Get matched with top generator install pros in Waterman, IL

Sizing a generator is a careful process that requires calculating the electrical load of your entire house. You have to take into account every device you want to use and their wattage requirements, plus the wattage needed to start them, and look for a generator that can safely run all that at around 80% capacity.

In more practical terms, a small home can run on a 10,000-watt generator (and if you only want to power a few key appliances, much less than that). A mid-sized home may need something between 15,000 and 22,000 watts. Larger homes require 25,000 watts or more. 

Whole-house generators can run continuously for extended periods, even for weeks at a time (around 400 to 500 hours), as long as they have a sufficient fuel supply. However, this type of extensive use will increase wear and tear and can shorten the generator's overall lifespan. During long periods of operation, it's important to check and refill the engine oil as needed, potentially as frequently as daily depending on the model. If your generator uses a fuel tank, ensure it is kept full to prevent unexpected shutdowns.

Here’s what you can run with different wattages and types of generators:

Portable generator:

• 2,000 watts can handle a large appliance like a freezer or refrigerator, plus a few smaller items like phones or computer chargers. 

• 4,000 watts will keep two large appliances operating and a few smaller devices.

• 8,000 watts should power most essential appliances and other devices, including a sump pump, well pump, or your dishwasher.

Partial to whole-house generator:

• 20,000 watts and above will make it seem like your home’s power is still on.

With proper maintenance, a whole-house generator can last between 20 and 40 years. The specific lifespan depends on how often and for how long the generator is used, and some models may have their life expectancy rated in hours of operation. To maximize its lifespan, expect to spend around $150 to $300 per year for annual maintenance checks from a qualified technician. During these checks, a technician will inspect the engine filter, starting mechanism, fuel, lubrication, and coolant levels. Consulting your installer and choosing a low-impact fuel like natural gas or diesel can also help ensure your generator lasts as long as possible.