Sustainable & Cost-Effective Hot Water For Healthcare

Around 40% of UK greenhouse gas emissions are accounted for by lighting cooling, ventilating and critically, provision of hot water and heating for the built environment. To help achieve climate-neutral building stock by 2050 health organisations need expert support when it comes to implementing immediate and practical measures.

The impetus is to reduce construction impacts with whole life carbon assessments, and critically, reduce operational energy use, prioritising reduction in energy demand and consumption over all other measures. Addressing in-use energy consumption should reduce bills and save carbon by driving an increase in renewable energy supply and prioritising on-site renewable energy sources.

GP’s surgeries, hospitals and care homes will typically exhibit significant, but varied, hot water and heating usage patterns. As well as the need for sustainable, low emission technology, what cannot be ignored are the financial implications of these changes, whether in the form of new built facilities, or, and far more likely, the refurbishment of existing, yet ageing facilities. As a result, one of the most difficult challenges facing facility or energy managers across the healthcare sector is obtaining a clear indication of the total cost of ownership so that operational savings and payback periods can be factored into development investment.

The Path To Lower Carbon Hot Water

The design of applications for commercial hot water systems has remained remarkably consistent and if a building is more than ten years old it is going to be built around either a condensing gas water heater or an indirect water heater and boiler. Gas-based hot water systems were specified because this was the most cost-effective and cleanest way of producing high-temperature hot water.

In the past decade though we have seen a seismic shift in thinking driven by the wide acceptance of the harmful effects of global warming and a need to address its root causes. With the closure of coal-fired power stations and increasing dependence on wind and solar, the carbon intensity of grid electricity has reduced in line with gas, which has, in turn, remained relatively static since the 1990s.

With the Government’s aggressive new Net Zero Strategy, despite virtually identical carbon intensities for heating from either gas or electric, the latest regulations as outlined in the Heat & Buildings Strategy will deem gas systems alone to be too carbon polluting in commercial-scale buildings such as seen in healthcare facilities. To decarbonise domestic hot water (DHW) applications there are currently two core technology options, air source heat pumps (ASHP) or solar thermal. Although both can provide low or zero-carbon heat, neither can fully replace an existing water heating system. Since commercial DHW systems must operate in excess of 60°C to prevent the threat of legionella, ASHP efficiency, designed to work with lower temperatures, rapidly falls away limiting supply. Solar thermal on the other hand is limited by the sun’s availability across the year, and it is worth remembering will not provide space heating either. However, both can be used as a source of preheat to reduce energy use. Both will work equally well with after heat provided by gas or electric water heating.

For buildings already on gas and that rely on large amounts of DHW - a large proportion of current UK healthcare properties - solar preheat is the preferable option. Depending on the site and energy consumption habits, solar thermal will typically provide around 30% of the hot water demand.

For new build properties, the expectation is for specification to default to a mixture of heat pumps and direct electric afterheat. For new healthcare builds, consultants are specifying for greater electrical load to account for the additional power demands. This though is a costly addition for large legacy properties wanting to introduce electrification for hot water and heating.

The electrification of buildings is the most common vision, and one the Government is driving with its aggressive target to achieve 600,000 new heat pump installations every year by 2028. Many of these will be for domestic properties, but a considerable proportion will be expected to be introduced via building projects in healthcare. New DHW systems will predominantly follow this model, taking advantage of heat pump performance efficiencies to create a hybrid approach to deliver pre-heating for as much as 75% of the water in a direct electric system. And with no gas to the building, no local generation of NOₓ and no flue to install this clearly has its advantages, and this can include smaller scale system refurbishments which may be suitable for GP surgeries.

However, this approach does not factor in running costs.  While the grid may have reduced its carbon, its cost per kWh has risen consistently over the past two decades. Gas prices on the other hand have remained essentially static until the latter quarter of 2021.  Of course, a proportion of the grid electricity is still generated by gas-fired power stations, so electricity charges also spike in response to any upward fluctuation in gas price. Despite the ASHP performance efficiencies, this has meant the running costs still increase approximately three times due to the difference in current gas/electric prices. For smaller hot water demands in new builds, where the need for a gas supply has been avoided, that additional cost may be acceptable.

Ten years ago, it was very difficult to argue for introducing solar thermal because the numbers really did not stack up against the price of gas. The capital costs of installation and maintenance versus the operational savings meant many early projects failed to recoup their investment, even with the support from the non-domestic renewable heat incentive (which closed new applications in March of 2021). Today we are in a very different situation, and if electrical costs can be offset, then the numbers really start to look favourable for adopting solar thermal.

A ten-year return on investment becomes very achievable and the property gains undisputed carbon and cost savings. Additionally, the current generation of condensing gas water heaters incorporate features such as flow regulation to automatically optimise the supplied output from the heat exchangers ensuring maximum efficiency. Models with multiple integrated heat exchangers offer load balancing for optimal long-life operation and inbuilt redundancy guaranteeing continuity of service.

Those offering titanium-stabilised stainless-steel construction are also highly resilient; meaning warranties on heat exchanger and burner components can be as much as a decade and operational lifespan should easily be 15+ years. That places replacement well into the early to mid-2030s and that is important because it means gas infrastructure remains in place for adaption to the next generation of hydrogen-based gas supply. The Government expects this will be a core component for meeting net zero at a national level, especially for buildings with higher energy demands. With hydrogen policy to be confirmed in 2026, retaining gas in existing commercial buildings keeps options open and future-proofs a building for other emerging heating technologies. Healthcare sites with existing gas should really look at continuing to use it.

While we must all recognise the importance of excluding fossil fuels from future commercial systems and advocate all-electric systems for new builds, it is important to understand the implicit costs and difficulties of retrofit and replacement of systems throughout the thousands of legacy healthcare buildings that define the sector. The hybrid approach is unavoidable for commercial projects and is the most sensible, practical, and cost-effective option. Whether all-electric or using gas after heat, healthcare organisations can actively drive sustainability and retain control of operational expenditure for decades to come.

A practical, measured approach

Proudly independent, Adveco brings a unique mix of application design and technology supply that embraces modern gas-fired appliances through to an ever-broadening range of renewables, offsite prefabrication and manufacturer grade servicing. That brings a consistency to bespoke hot water and heating systems, ensuring they are optimised to control initial investment and reduce operational costs for the lifetime of the system.

Far too often, healthcare hot water systems suffer from poor application design leaving them oversized and demanding more appliances, ancillaries, space and complex installation than necessary. Inefficient and less environmentally friendly, such systems will prove more costly to build and operate for their entire lifespan.

Oversizing inherently comes from a lack of understanding of different types of hot water system. When faced with healthcare DHW systems that have too many variables and decisions on diversity, sizing programmes will oversize to prevent perceived hot water problems.

Understanding the application demands - from intense peak/all storage to continuous demand/all power - is critical when sizing a dynamic hot water system. At Adveco, our dedicated application design team provide accurate, bespoke sizing, for both new build and refurbishment projects. Once correctly sized, we can recommend, supply, commission, and service the optimal appliances whether they be gas, electric or a mixed hybrid approach that incorporates low carbon and renewable technologies such as solar thermal and heat pumps. This is the best way of ensuring hot water demands are met in the most cost-effective and sustainable manner.

The changes to the way the UK is approaching heating and provisioning the demand for hot water is a challenge we are relishing because gaining advantage while being ecologically sound is core to everything we do as a business. The drive to adopt sustainable and renewable technology is encouraging, but there currently remains no single technology that supplies all the answers for commercial scale projects. Whether a new build or refurbishment project, the physical limitations of a site will always propel or preclude certain options. A practical, open minded approach to driving cleaner heat through a mix of replacement gas and renewables is what will really propel buildings towards 2050 net zero targets while also delivering considerable benefits to those using these buildings.

Contact Adveco to discuss your hot water and heating needs or visit our website.