Power Attic Venting

The importance of venting your attic cannot be overlooked.  In cold climates, improper venting can lead to moisture buildup, which causes mold to grow, wood rot in extreme cases, or even ice in the attic insulation.  In hot dry climates, stagnant air can dry out your trusses, increase your energy costs for air conditioning, and make your house uncomfortable.

If your home is like most that we inspect, it is severely under-vented.  You can add more soffit and exhaust vents, but at what cost?  Power venting may be a more cost-effective and efficient method of achieving your goal.  However, venting is just part of the problem.  A well-ventilated attic will reduce the convective load.  The largest component of heat gain or heat loss in any home is infrared heat.  Control this and you can really save!

Below, a typical home store attic fan is installed on a gable vent inside the attic.  Although the mounting may look secure, the application is incorrect because the space around the fan is not blocked off.   The fan will create a negative pressure behind the fan and will draw air from the closest point; in this case, from vent openings around the fan.

This means very little air will be exhausted from the attic and most of it will be drawn in around the fan.
The open area around the fan shroud (the round ring) needs to be blocked off with cardboard or wood to make this type of installation effective.  We see this type of installation on almost every home that has one!
Why is this so common?  Below is a picture of an installation at the point of sale.

Power Fans

Natural attic venting is best but, in many homes, a powered attic ventilator is more cost-effective, especially in tile roofs.

WE DO NOT RECOMMEND MOST SOLAR ATTIC FANS. THEY JUST DON’T MOVE ENOUGH VOLUME.  Great for a shed or small area, but not sufficient CFM air movement for a home attic. The model we tested here using a Dwyer Digital Draft hood, pointed south at noon moved 310cfm.    We now offer a range of powerful solar attic fans.

We import a vibration-free, powerful, reliable powered attic fan manufactured in Germany.  This attic fan is unlike any other available:  quiet, powerful, and very efficient. We include an adjustable thermostat and an optional mounting box with this system.  This fan features an external rotor to which the fan blades are welded.  This unique design reduces blade flex and vibration, and eliminates one of the shaft bearings.  The bearings are sealed and never need attention.  Install it, set the thermostat, and forget about it.  The 14″ fan consumes 245 watts.  At a national average of .10/kwh running for eight hours a day, that’s less than $6 per month.  There are sites on the Internet that say the power consumption of an attic fan does not offset the cost of running it.  The goal is keeping your A/C off as much as possible, which consumes 1600 watts per ton.  Logic would dictate running a fan for $6/month would be preferable to longer runtimes on your A/C unit from the stagnate, overheated attic air and the load on your ceiling.

• Adjustable thermostat included
• Costs 2 cents per hour at 10 cents per KWH
• CFM @ 0.0 ” SP: 1839 cubic feet per minute (Actual, not estimated)
• Integral Blades and External Rotor allowing precision balancing
• Formed steel wall panel with Venturi
• Shallow profile with no protruding motor
• External rotor motor, class B insulation.
• Quality design provides long and maintenance free operation for many years
• No maintenance required
• Automatic Reset Thermal Overload Protection
• Electro statically applied polyester/epoxy urethane powder coat finish
• Self lubricating, sealed for life precision ball bearings
• Can be installed in gable vent or under dormer vent

Pictured here is our 14″ fan correctly installed.  After the installation, all the area around the fan needs to be blocked off to prevent air from coming in around the fan.  This is critical to good performance in the installation of any fan.

The optional sheet metal mounting box makes installation straightforward, fast, and secure.  The thermostat and mounting box which is included is mounted 6′ from the fan to sense the attic temperature.  Set it at 105F and forget this fan is running, because no maintenance is required.

14″ 1800 CFM fan shown above and below
Here is a roof-mounted German fan mounted where a Home Depot fan used to be.

Two 10″ fans mounted side by side. This is done when a large vent isn’t available.
Warning: In homes that have gas appliances such as water heaters or furnaces in the attic, great care must be taken to ensure adequate intake venting is provided (gables/soffits), so as to not create a negative pressure that will draw fumes down the chimney of gas appliances.   Installing an attic fan in this application has the potential for fire or filling your attic with carbon dioxide.  Make certain that there are sufficient intake openings to circumvent this situation.

If you are considering the purchase of a solar-powered attic fan, we encourage you to read this page completely.  Get the facts before you buy any energy conservation product.

Times are tough, so saving energy means saving money. Here’s what you can do to help yourself.

The importance of venting your attic cannot be overlooked.  In cold climates, improper venting can lead to moisture buildup, which causes mold to grow, wood rot in extreme cases, or even ice in the attic insulation.  During the summer, stagnant, super-heated attic air can dry out your trusses, increase your energy costs for air conditioning, and make your house uncomfortable.

75, 140, 175 and 235 Watt Solar Fans – Free lifetime fan replacement warranty!

NOW AVAILABLE!
Three years of research and development have resulted in the ultimate solar-powered attic fan.   We’ve been following the various fans currently available and have also performed testing on the actual output of 10-watt, 20-watt, and 30-watt solar fans.

Our testing has shown that all of these fall short of having sufficient power to properly evacuate an attic area, especially in sunny climate.

Solturbine Solar Fans:

• 75-, 140-, 175-, and 235-watt systems to choose from
• Measured cfm performance
• 14″ and 16″ turbine fans range from 1,100cfm to 3,000cfm
• Turbine fan makes the most use of solar power, and is very efficient
• Electronically controlled brushless motor
• Sealed ball-bearing design
• Rated for 180F air
• Fusible link for fire safety
• Nothing is made in China
• Custom-made roof vent allows for minimum restriction, maximum air flow
• Can be installed on the roof (with vent shown above) or in the gable
• Lifetime replacement motor warranty, the best in the industry
• 25-year panel warranty
• Can be installed in any roof (tile skirts available for tile or ceramic roofs)

Shop and compare to other fans:

• Overstated cfm claims (10-watt fan is 310cfm at noon in Phoenix Arizona)
• 12″ stamped fan blades
• Multiple fans required for adequate venting (two or more per house)
• Motors have brushes that wear out and require maintenance
• No thermostat so the fan runs during the winter and shortens fan life
• No fire safety fusible link to shut off fan in case of an attic fire
• Bushings not sealed, bearings are used, which affects performance and shortens motor life
• Motors not rated for high temperatures
• Moving components made in China
• Inefficient fan paddle design not very effective
• Inefficient air flow path affects total cfm (fan blows against a flat surface)

Construction features:

• No maintenance required
• The 14″ fan has twice the power (and capacity) of a home store fan
• Adjustable thermostat included
• Costs 2 cents per hour at 10 cents per KWH (25 cents per day)
• CFM @ 0.0 ” SP: 1839 cubic feet per minute (actual, not estimated)
• Integral blades and external rotor allow precision balancing
• Formed steel wall panel with Venturi
• Shallow profile with no protruding motor
• External rotor motor, class B insulation
• Quality design provides long and maintenance-free operation for many years
• Automatic Reset Thermal Overload Protection
• Electro-statically applied polyester/epoxy urethane powder coat finish
• Self-lubricating, sealed for life precision ball bearings
• Can be installed in gable vent  or under dormer vent

Homes for which we have upgraded attic vents have significantly reduced attic temperatures during the summer.  This means lower A/C bills, more comfort, and the A/C equipment lasts longer.  In cold climates, these vents allow for the egress of accumulated moisture, which can be a source for many problems.

For an 18″ Aura vent installed on a pitched roof,  the round inner stack acts like a chimney and the double-grilled reverse vertical louvers keeps out rain, bugs, and birds, but allows air to freely flow out.

When dormer vents are installed on the back side of an apartment building, the lower vents on the roof are intake vents, the upper vents are exhaust vents.  This type of venting, if correctly sized to the attic size and volume, can adequately vent the hot air out during the summer and moisture during the winter.  These are not seen from the front of the building and therefore do not detract from the aesthetics.