Integrating solar into existing heating systems

Solar heating systems - reducing boiler energy consumption

The components we use in water systems see the highest demand and strain during the summer months and into the early stages of autumn. This is due to the seasonal increase in water consumption. There is also an increasing focus for homeowners to find efficiencies in order to save money during these peak demand periods.

Altecnic has been helping installers deliver these benefits to homeowners for over 30 years. Through new technology development and by providing quality approved, assured, accredited products, Altecnic is a brand to be trusted.

Integrating Renewables Into Existing Heating Systems

A popular solution to a homeowner’s desire to save long term has been the drive towards integrating renewable heat sources into existing building technologies. One way of achieving this is through the use of the suns natural heat, or solar thermal as it is known. Importantly, the installation of a solar thermal system does not necessarily mean the removal of a home’s existing combination boiler or hot water cylinder.

The Caleffi 262-263 series of storage to boiler connection kits allow for a smaller thermal store panel system to be installed to provide peak demand hot water. This hot water is heated by the solar panels and in the event that the sun is not sufficient to heat the store, this cooler water is diverted via the existing combination boiler to be heated to the correct safe temperature. This process saves fuel consumption as the water is preheated and the combination boiler doesn’t have to increase the water temperature so much.

Image of Caleffi 262 Series Boiler Connection Kit on white background

Caleffi 262 Series Boiler Connection Kit

The storage to boiler connection kits can be, either driven by electronic thermostat control or by the more conventional thermostatic mixing valve elements and are supplied in a number of formats. Innovative use of either two or three temperature sensing elements means that water is diverted to each relevant store or boiler accurately and efficiently.


Safety is paramount when dealing with and distributing heated water, therefore each unit is able to correctly protect the end user against scalding and legionella risks.

Reducing Scalding Risk

In solar thermal systems with natural circulation in the primary circuit and a water storage with heating jacket, the temperature of the domestic water in the storage can vary considerably depending on the degree of solar radiation and can reach very high temperatures over long periods. In summer, and if there is little water usage, the hot water at the storage outlet can actually reach temperatures around 98°C before the temperature and pressure safety relief valves are actuated. At these temperatures, the hot water cannot be used directly, because of the danger of scalding for users. Water temperatures over 50°C can cause burns very quickly.

It is therefore necessary to use a thermostatic mixing valve able to:

- reduce the temperature of the water distributed throughout the domestic water system to a value lower than that in the storage and suitable for the end user.

- keep mixed water temperature constant despite variations in inlet temperature and pressure

- continue functioning over time without any loss in performance and without problems due to the continuously high temperature of the incoming water

- enable the high temperature water in the storage to last longer, by distributing it to the user circuit at a reduced temperature

- have an anti-scald safety function in case of failure of the cold water supply.

Thanks to innovations in valve technology we are now able to integrate renewables into existing homes meaning the ability to be more efficient as installers and homeowners is easily accessible. Altecnic and Caleffi have a proud history of not only developing new market technology but also in supporting existing systems.