Do you want to find the best roof mounted attic fan?
These attic fans are installed directly on your roof instead of on your gable vent.
In this product review, I will go over...
- My #1 top pick for the best roof mounted attic fan
- How to pick the best attic fan
- And my attic fan reviews (pros and cons)
Let's get started with this guide!
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My Overall #1 Rated Pick
- 1600-cfm fan speed
- 14-inch balanced steel blade
- Thermally protected motor
- Permanently lubricated
- Brown finish
My overall top pick for the best roof mounted attic fan goes to the Broan 356BR1600. This brown finished attic ventilator will be installed on your roof. It includes a 14" steel blade, adjustable thermostat, and a permanently lubricated motor. You can install this attic fan directly on your roof and keep it cool, dry, and prevent mold growth.
Top 6 Best Roof Mounted Attic Fans
Only have a minute? Check out our top 6 roof mounted attic fans below! Keep reading to learn more about each pick.
What Size Attic Fan Do I Need?
Roof mounted attic fan sizes are rated in CFM which stands for cubic feet per minute. If an attic fan is rated at 1,000-cfm, it means that it can exhaust 1000 cubic feet of air per minute.
According the Home Ventilating Institute (an industry non-profit), they recommend that your attic should exhaust your entire attic at least 10 times per hour. And HVI provides an easy rule of thumb for choosing the minimum CFM for your attic size.
Simply take your attic size in square feet (the "floor" of attic) and multiply it by a 0.7 multiple. And if your roof is very steep or dark colored, increase it to a 0.805 multiple.
So if your attic is 1500 square feet, then you multiply it by 0.7 to get 1050-cfm (minimum).
Read Also: What Are The Best Gable Mounted Attic Fans?
How Much Passive Venting For An Attic Fan?
It’s important to note that attic fans (roof mounted or gable) works in unison with passive attic venting because that’s where it pulls in outside air. Passic attic venting includes the ridge vent, soffit vents, gable vents, and turtle vents.
If there isn't enough passive venting, then the attic fan performance (CFM) may drop significantly, and it may start pulling in air from your home's interior.
Interior air will get sucked into the attic from all of the cracks and crevices in the ceiling and walls adjacent to your attic such as from the attic hatch, top plates, and recessed lights.
If this happens, it definitely isn't good for your indoor comfort, but it can significantly lower the efficiency of your HVAC.
Carbon Monoxide Hazard
It may also create a carbon monoxide hazard if you have low efficiency gas appliances such as a furnace or water heater.
Backdrafting occurs when the exhaust gases of your appliances get pulled into the home rather than getting sent outside.
Read Also: How To Install An Attic Fan On Roof?
The Best Passive Vent
The best and most logical place to have adequate passive venting for an attic fan is at the soffits. This is because hot air rises from the soffit and naturally goes high up the ridge.
The soffit and ridge vent system creates a natural suction. And the best soffit venting is continuous so there aren't any breaks.
The Home Ventilating Institute recommends having at least one square foot of soffit venting per 300-cfm of attic fan performance. So if your attic fan is 1050-cfm, then you want to have at least 3.5 square feet of passive soffit venting (or 504 square inches).
Read Also: What Are The Pros And Cons of Attic Fans?
How To Use A Roof Mounted Attic Fan?
Roof mounted attic fans are operated using a thermostat.
The thermostat is usually a small metal box with a temperature dial that is secured to a rafter or truss right next to the fan. If you locate the attic fan in your attic, and follow the wiring, it should eventually go to a metal box which is the thermostat.
This thermostat turns on the attic fan when the temperature reaches a target temperature which is usually in the 90-F to 110-F range. And when the attic temperature goes below the target, the attic fan will automatically turn off.
Ideally, you want your attic temperature to get as close as possible to its outdoor surroundings or at least within 10-degrees of the exterior.
You can also wire the attic fan to a hallway switch so you can manually turn it on or off. In addition, some attic fans have humidstats which can detect attic humidity and turn the fan on and off just like a thermostat.
How To Inspect Attic Fans?
#1. Will It Turn On?
Locate the thermostat (small metal box) usually mounted on a rafter or truss next to the fan in the attic. Turn the temperature knob so it is below the current attic temperature. You can also use a heat gun, hair dryer, or lamp to heat up the thermostat if the attic is cold.
#2. Turn The Blades
If the attic fan doesn't turn on, try turning the fan blades. If the blades won't turn, you may have a seized motor.
#3. Operation Quality
If the the attic fan turns on, are their any weird noises? Does it run smoothly? Can you feel air flow or is it very weak? The fan screen or louvers should not be blocked with debris impeding air flow.
#4. Water Stains
A common problem with attic fans are leaks. Are there any signs of water leaks around the fan on the roof sheathing?
What Are The Benefits of Roof Mounted Attic Fans?
One of the biggest benefits of roof mounted attic fans is that it can be installed near the ridge of the roof and catch the rising hot air.
Attics have a natural suction and funnel of hot air. Hot air gets pulled into the attic from the soffits and then it rises to the ridge. Since the fan is roof mounted, it can be installed near the ridge and work more effectively. In contrast, gable mounted attic fans miss out on this natural stack effect of rising hot air.
Read Also: What Are The Best Solar Powered Attic Fans?
And probably the biggest benefit to homeowners is interior comfort. Hot attics can reach a temperature as high as 160-degrees on very hot days.
When attics are cooler, it will make the whole house more comfortable, especially the upper level of the home. And your HVAC system will run more efficiently, and will reach your target interior temperature more easily.
The least comfortable homes have extremely hot attics that ruins interior comfort.
These are the homes where the upper level bedrooms are always 10 degrees warmer than the rest of the house.
Even though the energy use of a roof mounted fan may offset any HVAC efficiency gains, it can still help your HVAC run better and extend its life.
If your A/C doesn't have to run as long to reach your target temperature, then it can extend its life.
When an HVAC system is constantly running because your home isn't effectively cooling down, you can just imagine how much wear and tear this puts on your system. And the average life expectancy of HVAC systems is in the range of 15-18 years, so if it isn't running efficiently, it may reduce its life to as little as 7-10 years.
And one of the little known benefits of cooling down your attic is that it can protect and extend the life of your asphalt roof.
Asphalt shingles is an oil-derived product, and when these shingles get very hot, they dry out and prematurely age. So very hot attics can reduce the life of your roof from 25-years down to maybe 10 or 12 years.
Read Also: What Are The Best Master Flow Attic Fans?
What Are Roof Mounted Attic Fans?
A roof mounted attic fan rests directly on top of the roof and helps regulate a property’s temperature by removing hot air.
Roof mounted attic fans are generally rated for only sloped and asphalt shingled roofs. They are generally not installed on flat roofs or slate shingle roofs. As a comparison, the other main type of attic fan are gable mounted attic fans which are mounted vertically on the gable vent.
Attic fans require cutting a hole into the roof sheathing and the asphalt shingles. Roof mounted attic fans are generally made of galvanized steel.
Roof mounted attic fans are wired into the homes electrical system, either hardwired at a junction box or plugged into an outlet. There are also solar powered roof mounted fans which don't need any electrical wiring connections.
Read Also: How Does An Attic Fan Work?
Reviews Of The Best Roof Mounted Attic Fans
Here are my reviews of the best roof mounted attic fans with their pros and cons...
My #1 top pick is the Broan Attic Fan which is a roof mounted attic fan rated at 1600-cfm and for attics up to 2285 square feet.
It has a PVC dome with a brown finish to help protect it from UV damage.
The fan itself is 14" (four blades) that are made out of stainless steel.
It includes an adjustable thermostat for automatic on and off.
The motor is permanently lubricated and will automatically shutoff if it ever overheats (safety feature).
This solar powered attic fan by Natural Light is a popular solar attic fan that is installed on asphalt shingle sloped roofs.
The solar panel is 36-watts and there is no wiring involved with the install. It is rated at 1628-cfm (under full sun) and is for attics up to 2625 square feet.
You can also buy an optional thermostat which is great if you live in a cold climate. The solar panel is adjustable up to 45-degrees.
This Broan Attic Fan is unique with its aluminum-based design.
It offers a comprehensive 1,000 CFM and can offer coverage up to 1,400 square feet without breaking a sweat.
This roof mounted attic vent fan includes a 14” steel blade fan and is accompanied by a 23-gauge metal flashing for complete results.
The Air Vent Attic Fan is a powerful solution with its brown-colored design, 1,170 CFM attic fan motor, and 25” diameter metal dome.
It has coverage for up to 1,650 square feet and comes equipped with an adjustable thermostat.
Through its 2.8 amp motor, the attic fan can easily manage hot air. It also includes a special warranty (5-year parts, 2-year labor).
The Cool Attic fan is a sleek, efficient roof mounted solution with a dome-based design.
It is made of galvanized steel and has accompanying mesh grills for complete protection against pests.
With its precision-balanced fan blades, high wind resistance, and 1080 CFM attic fan motor, the fan can easily cover a 1600 square foot attic.
This Broan Attic Exhaust Fan is a fascinating option in the company’s line up and offers a 1,000 CFM attic fan motor and coverage up to 1,400 square feet.
It also includes a 14” steel blade fan and is ideal for managing a property’s airflow.
The attic fan is made of galvanized steel for extended durability.