The Apricus evacuated tube design does not circulate water through the evacuated tube so if a tube is damaged, you will not experience any leaks. In fact, on a 30 tube system, even if you lost 3 x tubes from a branch or similar object falling on the collector, you will only lose 10% of your solar heating capability. The tubes are easily replaced by simply unclipping at the base, sliding the old tube out, and replacing with a new tube. In most cases, the copper heat pipe inside the tube will not need replacing.