The Great British Insulation Scheme GBIS

1 What is the GBIS ?
2 Connection to other schemes
3 Why insulate when installing a heat pump ?
4 Comments about the GBIS
5 Related articles on Designing Buildings

[edit] What is the GBIS ?

On September 14 the UK government launched a £1 billion drive to help those most in need heat their home for less - the Great British Insulation Scheme. It focusses on low-income and vulnerable households, and is also available to people living in homes with an Energy Performance Certificate (EPC) rating of D-G, and within Council Tax bands A-D in England (A-E in Scotland and Wales). The scheme was announced previously but the indication is that the most recent announcement includes an increased budget allocation following the rising costs of energy.

[edit] Connection to other schemes

Formerly known as ECO+ the scheme will be administered by Ofgem and will work by placing an obligation on medium and large energy companies to deliver measures that result in reduced energy usage. It is intended to run until March 2026. The measures were first proposed in May, with explanation that the existing levels of government support for energy efficiency were set when energy prices were lower by half. Reasons for the increased drive and funding include the increase in energy prices, the Government’s statutory fuel poverty and net zero targets supporting households on the lowest income, as well as those previously without support.

The scheme complements the Energy Company Obligation (ECO4) scheme, though it will focus on single insulation measures unlike ECO4’s which take an approach more in line with ‘whole house’ solutions.

Customers will be able to use a new online checker for the Great British Insulation Scheme to find out if they are eligible. The tool will ask a series of questions - including how they heat their home, whether their home has solid or cavity walls, and if they are receiving any benefits.

A separate checker has also been launched for the Home Upgrade Grant, which could help as many as 25,000 off-the-gas-grid homes that have an EPC rating of D to G. People can find out if they qualify for energy efficiency support - ranging from insulation and draft proofing to new windows and doors, as well as heat pumps and solar panels.

Customers using the online tools will then be referred to either their energy supplier, for support from the ECO programme and Great British Insulation Scheme, or their local council for the Home Upgrade Grant, to take the next step in making their home more energy efficient.

The scheme complements the UK Governments Boiler Upgrade Scheme (BUS) which supports the decarbonisation of heat in buildings. It provides upfront capital grants for the installation of heat pumps and biomass boilers in homes and non-domestic buildings in England and Wales.

Acting on behalf of property owners, installers can apply for: £5000 off the cost and installation of an air source heat pump or a biomass boiler or £6000 off the cost and installation of a ground source heat pump, including water source heat pumps. £450 million of grant funding is available over three years from 2022 to 2025.

[edit] Why insulate when installing a heat pump ?

Gas boilers heat water to relatively high temperatures of around 85 degrees. With heat pumps the flow temperature set out by the government Microgeneration Certification Scheme (MCS) is 55 degrees C, meaning that they become less efficient above that. This efficiency is referred to as seasonal co-efficient of production (SCOP), which is the amount of heat that can be produced in relation to the electricity invested averaged over the seasonal change. So a SCOP of 2.9, which is the minimum required by the MCS, means that for each input unit of electricity, 2.9 units are returned in heat energy.

When heating a space, how much of the heat that gets lost to the outside air will depend on the level of insulation (including cold bridges) and airtightness / ventilation approach to the space in question. The measure of this is expressed as the fabric heat loss (heat loss coefficient or heat transfer coefficient), which can be calculated by summing up all of the wall, floor, ceiling, window and door areas by their relative performance (thermal conductivity or U-values). Ventilation (and infiltration) losses are then assumed by calculating the volume of the space (m3) and number of air changes per hour (ACH). Together these calculations give an indicative energy loss figure in Watts / Metre squared (W/m2). Older houses might be somewhere around 65-85 W/m2, whilst buildings built after around 2006 might be around 20-40 W/m2, and Passivhauses nearer 2-10 W/m2.

When heating a space on relatively 'cheap' gas that heats hot water to 85 degrees, the losses are less noticeable (although still significant in terms of costs), but when heating a space with a heat pump the differences in fabric performance can more directly impact efficiency. Heat pumps, that run below 50 degrees C become more efficient (that is to say for each input unit of electricity greater heat energy is output), these temperatures compared with a older gas boilers systems are referred to as low temperature hot water systems, that often work well with underfloor heating or larger radiators. In fact the ideal flow temperature for a heat pump (ie to get the most heat per unit of electricity) is likely to be nearer 45 degrees, which can help to achieve a SCOP figure of up to 4 (ie 4x as much heat for the electricity put in). For this to work though the heat loss of the building needs to be at a reasonable level, which is where the fabric performance; insulation, ventilation and air tightness starts to become more key.

The efficiency of heat pumps are usually labelled as being from A++ (+) to G, however these ratings should also list the efficiency of the system when running at a low temperature of 35 degrees and at a higher temperatures of 55 degrees. The SCOP ratings at each temperature may vary from as low as 2.9 to as high as 5 at lower temperatures. The possibility of running systems at lower temperatures depends on the level of performance of the building fabric.

[edit] Comments about the GBIS

Mike Thornton, Chief Executive, Energy Saving Trust

"Improving the energy efficiency of our homes is a vital part of addressing both the energy crisis and climate emergency. By reducing demand for fossil fuels it provides a triple win long-term solution for cutting energy bills, decreasing carbon emissions and improving energy security. The launch of the Great British Insulation Scheme is therefore a welcome development as it will mean more households are eligible for financial support for insulation measures and comes at a crucial time as we approach the colder winter months."

Energy Security Secretary Claire Coutinho

"We are determined to help families keep their homes warm through the winter months and save on their energy costs. Our Great British Insulation Scheme will help hundreds of thousands of people, including some of the most vulnerable in society, get the upgrades their homes need, while cutting their energy bills."

Lord Callanan, Minister for Energy Efficiency and Green Finance

"Boosting the energy efficiency of homes creates the best long-term protection against fuel poverty for the most vulnerable That’s why we are helping families with extra support to make their homes warmer, while saving hundreds on energy costs."

Rocio Concha, Which? Director of Policy and Advocacy

"Which? research shows very few households are making insulation improvements to their homes and a key concern is affordability, so this government support to help eligible households reduce their energy bills and keep their homes warm during winter months is a step in the right direction. It is important that the government drives awareness of the support that is available, and ensures that eligible households can get insulation installed as soon as possible. Insulating a home can be complex and costly and the information and advice available to all households should improve so that people can feel confident making these vital changes to their homes. This should include information on how consumers can protect themselves from fraudsters and rogue traders who might take advantage of the scheme."

Commenting on the original scheme launched in April of 2023 Matt Copeland, head of policy at National Energy Action said progress on energy efficiency in the UK had “been far too slow for a decade”, and that the new scheme was “not well targeted at fuel-poor households, who need the most support with their bills”. He added: “Our own analysis from the most recent set of fuel poverty statistics for England found that it will now take approximately 300 years for the government to hit its statutory target for all fuel-poor homes to reach EPC C – far behind the 2030 deadline.” More recent comment on the current scheme is as yet not available.