I used to work for a Kohler generator distributor and agree that Generacs are on the loud side. FWIW, Kohler only has gas generators in their residential line. You can get a good ballpark idea of the kW size you need by seeing what your peak kW consumption was for the past couple of years. Your electric utility bill may have a month-to-month graph you can check for that info. Most manufacturers have a sizing program on their websites that allows you to plug-in your numbers and get a recommended size. Another thing to check is operating hours between oil changes, and maximum continuous run times. A lot of the smaller residential units call for 25 hours or so between changes. I'd suggest a Service Entrance rated automatic transfer switch if your entire house will be generator-powered during a power outage. It goes between the utility service and your main breaker and includes a built-in disconnect. You need to isolate your house from the electric grid to prevent having your home generator back-feed the power grid and possibly electrocuting a lineman doing the repairs. Hope this helps.