Clever Tech Turning Hydronic HVAC Systems into Energy-saving Powerhouses

Reducing the energy consumption of buildings doesn’t have to be complicated or prohibitively expensive, as a new approach to cutting fuel bills and lowering carbon emissions is demonstrating, says Dominic Wish, HMX UK’s Technical Director.


Hydronic heating and cooling systems (those using water as their primary heat transfer fluid) are at the forefront of a movement that is delivering energy and carbon savings of between 20 and 35%, with some projects returning savings far in excess of this. The average ROI is under two years.

The approach is simple – replace water in hydronic systems with a fluid that has superior heat transfer properties. Not only does the heating or cooling system reach the desired temperature more quickly (therefore, using less energy), but cycling is reduced, offering the potential of increased equipment lifespan and lower maintenance requirements. It’s a win-win situation and can even negate the need for new plant if increased heating/cooling is required.

In many ways, it’s an obvious solution to make commercial heating and cooling systems (and even water-based solar panel systems) work more efficiently. However, applying fluid technology to this area has been largely overlooked until now, and it’s challenging clients, specifiers and contractors to reconsider a fundamental element of HVAC systems.

How it works

The fluid replacing water in HVAC systems in the UK (and globally) is a cutting-edge heat transfer solution harnessing the power of nano-technology to improve thermal conductivity. It’s an accepted scientific principle that material properties change as size approaches the atomic scale, with surface-area-to-volume ratio increasing. A cup of nanoparticles offers roughly the same surface area as almost two football pitches, and increased surface area equals increased heat transfer capability.

Nanoparticles are already an established technology delivering benefits in a variety of fields, from paints to glass, aerospace to medicine and even school uniforms. Their use isn’t new within heating applications, but scientific advancements mean these tiny particles are now delivering substantial environmental and cost-saving advantages. Sound scientific principles support their use, and worldwide installations demonstrate results.

The approach is compatible with most HVAC systems, and no major plant or system changes are required. The nano-tech fluid itself is non invasive, inert, recyclable and guaranteed for 20 years. Depending upon the application and system characteristics, it will normally deliver energy, carbon and cost savings of between 20 to 35%.


There are two key elements to installation – assessing system volume and ensuring it is clean (which usually means flushing to remove sludge and inhibitors. This process can also help ascertain volume, if unknown) and in good condition with no leaks. Remedial work – for example, installing thermostatic radiator valves where appropriate – should be carried out prior to installation to ensure increased heat output can be managed. It’s then simply a case of re-filling the system with a 50/50 mix of water and the nano-tech heat transfer fluid. Boiler sequencing/thermostats will need adjusting accordingly post installation.

The hi-tech nano-fluid is suitable for almost any building utilising a hydronic heating or cooling system – so data centres, hospitals, schools, accommodation blocks, public buildings, care homes, swimming pools, even ice rinks, commercial greenhouses and social housing. It is a warranted direct replacement for water and inhibitor.


The nano-technology has been utilised in more than 30 buildings for one UK organisation committed to net zero, starting with a pilot project of five properties. Of these, three recorded before and after energy usage, revealing gas consumption savings of between 37.5 and 47% from November 2022 to January 2023 when compared to the previous year (with an HDD – Heating Degree Day – calculation applied). ROI ranged from 1.42 years to 2.18 years. It should be noted that the buildings had TRVs fitted (some post installation of the nano-tech heat transfer fluid because occupants were complaining of being too hot), and the organisation demonstrated a significant focus on energy saving, leading to these outstanding results. Feedback included comments that one of the buildings “felt hot rather than lukewarm” and that comfortable heating levels were achieved in areas that had previously been hard to keep warm. Reduction in carbon emissions is estimated to be around seven tonnes per site.

The Empire State Building in New York was an early adopter of the technology and is in the process of converting more of its hydronic systems to nano-tech heat transfer fluid. In addition, the Empire State Realty Trust has installed it into cooling circuits; two years ago, as part of an extensive upgrade, the trust installed it in an 11,000-gallon primary chill-out loop in a 25-storey office building that has two 350-ton electric chillers.

Tim Dailey, Director of Engineering for the Empire State Building, said: “We used to run both full out on a hot day, but now we never need to run the second chiller. The chillers are much more efficient machines, and the electrical use of the central plant is basically half what it was. Pumping is down, chillers are down, and a chiller reaches its sub point faster.”

In California, the technology has improved the efficiency of hydronic solar panels, with a test project at California State University showing ‘near-immediate efficiency gains’ when the loop was switched to a nano-tech heat transfer fluid. A university spokesman said: “From the data, it looked like we were getting an increase in productivity when we switched the fluids. While running on glycol, the capacity of each solar panel maxed out at around 105 Btu. With Hydromx (the nano-tech fluid), the capacity of the panels increased immediately to 120 Btu.”


The addition of nano-tech heat transfer fluid to HVAC systems speaks to net-zero strategies, decarbonisation targets, legislative drivers, reputational benefits, CSR ambitions, fuel poverty and the overall management of energy bills. The approach is also suitable for geothermal, solar and heat recovery applications and perhaps more that we have yet to identify. Compared to many energy/carbon-saving initiatives, it is relatively straightforward and offers substantial savings with attractive ROI rates.

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