Addressing The Costs of Low Carbon Hot Water in Care Homes

The guaranteed provision of safe and appropriately heated water isn’t just a convenience; it’s a fundamental necessity in care homes for the health, dignity, and comfort of residents, as well as the operational efficiency of the facility. In recent years, it has also become a key target for improving a building’s sustainability, as heating water can account for up to 30% of daily energy demands. 

Gas or Electric Water Heating

Gas-fired boilers and water heaters have long been the default choice for water heating due to their relatively low running costs and high output capacity. Natural gas has traditionally been cheaper per unit of energy than electricity and remains so, making it an economically attractive option for care facilities with high, continuous hot water demands. However, the significant drawback of gas heating lies in its carbon emissions. With increasing pressure to decarbonise buildings and meet net-zero targets, gas connections are typically precluded from new build yet remain the most popular choice for cost-conscious retrofit projects. The latest generation of water heaters is designed to provide universal connections for easier replacement and, importantly, introduce high-efficiency burners and controls to minimise energy consumption and reduce emissions. While a less sustainable long-term solution, the technology is recognised as a bridge to potentially important future green gas alternatives such as hydrogen. Most new gas water heaters will support the use of blended hydrogen without requiring any mechanical alterations, so they offer a future-proof option good for the next 15 years or more.

Direct electric water heaters at first sight seem to offer a simpler installation and zero on-site emissions. They don’t require flues or gas lines, which can simplify building design and reduce maintenance complexity. This makes them appealing for smaller demands or as supplementary heaters. However, their major disadvantage is higher running costs. Electricity is expensive, currently fluctuating between four or five times that of gas per unit of energy, and direct electric water heating converts all electrical energy directly into heat, making it less efficient from a primary energy perspective, especially when factoring in standing losses from instantaneous units such as those used for point-of-use supply. Such losses can easily exceed those seen in centralised (boiler room) systems, which inherently will have some energy loss from the secondary return. For a large care home with substantial hot water needs, relying solely on direct electric heating can lead to prohibitively high energy bills. The “cleanliness” of direct electric heating is also dependent on the electricity grid’s energy mix; if the grid is powered by fossil fuels, and the UK continues to depend on gas for electricity generation, the emissions are simply shifted upstream.

Sustainable Alternatives for Water Heating 

In care homes demands of operational costs and sustainability need not be mutually exclusive. Sustainable alternatives, notably air source heat pumps and solar thermal, both offer the means to enhance existing gas or new electric systems. Combining technology to create a ‘hybrid’ system design has been used across the commercial sector to solve complex building design and water heating needs. The approach demanded bespoke application design and therefore greater capital investment. Today, it is possible to offer hybrid systems that are designed and pre-configured to allow for an ‘off-the-shelf’ alternative. Adveco has been championing this approach with its award-winning FUSION system that combines a cylinder (the battery of the hot water system) along with an electric boiler (primary heat source) and the option of an air source heat pump (ASHP), which generates up to 70% of the necessary system energy as preheat. This offsets the energy demands, costs and emissions of the direct electric-powered boiler. An optional electric immersion ensures there is no single point of failure for an assured year-round supply of hot water.    

For every unit of electricity consumed, an ASHP can produce two to four units of heat, making them significantly more efficient than direct electric heating. However, for high-temperature, high-demand systems such as those used in care homes, ASHPs will consume more electricity themselves, so there are implicit operational costs. This is why it is so important to correctly size a system, easily achieved by metering use in an existing system and accurately calculating daily demands throughout the year. Heat pumps are costly, so avoiding oversizing delivers immediate capital savings if transitioning away from gas, for example, and ensures operational costs remain lower. 

ASHPs are ideal for care homes looking to significantly reduce their carbon footprint and should be considered during all new builds or major refurbishments where the building’s hot water distribution system can be optimised to work efficiently with the lower flow temperatures ASHPs typically produce. It is also worth adding a word of caution regarding new R290 high-temperature heat pumps, as these rely on propane as a refrigerant to extract heat from cooler ambient air. Regulations have yet to catch up with the increased use of propane in heat pumps, which recently led the Building Engineering Services Association (BESA) to issue a warning about the increasing safety risks associated with the use of flammable refrigerant gases.

The safest alternative is to use solar thermal systems to harness the sun’s energy to heat water directly, offering a truly renewable and zero-emission source of hot water. Flat plate collectors installed on or into the roof of a care home will absorb solar radiation and transfer the heat to a glycol fluid, which then heats the water in a storage cylinder via a heat exchanger. Though affected by seasonal availability of sunlight, in the UK, a correctly designed, compact solar thermal system will offset at least 30% of a building’s annual energy requirements for hot water. Highly efficient, lower cost and low maintenance, solar thermal currently also offers one of the shortest periods for achieving a return on investment. 

Ultimately, the necessity of hot water in care homes demands a response that is not only reliable and safe but also economically viable and environmentally responsible. A strategic, holistic approach to system design, embracing efficient and renewable technologies, is crucial for providing the best possible care while navigating the evolving landscape of energy costs and climate commitments. As with any major project work, talk to an expert first; the answer could well be far cheaper and less disruptive than you imagine, and the gains considerable.