How Waste Heat Recovery Systems Can Improve Your Business Energy Efficiency

Against a backdrop of ever-rising energy prices, targets such as the UK’s net-zero target for 2050 and other regulatory pressures, creative ways of using energy have never been more critical. And in this rapidly changing environment, waste heat recovery systems are an innovative and potentially powerful tool for businesses. 

But what are they, how do they work, and how can they improve the efficiency of your business? In this guide, we’ll break it down and explain everything. 

What Is Waste Heat Recovery?

Waste heat recovery is the process of capturing and reusing heat that would otherwise be lost during industrial or commercial operations. This could include heat from manufacturing processes, boilers, exhaust systems, and even wastewater or sewage. Instead of releasing this energy into the environment, where it, at best, is just wasted and at worst will only damage the environment, recovery systems redirect it for practical purposes, such as preheating water, generating electricity, or space heating.

There are several forms of waste heat recovery. Industrial heat recovery captures heat from furnaces, kilns, or exhaust gases in factories. Wastewater heat recovery extracts the residual heat from warm water discharged by buildings or processes. And sewage heat recovery utilises heat from municipal sewage systems to support district heating or building-level energy systems.

These processes can be extremely beneficial for industrial energy efficiency. Studies suggest up to 50% of industrial energy input is lost as waste heat. By effectively recycling this energy, businesses can reduce fuel consumption, lower emissions, and cut operational costs, making it a key strategy in the pursuit of greater sustainability and carbon reduction.

Why Waste Heat Recovery Matters for UK Businesses

Waste heat recovery is becoming increasingly vital for UK businesses, which face rising energy costs, tightening ESG expectations, and regulatory pressure from schemes such as SECR, ESOS, and the UK Emissions Trading Scheme. Unlike heat pumps, which require external energy input to generate heat, waste heat recovery captures and reuses thermal energy already produced, making it an inherently more efficient process.

By repurposing heat from industrial processes, such as boilers or wastewater, your business can significantly reduce fuel consumption and carbon emissions. This not only improves operational efficiency but can also strengthen sustainability credentials for reporting and compliance purposes.

The synergy is powerful: lower energy bills, reduced environmental impact, and potential eligibility for government incentives or carbon credits. For manufacturers, logistics hubs, and extensive facilities, waste heat recovery provides a strategic advantage in achieving both financial and environmental objectives.

How Much Energy Can Waste Heat Recovery Save?

Waste heat recovery can save more than 60% of industrial energy that would otherwise be lost through exhausts, cooling systems, or wastewater. By capturing and reusing this thermal energy, businesses can significantly reduce fuel consumption, lower emissions, and improve overall energy efficiency, making it one of the most impactful strategies for cost and carbon reduction.

Types of Waste Heat Recovery Technologies

So, we’ve established that waste heat recovery can be a highly effective way of saving energy, but what technology is employed to make this happen? Here’s a selection of the most common types.

Waste Heat Recovery Boilers

Waste heat recovery boilers capture thermal energy from flue gases or the vapour produced during industrial processes to convert it into usable steam or hot water. This recovered heat reduces fuel demand and boosts energy efficiency.

They carry significant benefits for businesses, including lower energy costs, reduced emissions and improved process efficiency. But they also come with some drawbacks. The upfront costs of installation can be high, as can the cost of maintenance, while they have not insignificant space requirements.

This type of boiler is best suited for heavy industrial processes, such as cement, steel, or glass manufacturing, or as part of Combined Heat & Power (CHP) systems. They also have a strong Return on Investment (ROI); 3 to 7 years for large industrial sites, although this may be longer for smaller operations.

Heat Exchangers & Heat Recovery on Wastewater

Wastewater heat recovery uses heat exchangers to capture heat energy from warm streams, such as greywater, sewage, or industrial discharge, repurposing it for heating or preheating processes. 

Even throughout the winter, wastewater temperatures typically remain above 10°C, making it a reliable source of energy. Sewage heat recovery systems, such as the HUBER ThermWin process, can extract heat from municipal sewer flows using above-ground exchangers linked to heat pumps. 

Industrial wastewater recovery is especially valuable in sectors such as food and beverage, where large amounts of hot water are discharged from processes and tasks like cleaning, cooking, or pasteurisation. Heat exchangers can reclaim this energy to preheat incoming water or support other processes.

Use cases may include (but are certainly not limited to):

• Food & beverage retailers, including the entire hospitality and restauranting industries, can reuse heat from washdown and processing water.

• Municipal heat networks, which can supply low-carbon heating to buildings from sewage heat.

• Commercial buildings, which can recover greywater heat from showers and sinks.

• Data centres, which can capture heat from their cooling systems and wastewater discharge.

Industrial Heat Recovery Systems

Industrial heat recovery systems capture and repurpose thermal energy from various manufacturing processes, including exhaust gases, cooling systems, and drying operations, to enhance energy efficiency and reduce fuel consumption. These systems can often be seamlessly integrated into existing infrastructure without disrupting normal daily operations.

Modular systems offer flexibility, allowing phased installation and scalability across different plant sizes. Technology such as shell-and-tube heat exchangers, plate exchangers, and thermal storage units are commonly used to recover heat from both high- and low-grade sources.

For manufacturing plants, heat recovery supports pre-heating, space heating, or even electricity generation, depending on temperature and process needs. It can be especially effective in sectors with heavy industrial settings, such as the cement, steel, and chemical processing industries. At the same time, it is also increasingly common in food processing and manufacturing.

Combined Heat Pump & Heat Recovery Solutions

Heat pumps extract heat from external sources (air, ground, or water) using electricity, while heat recovery systems reclaim waste heat from internal processes or exhaust streams. Heat pumps are ideal for providing consistent heating and cooling, whereas heat recovery systems boost efficiency by recycling existing thermal energy. 

Combining both - for example, pairing a ground source heat pump with a mechanical ventilation heat recovery (MVHR) system - can maximise energy savings, especially in buildings with high ventilation needs or industrial heat output. 

How to Choose the Right System for Your Business

Selecting the ideal heat recovery system for your business necessitates a clear understanding of your operational profile, energy usage patterns, and financial objectives. The ideal solution depends on the type of waste heat available, how consistently it’s produced, and your capacity to invest and maintain the system. Here’s a structured approach:

Identify the Heat Source

Determine where your business waste heat is generated, whether it’s wastewater, flue gases, steam, or residual heat from processes. Each source has different recovery technologies, from heat exchangers to economisers or sewage heat pumps.

Assess the Temperature & Volume

High-grade heat (above 400°C) is suitable for industrial recovery systems, but low-grade heat (below 100°C) may require heat pumps to boost the temperature. You’ll need to consider whether heat is available continuously or intermittently, as this can affect system sizing and ROI.

Evaluate Space & Infrastructure

Verify that your premises have sufficient physical space to accommodate the installation of equipment and that existing systems can be retrofitted. Modular systems provide flexibility for sites with size constraints.

Balance CAPEX vs OPEX

Compare upfront capital costs (CAPEX) with long-term operational savings (OPEX). Ensure that you include any maintenance costs, downtime risks, and other lifecycle costs. A typical Return on Investment should range from 3 to 7 years for industrial systems, depending on your specific circumstances.

Explore UK Grants & Incentives

There are grants and incentives for such technology, so make sure to investigate them. Check your eligibility for schemes such as the Industrial Energy Transformation Fund (IETF), Enhanced Capital Allowances or local decarbonisation grants. 

Choosing the right system means balancing technical feasibility alongside financial and sustainability goals, thereby ensuring that your investment delivers long-term value while also delivering regulatory compliance.

The Benefits and Real-world Impacts of Waste Heat Recovery for Businesses

Cost savings & Return on Investment

Waste heat recovery can reduce fuel consumption by 20–50%, depending on the process and system used. In the UK, typical ROI ranges from 3 to 7 years for industrial-scale installations.

Solutia UK Ltd

Solutia UK Ltd, a chemical manufacturer, installed a condensing economiser on its CHP plant, with support from the IHRS programme. The project saved 1.1 million kWh and 1,400 tonnes of CO₂, achieving a payback period of approximately two years.

Emissions Reduction

By reusing thermal energy, businesses reduce their reliance on fossil fuels and lower greenhouse gas emissions. A municipal sewage heat recovery system can reduce heating-related emissions by up to 70%, especially when paired with heat pumps.

Improved Carbon Footprint & ESG Performance

Waste heat recovery supports Environmental, Social, and Governance (ESG) goals and compliance with UK schemes, including SECR, ESOS, and the UK Emissions Trading Scheme. Solutia UK’s project prompted further energy initiatives, including ISO 50001 certification. Businesses that utilise heat recovery can secure stronger positions in both sustainability rankings and investor reporting.

Real-World Examples of Businesses Using Waste Heat Recovery to Their Advantage

Cardiff Steelworks

Cardiff Steelworks developed a waste heat recovery strategy using its existing steam distribution circuit to capture heat from flue gases and redirect it to internal processes. This approach stimulated significant capital investment and led to measurable reductions in CO₂ emissions. 

Dext Heat Recovery

Lancashire firm Dext partnered with Sheffield Hallam University to create a radiant heat recovery panel for commercial kitchens. Installed at over 400 Nando’s restaurants across the UK, the system captures heat from cookers and chargrills, transferring it into a sealed water circuit to provide hot water.

Waste Heat Recovery Implementation Tips for Businesses

Implementing waste heat recovery effectively requires a structured approach tailored to your operations, energy profile, and long-term goals. Here are key steps to guide UK businesses through successful deployment:

Conduct an Energy Audit

Begin with a comprehensive energy audit to identify where waste heat is generated, including flue gases, steam, wastewater, and cooling systems. Use tools aligned with ISO 50001 standards to assess temperature levels, flow rates and continuity of heat availability. This will enable you to select the right recovery technology.

Engage with an Energy Consultant or Specialist

Bring in a heat recovery expert or energy consultant to evaluate technical feasibility, Return on Investment and integration options. Specialists can model system performance, advise on compliance with schemes such as SECR or ESOS, and help navigate funding opportunities, including the Industrial Energy Transformation Fund (IETF).

Pilot Small Systems, Monitor Performance, Scale Up

Start with a small-scale pilot, such as a single heat exchanger or wastewater recovery unit, to test the viability of your project. Monitor performance metrics, including energy savings, temperature recovery, and system reliability. You can subsequently use this data to refine the design and, if necessary, justify scaling across multiple sites or processes.

Train Operations Staff for Maintenance

To ensure smooth functioning, you’ll need to ensure that your operations team is trained to maintain and monitor the system. This includes understanding heat flow, cleaning exchangers, checking sensors, and responding to alerts. Training modules such as those from ReUseHeat can be beneficial.

The move towards a more sustainable future is progressing rapidly, and you can bring your business into this effort by focusing on how you utilise your waste heat. Energy costs are continuing to rise, while regulatory pressures are greater than ever. If you want to reduce your costs and see a strong Return on Investment while demonstrating your eco credentials, treating your wastewater as an opportunity is an excellent place to start.