Don't push it to the max. Make sure you're comparing the rated capacity of various models, not maximum capacity. An electric generator can deliver its maximum capacity for no more than 30 minutes before starting to overheat - rated capacity is the level of power a generator can deliver on an ongoing basis. Usually, it's around 90% of the maximum power.

Include everything you need... Some of the more important devices to connect to a standby generator are some of the least visible: sump pumps, sewage ejector pumps, and ventilation fans. Do a careful inventory of your electrical devices before committing to a certain wattage level.

...and nothing you don't. The single best way to save money on a standby generator is to limit the amount of devices you expect it to power. Consider that most power outages last less than a day - can't your office deal without air conditioning for a few hours?

Turn to the pros for installation. Experienced interior electricians may not be as familiar with electric generators as they are with other types of electrical systems. Choose someone who's installed standby generators before and make sure they do all work up to code.

Expect occasional exercise. Standby generators start themselves up around once a week to "exercise" - making sure they're ready when needed. This only takes around 15 minutes, but if noise is a concern, some generators have a "low idle exercise" feature that lets them run quieter than usual during this weekly workout.