Dataset Overview
This dataset estimates the suitability of domestic and non-domestic properties for the installation of an Air Source Heat Pump (ASHP), which extracts heat from the outside air to provide space heating.
Each property is assessed using its building type, curtilage area, and peak heating demand. A property is deemed suitable if it has enough external space to accommodate an ASHP outdoor unit. Properties that are unsuitable are given a reason explaining why, which you can find in the data field titled 'Remark'.
Figure 1: Green shows a building suitable for ASHP installation, grey is unsuitable.
Methodology
Building data is extracted from OS NGD Building and OS NGD Address to determine building topography and type information. This is combined with land data extracted from OS NGD Land. For the domestic dataset, buildings are filtered to residential properties only. For the non-domestic dataset, only non-domestic properties are included. The building and land data is combined to calculate the total garden or curtilage area for each property. Road network data from OS NGD Highways is used to identify the front of the property and separate the area into front and back portions.
For ASHP, the total area (front and back combined) is used for the suitability check, as the 2025 amendment to the General Permitted Development Order (GPDO 2015, Class G, SI 2025/560) removed the previous 1 m boundary rule and now allows ASHP placement anywhere within the curtilage.
A property is suitable for ASHP when:
The building's usage type is suitable (based on its OS AddressBase classification). See ‘Excluded Classification Codes’ below for further details.
The total garden or curtilage area meets the minimum threshold for the property type (see table below)
Where a building contains multiple properties (e.g. a block of flats or multi-tenanted commercial building), ASHP suitability is assessed at the most granular level. Suitability is assigned to the Child record where one exists, otherwise the Parent, then the Shell.
The domestic thresholds (0.6 m² and 1.5 m²) reflect the minimum space needed for a residential ASHP outdoor unit and its clearance zone. The non-domestic threshold (6 m²) accounts for the larger outdoor unit footprint and clearance zone typical of commercial installations.
The recommended heat pump size is derived from the peak heating demand of the property, with a minimum size of 3 kW:
For domestic properties, see the Domestic Heat Demand article for how peak heating demand is calculated
For non-domestic properties, see the Non-Domestic Heat Demand article
Minimum outdoor area thresholds:
Field Name | Field Description | Dataset |
Self-contained flat (RD06) | 0.6m² | Domestic |
All other domestic property types | 1.5m² | Domestic |
All non-domestic property types | 6m² | Non-Domestic |
Excluded Classification Codes:
Domestic:
Within the Residential classification, the following property types are excluded from the suitability assessment as they do not have a conventional building footprint and garden/ curtilage arrangement:
RB Ancillary Building (e.g. outbuildings, sheds)
RC Car Park Space / Allocated Parking
RD07 House Boat
RG Garage / Lock-Up Garage
All non-residential classifications are also excluded as the domestic dataset covers residential properties only.
Non-domestic:
Non-domestic classification codes are mapped to a suitability flag using the OS AddressBase classification scheme. The following categories are excluded as they typically lack enclosed building fabric or a defined curtilage suitable for heat pump servicing:
Agricultural sites (CA) such as farms, fisheries, and horticulture
Ancillary buildings (CB, LB, MB) such as outbuildings and support structures
Mineral extraction and quarrying (CI02) and related processing/storage
Outdoor leisure and sport facilities (CL06 subcodes such as playing fields, golf courses, and equestrian facilities) and open-air attractions (CL08)
Transport infrastructure (CT) such as car parks, railway assets, marinas, and freight terminals
Utilities infrastructure (CU) such as substations, pump houses, telecoms masts, and waste treatment works
Storage land (CS), including builders' yards
Land classifications (L) such as agricultural land, forestry, allotments, amenity land, open space, and water features
Military sites (M) excluding Defence Estates (MG)
Navigation aids, coastal protection, and street furniture (O-prefix codes)
Monuments and underground features (Z-prefix codes excluding Stately Homes and Places of Worship)
Assumptions
The total garden or curtilage area is used for the ASHP suitability check. This reflects the 2025 GPDO Class G amendment which permits ASHP placement anywhere within the curtilage, removing the previous restriction requiring placement at least 1 m from the property boundary.
The minimum area thresholds represent the space needed for an outdoor unit and clearance zone. They do not assess noise compliance with MCS 020 or proximity to neighbouring sensitive receptors.
Roof-mounted ASHP installations are not assessed. A property without sufficient ground-level external space is marked unsuitable even if its roof would be a viable mounting location.
Land parcels larger than 15,000 m² are excluded to remove anomalous data (e.g. farmland or large industrial landholdings incorrectly linked to individual buildings).
Sources
Fields
Field Name | Field Description |
UPRN | Unique Property Reference Number |
Parent UPRN | Unique Property Reference Number immediately above in the building hierarchy |
Overall Suitability Rating | The overall suitability of the property for an air source heat pump |
Remark | Supporting note on suitability or constraints. |
Recommended Heat Pump Size [kW] | The recommended heat pump size for the property. |
Peak Heat Pump Demand (kWp) | The modelled peak building heat demand of the property. |
Building Size (m^2) | The area of the building within the land parcel. |
Total Garden Area (m^2) | The total area of the garden within the land parcel. |
Type | UPRN Type Parent, Child or Shell. |