Building retrofit spans insulation, windows, heating systems, controls and integrated upgrades across homes and commercial properties. These statistics show the scale of the global building stock, current adoption, modelled costs and measured or forecast outcomes, with geography and measurement periods stated throughout.
Key Building Retrofit Statistics
The most useful headline figures are:
- In 2024, buildings accounted for around 30% of global energy demand.
- In 2024, residential buildings represented about 70% of global building energy demand.
- In 2024, commercial and public buildings represented about 30% of global building energy demand.
- In 2022, average annual building energy-retrofit rates were below 1% in most major markets.
- The IEA pathway targets 20% of existing global building stock at zero-carbon-ready level by 2030.
- About two-thirds of today’s global building floor area is expected to remain in use in 2040.
- At least 40% of building floor area in developed economies was built before 1980 in the 2022-reported stock.
- In 2023, 52% of English dwellings were rated EER bands A–C, equal to 13.3 million dwellings.
- In 2023, 53% of English dwellings had insulated cavity or solid walls, equal to 13.5 million dwellings.
- In 2023, 89% of English homes had full double glazing, compared with 80% in 2013.
- In the 2022–2023 survey, 72% of English owner occupiers reported at least one energy-efficiency measure in the previous five years.
- In that survey period, 12% of English owner occupiers reported adding extra loft insulation in the previous five years.
- A deep renovation of a very low-performing EU building could reduce energy consumption by as much as 80%, according to a policy estimate.
- EU building energy-efficiency measures implemented between 2020 and 2024 achieved around 25 Mtoe of estimated energy savings.
- The DOE/LBNL commercial-retrofit dataset contained 12,000 U.S. commercial retrofit projects.
- In the 2023 English cost model, improving a pre-1945 dwelling to EER band C or above cost an average £9,300.
- In 2023, 64% of pre-1945 English dwellings with solid walls had uninsulated solid walls.
- The IEA pathway requires 100% of new buildings and deep renovations to be zero-carbon-ready by 2030.
Contents
- Global building retrofit scale and renovation rates
- Building retrofit data on insulation, windows and energy performance
- Retrofit participation and upgrade adoption
- Retrofit costs, savings and measured energy outcomes
- Building age, tenure and retrofit-depth trends
Global Building Retrofit Scale and Renovation Rates
The global context is large but uneven. The IEA estimated that buildings accounted for around 30% of global energy demand in 2024, while residential buildings accounted for about 70% of building energy demand and commercial and public buildings for about 30%.
The same IEA Energy Efficiency 2025: Buildings analysis reported global final energy consumption above 450 exajoules in 2024, up by about 25 exajoules between 2019 and 2024. These are all-sector energy figures used as context for buildings, not retrofit-only totals.
Retrofit speed is much lower than the scale of the stock suggests. The IEA Space heating pathway reported average annual building energy-retrofit rates below 1% in most major markets in the status reported for 2022.
The IEA pathway sets higher future milestones:
- It targets a 2.5% annual retrofit rate in advanced economies from 2030 through 2050.
- It targets 20% of existing building stock at zero-carbon-ready level by 2030.
- It targets 80% of existing building stock at zero-carbon-ready level by 2050.
- About two-thirds of today’s global building floor area is expected to remain in use in 2040.
- At least 40% of building floor area in developed economies was built before 1980, based on the stock reported in 2022.
The pathway also distinguishes new construction from existing-building work. Only 5% of new buildings were zero-carbon-ready in 2020 in the IEA baseline, while the pathway requires 100% of new buildings and deep renovations to be zero-carbon-ready by 2030; these are scenario milestones, not observed adoption rates.
Building Retrofit Data on Insulation, Windows and Energy Performance
England provides a detailed dwelling-level view, but these figures describe England rather than the whole United Kingdom. The English Housing Survey 2023 to 2024: drivers and impacts of housing quality measured the following energy-performance distribution in 2023:
| Energy or fabric measure | English dwellings in 2023 | Published count or definition |
|---|---|---|
| EER bands A–C | 52% | 13.3 million dwellings |
| EER band D | 39% | 9.8 million dwellings |
| EER bands E–G | 9% | 2.3 million dwellings |
| Insulated cavity or solid walls | 53% | 13.5 million dwellings |
| Uninsulated cavity or solid walls or other wall types | 47% | 11.9 million dwellings |
Wall and loft measures show how retrofit coverage depends on the component being measured. In 2023, 40% of English dwellings had at least 200 mm of loft insulation, while 46%, or 11.7 million dwellings, had less than 200 mm; 14% had no loft and therefore no loft insulation.
Window coverage was higher than wall-insulation coverage in the same survey. Full double glazing reached 89% of English homes in 2023, up from 80% in 2013, while cavity or solid wall insulation rose from 46% to 53% over that decade.
These measures are not interchangeable: full double glazing does not describe every aspect of window performance, and the loft-insulation percentage based on all dwellings includes homes with no loft.
Retrofit Participation and Upgrade Adoption
Self-reported owner-occupier activity gives a different view from the physical condition of the whole dwelling stock. In the English Housing Survey 2022 to 2023: energy report, 72% of English owner occupiers said they had installed or undertaken at least one energy-efficiency measure during the previous five years.
The survey included heating and controls as well as fabric measures, so the figure should not be read as a retrofit-envelope rate. Reported activities included:
- 40% serviced a central-heating boiler in the previous five years.
- 32% replaced a boiler.
- 17% replaced a central-heating thermostat.
- 14% installed a smart heating control, including examples such as Nest, Hive or Tado.
- 12% added extra loft insulation.
- 5% added cavity-wall insulation.
- 1%, equivalent to 207,000 households, added solid-wall insulation.
- 10% replaced single glazing with double glazing.
- 1%, equivalent to 231,000 households, installed solar photovoltaic panels.
The categories describe reported actions, not verified energy savings. Smart controls and solar PV are related building upgrades, but they are not identical to insulation or other building-envelope retrofit.
Retrofit Costs, Savings and Measured Energy Outcomes
Potential savings vary sharply with starting performance and retrofit depth. The European Commission estimate cited by the IEA Energy Efficiency 2025: Buildings report says deep renovation of a very low-performing EU building could reduce energy consumption by as much as 80%, with annual household savings of up to €881.
Those are upper-bound policy estimates rather than average realized outcomes. The same source estimated that EU building energy-efficiency measures implemented between 2020 and 2024 achieved around 25 million tonnes of oil equivalent in energy savings, and estimated that around 36% of EU natural-gas imports are used for heating in buildings.
Commercial evidence points to the importance of combining measures. The U.S. Department of Energy and Lawrence Berkeley National Laboratory summary, System Retrofit Trends in Commercial Buildings: Opportunities for Deeper Energy Savings, analyzed a dataset of 12,000 commercial retrofit projects.
| Commercial retrofit finding | Reported result | Scope and period |
|---|---|---|
| System retrofits in the dataset | Less than 20% of projects | U.S. commercial project dataset analyzed in the 2020 summary |
| System retrofits among high-savings projects | 40% | Study-defined high-savings category |
| System retrofits among low-savings projects | 16% | Study-defined low-savings category |
| Additional savings from systems-based versus component-only upgrades | 49%–82% | Cited commercial case studies |
The study’s comparisons are not an average across every commercial retrofit, and the association between system retrofits and savings does not prove causation. Its project dataset was assembled from utility, federal and energy-service-company sources rather than serving as a census of all U.S. commercial retrofits.
A separate DOE Integrated Retrofit Solutions project targets a 75% decrease in thermal loads in existing residential and commercial buildings. That is a project target, not a measured portfolio result.
Building Age, Tenure and Retrofit-Depth Trends
Building age changes both the technical challenge and the modelled cost. The English Housing Survey 2023 to 2024: climate resilient homes fact sheet estimated that about 8.9 million English dwellings were built before 1945 in 2023.
For pre-1945 English dwellings with solid walls, 64% had uninsulated solid walls and 5% had insulated solid walls in 2023. The same fact sheet modelled average costs to improve dwellings below EER band C to band C or above:
| English dwelling age group | Average modelled improvement cost in 2023 | Average annual CO2 emissions |
|---|---|---|
| Pre-1945 | £9,300 | 5.0 tonnes per dwelling |
| 1945–2012 | £5,100 | 3.3 tonnes per dwelling |
| Post-2012 homes below band C | £2,500 | 2.2 tonnes per dwelling |
The costs are modelled averages, not invoices or realized project prices. The emissions figures are survey/model estimates, and differences reflect age, construction and other dwelling characteristics.
Tenure also matters. In 2023, 61% of private-rented English dwellings had uninsulated cavity or solid walls, compared with 39% with insulated walls.
Across English dwellings, uninsulated solid or cavity walls were associated with damp in 8% of homes, compared with 3% where walls were insulated; this is a cross-sectional association, not proof of causation.
Loft insulation showed a similar association: damp prevalence was 7% among English dwellings with less than 200 mm of loft insulation, compared with 3% among dwellings with at least 200 mm. In the same 2023 survey, 12% of English households reported that at least one part of their home was uncomfortably hot, including 16% of detached-home households and 6% of high-rise-flat households.
The DOE project brief also sets a large U.S. implementation scenario. It aims to cover 64 million homes and 2.7 million commercial buildings, and estimates that retrofitting 64 million homes could produce at least $17 billion in annual energy-bill savings; both figures are project targets or scenario estimates rather than completed retrofit counts or measured portfolio savings.