Solar technology explained

Standard-System-SchematicFor those who do not fully understand the concept and operation of a solar thermal (hot water) system, Comfort Solutions Ireland have prepared an explanation in simple language, of a standard solar system, from the sun hitting the solar panels or tubes on the roof to the hot water in your taps. We hope this gives you a good understanding of the basics of our solar thermal systems. If at any point, you have any questions or would like a site survey or quotation for your home or business, please contact us.


Please note: It is extremely important that your solar hot water system is installed by competent and experienced installers. Solar hot water systems handle exceptionally high temperatures which can be highly dangerous if not correctly managed. Ensure your installer is fully qualifed in solar thermal systems and can prove accreditation.



DSC00135From the diagram we can see that a solar water heating system is really very simple. On the roof of the house there is a solar collector often called "solar panels". These are usually a dark blue colour (best at absorbing heat), with a network of pipes within containing water, and a glass cover on top. The panel absorbs the sun's heat, which is then absorbed by the water. The glass cover allows the sun's rays through, but traps a layer of air to insulate the panel from the atmosphere outside. This means that the panel can produce hot water even in cold air temperatures, so long as the sun is shining. More elaborate panels take the form of glass evacuated tubes with metal pipes inside, and these tend to be more efficient than flat panels especially in low-light or cloudy conditions ie. they do not require direct sunlight to work effectively. Good quality solar panels and tubes will last at least 25 years with minimal maintenance.


The water in the panel is moved through a closed loop of pipework by a water pump. The pump uses very little power, generally around 25 to 50 Watts of electricity. Although these systems do use electrical energy, the energy harnessed from the sun far exceeds consumption. More expensive systems might use a photovoltaic panel (Solar PV) to generate electricity from the sun, which is then used to run the pump.

Expansion Vessel

As the water in the system heats up and cools down, it expands and contracts. In order to keep the pressure in the system fairly constant, an expansion vessel is fitted which compensates for changes in water volume due to temperature. The pressure used is only around 2 BAR, which is not high enough to worry about.



The hot water generated by the solar system is generally transferred to a storage place in the form of a hot water cylinder. This is done using a heat transfer coil, which usually takes the form of a flat coil in the bottom of the cylinder. This is the coldest part of the tank, so the system can transfer heat into the tank even when sunshine is limited. In summer, this allows the solar system to heat the full cylinder of water, meaning that you shouldn’t need any oil, gas or electricity for water heating. In winter, your solar system will still work, although to a lesser degree. You will need your oil, gas or electricity to bring your cylinder up to full temperature, but they will have less work to do as the water will have been pre-heated somewhat by the solar heating system. Modern hot water tanks with these special solar heating coils are very efficient at transferring heat into the water, and only a little more expensive than a standard tank. They are also highly insulated, meaning that any energy gained is not easily lost but effectively stored until needed. Comfort Solutions Ireland use high quality stainless steel cylinders which carry a 25 year warranty.


The whole system is run by an electronic controller. This uses temperature sensors to work out when the panel is hotter than the water in the tank, so it knows when to switch the pump on and off. The controller is a very intelligent piece of technology and can also protect your system against frost, stagnation and other potential problems.

Hot water


It is important to realise that the water that comes out of your hot water tap has not been through the solar panel, it remains completely separate. This is partly because a pressurized, closed system is more efficient at transferring heat, and partly because the closed system must contain antifreeze to protect the panel from damage in cold temperatures. Using the same water through the system also protects system components against lime-scale due to minerals in water. You might be worried about the coil becoming damaged and leaking antifreeze into the hot water tank. Fortunately, this is not as big a concern as you might think. Solar water heating systems use a special kind of antifreeze called Propylene Glycol, which is a common non-toxic food additive. (Older systems used Ethylene Glycol, which is toxic when consumed, though minimally toxic through skin contact. The antidote is alcohol!) It also contains a lurid dye, usually luminous pink, green or yellow, which will alert you in the unlikely event of a leak. It may contain a special bitter chemical to stop you drinking it, although you shouldn't really be drinking from the hot tap anyway!


Solar-thermal water heating systems are becoming more and more cost effective due to recent rises in energy prices. Depending on the levels of sunshine where you live, and how much hot water you use, the system will generally pay for itself within 10 years, and sometimes less than 5. In addition, houses with eco-friendly features tend to stand out in the housing market and sell more quickly. You should notice an immediate fall in your fuel bills, particularly in summer. Costs may be offset even further if you are eligible for a government grant (See Grants section), which are still available to houses built before 2006. If you are looking for a way to reduce your carbon footprint and save money in the long term, solar thermal water heating could be perfect for your needs! 

Download our Solar Thermal leaflet below


For more information, updates on our latest technologies, or to have a solar system tailored for your home or business, contact us today.

Client Testimonials


Olive Kerrigan, Westport

Solar Thermal

Comfort Solutions provided a very professional service that resulted in the Solar System being installed on-time with minimum disruption and to budget.  A follow-up check was conducted to ensure everything was working correctly.

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Happy Customer, Newport

I decided to have the insulation of my 2005 built house checked after finding it difficult to keep the rooms warm during the bad winter of 2015/16. Draughts, cold spots and a boiler that was always on the go meant it was time to do something. After a lot of... Read more

Sean & Ann Tarmey, Ballintober

We found the house was difficult to heat and it became cold very quickly. Since the external wall insulation, attic insulation and new windows were installed, we have a much warmer comfortable home, and are making huge savings on our fuel bill. The colour render we chose on the exterior... Read more

Helen McLoughlin, Ballindine

Cavity Wall & Loft Insulation

I'm delighted with the service from Comfort Solutions! I would have no hesitation in recommending them to friends. My home is now so warm and snug - thanks Fergus


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Tom Healy, Ballinaboy

External Insulation & DPC

From start to finish my experience of Comfort Solutions has been very good. I found the Company to be first class in particular Fergus Mc Manamon. I am delighted with the final product and I am in no doubt we will see the benefit of it way... Read more

Dermot Lavelle, Westport

Cavity Wall & Floor Insulation

I thoroughly recommend Fergus and the team at Comfort Solutions. I recently had a cavity fill and underfloor insulation carried out at my father's house. As he is elderly and living alone, maximising heat conservation while saving on energy bills is of great benefit and it... Read more

Brian Mc Nulty, Wicklow

I had a pellet boiler installed incorrectly and after much searching, came across Comfort Solutions. While they didn't install the boiler initially, they re-installed the boiler correctly and corrected everything. I was not only impressed with the installation, but by the back-up and service afterward. I have no reservation in... Read more

Martin Roche, Ballinamore

External Insulation

I was very impressed by the no-nonsense approach of the contractor, the price was agreed the contract completion date set and I was kept informed of progress and problems at all stages of the contract, everything was completed on time with no extras, the site was cleaned up every evening,... Read more

Amy Healy. Glenisland

I upgraded the boiler in my home and needed a heating solution for my office which is in a separate building.
Comfort solutions advised on the best possible solution for my unique circumstance. I am delighted with my new heating system and the level of control it offers. I... Read more

Liam Moloney, Donegal

Energy Efficient Retrofit

Comfort Solutions were for me the ideal solution in providing a complete package of home energy and insulation improvements. I also appreciated their prompt and reliable service.

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