How many solar panels for a 150 m² (1600 sqft) home

1600 sqft is the typical US 3-4 person family home. Consumption climbs: cooking, AC, heating, laundry, dryer, electronics. The right number depends on what you have inside.

Consumption by gear

4-person family with gas heat and water: 5500 kWh/year. Same with heat pump (no gas): 9000 kWh/year. With EV: 12000 kWh/year. The key difference is whether you use fossil fuel or fully electric.

Panel calculation

7000 kWh/year ÷ 1500 = 4.7 kWp = 12 panels of 410 W. 9000 kWh/year = 6 kWp = 15 panels. 12000 kWh/year = 8 kWp = 20 panels. Oversize 20% for surprises and degradation.

Inverter type

Up to 5 kWp: single-phase 5 kW inverter. 5-7 kWp: 6 kW single-phase or three-phase 5 kW. Over 7 kWp with three-phase service: three-phase required. Hybrid if you plan battery later.

Space needed

15 panels (6 kWp) take 320 sqft. A 1600 sqft south-facing roof has plenty. Hip roof: limited to the best two slopes.

Installed cost

6 kWp with hybrid inverter: $14000-19000. With 30% federal tax credit + state incentives: $8000-12000 net. Payback 6-9 years.

Compare with 1000 sqft home and 2200 sqft home.