Letter Re: Selecting the Right Size Home Backup Generator


The folks out there have some good information re. electrical considerations, codes and such for installing a hookup for a generator for the home. However, unless I missed a post, no one has mentioned how big a generator one may need to power essentials to get by comfortably in a grid down situation for the short term, at least.
My family and I live in the eastern US and we are prone to power outages from hurricanes, ice storms and to a lesser extent tornados and heavy snowfall. Since moving to a rural area out near the end of our power line service we have had everything from one day to a week long stretch without power to our home.
I knew when we built our home that I wanted a transfer box wired in to our outside box for just such emergencies, but I didn’t know how big a generator I needed that would not break the bank, so to speak. If you have enough scratch for a 15KW to 25KW whole house standby generator, fine, but most of us will be getting along with smaller, more portable units to power the essentials. Also, there are pros and cons as to which generator to buy depending on the type of fuel(s) you wish to use that
are available. [JWR Adds: I generally prefer low RPM diesel generators, because of their far greater longevity and the superior storage life of diesel fuel. They can also run on home heating oil in a pinch.] Ours is a convention gasoline powered generator, though I gave consideration to a propane generator, since we have that fuel source handy as well. Others may wish to address the fuel issue. We got a reconditioned factory Coleman 5500 watt generator for a bargain price at one of the local discount retailers in the wake of one of the last big hurricanes, which was a bargain for the price and has not let us down yet. I found that my main concern was having enough wattage capacity in a generator to turn over the well pump so we can provide water for our livestock and family. The minimum required for our 300 ft. well was about 3500 watts initial surge to turn over the well pump which then falls back to just a thousand watts or so for continued use. Fans and lights, added one at a time as you turn them on with the generator running use very little wattage, so they can be added with little load on the generator during runs in the evening or morning, when folks are up and about. Large appliances, however (microwaves, ovens, toasters, etc.) take a lot of wattage that would best be served by a larger standby generator. I have heard that electronic appliances such as computers, charges, radios, televisions etc. might be damaged if run off generator current, but I am not sure of this – we just don’t use those items during an outage anyway.
To make a long story short, we settled on a 5000 watt generator that weighs about 225 lbs. We bought it with a wheel kit, cover, and custom 60 ft. 220 volt cord that can be directly linked to our outside power transfer box during an extended outage. This setup will give us water, enable us to flush and shower and run the fans and lights, which, combined with our gas heat and cooking, keeps us comfortable until the power returns. It is kept in our detached garage for safekeeping and for operation by the open garage door to vent the exhaust and keep the noise down. As they say, your mileage may vary, but I draw the line at about 5000 watts for home use in extended circumstances. I consider smaller more portable generators you can run out of the back of your pickup truck or other conveyance as convenient for remote work and for power tools, but not big enough for your home.
By the way – I have found that cranking the generator monthly to check it out and taking it in yearly for a check-up is advisable, so it will be ready when needed. STA-BIL [or similar] gas stabilizer in your generator gas tank can also help preclude gumming up the engine and leading to hard cranking, if it will start at all. Although I have a hand crank generator, I understand that electric start is preferred. Just my $.02 cents. Regards, – Redclay