Used for bathroom moves air fast quiet efficient only can recommendThe quiet axial fan is best installed in an attic or unoccupied space remote from the intake box register. The fan should the connected to the intake box and the exterior vent with flexible 4" duct as recommended by Fantech to ensure full flow and further attenuate noise. I've now installed these fans in 3 bathrooms - we were very pleased with the Fantech fan installed during our master bathroom renovation, I recently installed them in the other bathrooms myself. Since we live in PA where freezing winter temperatures are common, I used the insulated flex duct Fantech recommended. Patching the square drywall opening of the old bath fan to the 6" round opening of the Fantech intake was a challenge and tedious. I recommend using a count-down timer switch with these fans - they are so quiet you'll forget to turn them off.We purchased and installed two of these bathroom exhaust fans in our newly renovated bathrooms. This brand and style was recommended by our contractor. The fans are extremely efficient and very quiet. They are definitely worth the money.Works like I expected powerful and quite.This is as described in other reviews. Quiet. Quality fit and finish. Sharp edges. I would recommend this.I used a Sonoff wifi enabled switch to avoid running a switch. I could tap into an existing circuit in my crawlspace. "Alexa, turn on the vent."This takes a lot of diy skills but nothing too hard. Moderate to install. (Final wiring is work in progress.)I bought a non heated unit and installed it in a crawlspace. Giving the warmth category a rating is bizzaro and not relevant.Single issue I had is that screws for the electrical enclosure are too long and difficult to install.The fan was somewhat challenging to install on my bathroom vent pipe in the attic. It is louder than I had anticipated, even when using rubber connections at the duct connections. It does a great job of exhausting the bathroom.Great fan when used properly. If you can mount the fan deep into your attic, away from its noise, then all you will hear in your bathroom is the sound air makes when being sucked through the vent. I use this product a lot for my bathroom remodels. My last project I used the fan and I bought a separate fan grill, then modified it to be a heater duct. Great product, but must be used when the motor can be placed away from your ears. It is also great for mounting the intake above your head in the shower. No need for a GFI fan circuit because the motor is far away from any water source. I recommend putting the fan on a timer switch. I do this everytime for my customers. The best switch is the type which lets you choose 5 min, 10 min, 15 min, 30 min, on/off. this fan is so quiet you will forget to turn it off.......20 years ago, I purchased a couple of FanTech inline fans when I was remodeling two bathrooms in my home. The fans have been used every day, and are still running as quietly and well as they did when installed. The German-built fan motors are truly built to last. I was so impressed to see that the same German-built motors are the core of these fans that I just ordered for my daughter's house. The fans are well-built, easy to install, and I believe they will last for a long time. In operation, they are extremely quiet if installed per directions -- the only thing you will hear is the air flowing!