Evacuated Tubes

Evacuated Tube Solar Hot Water Systems

Once you see an evacuated tube in action, you will truly understand how they can smash your hot water heating bill.

Multiple colletcors of evacuated tubes used in solar hot water applications
Free heat from the sun
Easy to install
Heating Solution (2)
No job to big or small
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Are Evacuated Solar Hot Water Tubes the Right Choice for You?

Key Benefits of Evacuated Tubes

  • 92% efficient.
  • No moving parts. Made from Glass and copper there is little or no maintenance needed. Ever!
  • Passive tracking. The round shape of the glass means the sun will always be hitting the tube straight maximising the solar gain.
  • Pitching frame included. If your roof is flat, there is no need to purchase extra frame parts. they are all supplied.
  • Stainless steel frame. made from Structural stainless steel and powder coated for extra protection.
  • Multiple sizes. 20, 24 or 30 Evacuated tube manifolds available.
  • 15 Year warranty.

Designed in Australia

Evacuated tubes were invented to minimize heat loss in solar hot water heating typically experienced with Flat plate solar collectors. The construction of a flat plate collector uses a piece of glass to allow the heat into the collector but struggles to stop heat leaving the collector as glass is not a good insulator.

Evacuated tubes use 2 layers of glass with a vacuum in between the 2 layers. The outer glass is made of borosilicate glass which is very pure and does not contain any metal or materials that can become hot. The glass has very low thermal conductivity meaning it does not get hot. All the heat in the form of radiation that passes through the glass, does not get absorbed by the outer glass and is allowed to pass through it to the inner glass. The inner glass has 3 coatings of heat absorption and transfer material that takes the radiation and becomes hot. To learn more about close coupled/evacuated tube solar hot water click here.

Evacuated Tube Solar Hot Water

Here are some of the specifications of an evacuated tube solar system.


For Domestic and commercial applications

Exegi solar offers a range of close coupled evacuated tube solar hot water solutions to suit any situation. Tank sizes for the on roof systems are 165ltr with 20 tubes, 200ltr with 24 tubes and 250ltr with 30 tubes. For larger requirements the tanks can also be connected together in a manifold.

Low pressure stainless tank with a high pressure heat exchange coil

The water in the storage tank is separate to the water used at the tap. When hot water is needed, cold waterenters the submerged 30 mtr x 14mm-copper heat exchange coil, which runs down the centre of the tank, extracts the heat from the stored water instantly, and exits the tank hot. Having a low-pressure tank means that the system can be connected to a wood fire booster and elevates the issue of a PTR valve dumping heat from the tank once it reaches 100Deg C. The excess energy is vented to atmosphere via a open 3/4” fitting.

“Wet tubes” use the sun’s energy to directly heat the water in the tubes

The tubes are full of water and sealed to the storage tank using a triple silicon O-ring. The sun heats the water in the tubes directly then thermosyphons into the storage tank. No need for pumps or controllers.

Evacuated Tube Information

Ideal for wet backs/wood heaters

To connect a wood fire boosted solar hot water with a wet back or any wood boiler, the tank must be open to atmosphere. A fire is an unregulated heat source and cannot be under pressure. The close coupled system have flow and return ports built into the tank so a wood fire can be directly connected without the use of an external heat exchanger.

Great flexibility for boosting options

Wood fire boosted.

Electric element boosted. 2.4KW

Gas instantaneous boosted. 65 deg or 50 deg booster can be used.

Pre heat system to either an existing electric or gas storage system.

Best suited to metal roofs

The close coupled evacuated tube  systems come with either a 15 deg pitching frame for pitched roofs,  or a 40 deg pitching frame for flat roofs. A tile roof can be suitable but extra care is needed in mounting the frame as the weight on the roof can crack the tiles. We do stock metal top hat battens and also special long threaded bolts to mount to tile roofs. Please ask for more details.

Suitable for high frost areas

The evacuated tubes are frost resistant to Negative 30 Deg C.

10 year manufacturers warranty on tanks frames and tubes

The Parts Involved

Heat exchanger

The close coupled evacuated tube system uses a 30 mtr 14mm copper coil to transfer the heat from the low pressure storage tank to the mains pressure water used in the house. As the water enters the tank through the mains water supply line, it passes through the heat exchanger and extracts the heat instantly.


Low pressure storage

Having a low pressure storage tank with high pressure heat exchange has many benefits.


No legionella risk.

Open vented to safely relieve the pressure from the water expanding due to heat.

Wood fire boosting ready.

Low manufacturing costs.

Wet tubes

Exegi Solar uses 1800 x 58mm high quality evacuated tubes with tri coating technology.  Our split system manifolds use the same evacuated tubes combined with a heat pipe. Wet tubes are directly heated by the sun and transfer the heat to the water that is in the storage tank using a thermosyphon.


Mounting frames

The on roof system comes with either a low (15 deg)  or a High (40 deg) pitching frame.  The low frame is designed for existing pitched roofs and the high frame is designed for flat roofs or ground mounting.


Solar powered tank filling kit

The low pressure storage tank is kept full using a 12 volt solar powered solenoid coupled with a stainless steel Reed switch float. If the tank water level drops due to evaporation, the float opens the solenoid and lets water enter the tank. Once the tank is full again, the float rises and shuts the solenoid, turning off the water. All powered by the sun!


Every solar hot water system needs boosting in the winter as the days are shorter and the solar radiation is less due to the sunlight passing through  more atmosphere.

The close coupled heat exchange tank can be boosted using any of the following:

  • Gas instantaneous
  • Electric element
  • Wood fired wet back/boiler
  • Heat pump
  • Read Less.

How do Evacuated Tubes Work?

Evacuated solar tubes were first designed in Australia over 30 years ago and the basic design has not changed much over that period.

They work by absorbing the suns energy in the form of UV rays and convert that energy  into thermal energy using  conduction.

Each tube works independently and is over 93% efficient in capturing the suns energy.  This extraordinary efficiency is only possible due a vacuum within the tube that acts as an insulation barrier between the internal tube and the external air.  The internal layer of glass has three coatings to help with heat absorption and transfer and the external layer of glass is clear to let the heat pass through it. The insulation layer ensures that the heat entering the tube does not escape again. An evacuated tube can be over 200 Deg C on the inside but the external layer of glass will be within a few degrees of the ambient air temperature. Read More

The 2 Types of Evacuated Tube Solar Hot Water

Wet Tubes/flooded tubes

A ‘wet’ or ‘Flooded’ evacuated tube is full with water and the suns heat is directly transferred to the water within the tube. That heat is then thermosyphoned into a solar hot water storage tank.

Heat pipes/Dry tubes

A dry tube uses a heat exchange within the tube to transfer the heat from the internal layer of glass to the water. Within the tube there is a aluminium fin and a copper pipe. When the inner glass layer warms up, the heat is transferred through the aluminium fin to the copper pipe. The copper pipe is sealed and has a small amount of liquid inside it that boils at around 40 Deg C. When the liquid boils, steam is created within the pipe and the steam rises to the top of the copper pipe. The end of the copper pipe has a bulb that fills with steam and then transfers the heat to a copper manifold that is holding the liquid to be heated (usually water). As the water extracts the heat from the bulb, the steam condensers and the liquid runs back down the copper pipe to be reheated again. Once the water in the manifold is 8 deg C hotter than the storage tank, the solar heat pump will turn on and bring the solar heater water down to the storage tank.

Get Your Solar Hot Water Tubes from Exegi Solar

A solar tube hot water system is an incredible way to save money on your energy bills while also protecting the environment from the effects of global warming.

These systems need to be sourced and installed by professionals for the best results. As industry leaders, Exegi Solar is able to provide you with the very best solar hot water tubes and systems. To give you a better idea of why so many homeowners across Australia decide to work with us, here’s a closer look at what sets us apart from our competitors.

Competitve Pricing On All Our Solar Water Heater Tubes

The prices on our solar water heater tubes are the most reasonable that are available on the market. We are able to offer reasonable prices thanks to our decade of experience in sourcing the best materials from a range of different suppliers in the industry. The parts have been designed to include cost-effective materials while excluding moving parts, making our offering very attractive.

If you would like to find out more about our pricing, then you are able to visit our website to find out more. You can also reach out to our helpful team for a full quotation that is catered to your specific needs.

Generous Warranty On All Our Solar Tube Hot Water Systems

When it comes to solar hot water tubes, Australia homeowners decide to trust us thanks to our generous ten-year warranty. This means that you can enjoy your solar hot water system safe in the knowledge that it will stand the test of time and continue to drive value for you in the long-term.

The warranty that we offer is comprehensive and is only needed in the rarest of cases, given that all of our systems are compliant with the standards outlined by the Australian government. They also bear watermark certifications, so you know they are the best of the best.

Our Team Are Experts in Solar Water Heater Tubes

We have been operating our business for over seven years now, meaning that we have been at the forefront of an exciting and innovative industry. This means that we have not only developed the most attractive product and pricing, but also harnessed our abilities. Our sharp skills mean that we can safely, effectively and quickly help you install your system.

Our superior workmanship means you can have complete faith in your system and that it will continue to return a maximum yield for many years to come.

We understand that making the decision to install one of our systems is a big one, which is why we work to ensure that you’re as comfortable as possible throughout the entire process. Our team places you and your needs above all else, so our customer-centric approach gets great results every time.

Questions About Our Solar Tube Hot Water Systems?

If you would like to learn more about us and our systems – our solar tubes in particular – then visit our website today. You’ll find a wealth of information and also learn how to take the next steps with us. Our helpful representatives are here every step of the way, so if you have any questions or concerns then don’t hesitate to get in touch with us. Read Less

Capture then store the heat

The heat is then transferred using conduction to the water or liquid that is being heated. Once the heat is in between the 2 layers of glass, the vacuum does not let it out as a vacuum is an amazing insulator.  Sounds confusing? Well yes but the main points are the heat can get into the tube but not out again. This efficiency gives an evacuated tube an efficiency of above 92%. Meaning that 92% of the heat that hits the tube goes in, but does not come out again.

92% Efficient!

Try touching an evacuated tube on the outer glass that is in the sun, it will be almost exactly the same temperature as the air. PLEASE DO NOT TOUCH THE INNER GLASS! The inner glass can reach temperatures of over 250 Deg C in a matter of minutes.  Yes, 250 Deg C! Even on a 15 Deg day with clear skies.  The air temp does not affect the efficiency of the tube because of the vacuum. It’s all about the power of the sunlight.

Will you be part of making the change?

We all know that we need to make the switch to renewable and sustainable consumption. Generating Hot water is one of the biggest energy consuming processes in a home and there is technology available NOW that can minimise our impact. Invest in becoming part of the solution.