One, they are very expensive when purchased new (many thousands of dollars, plus installation costs). Regarding whole house generators, I have several major problems with them. It's quiet and only consumes one gallon of gasoline every 5.4 hours or so at normal loads.
It will power the electrical components, mainly the blower, of our natural gas furnace. It won't power our central A/C, but I have stored a window unit A/C that would cool down most of our home. It won't power our electric water heater, but we can heat what we really need with propane. It won't power our electric stove, but we have used a propane stove. I have a Yamaha 2400 iSHC (2,400 watts max., 2kW continuously) that I know from experience will run everything we really need and more just fine. Fourth, they are generally a lot heavier and harder to move around than smaller generators. Third, big generators can be a lot louder than small generators, especially louder than inverter generators. First, big generators are less fuel efficient, a lot less in many cases.
Some say that you should get a bigger generator to have 'room' to run more stuff, but there are problems with this approach. If you have other genuine needs that are very power hungry, a big generator is a must. Most well pumps run on 240 volts and often require a 5kW or larger generator to run. When you really need a large generator is when you have a well pump. However, propane works great for cooking food and heating water to bathe in, stored propane can heat your home or at least a small area, and a central A/C is really a luxury (a small window unit A/C in your bedroom is fine for most). You won't be running an electric stove, water heater, central A/C, or electric furnace with these though. This enables you to easily get one of the fantastic inverter generators made by Honda and Yamaha, which are very fuel efficient at low loads and make FAR less noise than a standard generator. Modern refrigerators and freezers have small compressors that run perfectly from a small generator. If you want to run your refrigerator, a freezer, lights, fans, TV, computer, sump pump, small window unit A/C, propane or natural gas furnace, and charge up your battery bank (a must for any prepper), a 2kW generator will do the job nicely. Click to expand.First, I think it should be mentioned that most generators for prepping purposes can be split into two groups: small and big generators.