Product review (4 stars): This should be a pretty noticeable electric savings
The fan cut drying time in half. This should be a pretty noticeable electric savings. The installation went well. I had a 4" metal dryer duct and mounted the booster fan at the mid point. Installed the current-sensing switch in a 4" electrical box under by breaker panel and routed the wiring into the 4" box as needed. I then installed a duplex outlet within reach of the booster fan's power cord. Determining which lead that needed to go through the sensing-switch was easy. I disconnected one hot leg and turned on the dryer. It started to tumble which told me that I needed to use the other leg as the sense lead. The hookup instructions were good. However, if the instructions do not make sense to you, then you need to call an electrician. I rated it 4 stars since this was just installed and I have no way of knowing how reliable it is going to be. I'm betting that I'll have wished I'd have installed this years ago.