An EDF & Simple Green Energy Cavity wall insulation (Case Study)
A homeowner experiencing heat loss and high energy bills reached out to EDF for guidance, who then referred them to Simple Green Energy. A thorough survey confirmed the absence of cavity wall insulation, leading to a seamless installation using Knauf Supafil wool. The process significantly improved energy efficiency, enhanced home comfort, and even sparked interest among neighbors. This case study explores how expert insulation solutions can create warmer homes and lower energy costs.
Cavity wall insulation is one of the most effective ways to enhance a home’s energy efficiency and reduce heating costs. Many homes, particularly older properties, were built with uninsulated cavity walls, leaving a gap between the inner and outer walls where heat can escape. This results in higher energy consumption as heating systems work harder to maintain indoor comfort, leading to increased utility bills. By filling this gap with insulating material such as Knauf Supafil wool, heat retention improves significantly. Insulated cavity walls reduce heat loss by up to 35%, ensuring that warmth stays inside during winter and excessive heat stays out in summer. This not only creates a more comfortable living environment but also decreases the household’s carbon footprint by reducing energy wastage.
Financially, cavity wall insulation pays for itself over time through lower heating costs. Homeowners can expect substantial savings on their energy bills while also adding value to their property. Additionally, insulation reduces condensation and damp issues, preventing structural damage. With rising energy prices, investing in cavity wall insulation is a smart, long-term solution. It enhances home efficiency, cuts costs, and contributes to a greener environment—making it a crucial upgrade for any energy-conscious homeowner.
Identifying the Problem
To determine the cause of excessive heat loss, our expert surveyor, Harpreet, conducted a detailed technical survey at the property. The assessment began with precise measurements of the property’s dimensions to ensure accurate insulation planning. Ventilation checks were also carried out to confirm compliance with safety regulations and to maintain adequate airflow after insulation. A key part of the survey involved inspecting the existing wall structure to evaluate its insulation status. Using specialized techniques, Harpreet examined the cavity walls and found that there was no insulation present. This discovery confirmed that heat was freely escaping through the walls, making it difficult for the heating system to maintain a consistent indoor temperature. As a result, the homeowner was experiencing increased energy consumption and rising heating costs.
The findings were documented in an Energy Performance Report (EPR), which provided a clear overview of the property’s energy efficiency levels. This report played a crucial role in determining the best insulation approach, ensuring that the solution would effectively address the heat loss issue while maintaining ventilation standards. With these insights, the next step was to proceed with the installation of high-quality cavity wall insulation to improve the home’s overall efficiency.
Energy Performance Report
The energy assessment conducted for a 54m² mid-terrace house highlighted a major issue contributing to excessive heat loss, and uninsulated cavity walls. Without proper insulation, heat escapes through the walls, making it difficult to retain warmth indoors. This results in increased energy consumption as the heating system works harder to maintain a comfortable temperature, leading to higher energy bills and unnecessary carbon emissions.
The property’s current energy efficiency rating is D (68), indicating moderate efficiency but still leaving room for improvement. If insulation and other recommended measures are implemented, the home’s rating has the potential to reach B (88)—a substantial improvement that would make it significantly more energy-efficient. This upgrade would lower heating costs, reduce energy wastage, and enhance indoor comfort by maintaining more stable temperatures throughout the year. As heating accounts for the largest portion of household energy use, properly insulating the cavity walls can drastically cut heat loss by up to 35%, reducing dependency on central heating. This means not only financial savings but also a reduced carbon footprint, making the home more environmentally friendly. Addressing this issue is essential for improving the home’s overall energy efficiency and ensuring long-term cost reductions on energy bills.
Key Findings
- The cavity walls were found uninsulated, allowing substantial heat to escape.
- Heating accounts for the largest energy use, with 5,556 kWh per year spent
on space heating and 1,695 kWh on water heating. - The total estimated annual energy cost is £722, with heating alone costing
£508 per year.
Insulation Installation
Our installation team arrived at the property on February 19th, fully prepared for the cavity wall insulation process. Before starting, they conducted a thorough on-site check to ensure all equipment was set up correctly. The Firemaster 500 insulation machine was positioned and calibrated to ensure precise material flow throughout the cavities. This step was crucial to achieving an even distribution of insulation without any gaps.
The team also inspected the supply of Knauf Supafil wool, confirming that the material met the required quantity and quality standards for effective insulation. Careful planning was essential to ensure the insulation was injected efficiently while maintaining proper ventilation. Once all checks were completed, and the setup was verified, the team began the installation, following a structured process to achieve optimal coverage and thermal performance.
With the Firemaster 500 insulation machine calibrated and the Knauf Supafil wool supply verified, the team moved on to the critical step of drilling holes into the external walls. A 22mm diameter masonry drill bit was used to create holes at strategic intervals, following a staggered elevation drill pattern. This pattern was carefully designed to ensure uniform insulation coverage while preventing thermal bridging—a condition where heat escapes through uninsulated sections. The team also accounted for the structural integrity of the walls, ensuring that each hole only penetrated the outer leaf of the cavity without affecting the internal structure. Special care was taken to avoid wall ties and maintain proper ventilation flow, which is essential for preventing damp buildup inside the cavity.
The holes were spaced at 1-meter horizontal intervals, allowing the insulation material to spread evenly once injected. Each hole was assessed to ensure alignment with the cavity space, avoiding obstructions such as existing mortar droppings or debris that could hinder insulation flow. The team periodically checked the drilled sections to confirm a clear cavity path, ensuring an efficient insulation process. Once the drilling was complete and the walls were prepared, the next step was to inject Knauf Supafil wool, ensuring a controlled and consistent fill throughout the cavity.
With the drilling phase complete, our expert cavity wall installer, Karl, began the insulation process using the Firemaster 500 to inject Knauf Supafil wool into the pre-drilled holes. The insulation material was blown in under controlled pressure, ensuring it expanded evenly within the cavity without causing blockages or gaps. Karl monitored the flow rate carefully, adjusting the machine settings to match the wall cavity’s depth and density requirements. This step was critical in achieving uniform coverage, preventing areas of inconsistent insulation that could lead to cold spots and thermal inefficiencies.
As the insulation progressed, Karl followed a methodical injection sequence, working from the lowest drill points upward to allow the material to settle properly within the cavity. Periodic checks were conducted to ensure adequate fill levels and that the insulation had reached all sections of the cavity. Special attention was given to corners and junctions, as these areas are prone to heat loss if not properly insulated. Throughout the process, Karl also ensured that the ventilation pathways remained unobstructed, maintaining proper air circulation to prevent condensation buildup. Once the insulation was evenly distributed, the final step was to seal the drill holes, blending them with the existing brickwork for a seamless finish.
With the insulation successfully injected, the next step was to seal the drill holes to restore the exterior to its original appearance. Using a high-quality mortar mix, Yuvraj carefully filled each 22mm hole, ensuring a secure and weatherproof seal. The mortar was blended to match the existing brickwork as closely as possible, taking into account variations in texture and color. For properties with older or weathered bricks, additional color adjustments were made to ensure a seamless integration. Once the filling process was complete, Karl inspected each repaired section, smoothing out the surface to ensure a uniform finish. This attention to detail ensured that the insulation work remained visually unobtrusive while maintaining the structural integrity of the external walls.