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Solar PV return: practical guide
This guide explains how to use the Count.ie solar pv return. Estimate self-consumption benefit, export income and payback. Follow the inputs, method and worked example below, then compare your own scenario.
Guide written .
Open the Solar PV return calculatorWhat to prepare
- Use meter readings, bills, equipment specifications and actual tariff periods where possible.
- Separate power in kW from energy in kWh and daily use from annual use.
- Identify whether efficiency, standing charges and losses are included in the chosen model.
Understand the inputs
The calculation method
Generation = kWp × specific yield. Benefit = self-use × import tariff + export × export tariff − maintenance.
Worked example
Illustrative inputs and their result.
Example inputs
- PV system size (kWp)
- 5
- Annual generation per kWp (kWh)
- 900
- Self-consumed generation (%)
- 45
- Avoided import price (€/kWh)
- 0.3
- Export payment (€/kWh)
- 0.15
- Net installed cost (€)
- 8500
- Annual maintenance (€)
- 100
Calculated example result
- Annual Net Benefit
- €878.75
- Simple Payback Years
- 9.67 years
How to interpret the result
Energy consumption and money saved are different outputs. Results based on entered prices or efficiencies are scenarios, not a performance guarantee, installer quote or measured emissions assessment.
Use the same demand and time horizon for each option. Test a less favourable tariff, lower efficiency or lower use to see how sensitive the estimated saving is.
Common mistakes to avoid
- Do not count the same efficiency loss twice.
- Keep standing charges and unit charges separate when the model distinguishes them.
- Check seasonal demand, export restrictions and tariff assumptions before extrapolating.
Assumptions and sources
Yield and prices are editable estimates. Excludes tax treatment, finance, degradation, inverter replacement and grants unless already deducted from installed cost.
If your case falls outside this scope, use a more suitable calculator or contact us about an unclear method.