How to size a solar system for your home

Sizing a solar system is the single most critical step in your clean energy transition. Get it too small, and you will find yourself in the dark or constantly relying on the grid. Get it too large, and you are overpaying for capacity you will never use. The key to perfect sizing lies in three numbers: your Daily Energy consumption, your Peak Load, and your Autonomy requirements.

1. Daily Energy Consumption (in kWh)

This is the total amount of electricity your home consumes in a single day. You can find this on your electricity bill (average monthly consumption divided by 30) or by calculating the sum of all appliances you intend to run. For example, running a 150W refrigerator for 24 hours consumes 3.6 kWh, while ten 10W LED bulbs for 6 hours consumes 0.6 kWh.

2. Peak Load (in kW)

Peak load is the maximum amount of power your home draws at any given moment. This determines the size of your inverter. If you run your air conditioner, microwave, and water pump simultaneously, your peak load will spike. To keep your inverter size reasonable, learn to stagger the use of high-power appliances.

3. Autonomy (Days without Sun)

Autonomy is the number of days your battery bank can power your home without any solar recharge. In tropical regions, we typically design for 1 to 1.5 days of autonomy to cover heavily overcast or rainy days without depleting batteries beyond safe thresholds.