Hybrid Water Heating: The Cost-Effective Route To Compliance?

Rinnai Director Chris Goggin espouses the financial and ecological benefits of adopting hybrid technology in heating & hot water delivery. Hybrid systems are an innovative decarbonising solution that provides a first step towards the limiting of emissions on projects that may not be able to fully adopt decarbonising technology.

Learn more about Rinnai Hybrid solutions and how they have delivered a practical, economical and technically feasible solution.

Learn About Hybrid Solutions

UK energy policy is aimed towards the reduction and eventual nullification of fossil fuels. During this transition away from coal, oil, petrol and high carbon gases towards renewables and alternative energies, how can the UK projects comply with future governmental policy in a retrofit environment and still ensure a plentiful supply of hot water?

A possible solution is to invest in a hybrid system that accepts two forms of fuel or power to ensure cost-effective and smooth operational performance that produces heat and hot water. What is a hybrid system and how do they operate to the benefit of the end-user.  

Hybrid technology that accepts two separate forms of fuel or power, one would be either natural gas or LPG for example, alongside solar thermal or a heat pump. Hybrid systems are designed to optimise factors such as outside temperature, current energy prices, property heating and DHW demand.

Rather than relying on one fuel source or technology such as renewable electricity and heat pumps, hybrid options instead use two forms of power or heat generators to complete daily functions inside commercial applications.

For smart DHW hot water systems such as continuous flow water heaters used with heat pumps, the renewable heat generator provides the base load as the water heaters “top up” the temperature. This approach is inherent within the system and ensure optimal performance. 

Using two separate energies offers a range of benefits for UK retrofit projects. The first advantage is from a financial viewpoint: as electrical costs are higher than natural gas, utilising a system that accepts both renewable electricity and traditional fuel sources means that costs could be lower and more manageable when compared to an exclusively electrical system. From a capital expenditure perspective, the cost of a hybrid is often lower than a full electric system creating lower whole of life costs.

In terms of operational performance, a hybrid heating and hot water system combines two technologies that ensures energy efficiency whilst supporting operational consistency. A hybrid system will benefit from the incorporated heat pump or solar thermal technology during favourable weather conditions whilst using the auxiliary appliance during periods of colder conditions. This will optimise the strengths of each technological approach in separate weather condition circumstances; the addition of a combustion-based water heating technology will boost the renewable base load to ensure DHW performance.

A further benefit for the end-user is that both lifecycles of each technology is lengthened. As each technology does not have to apply full effort to satisfy demand, component and overall system longevity will be increased due to a lessening of required workload.

Hybrid systems offer a practical route for environmental objectives to be accomplished. As not all customers can fully financially commit to decarbonising practises, an alternative mix of technologies that incorporates both renewable and traditional technologies and fuels is offered to bridge this gap. This practical approach introduces customers to alternative and clean energies whilst maintaining control over energy costs by still relying on conventional and more cost-effective methods of energy usage.

The Hybrid approach can also be instrumental within buildings that do not have the space, infrastructure or plant room facilities for full electrication and the increase in store hot water volumes.

A hybrid system is comprised of several features, components, technologies and fuels. The main elements of a hybrid heating and hot water system is listed below.

• Heat Pump: The renewable backbone of the system. Most hybrid systems utilise air source heat pumps (ASHPs). Ground source heat pumps (GSHPs) are also viable for specific applications, particularly in commercial settings.
• Condensing Gas Boiler / Water Heater: A high efficiency water heater serves as the auxiliary heat source. Modern condensing water heaters are designed to extract as much heat as possible from combustion gases, increasing energy efficiency.
• Solar Panels: When solar thermal collectors are included, they can contribute heat to the system directly or to a buffer tank. This heat can then be drawn upon before the system calls for either the heat pump, gas boiler and water heaters making it more energy efficient.
• Control Unit / Smart Thermostat: The 'brain' of the hybrid system, responsible for deciding which heat source to use based on real time conditions. Many units are integrated with weather compensation and predictive algorithms.
• Buffer Tank / Hot Water Cylinder: Optional but recommended for systems that provide domestic hot water (DHW). The buffer tank helps to smooth out demand fluctuations and improve efficiency. Other cylinders can include buffers for minimum water content and for additional hot water demand.
• Sensors and Meters: These measure temperature, flow rates, and energy consumption, feeding data back to the control system to enable automated switching.

Hybrid system water heating is a viable method of cost and carbon reduction that offers seamless operational performance. UK customers who cannot afford to fully comply with current UK decarbonising energy policy should consider investing in hybrid technology that can provide hot water for either a domestic or commercial dwelling.

Contact the Rinnai design team for a free of charge site assessment for your next project​.

Help Me Choose Product

Rinnai offers clear pathways to lower carbon and decarbonisation
Plus customer cost reductions for commercial, domestic
And off-grid heating & hot water delivery and off-grid heating & hot water delivery

• Rinnai’s range of decarbonising products - H1/H2/H3 - consists of hot water heating units in gas/BioLPG/DME, hydrogen ready units, electric instantaneous hot water heaters, electric storage cylinders and buffer vessels, a comprehensive range of heat pumps, solar, hydrogen-ready or natural gas in any configuration of hybrid formats for either residential or commercial applications. Rinnai’s H1/2/3 range of products and systems offer contractors, consultants and end users a range of efficient, robust and affordable low carbon/decarbonising appliances which create practical, economic and technically feasible solutions. 

• Rinnai is a world leading manufacturer of hot water heaters and produces over two million units a year, operating on each of the five continents. The brand has gained an established reputation for producing products that offer high performance, cost efficiency and extended working lives. 

• Rinnai products are UKCA certified, A-rated water efficiency, accessed through multiple fuel options and are available for purchase 24/7, 365 days a year. Any unit can be delivered to any UK site within 24 hours.

• Rinnai offer carbon and cost comparison services that will calculate financial, and carbon savings made when investing in a Rinnai system. Rinnai also provide a system design service that will suggest an appropriate system for the property in question.

• Rinnai offer comprehensive training courses and technical support in all aspects of the water heating industry including detailed CPD’s.

• The Rinnai range covers all forms of fuels and appliances currently available - electric, gas, hydrogen, BioLPG, DME solar thermal, low GWP heat pumps and electric water heaters More information can be found on Rinnai’s website and its “Help Me Choose” webpage. 

Rinnai full product availability 24/7 for next day delivery of all hot water heating unit models including 48-58kW units.

Average savings of:

20% REDUCTION of Opex cost

30% REDUCTION of initial cost

15% REDUCTION in carbon

75%    REDUCTION of space

For more information on the RINNAI product range visit our website.

Visit Rinnai