What Size Generator Do I Need for My Utah Home?

Whole-Home vs. Essential Circuits

Whole-home (managed transfer switch): Generator powers the entire home, automatically managing high-draw loads if needed. Typically 18-26kW for a standard 3,000-4,500 sq ft Utah home. More upfront, simpler -- you don't think about what's essential.

Essential circuits (sub-panel approach): A separate critical-loads panel powers only heat, fridge, sump/well pump, key lights, garage door, internet. Typically 8-14kW. $3,000-$5,000 less than whole-home but you decide in advance what circuits matter.

For most Utah homes 2,500-5,000 sq ft, we recommend whole-home with managed transfer switch.

Quick Sizing Chart

• Under 1,500 sq ft, gas furnace, no AC: 7-10kW
• 1,500-2,500 sq ft, central AC: 14-16kW
• 2,500-3,500 sq ft: 16-20kW
• 3,500-4,500 sq ft, dual zones: 20-22kW
• 4,500-6,000 sq ft, multiple HVAC zones: 22-26kW
• Over 6,000 sq ft, all-electric, EV charging: 26-36kW (sometimes dual)

Adjust up for: multiple AC units, electric water heater, electric range/dryer/EV, well pump, heat pump.

Adjust down for: gas furnace/water/range, single HVAC zone, no well pump.

Load Calculation Walkthrough

For a defensible number, add up running watts of every appliance you want on simultaneously:

• Central AC 3-ton: 3,500 running / 7,500 starting watts
• Central AC 4-ton: 4,500 / 9,500
• Furnace fan: 800 / 2,400
• Refrigerator: 700 / 2,200
• Microwave: 1,200
• Electric water heater: 4,500
• Sump pump: 1,000 / 2,500
• Well pump 1HP: 1,500 / 4,500
• Hot tub: 6,000 / 7,500
• EV charger 40A: 9,600
• LED lighting whole home: 300-600

Add running watts. Add the highest single starting-watts surge. Divide by 1,000 for kW. Most Utah homes with central AC, gas furnace, fridge land between 12-22kW.

Natural Gas vs. Propane

Natural gas (preferred where available): Most Wasatch Front homes have Dominion Energy gas lines. Runtime indefinite, no fuel storage, no refills. Slightly less BTU than propane (~10% lower output).

Propane: Required for rural Tooele, Summit County, off-grid properties. 500-1,000 gallon tank provides 7-14 days under load. Tank install adds $1,500-$3,500.

For homes with natural gas access, we install natural gas generators 95% of the time.

Installed Cost

• 8kW essential-circuits: $5,500-$8,500
• 14kW with automatic transfer switch: $9,000-$12,000
• 18-22kW whole-home: $11,000-$15,500
• 26kW large home: $13,500-$18,000
• Dual or 36kW commercial-residential: $20,000+

Cost depends on: gas line distance, pad work, transfer switch size, and panel modifications.

FAQ