Your inputs
Editable example valuesYour estimate
Live calculationDaily water-heating energy
6.51 kWh
Collector area
1.82 m²
Storage tank
240 L
Planning estimates, not equipment approval. Review the assumptions below before choosing a system.
No location or tariff is detected automatically. All results use the values you enter.
What is this tool used for?
This sizes a solar thermal water heater, not electric solar panels. Water demand and temperature rise give a first estimate; tank and pipe losses, winter backup and local installation requirements need separate checks.
How this is calculated
Q = n × V × 4.186 × ΔT ÷ 3600; A = Q × (f/100) ÷ H ÷ (η/100); Vₜ = n × V × k; n = People; V = Daily hot water per person · L; f = Solar share of hot water · %; H = Daily solar irradiation · kWh/m²; η = Collector efficiency · %; k = Storage allowance
Before you use the result
This sizes a solar thermal water heater, not electric solar panels. Water demand and temperature rise give a first estimate; tank and pipe losses, winter backup and local installation requirements need separate checks.
Tool guide
This sizes a solar thermal water heater, not electric solar panels. Water demand and temperature rise give a first estimate; tank and pipe losses, winter backup and local installation requirements need separate checks.