Economia kWh/mês solar térmico
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
This calculator estimates the monthly kWh savings provided by a solar thermal heating system. It converts the collector area into saved electrical energy, based on an average factor of 30 kWh per square meter per month. This value is an approximation for typical Brazilian conditions, considering the annual average solar radiation.
The operation is simple: you enter the total collector area in square meters, and the tool multiplies it by 30. For example, 4 m² results in 120 kWh/month. This energy corresponds to what an electric shower or other electric heater would consume to heat the same amount of water. It is a quick way to visualize the potential reduction in your electricity bill.
Use this calculator when planning to install a solar heater or evaluating an existing system. It helps quickly size the area needed to achieve a savings target, or compare expected performance with actual electrical energy consumption. It is especially useful for homes and small businesses looking to reduce water heating costs.
Important: the result is an initial estimate. Actual generation varies with geographic location, collector orientation and tilt, shading, season, and system losses. Use the value as a reference for planning, but consult a professional for a detailed calculation. Typical system losses can reduce savings by 10 to 20%.
Frequently asked questions
How many m² of collector do I need to eliminate my electric shower bill?
It depends on your monthly energy consumption for showering. Divide your kWh consumption by 30 to get the approximate area in m². For example, if you use 150 kWh/month, you need about 5 m² of collector.
Does this calculation apply to any region in Brazil?
The factor of 30 kWh/m²/month is a national average. Sunnier regions like the Northeast may generate more, while southern regions may generate less. Adjust the factor according to your location for better accuracy.
Can I use this calculator for pool heating?
Yes, but efficiency for pools is different because the target temperature is lower. The estimate still serves as a starting point, but specific pool factors are recommended, often higher due to larger heat exchange area.
What is the savings in reais with this system?
Multiply the saved kWh by your local electricity tariff. This calculator does not convert to reais, as tariffs vary widely by region and flag rates.
Does the result account for system losses?
No, the value is the estimated gross generation. Losses from piping, storage, and pumping can reduce effective heat delivery by 10 to 20%. Consider this when planning your system.