Priority Places for Insulation Index: Mapping Scotland's Home Insulation Needs

Introduction

Improving the energy efficiency of a home reduces energy bills, improves health outcomes and provides a warmer home for people. With high energy prices and the need to progress net zero ambitions, there has been further attention on the state of the UK’s housing stock, which is among the oldest and ‘leakiest’ in Europe. In Scotland, there is a problem with low levels of insulation, particularly for solid walls (only 17% are insulated) and a significant fuel poverty problem with a quarter of households in 2019 classed as fuel poor. 

In a bid to improve the energy efficiency of homes and reduce fuel poverty, the Scottish Government has designated energy efficiency as a national priority. Support is available through a variety of grant and loan schemes to help households fund energy efficiency improvements and provides online and telephone advice services via Home Energy Scotland.

Although improving Scotland’s housing stock is a national challenge, it will be tackled home by home and street by street. The number of homes with poor insulation and local household circumstances such as the level of fuel poverty, health and overall age of the population vary between different places. Understanding these differences is crucial for national and local governments to aid decision-making on targeting support and services to the people who need it most. To support this, Which? has put together data on a range of factors that determine the need for insulation and created the Priority Places for Insulation Index, which identifies areas which are likely to be the most urgent need for insulation.

Methodology

The Priority Places for Insulation Index is a composite index constructed using data from eight different indicators and each has specific metrics of measurement. Five of these indicators focus on the quality of housing stock and are created using data from Energy Performance Certificates (EPCs). These are the average level of all types of wall, loft/roof and floor insulation, the average age of local properties and the proportion of properties that are flats. We include age of property in addition to levels of insulation since older properties are likely to be harder to retrofit, while property type matters because flats and apartments need fewer measures to be adequately insulated. 

The three remaining indicators cover household characteristics and comprise socio-demographics and health circumstances of households in a local area. We include income levels as proxies of fuel poverty, as households in fuel poverty will benefit more from having their property insulated. We include the proportion of households aged over 65 because the elderly face worse health consequences from living in a cold home, and similarly, we include the incidence of health conditions such as cardiovascular and respiratory diseases as these are worsened by living in a cold home.

The index is constructed individually for each of the four UK nations (England, Wales, Scotland and Northern Ireland) and on four geographical levels. For Scotland, these are:

• Data Zones, which we refer to as local areas; and
• Westminster Parliamentary Constituencies and Scottish Parliamentary Constituencies; and 
• Local Authorities. 

Further details on the methodology can be found in the technical annex.

Identifying the priority places for insulation

Priority places are local areas which are in the bottom 9th and 10th deciles of the index, meaning they are in most need for insulation. Two-fifths of the priority places in Scotland are concentrated in South Scotland (23%) and West Scotland (17%). 

Figure 1: Priority places are primarily located in South Scotland and West Scotland

In South Scotland, these priority places are dotted throughout the region with clusters throughout the Borders and Dumfries and Galloway (see Image 1). Since the South of Scotland is a largely rural area with a number of historic textile centres, it has a higher proportion of older and stone-built houses and these can be challenging to insulate. 

Image 1

Moving towards the Central Belt, there are pockets of priority places across several former mining and industrial towns, such as Whitburn and Coatbridge, which are characterised by older properties with poor insulation and ongoing deprivation. Along with these high-priority towns, there are also a number of New Towns like Livingston, which are lower on the priority scale. However, poor quality housing exists in certain New Towns, such as Cumbernauld, which has a high number of priority places. Whilst the focus on insulation has typically been on older historic towns, several newer developments from the 50s and 60s also require insulation due to issues with their construction.

Meanwhile, in the West Scotland region, high-priority clusters are primarily located around coastal communities in the Ayrshire region (ie Prestwick, Girvan and Largs) and Greenock, as shown in Image 2. In some of these towns, extensive Victorian development has resulted in many hard-to-treat older properties. These coastal communities also tend to suffer from higher deprivation levels and poorer quality of housing stock, with an ageing population.

Image 2

Despite the North East being generally low priority due to its higher affluence, there are some clusters of priority places, primarily in inland towns such as Keith, Turriff, and Huntly (see Image 3). Further north, the population becomes increasingly rural, and there are more clusters of priority places. For example, many priority places are found throughout Sutherland, characterised by a high level of older properties due to its rurality and limited industry. This contrasts with Aberdeen, which has large clusters of low-priority areas in the city centre due in part to its energy industry, relatively young population, and the prevalence of newer flats. Looking beyond the city centre, we can observe a ring effect formed by clusters of high-priority areas in the outlying neighbourhoods (see Image 4). This effect is similarly observed in major secondary cities in England.

Image 3

Image 4

Scottish Parliament constituency priority places

The index also ranks the need for insulation by Scottish constituency, with 14 of the 73 constituencies categorised as priority places (in the bottom 9th and 10th deciles). Figure 2 displays these constituencies ranked from highest need for insulation, along with the indicators that are more dominant in driving the need. Indicators designated as ‘Very High Priority’ mean that the constituency is in the bottom 9th and 10th deciles for that indicator, “High Priority” meaning they are in the bottom 7th and 8th deciles, and so on. A couple constituencies are then selected as case studies. 

Figure 2: Scottish Parliament constituency priority places need heatmap

Supply of insulation installers

Alongside identifying areas most in need of insulation, it is crucial to ensure there are adequate levels of installers available to service those areas. Using our methodology, we are able to identify installation firms with an online presence and that specify insulation services on the scraped sites.

The median number of installers in Scotland is lower than in England and Wales, with only eight firms available per 100,000 people, or equivalently, one firm to service 4,808 households. While this indicates a national supply issue, certain areas are worse than others in terms of supply. Figure 3 illustrates the relative paucity of firms in constituencies such as Na H-Eileanan An lar, Argyll and Bute, Inverness and Nairn, and much of the North East.

Figure 3: Supply of insulation installation firms is worse in some constituencies

Combining the data on supply with the need for insulation, we find some of the constituencies which have high need and low supply are more rural, such as Na H-Eileanan An lar (ranked most in need and with the lowest supply), Dumfriesshire, and Argyll and Bute. In fact, out of the 15 predominantly rural constituencies, nearly half fall into the highest need and lower supply category (47%). Households in rural areas clearly require support, and although the Scottish Government has included a grant uplift for rural households, more still needs to be done to address the shortage of installation firms in rural areas.

In the retrofit market, certification schemes play an important role in enhancing consumer confidence by ensuring adherence to industry standards and providing methods of redress when issues arise. Therefore, we only categorise suppliers registered with certification schemes that we are confident provide adequate consumer protection, as certified. These schemes are TrustMark, Insulation Assurance Authority, and Which? Trusted Traders. 

When considering only certified installers, this further reduces the median number of firms in Scotland to only five per 100,000 people, equivalent to one firm per 7,692 households. However, we observe a relative scarcity of TrustMark-certified installers in constituencies likely to qualify for public funding. This is concerning since households eligible for public funding must engage an installer with TrustMark certification. 

Conclusion

Our research reveals that priority places for insulation are distributed throughout Scotland but are more commonly found in South Scotland (primarily the Borders and Dumfries and Galloway) and West Scotland (coastal communities, especially in the Ayrshire area), and the Highlands and Islands. Additional clusters of priority places can be found in the Central Belt near former mining and industrial town centres, including some New Towns. Meanwhile, the North East also exhibits some pockets of priority places in more rural areas and smaller towns despite the region’s overall level of prosperity. 

In addition to recognising the need for insulation, the availability of qualified insulation installers is critical in improving the energy efficiency of homes in Scotland. Acknowledging the importance of government at all levels to support the recruitment and retraining of installers, our research highlights the relatively low levels of installation firms in areas with a high need, especially in rural areas. This gap widens further when including only certified installers. 

We hope that the collation of this data into a single index will prove to be a useful tool for the Scottish Government, policymakers, local governments and others trying to support consumers in improving the energy efficiency of their homes.