A 4,000 square foot home in New Hampshire typically uses about 1,978 kWh per month at the state average rate of 21.9¢/kWh (EIA). With 4.2 peak sun hours per day, most homeowners need a 18.9 kW solar system — roughly 48 panels at 400W. After the 30% federal ITC, net cost is about $39,600, with 8.8-year payback and $149,900+ in estimated 25-year savings.
Content roles: This page is your New Hampshire-specific sizing decision for 4,000 sq ft. For national methodology and roof/orientation depth, see the 4,000 sq ft national guide. For bill-based sizing, see $300/month (~$433/mo equivalent in New Hampshire). Policy depth: New Hampshire solar data.
⚡ System Size
How Many Solar Panels for a 4,000 sq ft House in New Hampshire?
New Hampshire electricity rates and sun hours change panel count versus the US average:
System size (kW) = Annual kWh ÷ (Peak sun hours × 365 × 0.82)
For 4,000 sq ft in New Hampshire:
Estimated monthly usage: ~1,978 kWh
Peak sun hours: 4.2 h/day
System size:18.9 kW (~48 × 400W panels)
Metric
New Hampshire
US average
Rate
21.9¢/kWh
16.3¢/kWh
Sun hours
4.2 h/day
4.5 h/day
System size
18.9 kW
17.6 kW
Panels (400W)
48
45
New Hampshire requires a larger system than the national average for the same square footage. Use our solar system size calculator with your actual utility bills for a precise ZIP-level result.
Find your exact solar savings
Enter your ZIP code for a personalized estimate using your state's electricity rate and sun hours.
💰 System Cost
What Does Solar Cost for a 4,000 sq ft Home in New Hampshire After the ITC?
At $3.00/W installed (SEIA 2026), a 18.9 kW system in New Hampshire costs about $56,600 before incentives. The 30% ITC saves ~$16,980, for $39,600 net cost.
📈 Payback Period
How Long Is Solar Payback on a 4,000 sq ft Home in New Hampshire?
A 18.9 kW system saving ~$4,522/year pays back in about 8.8 years after the ITC. At 3% rate escalation, 25-year utility spend totals ~$189,500 vs $39,600 net solar — $149,900+ lifetime advantage.
Solar vs utility company · 25-year comparison
Total cost of staying on the grid vs owning solar for a $300/month bill (national average assumptions).
New Hampshire Solar Incentives for a 4,000 sq ft Home
New Hampshire’s Residential Renewable Electrical Generation Rebate Program provides rebates of up to $0.20/W (capped at $1,000) for solar PV systems. New Hampshire also has a strong net metering law and a Renewable Portfolio Standard. The NH PACE program offers financing for energy improvements.
Direct answers for US homeowners in New Hampshire.
At New Hampshire's average rate of 21.9¢/kWh and 4.2 peak sun hours, a 4,000 sq ft home (~1,978 kWh/month) typically needs a 18.9 kW system — about 48 panels at 400W. See the [national 4,000 sq ft guide](/guides/how-many-solar-panels-4000-sq-ft-house/) for methodology.
A 18.9 kW system in New Hampshire costs roughly $56,600 installed before incentives. The 30% federal ITC reduces net cost to about $39,600. New Hampshire's Residential Renewable Electrical Generation Rebate Program provides rebates of up to $0.20/W (capped at $1,000) for solar PV systems. New Hampshire also has a strong net metering law and a Renewable Po...
At $39,600 net cost and ~$4,522/year in bill savings, simple payback in New Hampshire is about 8.8 years.
Most New Hampshire homeowners in this size range see **$149,900+** estimated 25-year savings vs utility power. Equivalent monthly bill: **~$433** — compare the [$300/month bill guide](/guides/solar-panels-300-month-electric-bill/) for bill-based sizing.
The US average needs a 17.6 kW system at 11.0-year payback. New Hampshire needs 18.9 kW with 8.8-year payback at 21.9¢/kWh and 4.2 sun hours.
$300/month electric bill by state
System size and payback vary by electricity rate and sun hours — see your state.