New to this? Plain-English guide

Peak Sun Hours (PSH) — how many hours of full-strength sunshine your location effectively gets per day. Jamaica averages about 5.5. More sun hours means more savings from the same panels.

Installed Cost per Watt — the all-in price of a system (panels, inverter, mounting, labour, permits) divided by its size in watts. A 5,000W system at US$3/W costs about US$15,000 total.

Bill Offset Target — the share of your electricity bill you want solar to cover. 100% means the panels produce as much energy as you use in a year.

Utility Rate Escalation — how much electricity prices rise per year. Caribbean rates have historically climbed a few percent yearly, which makes solar savings grow over time.

Your Bill

Currency

Monthly Bill Amount

Rate per kWh

Bill Offset Target (%)

System Assumptions

Peak Sun Hours

Installed Cost per Watt

Utility Rate Escalation (%/yr)

Analysis Period (years)

Method: bill ÷ rate = monthly kWh; system kW = offset kWh ÷ (30 × sun hours × 0.80 derate). Year-by-year savings use escalating rates and 0.5%/yr panel degradation.

Guide

Reading Your Bill

Divide total charges by kWh consumed to get your true blended rate — in Jamaica this includes fuel surcharge and IPP charges on top of the base energy rate, which is why the effective JMD rate is far higher than the published tariff.

Why Not 100% Offset

Without net metering credits, exported daytime energy may earn less than you pay at night. 80-90% offset usually maximizes return; going bigger mainly benefits systems with batteries or favorable net billing contracts (JPS offers net billing in Jamaica — check current terms).

What Drives Payback

High utility rates and strong sun make the Caribbean one of the best solar markets in the world: paybacks of 4-7 years are typical versus 10-15 in North America. Rate escalation compounds this — every JPS increase shortens your payback retroactively.

Beyond This Estimate

A real quote needs your roof orientation, shading, and structural condition. Use the Solar Array Sizer for panel-level design, then request a WattWorks assessment for the installed price.

Results

Recommended System Size

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Estimated System Cost

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First-Year Monthly Savings

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Payback Period

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Lifetime Net Savings

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Return on Investment

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Monthly Energy Use

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Energy Bill Savings Calculator