What is the purpose of an attic fan

Attic fans are intended to cool hot attics by drawing in cooler outside air from attic vents (soffit and gable) and pushing hot air to the outside.

When should you use an attic fan?

An attic fan can be used to cool down your living space any time the air outside is cooler than the air in your home. An attic fan pulls air in through open windows and doors while pushing hot air out of the home through attic vents.

Should I leave my attic fan on?

It is only necessary to run your fan as long as it needs to replace the attic air with outside air. Running your fan any longer than this is just a waste of electricity. This is because you are pulling air outside your attic that is the same as the air you pull into the attic.

Does attic fan really help?

Attic fans do really work. They will help to circulate air in your attic and ventilate the space so that it stays closer to the outside temperature. Attics can reach extremely high temperatures in hot, summer months and gather an excessive amount of moisture in the winter. Attic fans will help fight these problems.

Are attic fans a waste of money?

Some of it will come from the soffit vents, and some will come from attic air leaks. If you have problems with ice dams, a LOT of air will come from attic air leaks. This means you’ll actually be sucking warm air IN to your attic. … Don’t waste your money on an attic fan.

Should I turn off my attic fan in the winter?

Q: Should I turn off my attic power fan and close the vents during winter? A: Although the natural instinct to keep the house warmer may be to close the attic vents, that is definitely not a good idea. … The chimney effect causes heat to rise into the attic, and this warm air can hold more moisture than cold air.

Are attic fans a fire hazard?

“Most attic fans are put up there and forgotten,” says Kenneth Kent, deputy marshal of the Arlington County Fire Department. “They’re not inspected for years, and when they malfunction, they can start a fire.”

What temperature should an attic fan be set at?

When it comes to an attic fan’s temperature setting, it’s best to adjust it to anywhere from 90 to 110 degrees Fahrenheit. It’s impossible to state a single number because your attic can effortlessly soar above 95 degrees (on average).

Does an attic fans save energy?

Ventilation fans, or powered attic ventilators, are designed to cool the attic, pushing out the hot attic air and rushing in a flow of cool outside air. … The intention of the ventilation fan is to save energy and the roof. Energy would be saved by reducing the burden of the air conditioner in the home.

Do roofers install attic fans?

Do Roofers Install Attic Fans? Roofers do install attic fans. Actually, it’s a good idea to hire a roofer to do it because the installation will require cutting a hole in the roof itself. … An electrician, a handyman or an HVAC installer is able to install an attic fan as well.

Article first time published on

When should I run my attic fan in the summer?

During the summer the fan should operate anytime the attic temperature is above the comfort level desired for the indoor living quarters. For example, if the air conditioning thermostat is set to 74 degrees, the attic fan might be set to 75 degrees.

How do attic fans cool a house?

Use high speed to ‘kick-start’ the cooling, and use low to run quietly through the night. Make sure at least one window is open. Opening two or more windows halfway or wider is recommended to allow the fan to do its job. For general cooling, open windows far away from the fan to provide airflow to the whole house.

How long do attic fans last?

Typically, attic fans have a lifespan of up to 15 years as long as they are properly maintained. This usually involves having the attic fan professionally serviced by an HVAC technician who will clean the fan shutters, lubricate the oil ports, and wash the fan blades as well as inspect the unit for any repairs needed.

How much of a difference does an attic fan make?

The heat in an attic on a hot day can be 20 degrees Fahrenheit or higher than the outside temperature, and using an attic fan can reduce the temperature in the attic by at least 50 degrees and in the highest floor of the home by as much as 10 degrees.

How do I cool down my hot attic?

Install an Air Conditioning Unit. …
Seal the Cracks and Gaps. …
Upgrade the Insulation. …
Add Ventilation for Improved Circulation. …
Install Radiant Barriers. …
Install an Attic Fan. …
Add Reflective Roofing.

Are attic fans loud?

Attic fans are great machines that can bring some refreshment by blowing out hot air. Even though we all enjoy attic fans, they are mechanical devices and sometimes they can be quite noisy and annoying. … In most of the cases, the noise will appear due to some parts of attic fan getting old or by being worn out.

Why does my attic fan sound like a helicopter?

Attic fan sounds like a helicopter Noise/rattling from a fan is often caused by loose parts or unbalanced blades. The blades of attic fans are dynamically balanced and tested but they can get bent during the shipping or installation.

How do attic fires start?

When it comes to residential attic fires, the most common cause of the fire is an issue related to an electrical malfunction. … In addition to electrical malfunctions, other common causes of attic fires include issues related to the heating system, as well as natural sources such as lightning or fallen trees.

What happens if attic fan stops working?

An attic fan that won’t turn on is usually an electrical problem, but it can also be an issue with the fan motor or the thermostat. First, check the circuit breaker that controls the attic fan. … If the circuit breaker or fuse are working properly, check the thermostat next by manually turning the fan on and off.

Do attic fans prevent mold?

You can’t have too much attic ventilation is the simple answer. Air constantly moving through an attic will help prevent mold. Your old home never had mold because old homes were so drafty that water vapor was constantly being transported outdoors or it evaporated off the sheathing surfaces before mold could grow.

How hot is too hot for attic?

Without proper ventilation, hot air becomes trapped between the insulation and the roof. Ideally, your attic should not exceed 130 degrees Fahrenheit during the summer. Problems related to attics hotter than 130 degrees: It will make it harder to cool your home in the summer.

Do attic fans help with ice dams?

An attic fan in winter can help prevent ice dams, reduce moisture in your attic during winter months, and prevent mold and mildew buildup due to moisture problems in the attic.

Can I use attic fan with blown insulation?

The screening, louvers, rain covers, etc. that are a part of roof and gable end vents create resistance to air flow. Many attics have blown-in insulation. … You can cover your attic fan from the top with strips of plywood that are then covered with batt fiberglass insulation.

How much does it cost to install an attic fan?

Cost to Install an Attic Fan Attic fan installation costs an average of $595. Most homeowners can expect to pay between $369 and $877. Depending on the quality of the unit you choose, location, and add-ons, the project can run as little as $200, or as much as $1,300.

Why is my attic so hot?

On hot summer days, the heat is going to radiate through the shingles and collect in your attic, creating hot air. The biggest reason why hot air fills up in your attic is due to poor ventilation. … A lack of proper insulation and poor air sealing also contributes to why attics get so hot.

What happens if your attic gets too hot?

An overheated attic can bake asphalt shingles on the roof and cause them to deteriorate. And it can cause your air conditioner to work harder than it needs to and send your energy bills soaring with the temperature.

Do attic fans have thermostats?

A powered attic ventilator, or attic fan, is a ventilation fan which regulates the heat level of a building’s attic by exhausting hot air. A thermostat is used to automatically turn the fan off and on, while sometimes a manual switch is used.

Why is my attic cold in the summer?

Many attics contain ductwork that supplies cool air to upstairs rooms during the summer and heated air during the winter. If the joints in your ductwork are not properly sealed, your forced air system can suck attic air into the ducts –air that’s either really hot in the summer or really cold in the winter.

What size attic fan would an electrician need for a 1500 square foot home?

Attic floor areaRecommended attic fan size1000 sq.ft700 CFM1500 sq.ft1050 CFM2000 sq.ft1400 CFM2500 sq.ft1750 CFM

How do I check my attic ventilation?

Look at your eaves and roof. …
Touch your ceiling on a warm, sunny day. …
Thick ridges of ice on your eaves in winter are a sign of poor attic ventilation. …
Warm air that escapes living space also carries moisture that will condense on rafters or roof sheathing.

How many attic fans do I need?

You need a minimum of 1 square foot of attic air venting for each 750 CFM of air flow. If you need 6,000 CFM of air flow through your house, divide 6,000 by 750 to get a minimum 8 square feet of attic venting. That translates to one attic vent 3 feet by 3 feet, or two attic vents, each 1 ½ feet by 1 ½ feet.