Fan Selection

I’ve installed more than a THOUSAND QuietCool fans and learned a few things. Some of the “conventional wisdom” seems helpful and some doesn’t.The single most common concern customers have is how to choose the appropriate size fan for their home. Below are some things I have learned  Iinstalling a QuietCool fan

What size is your home?

I classify homes into three categories

Size of Home: Recommended Fan Size:
Up to 2,000 sq ft 3,000 – 4,800+ CFM
2,000 – 3,500 sq ft 4,800 – 6,400+ CFM
3,500 sq ft and above More than 6,400 CFM

One story or two stories?

  • Single story homes need larger fan systems than two story homes.
  • Heat concentrates in the second story, leaving the downstairs relatively cool.
  • Single story homes have larger roofs, providing more surface area to collect heat from the sun.
  • Single story homes have larger attics, enhancing heat transfer into the living space.

What area do you live in?

Coastal communities and hillside communities (San Diego, Orange County, Big Bear) require smaller systems because summer evenings are cooler and there is less heat buildup in the home.

Inland valleys (Ontario, Riverside, Hemet) require larger systems because there is a smaller difference between daytime highs and night-time lows. More outside air needs to be pulled through the house to cool it down.

Additional factors

Sound levels:

QuietCool fans are all very quiet as compared to traditional whole house fans. Within the product line, there are ways to optimize a system for further sound reduction, however this usually translates into a higher up-front cost.

QuietCool Fan
Sound Levels
Comparative Decibel Levels
STL PRO 1.5:  43 db
STL PRO 2.5: 42/45 db
STL PRO 3.3: 42/48 db
STL PRO 4.8: 41/43/51 db
STL PRO 6.5: 43/45/48/50 db
TRI PRO 1.5: 43 db
TRI PRO 2.5: 43/45 db
TRI PRO 3.3: 42/48 db
TRI PRO 4.8 48/51 db
TRI PRO 6.5 44/46/48/50 db
ES-1500: 43 db
ES-2250: 45 db
ES 3100: 48
ES-4700: 47/51 db
ES-6400: 47/50 db
CL-1500: 43 db
CL-2250: 43/45 db
CL-3100: 42/48 db
CL-4700: 48/51 db
CL-6400: 47/50 db
20 db – Whisper, empty theater, ticking of watch

30  db – Recording studio, quiet conversation.

40  db – Average residence, normal private office, Library.

45  db – To awaken a sleeping person, bird calls.

50  db – Normal office noise, quiet stream.

60 db – Air conditioning unit at 100 ft., Background music.

70 db – Average radio, normal street noise.

80 db – Noisy office, garbage disposal, alarm clock, police whistle.

90 db – Levels above 90 regularly cause ear damage.

A general rule is that quieter systems are used more. Increased use of a QuietCool system translates into increased comfort and savings, so it is generally better to go with a quieter system.

Zone control:

Installing multiple smaller fans has several benefits.

  • Bedroom privacy: The bedroom fan may be operated with the door closed.
  • Less noise: Multiple smaller fans produce less sound than a single large unit.
  • Energy savings: Just like with sound, the total cost of running two smaller fans is less than one large fan.
Energy efficiency: In addition to the energy savings already provided by using a whole house fan, QuietCool offers the Energy Saver and Stealth lines of fans. These models use advanced ECM brushless motors that consume even less power.
Attic Ventilation: Sometimes we run into the problem of not enough attic ventilation. Usually this does not occur if we stay within the size parameters described here but because houses vary, we cannot guarantee it won’t happen.
Add more vents: The best solution is to add more vents because, if your attic doesn’t have enough ventilation to handle a QuietCool fan it most likely means your attic is under-ventilated.
O’Hagin Vents: These are the most popular. You see them all the time in new construction and probably didn’t realize they are attic vents. They are affordable and won’t leak when installed.

We charge a flat rate of $200 or less per installed vent, depending on how many are needed.

 Ohagin Vents
Gable Vents: Gable vents are a great solution for houses that can use them. They are affordable to install and don’t require a roof penetration.  Attic Vent
Solar Attic Fan: Solar attic fans have been seen on home improvement television shows. They are a good solution but are more expensive to purchase and to install. (Installation usually involves cutting roof tiles.)  solar attic fan
Use smaller fans: Where installation cost is the most important factor, it may be best to install a smaller fan so as to not over-pressurize the attic. The downside is that it will simply take longer to cool your home. A smaller fan works just like a big fan, it just doesn’t move as much air.One advantage to this approach is that in the future you could add another fan when it is feasible.
Use roof mounted fans: QuietCool produces two roof mounted fans intended for applications where there is limited attic space. This is usually the most expensive route to take but in some situations it is the best option.

Other Factors

Hallway heaters: If your furnace is located in the hallway of your living space, you will need to ensure there is a tight seal around the door to the furnace. These furnaces usually have a “breather” vent to the attic from where the furnace gets its combustion air. If the door to the furnace closet is not sealed, attic air may be pushed through there back into the living space.Water Heaters: Your water heater MAY NOT be located in the same space as the whole house fan intake or output. This is vital due to fire safety.


Q) How does the Quiet Cool whole house fan work?

A) When the air outside is cooler than the air in the house such as in the early morning, evening and at night, the fan brings in cool air from outside to cool your home, while  flushing out hot air through the attic. This is sometimes described as “Free cooling” because this cool air does not cost anything as opposed to using an AC system which uses huge amounts of power. You still use your AC sometimes, but far less than before.

Q) How does it bring in the cool air?

A) You open doors and windows in the rooms you want to cool the most, and as the system sucks in cool air from outside it blows out the hot air through the attic.

Q) How does the power consumption of a Quiet Cool compare with an AC system?

A)  An AC system can easily use 5,000 Watts or more. In comparison, Quiet Cool’s biggest fan, the Stealth Pro 6.5,  on its highest setting uses only 507 Watts, which is around 90% less than an AC! On its low setting it uses a measly 67 Watts;  that’s less than 2% of the power of a typical AC!

Q) How is the output of the fan measured?

A) The airflow is measured in cubic feet per minute, or cfm. The higher the airflow, the more cool air is being brought into your home and the faster it will cool your home. Quiet Cool divides the airflow by 1,000 in its naming system, so for example the Stealth Pro 6.5 has an airflow of around 6,500 cfm. The Stealth Pro 4.8 has approximately 4,800 cfm.

Q) What is the difference between the Stealth Pro range and the Trident pro range?

A) They are both great products. The main difference is that the Stealth pro has a more energy efficiency motor so although it costs a little more up front it could be a better investment in the long term or if you use the fan heavily.

Q) How do I know if my home has enough attic vents?

A) Typically, newer homes tend to have more vents because the latest building codes call for more vents. On older homes we can inspect the attic and if there aren’t enough vents we can install them at an additional cost.

Q) How much money will the Quiet Cool save on my electricity bill?

A) This depends on a number of factors including the daytime temperature, the night time temperature, the design of your home, how much shade you have, the AC set point, the age of your AC unit (Newer units tend to be more energy efficient), how well insulated your home is, air leakage from ducts,  how often you run the Quiet Cool, the model of Quiet Cool, the electricity rate per kWh, etc. So as you can se we cannot predict exactly how much it wil save. But according to data published by Quiet Cool, homeowners can save anywhere from 50-90% on their AC electricity bill.

Q) How do you size the fan?

A) The basic rule of thumb is that the fan output should be at least 2 cfm per square foot of floor area for a two story home. So fi the home is 2,500 sq ft the fan should be at least 5,000 cfm. In this case we would chose a 6.5 model. For single storey homes which tend to have a greater roof area which absorbs more sunlight we might specify 3 cfm per square foot. So for a 2,500 sq ft single story we might specify at least 7,500 cfm.

Q) How does the noise level of the Stealth pro and the Trident Pro compare?

A)  Looking at the specs, both fans are similar and are extremely quiet. Both fans don’t exceed 51db which is the sound of a very quiet office.

Q) How does the noise level of a Quiet Cool compare with a traditional whole house fan?

A) There really is no comparison. Sound waves are transmitted three ways: By passing through air in line of sight between the object and your ear, by vibration through a solid material, and by reflection from the walls inside a passageway such as an AC duct.  The Quiet Cool reduces sound transmission in all three ways: It moves the fan motor  away from line of sight by putting it in the attic and uses a duct bent at 90 degrees; it suspends the fan motor on straps rather than fixing it to the attic floor or room ceiling, and it uses flexible duct material to reduce reflection from the duct walls. Putting this all together results in an astonishingly quiet system.

Q) With all these features doesn’t the Quiet Cool cost more than a traditional whole house fan?

A) It costs about the same. In some cases  its actually cheaper.

Q) What kind of ROI can I expect?

A)  In terms of energy saved, the Quiet Cool can often pay for itself in around three years, meaning that for the rest of its life it is paying you.

Q) What about the build quality?

A) Quiet Cool uses only the best materials such as energy efficient EC motors in the Stealth range. Many fans in the market have a three year, or at most a five year warranty. Quiet Cool has an industry leading 15 year warranty. 
Q) I don’t think my AC bill is that high so I don’t think we’d bother just to save a few dollars on our electricity bill. Why would I do this?

A) It not just about saving money. The Quiet Cool brings in fresh air from  outside to make your home feel more comfortable.

Q) Isn’t it  just bringing in dirty air from outside?

A) Sometimes we don’t realize it but the air in our home get’s stuffy with cooking odors, pet dander and smoke and it can feel so refreshing to replace that stuffy air with fresh air from outside.

Q ) How long does it take to install?

A) Typically its just a few hours. We have installed hundred of these so we are pretty good at it. All our installers are professionally trained.

Q) I’m not familiar with Quiet Cool.  How long have they been around?

A) The company has been established for several years and they’ve sold tens of thousands of these products. We are a specialized installer and we have installed hundreds of these products as well.  We have many satisfied customers as you can see from the testimonials on our website.

Q) What kind of warranty does it have?

A) 15 years.

Q) How long does it take to cool my house?

A) You often  feel the cool breeze which makes you feel cooler right away. To cool your home completely depends on the size of your home and how cool it is outside, but typically within 20 minutes or so the home will start to feel cooler.  The longer you leave the system on, the more it will cool your home.

Q) How do you connect it to power?

A) The fan motor is up in the attic and we can usually find power up there.

Most homes have a dedicated circuit for the heating/air conditioning blower. We prefer to tie-in to this circuit because you don’t operate the Quiet Cool fan at the same time you are running your air conditioner.

Q) How do I control the fan?

A) There is a wall mounted switch with a timer. Our pricing includes a wall-mounted shut-off timer and speed control switch. We install the switch on the wall in your living space in a recessed junction box and run the wires in the wall.

Q) Can I use it with an automatic timer to come on at set times during the day?

A) The Quiet Cool needs door or windows to be open to ensure the correct airflow, so it is not usually installed with an automatic timer in case you forget to open the windows. it does have a push button timer as described above.

Q)  Why should I choose 951 Construction to install my Quiet Cool?

A)  We specialize in Quiet Cool and install hundreds of fans per year. We are experts and take extra care to keep your home clean and tidy.

Q) Where does the garage fan get its make up air from?

A)  Most modern garages have vents to allow air in. We can install new vents in older garages if required.

Q) How are the garage fans controlled?

A)  They come equipped with a thermostat. We also install a wall switch to override the thermostat and give you more control.

Q)  Can I do “Zoned”  cooling with Quiet Cool?

A) There are a few different ways to do this. We normally recommend one large fan centrally located in the home to cool the “Whole house”. If  you want to cool one specific room you can open the door and window in that room and turn on the fan to cool that room. If you want more powerful cooling in a specific room for example a master bedroom, you can install a smaller fan in their in addition to the main fan. So for a large two story home you install a 6.5 fan in the second floor hallway and a 1.5 or 2.5 fan in a master bedroom.