BTS supports delivery of UK’s 1st ECO3 Demonstration Action Project

The Energy Company Obligation (ECO) is a government energy efficiency scheme in Great Britain to help reduce carbon emissions and tackle fuel poverty. The latest version, ECO3, commenced on 3 December 2018, and applies to measures completed from 1 October 2018.

Airex smart air brick being installed

Under the innovation strand of the Energy Company Obligation (ECO), there are two mechanisms that require the measurement of as-installed performance. One is termed ‘Monitored Measures’ where an Energy Company is awarded an uplift simply for adopting the measurement of conventional ECO eligible measures such as CWI, SWI, LI and heating systems. The second, and most popular thus far, is via what is termed ‘Demonstration Action’ projects. This is where an obligated energy company receives an uplift for sponsoring the measurement and validation of lifetime fuel bill savings delivered by new and innovative retrofit measures.

Build Test Solutions and our trusted partner, Elmhurst Energy Consultancy, have been delivering a number of these projects and are delighted to have supported smart air brick technology provider, AirEx, and its DA project sponsor, EDF Energy, in achieving the status of the UK’s 1st fully completed Demonstration Action. 

The field trial was across 115 homes over the 2019/20 winter heating season and using BTS methods, Elmhurst supported AirEx to carry out the following measurements:

  • SmartHTC whole building heat loss pre and post AirEx treatment in 82 occupied homes in the space of a single winter.
  • Floor U-values were measured in a subset of 19 of those homes using heat flux meters.
  • Floor void temperature and humidity monitoring in 99 properties.

At over 5 million data points collected and a total of 164 HTC measurements across fully occupied homes, it is perhaps the largest study of its kind delivered at the fraction of the cost of what would otherwise have required monitoring over a much longer period or ‘co-heating’ style tests only possible in vacant properties.

The study found that the AirEx product delivers an average 20% improvement in floor U-values which, when combined with lower air leakage, delivers an overall average reduction of whole building heat loss (HTC) of 12%.

View full AirEx ECO Field Trial Report

Luke Smith, Managing Director of BTS said:

The innovation strand under ECO3 has provided a number of fantastic opportunities for new and emerging businesses to showcase their products and capabilities. It has been truly fantastic to work with the team on the AirEx project and to see it through as the first fully signed off DA project in the UK. For us however, this is just the beginning as we march on to demonstrate that measuring the true real world performance of buildings really can be delivered cost effectively at scale.

Agnes Czako, Co-Founder and Managing Director of AirEx said:

We are incredibly pleased about the fantastic results of this study, and thankful for our supporters, EDF Energy and BTS in helping the Airex team to make this happen. We are looking forward to the next phase of rolling Airex out across the UK social housing, contributing to the UK’s net zero goals while tackling Fuel Poverty. 

If you would like to know more about how BTS and its network of customers could help you to measure and validate the performance of your retrofit or new build works, please do get in touch.


Luke Smith

Luke Smith

Managing Director

Building performance measurement made simple.

Unique products and smart technologies designed for energy assessors, building surveyors, the construction industry, utility suppliers and other built environment experts.

Temperature sensors

SmartHTC Measured Thermal Performance

A low-cost and non-invasive way of measuring the true thermal performance of a house. It requires temperature and meter data to calculate an accurate heat loss rating over a 3-week period.

Learn more about SmartHTC Measured Thermal Performance
ISO 9869 U-value measurement system

ISO 9869 U-value Measurement System

System for measuring in-situ U-values of walls, floor and ceilings according to the ISO 9869 methodology.

Learn more about ISO 9869 U-value Measurement System