So just how loud is the dcbel Ara when it's in operation? The HES (Home Energy Station) produces a low hum of around 50 db – the equivalent volume of a flowing stream.
Given that the unit is typically installed in the garage or on an exterior wall, noise isn't as much of a concern as it would be for units inside the home. However, the unit may generate more noise than usual when installed in hot regions, as the noise is usually generated by cooling fans.