TjernlundDBF2 Dryer Duct Booster Fan, No Clogs, 4"Duct

Installed in the attic. I put mine on a timer switch. Had a unit with a pressure switch and when the house a/c turned on it would activate the switch. This unit cuts my drying time in half. Went from running 2 cycles to 1. This unit works so much better than the in-line fans. It creates enough suction that you can feel the air moving in the dryer when the fan is on. Sound is not bad, I can’t hear it over the dryer or in an other room in the house.

Easy to install and still works great. Makes a huge difference in drying times and has never clogged.I have had to clean the vents many times but never this fan works so good.

I purchased this model over the others simply because of its design with offset inlet and outlet so the lint does not block the passages. Overall the design and build quality is very good. It is made well. The bracket is strong and holds the booster fan in place. I added rubber gasket to the bracket mount to isolate any vibration. I also bought the current sensor (that was advertised with this fan. But it failed on the first try and kept the booster fan running. So I added a 15amp 120 VAC on/off switch to it for now. The supplied installation instructions were very clear and with wiring diagrams for various application. I have only tested it for a short time so I plan on providing a full review in a month or so. It is quite fan and does not vibrate at all. Works fine for now. Down the road i plan on installing a lint trap since this company's lint trap is expensive. 4 stars only because I have not run it for a longer period of time. Hope this helps you all.

I have a double whammy with my dryer venting. Apparently in 1998 when my house was built someone considered it acceptable and passed inspection to use 3” PVC for my dryer vent which was about 35 equivalent feet from the floor out. I had to use a reducer to get the 4” down to the 3”. Our dryer is gas, and it had always wanted us to check the filter because it was reducing air flow. It was always questionable on how long things would take to dry.I knew two things, first I was going to replace the PVC with 4” duct and second because of the equivalent length I should get a booster fan.After researching, I knew I wanted either the Tjernlund DBF2 or the LB2. For those that have looked the LB2 has the pressure sensor to activate. The DBF2 needs something to switch it on. Both need power available. The LB2 requires running a small cable to provide information on the status of the unit. Looking at the reviews it seemed like quite a few were having issues with the pressure switch. This unit seems like the same thing without the pressure setup for about $150 (current prices) less. Since I was going to have to run wire to the laundry room anyway, I chose to use a switch timer I got her on Amazon and just hit the timer when we start the dryer. It has lights at least showing the timer is active. https://www.amazon.com/gp/product/B0184PH9TM/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1When I went into the crawlspace, I realized that not only did they use PVC but that it wasn’t sloped properly so when cut it open water poured out. No wonder drying time was poor at best.I looked at the instructions for the LB2 and they seemed better for the distance the unit should be from your dryer, so I used them to know my minimum equivalent distance I needed to be. It is installed over halfway of the length. I got it installed and was ready to test. I have only had it for two days so there may be a follow up later.As others have said there is a noise to it, but it isn’t bad. Switched on with the dryer not on and going out to the dryer vent it is blowing well. Going in and running large loads of towels a load that normally would take at least two heavy cycles took less than 39 minutes. How much shorter I don’t know because that is when I checked it. Now the holdup will be washer time not dryer time. Now we get a “Good airflow” light instead of the “Check Filter”Unlike another user that mentioned his dryness sensor reducing the time, since installing this my sensor isn’t accurate. Maybe it is thinking clothes are still damp from the air being pulled out. Any suggestions? Apart from that we are very happy and that isn’t a deal breaker we may just have to go old school and use the timer till we can figure something out.

Great product, just know that it is not set up to just plug in, you will need to wire it in.

Sometimes you buy something only hoping it is what it says and works as described...but this is both. Well built, not hard to install (of course that depends on your house design/where you need to install it), and accomplishing the task well. Dryer runs great with this. I used the sensor switch so it runs automatically with the dryer. Awesome!

I have the equivalent of 80' dryer duct length because whomever built my house decided to cross the entire house to exit the dryer duct. As you can see my ducts were severely occluded from 20 years of lint buildup to the point of severe fire danger.I installed the Tjernlund DBF2 because I could boost the air flow across this length of duct without risking lint buildup in the booster fan. I also chose this model because I could direct wire it to a smart outlet. I also wired my dryer to a power meter so when I turn on the dryer, the DBF2 automatically turns on via a rule in Hubitat Home Automation system. My wife doesn't have to remember to turn a timer dial or turn it on or off, it automatically runs when the dryer is drawing power. Genius. I did this method over the other Tjernlud product because the negative reviews had issues with the air pressure on/off sensor. I didn't want to mess with a product that didn't work.How well does it work?With my dryer set to auto-sense dryness, the booster fan pulls enough airflow that the dryer stops running around 27 minutes on a 40 minute cycle time. I'm saving 13 minutes on my dryer time! Compare this with before I installed the DBF2 when I was running the dryer 2 or 3 times before my clothes were getting dry!How loud is it?The booster fan is audible, but it's not really loud. It has a hum but it's not distracting. I stuffed the thing up between my floor joists so I can hear it in the upstairs room. BUT I can barely hear it over the sound of the dryer and I my wife has a habit of running the dryer when we go to bed, and I have no problems going to sleep with the dryer on and duct fan running.If you have a long duct run I would recommend this product.I have not yet pulled the duct down to evaluate after 1 month if I'm getting any buildup in the duct work, but so far, so great.

Uncertain. We will conduct are own timing evaluation with and without the booster on. Initially, we seeonly slight improvement in drying time.

After trying 2 cheaper duct fans, I can say this works so much better. This has better air flow and you can tell the difference by how much more lint there is on the secondary lint collector. I've only had it for less than a month so I can't comment on the longevity, but I can say the other duct fans I purchased didn't last longer than 18 months each.Hoping this will last longer due to the design where the lint is passed through instead of getting stuck directly on the fan blades. It's also quieter than the other fans even though this one is larger.Downside with this model compared to the more expensive Tjernlund booster is this has no switches. So you'll need to find a different way to trigger it. I'm using an inline thermostat and it seems to work well. Another con is that this is heavier and the orientation is different so you may need to rework your ducts and mount this to something stable like a stud or drywall.

Before it used to take 2 to 3 cycles to dry our clothes, after installing this, same amount of load is always dried with only 1 cycle.If you want to save some time and electricity, you cannot go wrong with this.

This fan does what it claims: sucks hard and blows hard. I'm using for both a dryer exhaust booster (we have a long duct run) and also a ventilation duct for the laundry room. Plenty of airflow and does actually shorten the drying time. Very well-built too. All-metal construction.

Recently had our very long dryer duct run inspected after having this installed for ~1yr. The duct was perfectly clear