Electrical guide
How to size a standby generator for a Grand Rapids ice storm
Generator sizing starts with a list of what must run when the power is out for days in January, not with the biggest unit that fits the budget.
- Start with must-run loads
- Whole-house or essentials
- Realistic cost ranges
By Zachary Keating, Electrical Guides Editor
Updated September 2026
Quick answer
Size a standby generator from the loads that must run in an outage, usually the furnace blower, sump pump, refrigerator, well pump and some lighting, plus any large loads you want covered. Essential-circuit setups can use a smaller unit; whole-house coverage for many homes lands in the 14 to 22 kW class.
Start with the outage you are planning for
Grand Rapids outages come in every season. Severe storms in April 2026 cut power to more than 47,000 Consumers Energy customers across the region, and ice and blizzard-force winds in December 2025 did the same in winter. The winter outage is the one that matters most for sizing, because it is the one where the furnace and sump pump have to keep running.
Write down what must run: the furnace blower, the sump pump, the refrigerator and freezer, a well pump if you have one, some lights and receptacles, and anything medical. Then list what would be nice to have, such as central air, the range or the dryer.
Starting surge matters as much as running load
Motors draw several times their running current for a moment when they start. A sump pump or well pump starting while the furnace is already running is the moment a small generator struggles. Generator ratings account for this differently, which is why sizing should be done from nameplates and starting currents, not from a rough wattage chart.
An electrician's load calculation for the generator lists each load's running and starting demand, then checks the combinations that happen in real life.
Whole-house or essential circuits
Essential-circuit coverage moves the critical circuits to a small transfer switch panel, and a smaller generator carries them. It costs less, uses less fuel and covers what matters. Whole-house coverage uses a service-rated transfer switch and a larger unit, often with load-shedding modules that briefly hold back the air conditioner or dryer so the generator is not overloaded.
Many homes around Grand Rapids choose whole-house coverage in the 14 to 22 kW class; regional installed costs for that size commonly run $7,000 to $12,000, with a broader range of $1,516 to $8,810 for standby installs overall.
Fuel and placement
Natural gas is the easy choice where the house has it: unlimited run time and no deliveries, provided the gas meter can supply the generator and the furnace together. Propane suits homes without gas, and the tank size sets how long the unit runs between refills.
Placement follows clearance rules from windows, doors and air intakes so exhaust stays out of the house. Consumers Energy reminds customers never to run a generator in an attached garage or basement; a standby unit outside on a pad, or a portable one connected through an inlet and interlock, keeps it where it belongs.
What happens after the install
A standby generator runs a short exercise cycle every week and needs yearly service: oil, filters, battery testing and a real transfer test. Most no-start calls in the first ice storm of the year trace to a weak battery or a missed service. Booking service in early fall avoids that.
Whatever size you choose, the installation needs electrical and mechanical permits and inspection before it is relied on.
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Straight answers
Questions about generator sizing
Still unsure? Call (616) 699-4794 and ask a technician.
Many homes land in the 14 to 22 kW class; a load calculation confirms it.
Often, with load-shedding modules that hold back large loads when needed.
Regional ranges for 14 to 22 kW units commonly run $7,000 to $12,000 installed.
Natural gas where available; propane where it is not, with tank size setting run time.
No. Run it outside, away from doors, windows and air intakes.
At least yearly, and ideally before winter.
