Was Solar Worth It?

I wanted a clear answer to a simple question: is my solar system paying off? So I pulled real data from my Duke Energy bills and SolarEdge monitoring and ran the numbers.

Below is a plain-English breakdown of the system, the numbers, and the ROI.

The System

Installed: June 7, 2021

System size: 8.16 kWp

Inverter: SolarEdge SE7600H

Optimizers: 24 × P401

What I Paid

Total system price: $23,223

Loan terms: 1.49% for 20 years

Estimated payment: $122.32/mo

Federal tax credit claimed: $6,500

So my net cost after the tax credit is:

$16,723 (using contract price)

Net Metering Assumption

I reviewed the last year of my Duke Energy Progress bills and came up with some asnwers. Exports are netted 1:1 at the retail rate within each billing period.

Would a battery help? Short answer: no — not right now. Because Duke’s 1:1 net metering already gives me full retail value for exports within the billing period, so a battery doesn’t add much financial benefit. It could add backup power, but for ROI it’s hard to justify. The only scenario where that changes is if Duke moves to time‑of‑use rates or reduces export credits. Under TOU, a battery could help by shifting solar into expensive evening hours — but until that happens, net metering does the same job for free.

2025 Snapshot (Usage + Production)

From Duke Energy bills (12 unique 2025 bills) and SolarEdge:

Grid import (Energy Used): 15,858 kWh

Grid export (Energy Delivered): 2,409 kWh

Net billed usage: 13,449 kWh

SolarEdge production: 6,663 kWh

Blended rate (all charges): ~$0.163/kWh

Important note:

In Jan–Mar 2025 the inverter stopped producing for about 10 weeks. I didn’t notice right away because the Wi‑Fi monitoring was throwing false positives. I’ve now hard-wired the inverter to fix that. It turns out a simple reboot was all that was needed, but it was still frustrating to lose ~2.5 months of production.

Annual Savings Estimate (Year by Year)

Using the 2025 blended Duke rate ($0.163/kWh) applied to SolarEdge production:

Year

Solar production (kWh)

Estimated savings ($)

2021

4,565

744.55

2022

7,495

1,222.40

2023

8,042

1,311.71

2024

6,833

1,114.41

2025

6,663

1,086.70

ROI and Payback

Simple payback (no inflation or escalation):

Net cost: $16,723

Payback: ~15.4 years

ROI: ~6.5%/yr

2025 Monthly Detail (From Bills)

Bill date

Billing period

Import (kWh)

Export (kWh)

Net billed (kWh)

Charges ($)

Jan 27, 2025

Dec 21–Jan 23

1,578

157

1,421

220.07

Feb 26, 2025

Jan 24–Feb 24

1,554

99

1,455

224.98

Mar 26, 2025

Feb 25–Mar 24

1,276

0

1,276

200.99

Apr 25, 2025

Mar 25–Apr 23

1,465

115

1,350

213.47

May 27, 2025

Apr 24–May 22

1,175

347

828

143.30

Jun 25, 2025

May 23–Jun 23

1,353

287

1,066

178.22

Jul 28, 2025

Jun 24–Jul 24

2,038

99

1,939

305.59

Aug 26, 2025

Jul 25–Aug 22

1,598

128

1,470

236.77

Sep 25, 2025

Aug 23–Sep 23

1,276

315

961

162.29

Oct 28, 2025

Sep 24–Oct 24

886

363

523

100.38

Nov 24, 2025

Oct 25–Nov 21

680

366

314

70.08

Dec 26, 2025

Nov 22–Dec 22

979

133

846

152.02

Chart: Estimated Solar Production vs Net Billed (2025)

This chart uses bill data plus a simple self-consumption ratio to estimate monthly solar production. It is directional, not exact, and will not perfectly match the annual SolarEdge total.

Jan | P:############ (587) B:---------------------------- (1421)
Feb | P:########## (523) B:----------------------------- (1455)
Mar | P:####### (348) B:-------------------------- (1276)
Apr | P:########## (515) B:--------------------------- (1350)
May | P:############# (668) B:----------------- (828)
Jun | P:############# (656) B:--------------------- (1066)
Jul | P:############# (655) B:--------------------------------------- (1939)
Aug | P:########### (564) B:----------------------------- (1470)
Sep | P:############# (663) B:------------------- (961)
Oct | P:############ (605) B:---------- (523)
Nov | P:########### (551) B:------ (314)
Dec | P:######## (400) B:----------------- (846)

The Takeaway

Based on real 2025 billing data and SolarEdge production, the system is on track for a 15 year payback and a ~6% simple ROI after the federal tax credit. That’s not as good as I’d hoped honestly. But, it’s a solid, predictable savings — and likely improves as electricity rates rise.