Quick Answer
Calculate the ideal inverter size by multiplying the total AC power requirements of your system (in watts) by a derating factor, usually 1.2 to 1.5, to account for inverter efficiency and other losses.
Understanding System Requirements
To calculate the ideal inverter size, you need to determine the total AC power requirements of your system. Start by calculating the maximum AC power requirements for your tiny home in watts. Consider factors such as appliance loads, lighting, and heating/cooling systems. For example, if your home has a 10 kW heater, a 2 kW refrigerator, and 1 kW of lighting, the total AC power requirements would be 13 kW. However, it’s essential to derate this value to account for inverter efficiency and other losses.
Derating for Inverter Efficiency
To derate the AC power requirements, multiply the total by a factor between 1.2 and 1.5. In this case, a derating factor of 1.25 would be applied. Multiply 13 kW by 1.25, resulting in a total derated power requirement of 16.25 kW. This value represents the minimum inverter size needed to handle the system’s requirements.
Choosing the Right Inverter Size
When selecting an inverter, consider the system’s derated power requirement and the inverter’s maximum output capacity. A rule of thumb is to choose an inverter that is at least 10-20% larger than the system’s derated power requirement. In this case, an inverter with a minimum capacity of 18 kW would be sufficient. However, be aware that a larger inverter will also be more expensive and may require additional electrical infrastructure to support it.
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