Evacuated Tube Hot Water Systems

Residential House with Apricus System

Evacuated tube solar hot water systems are the smartest residential water heating solution available today. While flat panel solar hot water systems were a great start at the time, they are really not much more than a black water hose (behind glass) on the roof. Evacuated tubes offer a number of significant advantages


  • The round shape of the tubes works like a passive sun tracker resulting in extended heating periods and therefore better performance.
  • Evacuated tubes can extract the heat out of the air and do not even require direct sunlight.
  • The vacuum in the tubes allows solar radiation to penetrate, but prevents heat from coming out (in fact, the tubes stay cool to touch).
  • The water only flows through the heat exchanger at the top (known as the manifold) which is insulated.
  • The thick insulation inside the manifold allows operation in frost prone locations (to -15°C).
  • The low weight / low maintenance / modular design allows installation by a single person (licensed plumber).

How do evacuated tube solar hot water systems work?

Each tube contains two layers of toughened glass separated by a vacuum. The tubes absorb and retain heat from the atmosphere. Inside the tubes are evacuated copper heat pipes that carry a small amount of liquid. The liquid boils at a very low temperature and vaporises to the top. At the top of the pipe, inside the manifold, is the actual water pipe, absorbing the heat from the condenser of the heat pipe. A slow flow circulation pump moves the water through the manifold to the insulated storage tank. View a short animation.

Evacuated tubes explained - (c)Apricus

  1. Evacuated tube absorber layer receives incoming solar radiation.
  2. The absorber moves energy to the copper heat pipe where energy is stored by the working fluid.
  3. The working fluid boils (at ~30°C), turns to vapour and rises to the heat bulb at the top.
  4. The heat bulb transfers energy into the water as it passes by through the manifold.
  5. The vapour cools, condenses and returns to the base of the heat pipe where the process is then repeated.

How to proceed?

Rainbow Power Company only supplies solar hot water systems; we do not install. Have a look at our selection of solar hot water systems in our online shop or compile an Apricus system yourself by answering a few questions to get an instant quote for materials only (excluding pipes). All our prices exclude STCs. To generate STCs, installations need to be carried out by a licensed plumber. If you live in the Northern Rivers, we can refer you to one of our affiliated tradies.

We install solar systems in Northern NSW and Southern QLD.

Gold Coast (from Coolangatta to Southport), Nerang and Hinterland (Beaudesert) and out West (Warwick, Stanthorpe, Killarney)

Northern NSW (Tweed Heads to Yamba, including Evans Head, Byron Bay and Ballina); the Far North Coast Hinterland (Grafton via Lismore to Murwillumbah) and out West (Casino to Tenterfield, including Drake and Tabulam, as well as Woodenbong and Bonalbo)

For larger system we also go up to Brisbane or down to Coffs Harbour and even Glen Innes. Other places by arrangement.