Scottish House Condition Survey: 2023 Key Findings

Annex A

Scottish Housing Quality Standard (SHQS) Compliance (2022) Updated estimates based on new Energy Efficiency Criteria[1]

On January 1st 2021, the energy efficiency criterion of the Scottish Housing Quality Standard (SHQS) was replaced by the Energy Efficiency Standard for Social Housing (EESSH).

As discussed in the housing conditions chapter we have re analysed the SHQS data for 2022 and produced updated failure rates for the energy efficiency criteria of the SHQS based on the EESSH criteria, as well as overall failures by key variables.

However, as there is a strong correlation between the previous Energy Efficiency criteria (based on a dwellings levels of insulation, and heating system efficiency) and the current criteria (a minimum SAP score) there in not a substantial difference in the overall SHQS compliance rates between the two methodologies.

As shown in table 3 of the excel files under the EESSH criteria, the overall failure rate for the Not Energy Efficient category of the SHQS rises by around five percentage points from 31% to 36%. However, when breaking this down by tenure while the rate has risen in the private sector by around 6 percentage points from 32% to 38%, there has been no overall percentage change to the Social sector figure of 29%.

This is likely due to the prevalence of pre 1919 buildings in the private sector (23% of total stock) compared to the Social sector (3% of total stock), as under EESSH the overall SHQS failure rate for pre 1919 dwellings increased from 61% to 79% (table 4a excel files). Indeed only looking at the Not Energy Efficient Criterion the failure rate for pre 1919 dwellings increased by around 35 percentage points from 27% to 62%[2] (Table 5a excel files). This is likely due to the overall lower average SAP scores of pre 1919 buildings compared to other dwelling age categories, (as discussed in chapter 2 of the SHCS Key Findings report) which under EESH are the criteria assessed for the Not Energy Efficient Criterion.

When looking at overall SHQS failure rates in 2022 using the EESSH criteria we estimate around 58% of all dwellings failed the SHQS, a two percentage point increase (around 58,000 households) compared to the previous criteria. This was mirrored when broken down by tenure as both the private and social sector saw 2 percentage point increases in overall SHQS failure rates, moving from 60% to 62% and 41% to 43% respectively. An increase of around 45,000 private and 13,000 Social sector households (tables 4a and 4b excel files)

Tables 4a and 4b (excel files) also show the overall SHQS failure rate broken down by key characteristic. As discussed above the largest change has been for pre 1919 dwellings which saw an 18 percentage point increase in failures. Likely due to their overall lower average SAP scores which the EESSH criteria is based on. By comparison post 1982 dwellings saw a decrease of 3 percentage points in their overall failure rate, likely due to their higher average SAP scores.

Additionally, tables 5a and 5b (excel files) show the failure rate for the Not Energy Efficiency Criterion broken down by key characteristics. Similar to the overall SHQS failure rate the largest increases have been for pre 1919 dwellings (an increase from 27% to a 62% failure rate). Conversely, the failure rates estimated for newer dwellings have decreased, with a 3 percentage point decrease for 1965-1982 dwellings and a 4 percentage point decrease for post 1982 dwellings3.

As noted above under the EESSH criteria while there has been no change to the overall percentage rate of social sector dwellings failing the Energy Efficiency criterion, the overall SHQS failure rate is around 2 percentage points higher than the previous criteria. This is due to the relationship between failure rates under the old and new energy efficiency criteria and other SHQS criteria.

Table 7 (excel files) provides a detailed breakdown of these failure rates. It shows that 29% of social sector stock failed the energy efficiency criteria under both the old and new criteria, totaling 179,000 and 177,000 dwellings respectively, with 97,000 dwellings failing under both criteria.

However, to isolate the impact of the change in the energy efficiency criterion on overall SHQS failure rates, we need to consider dwellings which did not fail on any other SHQS criteria. Table 7 (excel files) shows that 131,000 (22%) social sector stock failed the old energy efficiency criteria with no other SHQS failures, but this increased to 143,000 (23%) based on the new criteria, resulting in a 2% point increase in the overall SHQS failure rate.

Table 8 (excel files) shows that 32% (or 621,000) private sector dwellings failed the old energy efficiency criteria, with 38% (or 744,000) failing the new energy efficiency criteria, a difference of 6% points or 123,000 dwellings. It should be noted that 421,000 dwellings failed both the old and new energy efficiency criteria.

To isolate the impact of the change in the energy efficiency criterion on overall SHQS failure rates, we need to consider dwellings which did not fail on any other SHQS criteria. Table 8 (excel files)  shows that 322,000 (17%) private sector stock failed the old energy efficiency criteria with no other SHQS failures, but this only increased to 367,000 (19%) based on the new criteria, resulting in a 2% point increase in the overall SHQS failure rate.

The resulting shift discussed above has also had a slight impact on the total number of individual SHQS criteria failures recorded by tenure.

As shown in tables 6a and 6b (excel files) using the EESSH criteria there is a slight drop of around 2 percentage points in the number of dwellings with no failures, with a slight increase of around 2 percentage points in the number of dwellings failing two criteria, and the number of dwellings failing one or  three or more criteria, remaining approximately the same.

This trend is somewhat similar when broken down by tenure as under the EESSH criteria the social sector also sees a decrease in the number of dwellings with no failures of around 2 percentage points, with the number of dwellings failing three or more criteria remaining approximately the same. However, the social sector does see an increase of around 5 percentage points in the number of dwellings with 1 failure, and a decrease of around 2 percentage points in the number of dwellings with 2 failures.

Similarly, the private sector sees a drop of around 2 percentage points in the number of dwellings with no failures, with an increase of around 3 percentage points in the number of dwellings with 2 failures, and a small overall increase to the number of dwellings with three or more failures. Dwellings with 1 failure decreased by 1 percentage point.