How to Calculate Your Solar Payback Period in Antigua

The payback period — how many years before your solar installation pays for itself — is the most important number in any solar investment decision. In Antigua at EC$0.45/kWh and 4.8 peak sun hours per day, the math favors solar more strongly than almost any time in the island's history.

The Basic Formula

Payback = Total system cost ÷ Annual energy savings. A 5kW system produces ~17,520 kWh/year. At EC$0.45/kWh that offsets EC$7,884 annually. With XCD 45,000 installed cost, simple payback is 5.7–8.5 years depending on self-consumption rate.

What Shortens Payback

Higher consumption, APUA rate increases, and EV charging all improve the economics. Every rate increase shortens your payback automatically. Adding an EV to your load profile can cut payback by 1–2 years.

What Lengthens It

Oversizing, financing costs, and lower-quality equipment. Cash purchases have the shortest payback; financed systems are still usually cash-flow positive from day one if payments are below monthly savings.

Adding Battery Storage

A 10kWh LFP battery (~XCD 42,000 installed) extends solar usage into night hours. Combined system payback is 11–13 years — longer than solar alone, but the energy independence has real value. Use the Solar Calculator to model your specific scenario.