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Truth Of The Matter Is, Many Consumers Are Being Misled When Considering A Whole House Fan...
When purchasing a whole house fan, there are a number of issues to consider beyond how much air it moves, how it installs, and how much power it consumes.
Alert #1: DO NOT USE A WHOLE HOUSE FAN IN A COLD CLIMATE - UNLESS YOU SEAL IT DURING WINTER MONTHS - OR CAN DUCT THE EXHAUST DIRECTLY OUTSIDE - SERIOUS DAMAGE TO THE HOUSE CAN RESULT!
By design a whole house fan is mounted between the ceiling and attic of your home. When the fan is not running, the hole that air moves through must be closed. Or, the air will continue to move from the house to the attic. It is like leaving a window open. In a cold climate, during the winter months - warm humid air from the house will flow into the attic. The moisture in the air will condense on the cold surfaces (just as it does on cold window surfaces), and water will drip on the insulation and mold will grow. Cover It, Seal It - Or Duct the Exhaust Directly Outside to prevent damaging your home.
Alert #2: A WHOLE HOUSE FANS PRIMARY AND ONLY APPLICATION IS TO REMOVE HEAT FROM YOUR HOME!
Some companies, have been touting whole house fans as a way to remove cigarette smoke, cooking orders, etc. from their living space. Claims are being made that using a whole house fan will improve your home's Indoor Air Quality. This not entirely true and in some instances can be dangerous!
A whole house fan will bring in fresh, cooler outdoor air - when you use it to cool your home. However, the amount of air required to cool your home is significantly more - than if you were attempting to improve your home's indoor air quality.
The American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) have implemented the only standardized code. "ANSI/ASHRAE Standard 62.2, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings, is the only nationally recognized indoor air quality standard developed solely for residences." ASHRAE Standard 62.2 states - whole-house mechanical ventilation system rated at 7.5 cfm per occupant, plus one cfm for every 100 square feet of floor area that can be occupied.
If we take this example, a 2000 square foot home with 3 occupants, would require a fan rated at 42.5 cfm to improve the indoor air quality of the home. A far cry from levels of air moved when using a whole house fan.
This also brings us back to the issue of using a whole house fan during the winter months to now "Improve Your Home's Indoor Air Quality". Damage will result to your home if exhausting directly into your attic...
Alert #3: FAN AIR FLOW IS DEPENDENT ON SYSTEM DESIGN AND INSTALLATION. SOME MANUFACTURERS PROMOTE SERIOUSLY OVERSTATED PRODUCT PERFORMANCE.
How do we know this? For years we saw manufacturer's making claims about the air flow on their fans. The flow rates were just to good to be true, but to you the average consumer - you would not know the difference!
We took several competitor's fans to a third party laboratory and had their air flow tested. The results were as we suspected, overstated airflow rates...
Flow through a fan changes as obstacles are put in the path. Grilles, ducts, and gravity dependent back draft dampers will all reduce the amount of air a fan is able to move. In some products, such obstacles can reduce the installed airflow by 40% or 50%! Independent laboratories (such as HVI) can rate the airflow of the product as a system. For example, a fan rated at 1500 cfm that uses a grille, ducting, and gravity damper could easily have a true flow rating of 800 cfm or less!
Alert #4: AIR FLOWING INTO THE HOME MUST BE ALLOWED TO FLOW OUT! PROPER ATTENTION MUST BE GIVEN TO THE PRESSURE RELIEF SPECIFICATIONS.
Air blown into the attic must be allowed to escape from the attic to the outside. Otherwise the air will seek other outlets like flowing back down the walls of the house and in through outlets and light fixtures. If you do not have the required net free area of roof venting, you will not only be pumping heat back into your home but the dusty, smelly attic air as well.
Divide the fan’s flow by 750 to determine the necessary, clear opening to the outside. (Insect screens are particularly restrictive to airflow.) For example, a 3000 cfm fan would require in roof venting the equivalent of a 4 square feet to the outside. If the hole is covered by an insect screen, the hole would need to be twice that size.
Alert #5: BEWARE OF "SOUND" RATINGS
Any sound rating of a fan in “sones” must be performed in a certified laboratory, if it has not certified - Then Don't Believe It! Any sound rating in “sones” in the specifications of a whole house fan is only a manufacturer’s guess, unless of course they have had their fans tested and certified.
It Is Our Hope That Whole House Fan Manufacturers' as well as Distributors' Stop Fleecing Consumers with Bogus Flow Rates, Sound Levels & General Misinformation.
With Over 200 Years Of Combined Industry Experience In The Field Of Residential Ventilation, We Hope Our Expertise In This Field Has Given You A Little More Insight Into The World Of Whole House Fans. Free Expert Advice Is Always Available, M-F From 7 am - 5 pm PST At 1.888.845.6597
Sincerely,
George Karonis
President/CEO
wholehousefan.com
R.E. Williams Contractor Inc.
 
Big Mistake Number One:
 Heading down to the local hardware store and purchasing a house fan without doing the proper research first is one of the biggest mistakes a home owner can make when installing one. If you assume that you have the right size fan, the best manufacturer, or all of the information you need in order to install the whole house fan yourself, chances are you will have to call someone to correct your do-it-yourself mistakes.
Solution Number One:
Hire an electrical contractor who has a good reputation for installing whole house fans. Even though the project can be relatively small, there is a lot more to it than just cutting a hole in your ceiling and turning it on. A good qualified electrician will know: What size fan to use, whether or not you have adequate attic ventilation, where to place the fan opening, and when is the best time to use the fan to maximize its benefit.
Problem Number Two:
Installing the fan without the proper tools, right insulation, and proper placement of the main intake vent is a big mistake.
Solution Number Two:
A electric services company will always recommend a fan that comes with built in insulation. When it is cold, it is important that the fan, the fan housing, the vent opening, and the attic vents have the right insulation so that you are not losing money by escaping warming air. In addition, a good licensed electrician will know that the whole house fan needs to be installed in a place that permits maximum airflow starting at the windows and into the attic.
Mistake Number Three:
Purchasing the most inexpensive attic fan from a website is definitely a really big mistake. These units are a cheap investment when compared to HVAC. The less expensive models are not insulated, have generic fan assemblies, and are very loud. The last thing you need is to hear what sounds like a rocket taking off inside your house, or a squeaky fan assembly each time the house fan is switched on.
Solution Number Three:
Go ahead and get a quality attic fan that has good reviews and low maintenance. A quick search on several consumer goods review sites will steer you in the right direction. Also, consult with your electrical contractor. They might carry a certain brand of whole house attic fan that they trust and that has a great reputation for being a quality product. Definitely do not go with a brand that has no history of past performance or good reviews by lots of people.
Mistake Number Four: (And this one is a big one)
Having an attic fan installed that is too large for the home is one of the biggest mistakes a home owner can make. If there is not proper attic ventilation, a house fan that is too large can draw all of the hot air up from the interior space and into the attic, and then push that hot air back down into the home through the ceiling lights, electrical outlets, HVAC vents, small cracks, wall switches. In fact, a fan that is too large for the house may make it hotter, not cooler.
Solution Number Four:
Before installing a house fan, consult with a electrical contractor and chose the model that is right for the house. If you do not have enough attic ventilation, there are some simple steps that may be to provide that ventilation. A ridge vent, gable vent, soffit vent, and whirly gig are all worthwhile options for attic ventilation. A good electric services company will also work with a licensed builder who can usually add the correct attic ventilation in about a day if there is not any in place.
Usually, a smaller whole house fan will cool a dwelling with less wasted energy than a larger fan, which is more often than not overkill. The goal with a whole house fan is balanced airflow. With constant movement of air throughout the house, it will stay cooler with less energy needed. In addition, a smaller whole house fan means less installation work, which is always a bonus.
Mistake Number Five:
Using the whole house attic fan with the windows closed can cause a potentially hazardous. The whole house attic fan functions by drawing cooler air in from the exterior of the house through the open windows and pushing the warm air up into the attic where it leaves the home through the attic vents. If you close the windows, there is a great chance that air will be pulled from the diverter that is on top of the water heater or boiler. What this means is that poisonous carbon monoxide can be pushed into the living space, creating a potentially fatal situation.
Solution Number Five:
Make sure to open the windows before turning on the whole house fan! The whole house attic fan is not there to re-circulate bad stale air throughout the dwelling. Its primary function is to remove hot air from the home, and provide a less expensive, environment friendly cooling solution than HVAC. In fact, a properly installed whole house fan can cool an averaged sized house for a tenth of the cost of air conditioning.
Jim Christian and a licensed Coral Springs Electrician brought this article to you. To learn more about a whole house fan, visit Vozzcom Electric. 3617 NW 124th Avenue, Coral Springs, FL 33065.
Attic Ventilation
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