Whole House Generators - How To Pick The Right One
Brands
When we talk about whole house generators, there are so many things we need to know, but where do we start? First, let’s talk about who makes them. In the residential market, there are three major brands in that space. Kohler, Cummins and Generac. But how do we know which is best? For the sake of this article and what we are trying to accomplish, we will make some general statements. All three of these brands have been around for years and have proven their commitment to quality and customer service. They all have similar offerings and price points. We happen to work the most with Generac, and they seem to dominate the marketplace in our area. We at Electrical Specialists do not believe you can go wrong with any of these brands, but the decision will be yours to make if you purchase the unit yourself.
SizEs
Generators come in a range of sizes. Typically, from 14KW to 25KW. So, what does that mean? KW stands for kilowatts, which is a thousand watts. If we use basic OHM’s Law and divide those by standard line voltage of 240 Volts, we get roughly 58 and 104 Amps. So now comes the question we get the most on size. “But Brandon, I have a 200 Amp panel, will that be enough? “
This is when we run a load calculation on your home. First, we are going to add up all the critical circuits. Meaning all the things you don’t want to have an interruption in power. For example, sump pumps, refrigerators, freezers, AC/Heat and medical devices. Then we run tests on the rest of the circuits or what we call “convenience circuits.” These include the microwave, range/stove, dryer, and general use lights and plugs.
Studies have shown that most households typically use less than half of their peak power at any given time. This means if you have a 100 Amp service/panel, you are typically not using more than 50 Amps at a time. Same goes for 200 not using more than 100 on average.
Summary
So to sum up the selection process, you must first choose a brand and then have it sized to ensure that it will handle everything you need it to cover. One way some people do it is to get the smaller unit to cover their critical loads, and just suffer through not being able to use the convenience items during an outage. Our opinion is if you are already making the investment, why not have it cover everything? The value you get from the relatively minor price increase is worth its weight. But every situation is different, and all options should be discussed in detail.
