Scottish House Condition Survey: 2021 Key Findings

1 Key Attributes of the Scottish Housing Stock

The Scottish House Condition Survey provides a snapshot of the Scottish housing stock in each survey year. This chapter sets out information on the basic attributes of occupied Scottish dwellings as captured in 2021. Subsequent chapters build on this and provide more details on energy efficiency, fuel poverty and external disrepair.

The following topics are included:

• the construction age and built form of Scottish domestic buildings
• the dwellings’ location in relation to the gas network and the type of fuel used to heat them
• the relationship between the dwellings’ attributes and household tenure and
• the composition of the households who occupy them.

When interpreting and using the results presented in this chapter, readers should be mindful of the impact the external+ approach used for the 2021 SHCS has had on data quality. This is discussed in detail in Chapter 6 of this report.

In particular, readers should note that calibration totals for construction age, built form and urban/rural location have been rolled forward from the 2019 survey. To account for non-response bias, survey responses are given calibration weights so that weighted totals agree with (usually) external calibration totals, e.g., the number of households by dwelling age. Calibration totals for the SHCS are usually derived from the dwelling descriptions and abbreviated dwelling descriptions. However, as it was not possible to undertake these in 2021, the calibration totals have been rolled forward from the 2019 SHCS. For further details see section 6.4.2 of this report.

Renters, families, and low-income households were under represented in the achieved sample for the 2021 SHCS. Calibration totals for household tenure were set by rolling forward estimates for owners and renters from the 2019 Scottish Survey Core Questions. This addressed the over representation of owners relative to renters.

However, calibration weighting cannot resolve all non-response bias in the 2021 SHCS. Families and low-income households remain under represented while other households (see section 1.4) and high income households remain over represented.

It is also likely that the results on dwelling size (floor area) presented in this chapter have been impacted by the change in the mode of data collection. For the 2021 external+ SHCS, surveyors were only able to take dwelling measurements externally, whereas previously they were able to take them internally if more convenient or necessary. It can be difficult to estimate the size of the floor area of some dwellings from an external-only inspection. It was noted that there was an increase in the number of cases where dwelling measurements were missing and had to be imputed using online tools such as Google Maps and Rightmove.

 

1.1 Dwelling Age and Type

The age of construction and the built form of a dwelling has consequences for energy performance, running costs and living conditions. For example, older dwellings built with solid stone walls are typically less effective at preventing heat transmittance between the inside and the outside of a building than properties that have been built using modern construction materials and that, since 1982, have been subject to increasingly rigorous minimum standards of energy efficiency and airtightness.

More information on the main dwelling types used in the SHCS is provided in section 7.6.1.

At the same time, types of dwellings can differ in terms of the size of the external surface area; dwellings with a smaller area of exposed wall, for example those that are shielded by adjacent properties, typically have lower levels of heat loss than in buildings with fewer sheltered sides.

The Scottish housing stock is diverse and varies across the country and between rural and urban areas. However, some common types can be recognised in Figure 1.1:

• Old (pre-1919) detached houses (4%; around 94,000) and tenement flats (8%; 208,000)
• More modern post-1982 detached houses (10%; 263,000) and tenements (7%; 176,000)
• Post-war terraced houses (14%; 340,000 built between 1945 and 1982)
• Semi-detached houses, common across all age bands and accounting for around 20% of the stock alone.

These six broad categories account for 63% of the overall housing stock (approximately 2.529 million occupied dwellings) however there is also variability within these groups. For example, among pre-1919 tenement flats, of the type common in Edinburgh and Glasgow, there is a wide range of sizes, layouts, and areas of exposure (for example in top floor flats the roof is exposed) which affects their energy efficiency and the living conditions experienced by the household.

Figure 1.1: Number of Occupied Scottish Dwellings by Age Band and Type, 2021

Data Source: Table KA1b in 'Key Attributes of the Scottish Housing Stock' spreadsheet.

Table 1.1: Proportion of Occupied Dwellings by Age Band and Type, 2021 (Percentage of Whole Stock) [note 1]

Dwelling Age	Detached	Semi-detached	Terraced	Tenement	Other flats	All Dwelling Types
pre-1919	4%	2%	3%	8%	2%	19%
1919-1944	2%	3%	1%	1%	3%	11%
1945-1964	2%	6%	7%	3%	3%	21%
1965-1982	5%	5%	7%	4%	2%	22%
post-1982	10%	4%	3%	7%	2%	27%
All Age Bands	23%	20%	21%	24%	13%	100%
Sample size (number)	966	628	594	614	372	3,174

The category ‘other flats’ includes houses that have been converted to flats (41,000), towers / slabs (70,000) and so-called “4-in-a-block” flats (208,000).

• “4-in-a-block” flats were commonly built as social housing between 1919 and 1965 (63% of “4-in-a-block” flats fall in that age category).
• 85% of towers / slabs were built in the 1945 to 1982 period, again often as social housing.
• Converted flats are almost exclusively pre-1919 structures (87%), where a house has been divided into multiple residences.

1.1.1 Dwelling Size (Floor Area)

The size of the internal floor area has implications for the heating requirements of a dwelling. Larger dwellings require greater heat inputs and therefore cost more to heat. This has a direct impact on fuel poverty (see Chapter 3).

Pre-1919 dwellings tend to be larger than the other two age categories across dwelling types with the exception of tenements which on average are comparable in size to more recently built ones (Figure 1.2). Semi-detached houses built after 1919 are on average around three-quarters of the size of those built pre-1919. Terraced houses built after 1919 are around two thirds the size those built pre-1919.

The overall average for post-1982 dwellings is somewhat higher compared to those built between 1919 and 1982. This is largely driven by differences in detached houses, which are both larger in size and more common in the post-1982 stock (see Figure 1.2).

Rural dwellings are, on average, 38% larger than urban dwellings based on internal floor area, as shown in Table 1.2. The difference is smallest for dwellings built between 1919 and 1982 at 23%. Among pre-1919 and post-1982 dwellings, rural properties are around 50% larger.

Figure 1.2: Mean Floor Area (m2) by Dwelling Type and Age, 2021

Data Source: Table KA3 in 'Key Attributes of the Scottish Housing Stock' tables.

Table 1.2: Average Internal Floor Area (m2) by Urban/Rural Location, 2021 [note 1] [note 2]

Dwelling Age	Urban Rural Location	Average Internal Floor Area (square meters)	Sample size (numbers)
Pre-1919	Urban	95	449
Pre-1919	Rural	141	215
Pre-1919	All Locations	106	664
1919-1982	Urban	88	1,277
1919-1982	Rural	108	291
1919-1982	All Locations	91	1,568
Post-1982	Urban	95	685
Post-1982	Rural	139	257
Post-1982	All Locations	103	942
All Age Bands	Urban	91	2,411
All Age Bands	Rural	126	763
All Age Bands	All Locations	97	3,174

 

1.2 Gas Grid Coverage and Rural/Urban Location

Approximately 12% of dwellings in Scotland are estimated to be outside the coverage of the gas grid. As shown in Table 1.3, the majority (92%) of urban dwellings are within the coverage of the gas grid, whereas 61% of those in rural areas are not.

Table 1.3: Gas Grid Coverage Overall and by Urban/Rural Location, 2021 [note 1] [note 2] [note 3]

Gas Grid Coverage	Urban	Rural	All locations
On Gas Grid	92%	39%	88%
Off Gas Grid	8%	61%	12%
Total	100%	100%	100%
Sample size (number)	2,411	763	3,174

Gas grid coverage is determined on the basis of the distance of the dwelling from a low / medium / intermediate pressure gas distribution pipe. Based on the usual maximum distance for standard domestic connection (63 m), dwellings are classified as being “on” or “off” the grid.  This does not reflect whether the dwelling is actually connected to the grid. For 2021 an improvement has been introduced whereby in addition to this definition a dwelling is also classified as “on” the grid if a mains gas connection has been recorded in the physical survey, irrespective of the distance to the gas distribution pipe. Further details on the method for estimating distance to the gas grid are available in section 7.6.4 of this report and in the SHCS Methodology Notes.

Connection to the gas grid allows households to use gas for heating and hot water. As gas is currently the cheapest of the major commercial fuels, gas grid access can be a significant determinant in the required cost of heating a home to a satisfactory temperature.

Figure 1.3 shows the number of dwellings in rural (423,000 households) and urban areas (2.106 million households) by property type. More than half (54%; 227,000 households) of all rural dwellings are detached, and 20% (84,000) are semi-detached. Only 9% of rural dwellings are flats; 40,000 in total.

The most common dwelling type in urban areas is the tenement flat (577,000), accounting for around 27% of urban housing. Around 59% of urban stock are detached, semi-detached and terraced houses, in total accounting for 1.2 million of the 2.1 million urban dwellings.

Figure 1.3: Dwelling Types in Rural and Urban Areas, 2021 [note 2]

Data Source: Table KA5b in 'Key Attributes of the Scottish Housing Stock' tables.

 

1.3 Heating Fuel

This section examines the distribution of dwellings in terms of the primary heating fuel used and a range of other characteristics, such as age and type of dwelling. The relationship between the type of fuel used, the energy efficiency rating and fuel poverty will be explored further in later chapters.

Overwhelmingly the most common heating fuel is mains gas: 80% of Scottish households (around 2.0 million) use mains gas for heating, 11% use electricity and 6% use oil (see Table 1.4).

Around 314,000 households (12% of all households) were estimated to heat their homes with electricity, communal heating, or biomass.

Table 1.4: Primary heating fuel by sector, 2021 [note 1] [note 4]

Primary Heating Fuel	Owner Occupied	Private Rented	Social Sector	All Sectors
Mains gas	81%	71%	83%	80%
Electricity	8%	19%	13%	11%
Oil	8%	5%	1%	6%
Communal Heating	[low]	2%	3%	1%
LPG bulk or bottled	1%	1%	[c]	1%
Solid mineral fuel	1%	1%	[c]	1%
Biomass	1%	1%	[w]	[low]
Total	100%	100%	100%	100%
Sample size (number)	2,100	423	651	3,174

Mains gas and electricity are the primary fuel types present in 96% of social housing with a further 3% (19,000 households) using some form of communal heating. Conversely, oil is rarely used to heat social housing, but is the primary heating fuel in 8% of owner-occupied dwellings and 5% of private rented dwellings.

Mains gas use is less prevalent in private rented households at 71% compared to 81% in owner occupied dwellings and 83% in social housing.

Owner occupier households were less likely to use electricity as their primary fuel type at 8% compared to 19% of private rented dwellings and 13% of social sector dwellings.

84% of dwellings built between 1919 and 1982 use gas as their primary heating fuel (see Figure 1.4). In comparison, 77% of dwellings built after 1982 and 73% of dwellings built pre-1919 use gas. Older dwellings more commonly (18%) use other fuel types (such as oil) aside from gas or electricity than newer dwellings.

Primary heating fuel also varies by type of dwelling (see Figure 1.4). Households living in detached houses are least likely to use mains gas for heating; 70% of them do, compared to 80% of households for Scotland as a whole and 89% of those households living in terraced houses. This is due to the greater prevalence of alternative heating fuels amongst pre-1919 detached houses. 30% of pre-1919 detached houses use gas as their primary heating fuel, 10% use electricity, and around three fifths of them (60%) are reliant on an alternative fuel source for space heating and hot water. As shown in Figure 1.3 this is largely due to the higher proportion of detached dwellings in rural areas and Table 1.3 demonstrates that dwellings in rural areas are less likely to be within the coverage of the gas grid.

“Other” fuels (than gas or electricity) are most commonly used in detached houses. Flats have the highest levels of electricity (18%) as main heating fuel.

Figure 1.4: Primary Heating Fuel by Age and Type of Dwelling, 2021

Data Source: Table KA7a in 'Key Attributes of the Scottish Housing Stock' tables.

Primary heating fuel varies by geographic location. 88% of dwellings in urban locations use mains gas as their primary heating fuel compared to 40% of those in rural locations. By contrast, there are higher rates of electricity and oil as primary heating fuel in rural locations, 19% and 30%, respectively, compared to urban locations where electricity is used in 9% and oil in 1% of dwellings (see Table 1.5).

Table 1.5: Primary Heating Fuel by Urban/Rural Location, 2021 [note 1] [note 2] [note 4]

Primary Heating Fuel	Urban	Rural	All Locations
Mains gas	88%	40%	80%
Electricity	9%	19%	11%
Oil	1%	30%	6%
Communal Heating	1%	[c]	1%
LPG bulk or bottled	[c]	6%	1%
Solid mineral fuel	[low]	2%	1%
Biomass	[low]	2%	[low]
Total	100%	100%	100%
Sample size (number)	2,411	763	3,174

 

1.4 Household Type

In this report we describe households in terms of three main types which are derived from the more detailed classification used in the Scottish Household Survey:

• Families. These are households which contain at least one child aged under 16. The resident adult(s) may be of any age.
• Older households. One- or two-member households which include at least one resident aged 65 or older.
• Other households. These are all other household types which are made up of adults only and have no resident children.

More details about the definitions are provided in section 7.6.2. This grouping was introduced in the 2015 Key Findings report and is different from the one used in previous reports, where the pensionable age for women was 60 and 65 for men. From 2015 onwards, 65 is adopted as the common age threshold for both men and women for older households reflecting the gradual increase in the state pension age for women.

There is a broad association between household types and the type of dwellings they occupy, as shown in Figure 1.5. While families and older households are more likely to live in houses (69% and 75% respectively), other households are more evenly split between houses and flats (54% and 46% respectively).

Families have the highest proportional occupancy of post-1982 houses: 22% of households with children live in post-1982 houses, compared with 17% of older households and 18% of other types of households. The highest occupancy of pre-1919 flats is observed among other types of households, 16%, compared to 5% for families and 5% for older households. 47% of older households live in dwellings built in 1919-1982, which is higher than the proportion of families (38%) and other households (30%) that live in such dwellings.

Figure 1.5: Households by Dwelling Type and Age Band, 2021

Data Source: Table KA9a in 'Key Attributes of the Scottish Housing Stock' tables.

 

1.5 Tenure

Statistics on tenure in the 2021 SHCS are based on the achieved sample of dwellings in the physical survey and are calibrated against figures rolled forward from the 2019 Scottish Survey Core Questions. For more information see Chapter 6 of this report. For estimates of the total number of dwellings by tenure, readers are referred to the Scottish Government Housing Statistics for Scotland publication which uses information from social landlords’ returns which comprehensively cover the social housing sector and therefore provides more accurate estimates of the total stock.

In this section we explore data from the SHCS sample which provides more detailed information on the composition of each tenure type.

1.5.1 Household Type and Tenure

There are some clear differences in household type across tenure, as shown in Figure 1.6.

Figure 1.6: Proportion of Households in Each Tenure Group by Household Type, 2021

Data Source: Table KA10a in 'Key Attributes of the Scottish Housing Stock' spreadsheet.

Owner occupiers with mortgages are predominantly families (36%) and other households (59%). The majority of those who own their properties outright are older households (64%) and other types of households (33%).

The majority of those who live in the private rented sector (PRS) belong to other households (65%) and only 17% are older households. Around a quarter of renters in social sector (22%) and 18% in private sector are households with children, which reflects their share in the national population.

1.5.2 Dwelling Type and Tenure

Figure 1.7 shows that rented properties in the Housing Association (HA) and private rented sectors are more likely to be flats. Flats account for 64% of Housing Association (HA) stock and 71% of dwellings rented from private sector landlords.

Owner-occupied dwellings are more likely to be houses: 83% of dwellings owned outright and 72% of those with a mortgage, compared to 51% of dwellings owned by Local Authorities, 36% of Housing Association stock and 29% of private rented properties.

Almost all properties (90%) owned by Local Authorities were built between 1919 and 1982, while less than half (43%) of the Housing Associations stock was built in this period. Private rented sector dwellings are older, with 37% built before 1919, compared with 33% built between 1919 and 1982 (see Figure 1.7).

Figure 1.7: Proportion of Dwellings in Each Tenure Group by Age Band and Type of Dwelling, 2021

​​​​​​Data Source: Table KA11a in 'Key Attributes of the Scottish Housing Stock' tables.

 

1.6 Household Income Band

As we might expect, income and tenure are closely correlated. For social sector residents the distribution is skewed towards lower income groups, as shown in Figure 1.8, while for households with mortgages the distribution is skewed towards the highest income group.

The distribution of households by income in the PRS is broadly similar to that for outright owner occupiers.

Figure 1.8 Households by Tenure Group and Annual Household Income Band, 2021 Data Source: Table KA12a in 'Key Attributes of the Scottish Housing Stock' tables.