Solar Savings Calculator

Enter Your Details

Country / Location (sets irradiance & tariff) PSH = Peak Sun Hours per day (annual average)

Monthly Electricity Bill

₦

Electricity Tariff (pre-filled, editable)

₦

per kWh · NGN per kWh

Available Roof / Area (m²) — optional Leave blank to skip area feasibility check. ~6 m² per kWp required.

System Type

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Your results will appear here

Fill in your monthly electricity bill and country on the left, then click Calculate My Savings to see your personalised solar estimate.

Reference: Irradiance Data Used

Country	PSH	Tariff
🇳🇬 Nigeria	5.5	₦68/kWh
🇺🇸 USA	5.0	$0.13/kWh
🇩🇪 Germany	3.5	€0.30/kWh
🇮🇳 India	5.2	₹8/kWh
🇬🇭 Ghana	5.3	GH₵0.42/kWh
🇦🇪 UAE	5.8	AED 0.23/kWh
🇬🇧 UK	3.2	£0.28/kWh
🇿🇦 South Africa	5.5	R2.50/kWh
🇰🇪 Kenya	5.4	KSh25/kWh
🇧🇷 Brazil	5.0	R$0.80/kWh

Your Solar Estimate

Based on your inputs and real irradiance data. Results update if you recalculate.

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System Size

Optimal installed capacity

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Daily Energy Yield

Average daily generation

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Annual Production

Total yearly kWh generated

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Annual Savings

Estimated electricity bill reduction

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Estimated Installed Cost

Based on $800/kWp benchmark

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Payback Period

Installed cost ÷ annual savings

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CO₂ Offset

Equivalent emissions avoided

25-Year Total Savings Estimate

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Conservative estimate without accounting for electricity tariff inflation (which typically increases savings further over time).

Disclaimer: These estimates are based on typical irradiance data (NASA POWER / Solargis averages), standard electricity tariffs, and an assumed all-in installed cost of $800 per kWp. Actual results will vary based on site-specific shading, roof orientation, actual tariffs, chosen equipment, and local installation costs. This calculator is provided for indicative purposes only.

For a precise engineering proposal, contact our team for a free assessment.

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Methodology

How the Calculator Works

Transparent formulas based on industry-standard solar engineering principles.

System Size (kWp)

monthly_bill ÷ tariff ÷ 30 ÷ PSH ÷ 0.80

We calculate your daily energy demand, then divide by your location's peak sun hours and apply an 80% efficiency factor to account for real-world system losses (inverter efficiency, wiring, soiling, temperature).

Annual Savings

system_size × PSH × 0.80 × 365 × tariff

Annual energy production multiplied by your local electricity tariff. This represents how much you save by generating your own power instead of purchasing from the grid.

Payback Period

installed_cost ÷ annual_savings

Installed cost uses $800/kWp (industry benchmark). We convert to local currency using the approximate exchange rate. Actual costs vary by country, equipment tier, and site conditions.

CO₂ Offset

annual_production × 0.43 kg/kWh

We apply the IEA's global average grid emission factor of 0.43 kg CO₂ per kWh. This varies by country — grid-heavy economies like South Africa have higher factors; hydro-heavy grids have lower.

Peak Sun Hours data sourced from NASA POWER dataset and Solargis irradiance maps. Tariff data based on 2024 published rates.

FAQ

Frequently Asked Questions

What are Peak Sun Hours (PSH)?

Peak Sun Hours (PSH) represent the number of hours per day when solar irradiance averages 1,000 W/m² — the standard test condition for solar panel rating. For example, Nigeria's 5.5 PSH means that on average, the sun provides an equivalent of 5.5 hours of full-strength irradiance per day. PSH varies significantly by latitude, season, and local climate. We use annual averages from the NASA POWER dataset.

Why is there an 80% efficiency factor?

A solar panel rated at 400Wp never delivers exactly 400W in real conditions. System losses occur due to: inverter efficiency (typically 96–98%), DC wiring losses (1–2%), module temperature derating in hot climates (5–15%), soiling and dust (2–5%), mismatch between panels (1–2%), and shading. The 80% performance ratio (PR) we use is a conservative industry standard. High-quality modern systems often achieve 82–86% PR.

How accurate is the $800/kWp installed cost assumption?

$800/kWp is a reasonable global benchmark for a complete grid-tied solar installation, including panels, inverter, racking, cabling, protection devices, and installation labour. In practice, costs range from $600–$1,200/kWp depending on: country (labour costs, import duties, VAT), system size (larger = lower per-unit cost), system type (off-grid with batteries can be 40–60% more), and equipment tier. Contact us for a site-specific quote.

Do the savings account for electricity price increases?

No — this calculator uses current tariff rates throughout the 25-year projection, making it a conservative estimate. In reality, electricity tariffs in most countries have increased at 3–7% per year historically. If we applied even a 5% annual tariff escalation to a Nigerian household, their 25-year savings would be approximately 2.5× higher than the static estimate shown. Our full engineering proposals include an escalation sensitivity analysis.

What about panel degradation over 25 years?

Modern monocrystalline panels degrade at approximately 0.3–0.5% per year. After 25 years, a panel will produce approximately 87–91% of its original rated output. This calculator does not apply a degradation curve — all years are calculated at full capacity. A full proposal from SolarPro Global includes a year-by-year production model accounting for gradual degradation to ensure conservative, bankable projections.

Enter Your Details

Your results will appear here

Reference: Irradiance Data Used

Your Solar Estimate

How the Calculator Works

System Size (kWp)

Annual Savings

Payback Period

CO₂ Offset

Frequently Asked Questions

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