As the UK moves towards net zero, the challenge of tackling fuel poverty in social housing remains pressing. According to government statistics, around 11% of households in England (2.73 million homes) were in fuel poverty in 2024 under the Low Income Low Energy Efficiency (LILEE) metric – a figure that is expected to rise further in 2025.

For social housing landlords and housing providers, this reality underlines the importance of adopting technologies that reduce energy use without compromising comfort or reliability. One of the most effective yet underutilised solutions is Waste Water Heat Recovery Systems (WWHRS).

 

Why hot water matters in fuel poverty

Hot water use typically increases during the winter months, with a 16% increase in daily energy demand and a higher total energy consumption of 36% compared to summer.

The incoming water is much colder in the winter months, meaning more energy is required to achieve the same hot water temperature.

Additionally, personal bathing, including showers and baths, accounts for around 45% of all household hot water use. For residents already struggling with fuel bills, this represents a major and unavoidable cost, especially in the winter.

 

What is WWHRS?

WWHRS captures the heat from used shower water before it disappears down the drain. This recovered heat is used to pre-warm the incoming cold water supply, meaning the boiler or heat pump does not need to work as hard.

 

How WWHRS helps residents

WWHRS has been proven to reduce electricity consumption for hot water by 31-36% while working alongside heat pumps, as well as achieve savings of up to 47% when immersion heaters are used.

For occupants, this means lower energy bills, while housing providers benefit from improved compliance with government efficiency standards.

 

WWHRS in modern homes

From 2025, most new build properties will use air source heat pumps (ASHPs) instead of gas boilers. While highly efficient for space heating, heat pumps are less effective at rapidly producing large volumes of hot water.

WWHRS reduces overall hot water demand, allowing for smaller and more affordable cylinders to be fitted into the home. They also reduce reliance on backup immersion heaters, which are costly to run and can undo other energy-saving measures residents have adopted.

 

WWHRS and IES

When combined with Instantaneous Electric Showers (IES), which heat water on demand, WWHRS helps prevent both oversized and undersized cylinders. These are common problems that lead to wasted energy, unnecessary costs and space constraints in social housing.

 

WWHRS costs

Immersion heaters typically use 3kW of power, which can cost up to £0.87 an hour. To heat a cylinder fit for a home with two bathrooms running two full heating cycles a day would typically take three hours. This could cost the resident up to £5.22 per day.

WWHRS can start from around £650 to purchase, with additional installation costs. Once installed, they can reduce hot water energy use by up to 55% and cut energy bills by £150–£200 annually for a typical household, meaning a payback of under four years for residents and landlords.

 

Benefits of WWHRS in social housing.

For social housing providers, WWHRS delivers a wide range of benefits for long-term tenants, who are often on low incomes and therefore most affected by rising fuel prices. These include:

  • Built-in efficiency measures that require no behavioural changes from residents.
  • Savings that happen automatically.
  • Virtually maintenance-free operation, with no action required from tenants.
  • Support for landlords in meeting Part L of the Building Regulations, achieving carbon reduction targets and future-proofing homes for net zero.
  • Extremely low embodied carbon alongside ongoing energy efficiency gains.

As energy prices continue to rise and fuel poverty worsens, WWHRS is one of the simplest and most effective ways to cut household bills in social housing. By capturing heat that would otherwise go to waste, the system not only improves the performance of home heating systems but also delivers financial relief to residents.