I moved into a house with a fireplace with an old "heatalater" unit. The fan had obviously been there awhile and had a bit of a whistle to it and also was loud. It was a double squirrel cage, single motor, unit. It was placed on a magnetic plate at the back wall under the fireplace. The hot air was then sucked in at the bottom of the firebox and sent out of the top. This is a nice very simple way of doing things. I like that. In this type of construction there is no air connection between what is happening in the fireplace and the hot air that is pushed out into the room. The heat comes from the outside of the metal box in which the fire burns.
The Tjernlund 950-3307 Universal Fireplace Blower fit under the fireplace in the same way as the other blower. I set it on the old plate at the back of the fireplace intake where the other fan had sat. Make sure you measure the area under the fireplace to make sure you have enough height for the fan to fit. I didn't attach it with any screws to anything and it seems to stay in place just fine. There is no noticeable vibration to the blower. The unit is very quiet, blows hot air to about the same level as the old one and does not have any notable whistle or noise vibration that the old unit had developed. For the price, it was a great improvement and worth changing even though the other unit still functioned.

Replaced my blower on my wood stove insert with this blower. Over 3 months nearly continuous running without a single issue. Great deal for the money.

Very satisfied with product (a replacement), packaging and fast delivery (2 days sooner than expected). Fairly easy to install and operates more quietly than some of the other reviews would have you believe. I screwed the device to the back of the insert which may contribute to the reduction in noise. The price was very reasonable compared to other vendors. The wires to the motor were plenty long enough to connect to the existing power cord.

Been using this for almost two months now. Fits in nicely. The thermostat and fan speed control work without issues. Moves a good amount of air at 1/2 speed. I used foam tape and rubber mounts to help reduce noise but the fan is so unbalanced it makes a vibration / metal rattling noise. At half speed it's about as loud as a box fan on low. Rather annoying. Maybe I just got a bad unit but its bad enough that I'm considering a different fan. Also would be nice if the motor could be swapped to the other side.

I replaced my pilot light assembly in our NG fireplace and installed this unit at the same time. I have always wanted a blower for the unit however the OEM unit was over $200 and not worth it for us. I saw this unit and took a chance installing it. We really like this unit. It came with an adjustable thermostatic switch and variable speed control that I placed just inside the bottom access grill. I bench tested the unit using a hairdryer to throw the thermo switch prior to install and both my wife and I were surprised at how quiet the unit was. I installed it by placing some self adhesive Velcro fabric on the ends. The Velcro helps with fast, easy removal if needed and dampening for the unit. We are very happy with the unit and for a 1/3 the price of the Lennox unit it is a very good value. The unit moves quite a bit of air even at 30% speed. With that it warms the room wonderfully.