqft.

The relation between the capacity of the room (CFM value – cubic feet per minute) and the floor area is; 1 CFM per 1 sqft.

So your solar exhaust fan capacity should be more than 150 sqft to cover your space properly.