Aquecimento solar — L quentes/dia
- 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 daily hot water production of a solar heating system based on the collector area. The standard ratio is approximately 1 square meter of collector for every 50 liters of hot water per day, considering average solar radiation conditions in Brazil.
The calculation is simple: enter the total collector area in square meters, and the calculator multiplies by 50 to get the estimated liters per day. For example, 4 m² yields about 200 L/day. This value serves as an initial reference for sizing residential or commercial systems.
Use this tool when planning a solar water heater installation, whether for showers, pools, or industrial processes. It helps determine how many collectors are needed to meet your hot water demand, reducing electricity or gas costs.
Important: actual production varies with geographic location, season, panel orientation and tilt, shading, and system efficiency. The 50 L/m²/day value is an average; in less sunny regions, it may be lower. Consult an engineer for a precise design.
Frequently asked questions
What is the basis of the 1 m² to 50 liters per day ratio?
This ratio is a practical average for Brazil, based on typical solar radiation and flat plate collector efficiency. Exact values depend on your region and collector type.
Can I use this calculator to size a system for a pool?
Yes, but pools require large volumes and lower temperatures. The collector area needed may differ; consult a specialist.
What if my hot water demand is higher than calculated?
Increase the collector area or consider a hybrid system with electric or gas backup for cloudy days.
Does roof tilt affect the result?
Yes. The ideal tilt for maximum production is roughly the local latitude. Deviations reduce efficiency, lowering the liters per square meter.