Depending on where you are in the country and the orientation of your solar panels, they may require regular cleaning. Panels should be cleaned in the early morning or late evening when they are not hot. Use a normal garden hose to simulate rain, do not use pressurised water blasters. Because there are no moving parts, your HRV Solar Solution requires very little in the way of replacement parts. Note that it is recommended under the New Zealand electrical standards that your system receive a review once a year. Call us on 0800 HRV 123 if you have any questions.