Tjernlund DB-2 Duct Booster, Increases Heating and Cooling Power, 275 CFM

Booster was easy to install. Works well. I should have went with the next level up. Great if you want to boost a duct close to a register. The 25-30ft I needed it to go is just a tad too far. It has increased the flow but would like to have had more. The noise is ok. Typical of an electric fan.

Works amazing. Definitely helps with air flow in the hard to reach places

It is a nice fan...it makes a little bit of noise..needs to be carefully installed to avoid vibration in ducts/ walls etc... I used it for a drywall cavity ( return )..and after I messed around with the set up, the noise was not too bad. I would say it doesn't add much noise to the existing AC noise kev. It is especially useful for shallow ducts...where the more high tech booster fans dont fit ..

So we live in a 1950s bungalow with inadequate air distribution and our upstairs is freezing in the winter, hot in the summer. 8-10 degree differential. Bought this along with the pressure switch. Easy to install and quiet. Pressure switch and booster fan instructions hard to understand, so here is how I did it. Three colors in fan, I used 14/2 wiring and connected green to green, black to black and white to white inside the fan. The pressure switch must be completely vertical when installed. Wire the wire from fan to pressure switch as green to ground inside pressure switch, black to switch side of pressure switch. White does not get used in pressure switch. Run 14/2 from a junction box and hook black to common of pressure switch, white to other white (neutral is not needed in switch). Hook green to ground in switch, and I used a clamp ground on the cold water line. And it works anytime the heater/ac kicks on because the pressure switch takes the ways on power and connects to fan power. Instructions do not explain like that. In my house, black is power, white is neutral, and green is ground, just like it is supposed to be.

I installed this identical blower in my parents house about 15 years ago. Used during both Heat and A/C operation. You cut a rectangle in line in the duct. It stays 90% outside of the duct with just the baffle and bottom of the squirel cage dipping into the duct. This is nice because if you have times that you don't use it, it won't restrict the duct's regular air flow. Be sure to face it in the correct direction. I installed it centered in a square duct near the end of the supply that later branches off supplying air to a register down stairs and another one up stairs. Plenty of air for two ducts and very quiet. I would say that with it being mounted in a 12 inch square air duct is an advantage over a smaller duct. I am sure that it is moving quite a bit more air than the 275 cfm rating. The air that it speeds down the duct pulls or induces additional air along with it. Naturally the two ducts it branches to later are smaller. The motor is fully enclosed and thermally protected. You have to have the motor out in the ambient air, not insulated or blocked off as it would quickly overheat and shut down. The old one needs replacing now and I am happy to be able to get the same product.

Like the pervious reviews state, don't expect miracles from this booster. I used this fan to boost the air flow to the bedrooms in my split level house. So far it seems to work fine. It is loud and the vibration can be heard throughout the house. I tried softening the noise by cushioning the mounts, but not much relief. Hopefully this fan lasts longer than some of the other reviews state. The reason for the three stars is the noise and lack of real air flow boost.

I'm very happy with this fan. If you can cut ductwork, the install is easy. Its very quiet, I'm getting no vibration and very little noise, even when standing next to it. Feels like it doubled the airflow down the 6" pipe it's on, but if you have more than a room or two, you might need something bigger. Its heavy enough for it's size to feel well built. My furnace puts out air as hot as 165 degrees, this is the only fan I've seen able to handle heat that high.

We have a subfloor basement that once flooded (pre sump pump), and this was installed to help dry it out… we ran the first one 7 years NON STOP, then it quit. Still pretty good lifespan. The next one we got has been in for 8.5 years (so far) and still going strong. I bought this one as backup expecting the second to quit @ about 7 years also. However, the difference has been the second one I researched how to get the most life from these fans, and discovered that if you run the power through a timer, and turn the fan off 15 mins in every 12hour period, it should extend the life. This has worked so far - so I’m very happy to be getting closer and closer to 10 years life this time :) Recommended with the hack ti extend life… ;)

Installed in less than 1 hr, runs great. Have it connected with the furnace blower motor, comes on at right time and shuts down with the furnace. I have it mounted in the main trunk of a side split, far bedrooms were cool, bow it is even throughout. My guy wanted me to changed up all my trunk sizes, much easier and cheaper fix installing the blower.

the blower runs very quiet

Booster works awesome

I tried using this to increase air flow from the a/c in my basement to my second floor master bedroom. Unfortunately, there just wasn't enough air flow to make a noticeable difference. Also, the unit made a slight humming noise -eventually it became annoying- which could be heard in the bedroom.

I bought 2 of them. 1 is good but the other one is noisy. It is winter and very cold last fast weeks. I will took too much time to return and get back a new one, I am not very happy. They should inspect,test and make sure this item is quite in use before sending to the buyer. Hopefully my review will be read by my sender and if possible send me a quite one and I will be happy to return the noisy one that I have from them.