How do you calculate generator wattage for a house?
Calculate generator wattage by listing every appliance you want running together, adding their running watts, then adding the single largest starting surge on top. Nameplates on the equipment show the numbers. Round up so the generator is not working at its limit, because overloaded units shut down or wear out early.
Start with a written list. Put the refrigerator, freezer, lights, internet equipment, garage door opener and any medical devices on it first. Then decide on the big loads: air conditioner, electric water heater, well pump, pool pump and electric range. Every item you add pushes the required size up.
Nameplates are usually a sticker on the side or back of each appliance. Some list amps instead of watts. Volts multiplied by amps gives a rough wattage, but motor loads need extra attention, which is where a licensed electrician earns their time.
Why does the air conditioner decide generator size in Arizona?
The air conditioner decides generator size in Arizona because its compressor draws a large starting surge, and a central system is often the biggest single load in the home. Choosing to run cooling during an outage moves you to a much larger generator than lights and a refrigerator alone.
With summer afternoons above 110 degrees and monsoon outages that can last hours, many homeowners want at least some cooling. A mini split or a single smaller system is easier to support than a large central unit, so the cooling plan and the generator plan should be made together.
Some homes use a soft start device on the compressor to lower the starting surge. That can let a smaller generator carry the load. Whether it suits your equipment is a question for the technician who looks at the unit in person.
What is the difference between a portable and a standby generator?
A portable generator is moved by hand and connects through extension cords or a properly installed inlet, while a standby generator is permanently mounted outside and starts automatically through a transfer switch. Standby units are sized to circuits you choose, and installation involves gas supply and electrical work.
Portable units need no permanent installation, but you have to set them up, fuel them and keep them well away from windows and doors, because exhaust carries carbon monoxide. Never run one inside a garage, even with the door open.
A standby generator needs a transfer switch so house power cannot flow back toward the utility lines, which is a danger to line workers. This is licensed electrical work, and installation generally requires a permit and inspection.
Can I plug a generator into my house myself?
You should not plug a generator into a house outlet or wire it into the panel yourself. Backfeeding power through an outlet is dangerous to utility workers and can start a fire in your home. The safe options are extension cords to individual appliances or a licensed electrician installing a transfer switch.
Homemade cords with two male ends are a known cause of injury and should never be used. If you want the generator to power hardwired circuits like a furnace blower or well pump, the connection has to be a transfer switch or interlock installed to code.
If you smell burning, see sparking, or notice a hot panel while a generator is running, shut everything down and call for help. Do not keep testing the setup. When you are ready to plan a proper installation, Vortech has licensed electricians who can walk through your loads with you.
More questions: Home Generators: 12 Most Asked Questions Answered