This page covers planning and safety. For the generator’s engine oil, storage and exercise routine, see the generator care page. Sizing here is a rough planning method; an electrician should handle any connection to your home’s wiring.
Rough sizing in three steps
- List what must run: furnace blower, well pump, sump pump, refrigerator, freezer, a few lights, phone chargers.
- Add up running watts from each appliance label or manual.
- Add the largest starting (surge) watts. Motors such as well and sump pumps draw much more for a moment when they start. Start large motors one at a time.
Compare the total with the generator’s running (rated) watts, not just its peak rating, and leave some headroom.
Safety that matters most
- Carbon monoxide kills. Never run a generator indoors, in a garage (even with the door open), in a basement or near windows, doors and vents. Use battery-powered CO alarms inside.
- Never back-feed through a dryer outlet or similar. Use a transfer switch or interlock installed by a licensed electrician.
- Use the right cords: outdoor-rated, heavy enough for the load, and undamaged.
- Refuel only when cool and store fuel in approved containers away from the house.
- Keep it dry using a cover designed for running generators, never by running it inside.
Before-the-storm checklist
- Start and run the generator under load for the time the manual recommends.
- Check the oil level and change it if due. New generators often need an early first change.
- Have treated fuel on hand in approved containers, enough for at least a day or two.
- Test CO alarms and replace batteries.
- Lay out cords and the transfer-switch steps so anyone in the house can follow them.
- Clear a safe running spot outdoors, well away from openings, and clear snow from it.
- Keep spare oil on hand for long outages, since many generators need checks every several hours.
Frequently asked questions
How big a generator do I need for my furnace and well pump?
It depends on the specific motors. Add their running watts, add the largest starting watts, and compare with the generator’s running rating. An electrician can confirm.
Can I run my generator in the garage with the door open?
No. Carbon monoxide can build up quickly in a garage and seep into the house. Run it outdoors, well away from openings.
How often should I check oil during a long outage?
Check at each refueling or as often as the manual says. Many air-cooled generators use some oil during long runs.
AMSOIL products for this job
- AMSOIL 10W-30 100% Synthetic Small-Engine Oil. AMSOIL says: “Protects up to 200 hours”; “Shear-stable, high-film-strength formulation fortified with anti-wear additives”.
- AMSOIL Gasoline Stabilizer. AMSOIL says: “Helps keep fuel fresh up to 12 months”; “Fights ethanol corrosion”.
- AMSOIL Quickshot. AMSOIL says: “Cleans gummed/dirty injectors and carburetors”; “Stabilizes fuel during short-term storage”.
Product wording above is quoted or summarized from amsoil.com. Read each product’s label and data sheet for directions.
Use AMSOIL’s official lookup guide to see what is listed for your vehicle or equipment, then order online whenever it suits you.