At first glance, the Highfield Bungalows estate in Maghull, Liverpool appeared to be a housing development that had already benefited from multiple energy efficiency upgrades over several decades. Yet despite repeated interventions, residents continued to report cold homes during winter, overheating during summer and persistently high heating costs.
This project demonstrates why successful retrofit is not simply about adding insulation, but about understanding how a building actually performs.
Looking Beyond Conventional Retrofit
The Highfield Bungalows are a system built archetype that make up an entire estate. Like many non traditional properties, they have undergone numerous alterations since their original construction.
The original homes were constructed using a timber frame system. At a later date this was replaced with a single blockwork wall. Internally, studwork was added to create a cavity. A further upgrade was subsequently undertaken, with insulation board applied externally to the blockwork and a new outer brick leaf constructed.
On paper, the properties appeared to have received substantial thermal improvements. In reality, the benefits delivered were far below expectations.
Residents continued to experience significant discomfort and energy consumption remained much higher than anticipated.
Identifying the Real Problem
As part of the PAS 2035 retrofit process, a detailed investigation of the building fabric was undertaken.
Our analysis identified a significant thermal bypass pathway that had remained hidden despite previous upgrade works.
The cavity heads between the various wall constructions had been left open into the cold roof void. At the same time, loft insulation did not extend far enough to cover the additional wall build up that had been created during previous refurbishment works.
This allowed cold air movement through the structure and effectively bypassed large portions of the insulation that had been installed over the years.
The result was a building that looked insulated but was performing substantially below its theoretical potential.
Developing a Whole House Solution
A planned roof replacement provided the ideal opportunity to address the underlying issues.
Rather than treating individual elements in isolation, a coordinated whole house retrofit strategy was developed.
The works included:
- New roof installation as part of planned maintenance works.
- Sealing and insulating all cavity heads to eliminate thermal bypass routes.
- Additional loft insulation extended to fully connect with the external wall insulation system.
- Installation of a new External Wall Insulation system.
- Removal of redundant heating flues left in situ from previous heating systems.
- Raising and improving suspended floor ventilation details where external ground levels created potential moisture risks.
- Installation of innovative Aereco smart airbricks to maintain effective underfloor ventilation while reducing unnecessary heat loss.
- Improved ventilation throughout the dwellings to support long term moisture management and indoor air quality.
The Results
The impact of addressing the thermal bypass and creating continuous insulation around the building envelope was significant.
The completed retrofit delivered:
53.5% reduction in heat demand
This translated into immediate reductions in heating costs and improved comfort for residents, many of whom are older occupants particularly vulnerable to rising energy prices and cold indoor temperatures.
Beyond lower bills, residents benefited from:
- Improved thermal comfort.
- Reduced cold spots and draughts.
- More consistent internal temperatures.
- Reduced risk of condensation and moisture related issues.
- Improved overall building performance.
Why Specialist Retrofit Design Matters
This project highlights one of the key principles of PAS 2035: understanding the building before selecting the solution.
Simply adding more insulation does not always solve the problem. In many hard to treat properties, performance gaps occur because critical junctions, thermal bridges and air movement pathways have not been properly addressed.
Without detailed investigation, it would have been easy to assume these homes simply required additional insulation. Instead, the primary issue was continuity of insulation and uncontrolled thermal bypass.
By identifying the root cause and designing a coordinated solution, the project delivered performance improvements far beyond what could have been achieved through isolated measures alone.
Delivering Better Outcomes for Hard to Treat Homes
Many of the UK's most challenging properties have undergone multiple alterations over their lifetime, creating hidden defects that are not immediately obvious from construction drawings or visual inspections.
This is where specialist retrofit expertise adds significant value.
At PAS2035 Consultants, we specialise in identifying complex building performance issues, developing practical solutions and ensuring retrofit measures work together as a complete system.
The Highfield Bungalows project demonstrates that successful retrofit is not just about installing measures. It is about understanding buildings, solving problems at their source and delivering measurable improvements that genuinely improve people's lives.
For these residents, solving a hidden thermal bypass has resulted in warmer homes, lower bills and a 53.5% reduction in heat demand, proving that good retrofit design can transform even the most challenging housing stock.