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Videos: the Fan Man Discusses Features and Benefits of Centricair Whole House Fans

The Whole House Fan Man explains the features and the differences between the CentricAir and Quiet Cool.

The Whole House Fan Man explains the features and the differences between the CentricAir and Quiet Cool whole house fan damper inlet boxes.

The Whole House Fan Man explains the features and the differences between the CentricAir and Quiet Cool whole house fan 2-speed operation

Whole House Fans Are Ideal When Cross-Ventilation Design Is Inadequate

Whole house fans are ideal for cooling homes, particularly where cross-ventilation design is inadequate.

The whole of house fans should be positioned centrally, e.g. stairwell or hallways.

Typically, a single fan unit is installed in a circulation space in the center of the house (hallway or stairwell) to draw cooler outside air into the building through open windows in selected rooms, when conditions are suitable. It then exhausts the warm air through eaves, roof or gable vents. This also cools the attic space and reduces any temperature differential across ceiling insulation.

You should not operate the system when external air temperatures are higher than internal.

Traditional whole house fans can be noisy; however, the newer style ducted whole house fans like those from Centric Air are extremely quiet and designed to operate throughout the night provided the windows and doors are left open for circulation. On still nights this can be more effective than air conditioning for night-time sleeping comfort.

8 Benefits of a Whole House Fan To Reduce House Temperature

As the name suggests, a whole house fan can greatly reduce the temperature in an entire house. However, the model and make of the fan must be suitable for the house and its size to be effective.

A whole house fan is installed in the ceiling of the upper level of a house, so that it is connected to the attic. A central location and good ventilation are all crucial to the successful operation of this system. The following are several advantages to using a whole house fan in your home.

  1. Fast Operation

These fans work by drawing hot air from the house into the attic and then outside via ridge, dormer or gable vents. The empty space left by the hot air is filled with cool, fresh air from outside the house. Compared to a central air conditioner, a whole house fan works much faster, and you begin to feel the cooling effects in minutes. However, a whole house fan will obviously only work if the external air is cooler than the air indoors.

  1. High Energy Efficiency

A whole house fan is a much more environmentally friendly option than central air conditioning or room AC units.

  1. Low Operating Costs

During operation, a modern whole house fan, like those from Centric Air, costs just penny’s an hour to run compared to an air conditioner that can cost several dollars an hour to operate. It is far cheaper, and you can save hundreds of dollars in your electric bill every summer.

  1. Easy Installation

Installing a whole house fan can be easy and uncomplicated. Modern whole house fans are built to accommodate roof trusses and attic joists, so it can actually be a do-it-yourself project, with minimal assistance from another person.

  1. Low Cost of the Appliance Itself

A whole house fan can be 10 times cheaper than a central air conditioning unit, not to mention the cost of the ductwork and installation. If you do not have extreme summer weather, this appliance can replace your AC entirely.

  1. Removal of Stale Indoor Air

Because a whole house fan draws in hot air to the attic and then lets it out of the house, your indoor air is considerably fresher. This helps remove and prevent odors and provides excellent ventilation all around the house.

  1. Quiet Operation

Newer models like whole house fans like Centric Air operate very quietly, and do not emit the loud, disturbing noises associated with traditional larger whole house fans. You can operate a whole house fan throughout the night and enjoy a good night’s sleep even if you’re a light sleeper.

  1. Reduced Need for Air Conditioning

When you use a whole house fan, the entire house can be effectively cooled down by drawing in air from the outside. When operated during summer mornings, evenings, or nights, there is usually no need for other air conditioning. In fact, you should not use an AC at the same time as a whole house fan, because the cool air from the air conditioner will be let out of the house and replaced by air from outside.

Should You Consider a Traditional or Modern Whole House Fan?

It doesn’t make much sense to use an air conditioner to cool a home when the outside air is cooler than the inside. So in areas with hot days and cool nights, people often use whole-house fans to exhaust the hot indoor air once the outside temperature drops below 78°F.

Whole house fans are installed in the ceiling, in an opening that is cut into the attic. They flush indoor air out through the attic, replacing it with outside air drawn in through the open windows. Residents turn on the fan and open windows when the outside temperature drops below the inside temperature, and for best results, they leave the fan on for several hours – preferably overnight. This cools the house down and also flushes built-up heat (much of which would otherwise find its way back into the home) from the attic.

In some climates – those with wide swings between day and nighttime temperatures, such as drier, inland areas – whole-house fans can sometimes replace air conditioning altogether. In others they can reduce the run time of the air conditioner and precool the home so the air conditioner doesn’t have to work as hard. Residents with air conditioning are often able to use a whole-house fan exclusively in spring and fall, and during much of the summer, turning on the air conditioner only on extremely hot days.

Many people prefer to use outdoor air for cooling, because they find the air conditioner dries the air out too much, or because they enjoy the gentle breeze a fan can create. However, whole-house fans should not be used during very humid days because they bring in moisture with the air.

But how big should a whole-house fan be? Traditional whole-house fan sizing methods are based upon getting enough air flowing through the home to create a cooling breeze while providing 15-20 air changes per hour (ACH) and flushing heat out of the attic. A gentle breeze causes evaporation off the human body and therefore can make the temperature feel several degrees cooler than it actually is. However, whole-house fans that are big enough to create a breeze sometimes produce unintended effects, such as heat loss, noise, and house depressurization.

The Fan and the House System

Traditional whole-house fans use anywhere from 700 to 1100 watts and are typically sized to move 4,000 to 7000 cubic feet per minute (CFM) of air, depending on the size of the home. The fan blades are usually 24 to 36 inches long; fans with larger blades have higher CFM ratings than those with smaller blades. Common sizing methods include dividing the volume of the house by three (for 20 ACH) or four (for 15 ACH), or–assuming 9-foot ceilings–multiplying the floor area of the house by three to get the fan’s CFM for 15 ACH. Although this presents quite a range of possible fan sizes for a given house, a fan sized by any of these methods would provide a complete house air change every few minutes.

When this much air is being sucked out of the house, it is vital that the house system be set up to handle it without causing harmful side effects from depressurization. This includes having enough attic vents for the air to escape through and having enough open window area to replace the air being exhausted.

Attic Vents

To make sure the air drawn up into the attic can escape, there should be about 1 sq. ft. of net free area for every 750 CFM of fan airflow. Not all houses have enough existing attic ventilation to accommodate a traditional whole-house fan. For instance, to install a 4,800 CFM fan, there should be about 6.4 sq. ft. of net free vent area in the attic. Standard building code requires a minimum of 1 sq. ft. of net free vent area in the attic for every 300 sq. ft. of attic floor area. For example, a 1,500 sq. ft. single story house would probably have about 5 sq. ft. of net free vent area already installed to meet the minimum code. A 4,800 CFM fan would require an additional 1.4 sq. ft. of net free vent area to this attic.

What happens if there is not enough vent area in the attic? First, the fan cannot move as much air, because the lack of an escape route causes back pressure on it from the attic air. The fan cannot work well, even though it may look as if it does. Second, the pressurized and hot attic air will find its way back into the house through leaks in ceiling and walls. And finally, the back pressure on the fan will cause it to be noisy.

Open Windows

Residents need to remember to open windows while the whole-house fan is running. Without sufficient open-window area, the fan motor has to work too hard to pull air through the smaller openings within the structure, and thus may burn out early.

For air to flow freely through the house without causing depressurization, the total open-window area should be approximately the same as the attic’s net free vent area through which the air is escaping. So for the 4,800 CFM fan discussed above, there should be about 6.4 sq. ft. of total open window area.

Insulation and Air Sealing

Whole house fans are installed in a hole in the ceiling leading into an attic. This creates an uninsulated area of the attic, up to 9 sq. ft. for a 36-inch 6,000 CFM fan. The fans themselves generally have louvers that close when they’re turned off, but these louvers are not airtight.

Energy specialists sometimes recommend that homeowners build insulated boxes to place over the fans in the winter. However, a homeowner has to be pretty dedicated to build and use a box cover, and none of the traditional fan manufacturers sell such covers. Homeowners who do build an insulated cover must remember to take it off before turning on the fan, to avoid burning out the fan or starting a fire (this is likely the reason why no company sells the covers).


Traditional whole-house fans tend to be very noisy. This can cause residents to use them sporadically, turning them off whenever the noise bothers them.

Some fans are noisier than others. Belt drive fans are a little quieter than direct-drive fans because they can move more air at a slower fan speed. However, belt drive fans require maintenance every two years. Other factors can cause fan noise as well. Loose installation will cause the unit to vibrate and make excessive noise. And a fan trying to force air out through vents that are too small will emit an annoying whistle.

Keeping a Whole House Approach

Given their drawbacks, can whole-house fans be included on a modern energy efficiency retrofit list? Yes, they can. In many cases, they provide efficient and effective cooling without causing problems. And they are very cost-effective – most fans cost only about one-tenth as much to operate as a central air conditioner. However, it is essential that the fan and vents be properly installed and that homeowners understand the need to open enough windows when the fan is on.

A better solution to the traditional whole house fan

An alternative to traditional whole-house fans is a modern and ultra quiet whole house fan from Centric Air. Although Centric Air fans move less air than the traditional style whole house fans, they require no framing to install; no extra attic vents; and keep the home’s insulation and air sealing barriers intact. They also offer a range of whole house fans that will accommodate the existing attic ventilation for most homes ranging from 750 sq. ft. to 4400 sq. ft.

The key to using a smaller fan effectively is to run it for a longer time so it can remove built-up heat from the home and the attic. Even with a small fan, however, homeowners need to understand the importance of opening windows to prevent backdrafting.

Whole-house fans have been around for decades and for many homeowners they are a great alternative to expensive air conditioning for cooling their home.

To learn more about the benefits of Centric Air whole house fans please visit www.CentricAir.com

Centric Air – A Better Whole House Fan

At Centric Air our mission is to provide homeowners with an affordable alternative to expensive air conditioning. Although no whole house fan can completely replace the need for air conditioning, a Centric Air system can reduce its dependency by as much as 50 to 90% saving homeowners hundreds of dollars a year in energy costs.

Unlike conventional whole house fans that are large, noisy and unattractive, a Centric Air system is modern, powerful and ultra quiet. Contributing to its exceptionally quiet operation is the German engineered, acoustically designed and precision balanced fan that is rated for 40,000 hours of operation. These high efficient fans are made of composite materials with wing tip design for increased performance and efficiency, while reducing noise up to 3 decibels.

Other whole house fan manufactures typically use an open motor with exposed electrical windings, which allows dirt and debris to plug the motor causing it to over heat, and prematurely fail. They also use cheaply made propeller fans, which can become unbalanced over time causing the fan to be unstable and noisy.

Adding to Centric Airs remarkably quiet operation is the acoustical ductwork. Unlike standard ducting, acoustical ductwork not only dampens the noise of rushing air but also absorbs vibration, allowing the system to quietly operate even while you sleep.

While traditional whole house fans consists of large louvered shutters that can rattle, squeak and vibrate over time, Centric Air systems use a modern eggcrate style grill, which not only looks nice but also allows for 30% more airflow compared to standard return air grills. Located above the grill in the attic and out of sight, is an industrial grade damper box, which is designed to seal off the living space from the attic when the system is not operating.

The cost to operate a Centric Air whole house fan is just pennies an hour making it one of the most energy efficient upgrades you can make to your home. Centric Air is also one of the few ducted whole house fan manufactures that meet the strict energy efficiency standards set by the California Energy Commission. To learn more about Centric Air whole house fans or to purchase a system online, please visit www.CentricAir.com

Centric Air vs. Quiet Cool vs. Traditional Whole House Fans

A Centric Air whole house fan is modern, powerful and ultra quiet. The fan motors used in Centric Air systems are acoustically designed and precision balanced. These highly efficient fans are made of composite materials with wingtip design for increased performance and efficiency.

Adding to Centric Air remarkably quiet operation is the acoustical and heat resistant ductwork. This specialty ductwork not only dampens the noise of rushing air but also absorbs vibration, allowing the system to quietly operate even while you sleep.

Other whole house fan manufacturers like Quiet Cool typically use an open face motor with exposed electrical windings, which allows dirt and debris to plug the motor causing it to overheat, and prematurely fail.

centric air quiet cool traditional whole house fans

They also use cheaply made unbalanced fan blades, which over time, can cause the fan to become unstable and very noisy.

unbalanced fan blade

While traditional or older style whole house fans consists of large louvered shutters that can rattle, squeak and vibrate, Centric Air systems use an industrial grade damper and high airflow grill, which not only looks attractive but allows for 30% more airflow compared to standard return air grills.

traditional older style whole house fans

The cost to operate a Centric Air whole house fan is just pennies an hour making it one of the most energy efficient upgrades you can make to your home. To learn about the differences between Centric Air,  Quiet Cool and traditional whole house fans watch the following video

Time To Rethink What A Whole House Fan Is

I have to admit that my experience with whole-house fans has not always been positive. I remember almost 20 years ago as an HVAC contractor when homeowners would ask me to quote a whole house fan installation, I’d quickly steer them away. The noise from these traditional whole house fans reminded me of my time in the Army being around helicopters. Sure they moved a ton of air but try having a conversation, listening to the television and don’t even think about trying to sleep while it’s running.

Fortunately times have changed and the newer ducted style whole house fans are ultra quiet and extremely energy efficient.

Simple Concept

A whole-house fan is a fairly simple device. The fan is typically mounted above the ceiling of a central hallway (in the top floor of a two-story house) and draws cool outside air in through open windows while forcing the hot indoor air out the existing attic or roof vents. This cycle creates a comfortable living environment and reduces the air conditioning load.

A whole-house fan is effective whenever the outside temperature is lower than the indoor temperature, which is usually in the evenings, at night or early in the morning. It uses just a fraction of the energy of air conditioning, which means drastically lower energy bills for the typical residence.

In dry climates, a whole-house fan is a no-brainer, as it can minimize or nearly eliminate the need for air conditioning completely. What many people don’t realize, however, is that even in most other areas of the United States, you can use it in conjunction with your a/c to dramatically reduce your energy consumption.

Several years ago a study was done on whole-house fans in Florida, and the conclusion was that, while they can increase humidity, they also reduce the temperature in a home. The study involved 384 single-family homes, apartments, and condos, and it showed that by using natural ventilation instead of air conditioning, 777 kWh was saved. So if you can use a whole house fan, it does reduce the air conditioning costs wherever you are.

Obviously, the warmer and more humid the evening air, the less effective natural cooling becomes; however, whole-house fans are often used successfully to complement air conditioning systems. A typical rule of thump is that as long as the outside temperature is 10 degrees cooler than inside, a whole-house fan can begin to reduce the temperature inside the home.

New Design, Easier Installation

The traditional or older style whole-house fan is very large and extremely noisy but can move between 5,000 and 7,000 cfm (cubic feet of air per minute). This type of fan is installed in the ceiling, and louvers open when the fan is turned on. Newer whole-house fans have a typical flow range between 1,000 and 4000 cfm.

The real distinction between the two is that if people want to feel a breeze moving through the house, then they need to get the older style whole house fan. If they are willing to cool the home down slower over a longer period of time, then the ducted style whole house fans work great. They’re quieter and more energy efficient, but they won’t create the kind of breeze that a 7,000-cfm fan will.

Besides being significantly quieter, the new fans have optional motorized, insulated, sealed damper doors; no framing is required during installation; and a smaller fan running all night long will use much less energy compared to air conditioning. In addition, the house will be cooler in the morning.

The one major requirement for a whole-house fan is that the home must have an attic with a certain amount of clearance. In addition, a home must have a sufficient amount of attic ventilation in order to exhaust the air. If there is not enough ventilation, the resulting positive pressure will force hot, dusty attic air back into the house through light fixtures and other cracks. According to Pacific Gas and Electric Company, 1 square foot of unobstructed venting should be allowed for every 750 cfm.

Is A Whole House Fan The Same As An Attic Fan?

There’s a big difference between a whole-house fan and an attic fan. Attic fans are designed to ventilate the attic space only, while whole-house fans are designed to ventilate both the living space within a home and the attic.

The Home Ventilating Institute (www.hvi.org) refers to whole-house fans as whole-house comfort ventilators, and they are designed to bring in cooler outside air, draw it through the house, and push the house air out through the attic vents. Attic fans are used to reduce heat buildup in an attic only.

To learn more about the benefits of whole house fans visit www.CentricAir.com

How To Use A Whole House Fan During A Heat Wave

Much of the country is experiencing a heat wave, which is typical for the month of August. Daytime temperatures can reach 90 to 100 degrees and temperatures during the evening and early night are not much cooler. At about 9:00 PM the outside temperature where I live was 84 degrees, definitely not a good time to use a whole house fan. This was one of those nights I was grateful for air conditioning.

In the morning, however, at about 6:00 AM the outside temperature was 67 degrees. Although you may think, why would I use my whole house fan when my home is already cool from running the air conditioner, the reason is quite simple. Even though the temperature inside the home may be cool, the temperature in the attic and walls are not. They retained the heat from the day before and the temps in those spaces could be well above 100 degrees. As a result, unless that heat is removed it will radiate into the house, quickly heating up the living space. It’s for this reason that you want to run your whole house fan.

At 6:00 in the morning I opened a few windows and turned on the whole house fan while making sure that the temperature outside never exceeded the indoor temperature. After about an hour, I turned off the whole house fan and closed the windows. My entire home (living space, walls and attic) were now cool and comfortable, delaying the need for air conditioning.

While some of my neighbors air conditioners turned on as early as 9:00 this morning, I knew I would not have to run mine until much later, significantly saving on my cooling bill.

Although a whole house fan is not designed to completely replace air conditioning, it can help reduce the need for it, even during a heat wave.

To learn more about the benefits of whole house fans, visit www.CentricAir.com

RIP Affordable Energy. CA Rates go up 80%

State power regulators decided today (May 15, 2015) how to divvy up the biggest electric rate hike in California history, boosting rates by as much as 80 percent for residential customers who use the most power.

More than half of the residential ratepayers served by the state’s two largest utilities will see no increase at all in their rates. But for those who consume the most, the new rates translate into an average increase of $85 per month for electricity.

The plan, approved 3-2 by the state Public Utilities Commission, affects about 9 million customers of the state’s two largest utilities, Pacific Gas and Electric Co. and Southern California Edison Co.

The new rates, which will appear on June bills, were approved seven weeks after the PUC mandated a $5 billion rate hike. The plan’s passage came after a week of intense lobbying by industrial, commercial, agricultural and residential groups — all trying to influence how the PUC would allocate the rate hikes.

Big Loss for Big Users

The average rate increase for all residential customers of the two utilities is 19 percent. But low-income ratepayers and those who use the least electricity will face no rate hike at all.

The biggest losers are the biggest users.

Residential ratepayers are divided into five tiers, and those in PG&E’s top tier — about 9 percent of that utility’s residential customers — will see electric rates jump from 14.3 cents to 25.8 cents per kilowatt hour. That’s an 80 percent increase.

That translates into an average increase of $85 — from $232 to $317 — on monthly bills.

For Edison’s heaviest residential users, the rate hike is 71 percent or an average increase from $194 to $265 on monthly bills.

Industrial customers of PG&E and Edison face rate hikes of about 50 percent, while commercial and agricultural ratepayers will see less significant increases.

Hike Fuels Protesters

The increases will be retroactive to March 27 — the day the record rate hikes were approved.

“This is probably the worst economic calamity the state has ever seen,” said David Marshall, chief financial officer at Gregg Industries, a 400-person iron foundry in El Monte. “It has got ramifications well beyond anything that we can begin to understand.”

Today’s vote took place amid the jeers of protesters, who wore tombstone-shaped placards that read: “R.I.P. Affordable Energy.”

PUC Commissioner Jeff Brown bellowed back.

“We cannot walk away from it. We cannot pretend that this is some sort of problem that we can walk away from,” Brown said.

The final plan was a revised version of the plan released by PUC President Loretta Lynch last week. Lynch reworked her plan after an outcry from businesses proclaiming the proposed rate hikes would doom California’s economy and a critical statement from Gov. Gray Davis.

Since it unanimously the approved rate hikes in March, the PUC has crammed a year’s worth of work into six weeks, struggling to fashion rates that simultaneously recoup the $5.2 billion the state has spent buying power for the customers of the state’s two largest utilities and trigger enough conservation to help fend off some of this summer’s expected rolling blackouts.

Customers of San Diego Gas and Electric Co. and those who buy electricity directly from energy wholesalers, such as the California university system, are shielded from rate hikes.

Reported by ABC News: