The Holmes Twin Window Fan is a powerful fan that operates quietly and amounts to nothing more than pleasant background noise if customer reviews are to be believed. And you\u2019ll have to believe them, because there\u2019s no dB rating to tell you otherwise. Check out our best window fan list for more great fans!\r\n\r\nWhy We Like It - Holmes Window Fan\r\nThe Holmes Window Fan is a two-speed setting fan that fits most double hung and slider windows as long as those windows are 25 inches wide and 12 inches high at minimum. And though it\u2019s recommended to use a screen, the motor is water-resistant as an extra layer of protection.\r\n\r\nPerformance\/Power\r\nThe Holmes Window Fan has two speed settings, dual blade operation, and independently electronically reversible motors to allow for air intake, exhaust and air exchange. We appreciate the motors for their ability to pull out hot air and push in cool air, but the two speeds are a little unfortunate. Check out the Bionaire Dual Window Fan for one with three speeds.\r\nDurability\/Build\r\nThe Holmes Window Fan is designed to fit most double hung and slider windows. It\u2019s recommended to fit windows 25 inches wide and 12 inches high minimum. The fan comes with an adjustable extender screen and an adjustable panel for a better, more secure fit on your window. And like the Genesis A1, the Holmes Window Fan is relatively lightweight, coming in at just short of eight pounds.\r\nNoise\/Sound Level\r\nThe Holmes Window Fan claims to operate quietly, and we really have no reason to doubt them. Still, we wish they would have provided some dB levels, like with portae fans, just as proof and for accurate measurements. But going off customer reviews, the fan is indeed quiet, amounting to not much more than pleasing background noise.\r\nVersatility\/Modern Features\r\nThe Holmes Window Fan is built with a water-resistant motor so your fan won\u2019t fail on you if there\u2019s some rain outside. It also comes equipped with a one-touch thermostat. This allows you to set and control your fan speed and temperature throughout the day so you\u2019re always achieving optimal airflow\r\nValue\r\nThe Holmes Window Fan is an energy efficient fan and uses up to 60% less energy. So not only will you be saving on energy costs, you\u2019ll be helping to reduce your carbon footprint too. There\u2019s no assembly required, the same as its cousin the Holmes Fan, so all you have to do is take it out of the box and set it up in your window!\r\nHolmes Window Fan Wrap Up\r\nThe Holmes Window Fan is a lightweight and assembly-free fan that still manages to both be powerful and quiet. It only has two speeds, unfortunately, but this is negated when you factor in the fan\u2019s energy efficiency. Finally, the thermostat allows for control over fan speed and temperature at all times throughout the day!