The Master Flow 4500 CFM 24 in. Direct Drive Whole-House Fan is a smart energy saver for any home in a climate where air conditioning costs are a concern. It will allow you to beat the heat by forcing hot air out of your home through your attic space while bringing in cooler outside air through your windows and doors. A Whole House Fan is an important part of a complete home ventilating system! Unit comes with a white shutter and features a low-vibration direct-drive mechanism for reliable performance. A minimum 1100 sq. ft. of attic space with a minimum of 1008 sq. in. of net free area attic exhaust is required for proper operation.
(69 reviews) 69
72%of customersrecommend this product49 of 68reviews
Rating Breakdown69 reviews
72%of customersrecommend this product49 of 68reviews
Although I have only had this fan installed for several days, I LOVE it! I decided to go with the 24" fan because my house is less than 2200 sq. ft. and I was told that if there wasn't adequate ventilation, the 30" fan would/could make excessive noise. I'm not sure if people have difficulty installing the fan, but the way I did the install makes the fan seem "quiet". The fan noise is very comparable to a traditional box fan. I truly do not mind the noise it makes. I also put the fan on a 60 min. max timer. What I have been doing is setting the timer anywhere from 30-40 minutes, with a couple of windows open down stairs and one or two open up stairs. This cools the house down extremely fast. I am so glad I decided to put a whole house fan in our home. You should do it too! You won't be sorry!
Pros: Performs Well
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23out of23found this review helpful.
Review 2 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
I didn't follow the directions, This is what I did and the fan is quiet. My house is 2300 sqft and it pulls the air thru nicely. I open the windows about an inch in the bedrooms and other rooms I want air to come in from the outside. My attic has vents on both ends of the house and affords plenty of exit space for the fan exhaust air. I got these Ideas off the internet and found them to be absolutely correct. First I mounted the fan in my attached garage ceiling. The fan will pull air from your home and into your attached garage ceiling. You don't have to mount it in the house. You will not get that central fan noise in the house that way. We have a screen door in the kitchen that goes to the garage. The air flows out thru the screen door. The next thing I did was to build a box for the fan to sit in on top of the ceiling joists. I cut the center joist and boxed it in. Then built a frame to hold the fan on top of the joists. I cut lengths of pipe insulation to fit on the fan wood frame. The glue on the insulation seam holds the insulation on the frame.$1.79 each for 2 insulation tubes at HD. The frame, is snug to the insulation but not tight. Hence when the fan runs, it is not vibrating on wood to wood contact. All you hear is the fan blade turning like you would any fan. There is a pull chain to turn it on and off. It is a 2 speed fan. I run it on high. I used the same size wood the ceiling joist were made of, to box in the joists where I cut one out. I used 2x4 s to make the box on top of the joists. I used a sawzall to cut the sheetrock, and the center joist. If you bridge across the top of your joists before you cut the center joist, you will not get any sag from the two ends of the cut joist. All will be strong after you box them in. I attached a wire and a plug on the fan wire to power the fan. I plugged it in to a receptacle in the attic. The pull chain is right outside the kitchen door in the garage.
Pros: Easy to Use, Performs Well, Easy to Install, Quiet, Good Size & Weight, Seals Well, Good Shape, Great Value, Easy to Clean, High Quality, Economical, Light Weight
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31out of31found this review helpful.
Review 3 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
from El Sobrante, CA
Age Range:45 to 54
Home Improvement Profile:Other
This fan really works great. You can feel the air stream by you and it cools down the house in no time!
It is amazing how many people do not know what a Whole House Fan is. Even contractors. It is a very efficient way to replace the air in your house and attic just by running this fan for about 15 minutes once the air outside is cooler than the air in your house.
This fan was not the biggest, but it seems to be built really well. I am very impressed!
Pros: Easy to Use, Performs Well, Easy to Install, Easy to Work With, Good Shape, Great Value, High Quality, Economical, Reliable
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8out of8found this review helpful.
Review 4 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
almost 4 years ago i wrote the lengthy (and helpful) product installation & description review regarding this whole house fan.--- Indy 2010 whole house fan Well the fan is still problem free and fantastic for spring through fall use. Wonderful breezes are pulled through the open windows/doors-- like you are riding a bike while you sit on the couch or at the table.
We have actually become more users of the house fan than our AC -- the abundant, and constant, fresh air breeze beats the AC. But sometimes... the AC is called upon, but not like it used to be. We run this thing as the primary cooling device, many hours straight, no problems. Great "white noise" to sleep through. Periodic cleaning of the louvered vents and about once a year I clean the fan motor and blades, check the blade for tight/secure, no slippage. Do yourself a favor, save money and stay cool with this thing.
Pros: Performs Well, Great Value, Reliable
20out of22found this review helpful.
Review 5 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
I installed this fan in our split level home 12 years ago. The start capacitor has now failed and I located one on Amazon for about $10 with shipping. In the interim the fan starts by using a wood stick to push start the fan blades in the counter clockwise direction when the power is on. The only complaint I have after all of this time is we have gone through a few of the cheap pull chain switches. Power for our fan comes off of a hallway outlet, which I changed out for a GFCI. This allows me to use the outlet as a switch when the pull chain switch fails to work. I am planning on replacing the chain switch with a wall mount switch when the new capacitor arrives. Our start capacitor is a GE model 27L566, printed on the capacitor label hidden under the mounting bracket. If your fan fails it might be the capacitor, not the motor. Also, we have a very low attic space, 2 1/2 foot peak, so I added a roof mounted exhaust fan that is wired into the whole house fan to power on and off when it does. This works great for our needs and cools the house in about 45 minutes. The low speed is quiet enough to listen to the TV which is about 20 feet away. High speed is a bit noisy, but once the hot air is out the low speed keeps thins cool and quiet.
Pros: Easy to Use, Performs Well, Good Size & Weight, Great Value, Reliable
6out of7found this review helpful.
Review 6 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
This fan has worked fine for me for over 10 years. It blows a lot of air, but I wish it were quieter. When you are close to it, you can't hear anything else. The motor finally burned out a winding. The exact replacement motor is only available from the manufacturer of the fan, which is a big disadvantage. Replacement parts should be generic and easily available, otherwise, the fan blows no air at all. If I was starting from scratch, I would look for a quieter fan with a motor that is easy to oil and replace. This is the second one I have bought and installed. The bottom line is that it blows a lot of air, lasted me over 10 years of intense use every summer, and the price was reasonable, but you have to accept that it is very noisy.
29out of29found this review helpful.
Review 7 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
I have owned several homes with whole house fans ... this is the loudest one I have heard. However, if you have a hallway to the garage or other out of the way location, it is not too bad. If you go with the standard "over joist" mount, plan on cutting up two two by fours to build a base around the joist, and if you have blown in insulation, plan to cut up two six foot one by tens to build a box that extends above the fan to hold back the insulation. It takes only a few minutes to draw cool air through the entire house. Only wish is that the low speed would be lower. Even low still creates quite a breeze through the house!
38out of41found this review helpful.
Review 8 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
Home Depot is fine. The unit however, is very loud, even on low fan speed. It was unexpected that the fan noise would be this loud since I was replacing with an identical unit (the old unit: the low fan speed noise level was acceptable - the bearings wore out, thus the replacement). Once I/you install the replacement unit and discover the noise/decible level it's too late to return without severe effort: time, sweat, reinstallation cost, etc.
22out of22found this review helpful.
Review 9 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
Poor/cheap fan blade design
PostedOctober 19, 2014
No, I do not recommend this product.
I have purchased a whole house fan over 12 years ago and finally the motor wore out and no longer had the ability to move air throughout the house. Instead of replacing the motor I thought the manufacturers would have design a better and quitter fan but alas this was not true. The fan blade is of very poor design and is loud because the blades are flat which causes buffeting. Additionally, it wasn’t moving the air as well as my old whole house fan did.
Corrective action, I replaced the new fan blade with the old one and the fan is much quieter with no buffeting and moves the air much more efficiently.
The installation instructions are lame plus there were some parts missing. Glad I had the old fan so I could use it for parts.
Wish I would have just replaced the motor. It would have cost less and have taken less time to replace than a whole fan. Hindsight is 20-20
Cons: Noisy, Difficult to Install
0out of1found this review helpful.
Review 10 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
My brother recommended a whole house fan, so I installed one myself. I bought this one because it was small enough to install in the attic access opening. I mounted it on a separate baffle that is hinge mounted on the 2x4's. Our house had adequate ventilation, about 4 to 1 as compared to the fan. I also used a wireless controlled power strip. That let me turn the fan on and off from my bedside.
Loud? yes, this thing pumps lots of air, so its bound to be loud. Here is what helped me:
The instructions indicate you need to flip the fins upside down, but if the fins are too close to the braces holding the motor in place, it creates extra noise. So, when you flip the fins, don't push it all the way down on the motor shaft. Push the fins up on the shaft so that the shaft is flush with the mounting hub. Also, make sure you cover the electrical box with the supplied cover. If left open, it too creates extra noise. Finally, because mine is mounted on a hinged baffle, I used a 1/2" thick weather stripping gasket all the way around the baffle. This helps reduce the amount of vibration that transfers from the fan to your ceiling joists reducing noise. Now, when we are downstairs, we can hear a soft rumble, but not so loud its objectionable. At night, this fan is right outside my bedroom door, so its just a little too much noise for comfort.
If you take these steps, the amount of noise is significantly reduced. I am not sure I could sleep while this thing is running, well actually I can sleep through most anything, but my wife and kids had a problem with the noise at night, so I shut it down after 10pm. Home Depot has a wireless / timer power strip for outdoor lighting and such. That might be better. Please make sure the power strip you select can handle the 1/3HP motor. It should draw 5-6 amps. The one I purchased is rated for 14 amps.
Pros: Good Size & Weight, Great Value, High Quality, Economical
Cons: Noisy, Vibrates
3out of3found this review helpful.
Review 11 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
I spent a good bit of time installing this fan in the house I just bought. Upon completion of the project I was ready to test the new fan. It works is the best I can say about it. I have a whole house fan in my previous home and wouldn't think of not having one in this house. After turning this one on I was very disappointed in noise level. I walked outside to the street and could still hear it. I won't buy another of this brand. It's loud, what? It's Loud, what? IT'S LOUD.
44out of47found this review helpful.
Review 12 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
Only gave it 3 stars due to the fact that the pull chain speed switch for it did not function correctly out of the box, id have to pull it 3-5 times in order for it to change speeds or shut off. Luckily I replaced it with the switch from my old fan I was replacing. Other than that it is a good fan with a better shutter than my 15 year old fan had
Pros: Easy to Use, Performs Well, Easy to Install
0out of0found this review helpful.
Review 13 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
The fan is good for the cost with a solid motor and a decently built frame. When installing additional joist support the louvre cutout is bigger than the fan frame so a complete flush frame on which the fan can sit is impossible. However, the provided plastic pieces bridge the gap well to channel airflow. My only complaint is the switch was pretty cheap and broke after 1 day of use (would not reset and allow me to shut off the fan - it stuck). Company has offered to send out another one in 5-7 days. Brother-in-law has the same fan and also had the provided chain switch break in the first week. Definitely look into constructing some kind of insulation box for summer and winter since it is literally a 30" hole in your ceiling that is only insulated by some thin plastic flaps.
17out of17found this review helpful.
Review 14 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
*Tip* I grabbed a roll of wide camper mounting foam tape to put between the fan and the frame, suppose to make it less noisy
I special ordered the belt driven fan and it arrived in 2 weeks. The measuring, cutting, fitting, mounting wasn't to bad. Wiring is confusing (I'm not an electrician) and I had to make a new hole in the wall for switches and finally after it was all wired up, the motor was dead. I thought maybe the belt tension or wiring but nope dead motor. I returned the belt driven fan and had to grab this direct drive fan off the shelf because I didnt want to wait 2 more weeks with a giant hole in the ceiling. Having had both in the same weekend
Reasons to go with the direct drive fan -Includes a shutter template to cut out the ceiling. With the belt driven fan, I had to use long sticks and a square and it came out a little crooked (you know, you don't cut straight either) -The direct drive shutter is square (a little bigger), the belt driven shutter is a smaller rectangle. It would make a difference when replacing -This shutter is nicer, shinier, better flaps and a bit more solid -Includes a very nice joist-in mounting bracket/set up -It's easier to assemble (2 minutes to flip the fan blade and tighten) vs belt driven remove the motor, put it on right, adjust belt and re-adjust -It's lighter which makes it easier to lift and get it up there -The wiring is so much easier, no holes in the walls or fishing out wires. It is just 2 wires and a pull chain for the switch
Reasons to go with the belt driven fan -It's cheaper -It has 4 blades on the fan vs 3 on the direct drive so maybe better air flow -The belt driven is suppose to be quieter. I can't say because mine didn't turn on but I think they are all noisy, not motor noise. It's a big fast moving fan moving a lot of air noise. Even my 20" box fan on high is noisy
Starting from scratch I would go with the direct drive. Sometimes stuff is on the shelf because they are better and easier to put in
Pros: Easy to Use, Easy to Install, Easy to Work With, Straight, Good Shape, Great Value, High Quality, Light Weight
5out of6found this review helpful.
Review 15 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
This whole house fan is the first one I have installed. The job came out perfect. I first read the instructions three times. I didn't think the instructions were worthless like some reviews said. Maybe they have updated them. If anything, they were very detailed and you had to avoid the parts that didn't concern your particular type of install.
This unit seems to be designed to be placed on one of the joists. The middle of the fan and shutter has a notch so it can be placed directly on to the joist. Once I found a place for the fan, I found that the joists next to the joist I had placed the fan on were too far to hold the edges of the fan. I had to cut some 2X4's to make up the difference. After adding the 2X4's, I placed the shutter template on the attic floor and traced around it. I cut the hole for the shutter from inside of the attic. Once the shutter hole was done I installed the fan and then the shutter.
I don't believe this fan is made to be ran all day or evening. This fan will cool my whole 2500 foot house in less than 20 minutes depending on the temperature of the air outside. I just open a few windows on the first floor and turn on the fan. You can feel the cool air coming in from outside. It also pushes all of the hot air out of the attic.
As far as the noise, the noise is comparable to the amount of air the fan moves. If you look at one of those slow turning fans that are usually installed in a factory that are very quiet, you will also find they have to be quite large to move any air. This fan is quite small for the amount of air it moves. It will be louder because of the amount of air being moved. I can put up with noise for 20 minutes to get my house cooled down. But I really don't think this fan is loud. If you are married, you will fine this fan is quieter then a wife (or husband). Just kidding !!!
After about four hours, the fan was installed and ready for use. I love this fan. It is much cheaper then using the central air conditioner.
33out of34found this review helpful.
Review 16 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
For the cost this fan does a great job. Direct drive is typically a bit noisier than belt drive and definately noisier than in line fans. However, in line fans are about four times the cost. The consistent noise easily becomes white noise. Installation is not difficult but is not for the weak! You are cutting a hole in your ceiling and need to do some electrical wiring. I installed mine in the attic access so I did not mount it on all sides. I built out a frame that the fan sits on and mounted it with hinges so I can simply push it up to access the attic. I added weather stripping to seal it and the back pressure when the fan is on really keeps it tight. Instead of the pull switch, I added a dual on/off timer switch for more control. Typically, I want the fan to go off once we fall asleep because it can get too cold if it stays on all night in So. California. Something else to remember is that you do not want to open all the windows in your house. A few strategic windows across the house works much better. It will create a breeze in the house. Bottom line is that venting the attic alone will help cool the house and a whole house fan will draw air through your house creating a nice breeze but the temperature of the air is still up to mother nature! Hope it helps.
19out of19found this review helpful.
Review 17 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
I had some installation issue but not due to the fan. It would be a snap for most attics. Placed in an upstairs landing, it creates a cooling vortex throughout our 2600 sf house. It has replaced our central AC use by 80% and that's saying something for mid July in Texas. A bit noisy when you are close to it but will pay for itself in 45 days.
Pros: Performs Well, Great Value
1out of1found this review helpful.
Review 18 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
24 in Master Flow direct drive WHF installed this model in early July 2010, Indianapolis. Blower went out on my furnace (18 yrs), so no AC. This was a VERY HOT SUMMER, record breaking "most above 90 degree" days, most consecutive above 90 days in history. Hot, humid, miserable.
Had 1 helper, neither of us are trade educated but both are pretty handy. A 60 and 40+ year old doing the work here. Only "special tool" we used was a saws-all (reciprocating saw). A circular saw would work but not as easily. I think you can rent a saws-all Standard tools: drills, chalk-line, tape measure, ratchet or socket wrench, utility knife, dry wall saw. If possible keep a "set of tools" with each worker (attic man and inside house man). Get some knee pads if you don't own a pair. You will both want them if you need to work up on the roof as we did.. and gloves.
Understand that the real "cooling action" from this fan takes place @ night. I would open windows, turn on the fan about 6-8 pm. The inside house temps were usually about 82-85 degrees at this time on bad/worst days. With the hottest hours of the day past, open up and draw fresh air in. I run the fan through the eve/night and then shut the fan off, close all the windows/blinds-curtains and doors about 7-9 am. Just seal the house up. The inside temps would usually/only be 74-76 on the worst days. Just depends on how cool it during the night. Then the morning/daytime heat returns and the house slowly heats back up again. Keep the house closed, keep as much of the 90 degree heat from coming inside That's how this thing works. Cool off at night, close up the house, locking the cool air in and go to work. If you stay home I ran a box fan just to move air around inside the house and waited. It was not bad at all, 77-81 degrees well into the afternoon, 2-3 pm. This is the bad days, of which there were way too many this summer. With normal night temps the house gets even cooler, low/mid 60's, so the house stays VERY NICE AND COOL. When the temps went into the hi 50's one night we(somebody) had to shut the fan down... it was too cold for my wife.
But remember It is not "air conditioning".
My electric bill usually runs $100++/- in the summer (gas water/heat/dryer). Using the house fan and NO AC, zero AC during this horrible summer: July $68, August $56. So this model will pay for itself very fast.
Installation was simple but not easy.And i did make a few changes i felt would be improvements, though not necessary.
I chose to place the fan in a central hallway, center mounted on top of a single ceiling joist. This is a standard/primary way of installation. The hardware supplied is sufficient to get this done. But i added some support/stability with 2 furring strips on the OUTSIDE of the fans wood box/frame PERPENDICULAR to the joists. My joists are 16 on center, so the 24" fan unit, when center mounted, had 12 inches left/right of the joist it rested on above nothing. It STILL rests above nothing on 2 sides, but i spanned 3 joists (the Lt-CTR-Rt) with the added strips of wood. Depending on how you mount the frame you may want to support either Lt/Rt or Top/Bottom sides. But the entire fan unit weighs little, the hardware supplied is probably adequate, i just felt better securing it across 3 boards. IF you use the CTR mount/single joist setup you CANNOT pass the fan upwards into the attic from below. The opening that gets cut for the louvers, and the joist that you will be using for installation will not allow passage. The fan is just a bit too big top to bottom to pass through. If you have a decent attic access you are fine (i don't).
The other installation option is cutting through a joist and securing the fan into a custom made (by you)frame. I did not use the "cut joist" method, but it did cross my mind at one desperate moment.
This fan can be installed vertical or horizontal. It cycles Hi/Low/Off from a pull chain. You can wire it to a wall switch, but i did not get into any of that. If you install vertically you will need to use a switch because the pull chain won't work. DO NOT INSTALL near gas pilot lights. So much air is drawn in it's possible to extinguish the pilot lights, resulting in a gas leak... so they say. The air drawn in part i have no doubt about, this fan moves air.
THIS IS A MUST: You MUST have adequate ventilation OUT OF the attic for the fan to work. It draws in thousands of cubic feet of air every few minutes, and that air has to escape the attic. I installed 7 more roof vents to be certain the air could get out. There is a formula you can look up, but it got too WTF? for me. My ventilation/roof area is about 30 ft 16 or so. I have 8 pan style vents (4 on either side), a turbine type vent and 2 gable end vents. I run the fan on Hi speed and have no problems with noise, ventilation, anything. But you have to allow for the incoming air to leave the attic peacefully. MUST. I guess it will sound like inside a car on the highway with only one window open, the fast air coming in hits the trapped air trying to escape and that horrible headache noise occurs... until you open another window, problem solved. The opposite also applies. When the fan is on you must provide enough air to feed the fan. And it's not like every window has to open or even cracked. Just get enough of a flow through to the fan. If not you burn out the motor.
When i was cutting the openings for new vents, i made a cardboard template of the vent opening. Using some kids "sidewalk chalk" i spaced & marked my 8 positions from inside of attic. Drilled a hole at the top of each template outline and pushed a nail up into/through the hole. The template outlines should be positioned as diamonds, NOT SQUARES. Went out onto the roof, located nails, placed top of template DIAMOND at the nail and sketched/chalked the outline i would need to cut on the roof. Drilled 2 holes with an inch and a quarter bit in each diamond outline, one at the top, one at the bottom. You will destroy about 2-3 bits doing this, and you think you're about to start a fire from the heat/friction/roofing tar/asphalt/drilling going on. Have your gloves on because you will need to wipe off the drill bit and it will be HOT HOT HOT. Be ready to throw away/change the ruined bits. Then through the top/bottom holes use the saws-all to cut along the chalked outlines for the roof vent openings. Nail and putty the vents in place. I puttied all around the openings and the underside of the vents.
Regarding operating noise we are fine with the level(s). I can hear crickets, i can have a phone conversation, hear the toilet flush, the shower running, the dog bark, toast pop up. I/we have no issues. And this is a Direct Drive model, not a belt drive. I CAN hear when it's running, but that's not all i hear. Maybe others are not venting the attic air fast enough.
I would rate 5 star, but i need to know a lifespan/reliability to go there. I wish i had done this years ago. Even if you pay somebody to install it you will probably regain the cost. But be certain the roofing vent issue is covered. Ridge vent and soffit vents count if you have them. But you will never have too much on the exhaust side of the fan.
well i hope this helps somebody get through the installation job and stay cool. Wear eye protection if you're cutting overhead, have a few different lengths of screws on hand, 2-3 inch, in case wood is far off.... that's all i got
50out of54found this review helpful.
Review 19 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
PostedMay 24, 2011
No, I do not recommend this product.
I purchased this unit to replace another fan that quit after 15 years. This fan is smaller than the one I replaced. 24" vs 30". This fan worked OK but it was loud. I could hear it in the basement. I tried a foam gasket between the fan housing and the rafters but it didn't help much. I returned it and got my money back but the manager said that was an exception, They usually don't let installed items be returned. How can you tell how noisy a fan is until it's installed. I wouldn't reccommend this unit. It's loud. sounds like an airplane ready for thke off. Did I mention it's loud?
18out of21found this review helpful.
Review 20 for 4500 CFM 24 in. Direct Drive Whole House Fan with Shutter
I installed this fan in the garage. Usually, the door from the garage into the house is closed, so I leave the overhead door open about 4 inches and this fan just keeps the garage (and attic) cooler. When the weather is right, I'll open the door to the house, fully close the overhead garage door and it's a whole house attic fan.
One of the fan shroud rivets came warped and sheared. I just replaced it with a bolt and nut. That's why I couldn't give this fan 5 stars.
Pros: Performs Well, reduces total energy use in summer