This dataset estimates the space heating demand for domestic properties, calculating annual heat demand (kWh), energy use intensity (kWh/m2) and peak heating load (kWp).
Heat usage has been modelled using building fabric data, building geometry, obtained from aerial imagery, and housing archetypes based on property type and property age.
Our latest update includes inputs from new data source Ordnance Survey’s National Geographic Database and Energy Performance Certificate records. Premise height and area are adjusted following multi-occupancy criteria in multi-occupancy buildings. The data has been validated against BEIS Energy Statistics data obtained from meter readings.
Figure: Red indicates high annual heat demand and yellow indicates low annual heat demand.
Annual heat demand is calculated using the following formula:
KWp – peak heating load (kWp). Calculated using CIBSE Domestic Heat Design Guide Section 3.8.3
ΔT – temperature difference between desired internal air temperature (assumed to be 20 oC) and outdoor design temperature (oC).
HDD – heating degree days in a given location (a measure of how much (o), and for how long (in days), the outside air temperature was below a base temperature).
The energy use intensity of heating then estimates demand per unit of floor area:
Peak Heating Load
Peak heating load is equal to the total heat loss of the premise when assuming an internal design temperature (comfortable inside temperature) and an outdoor design temperature (realistic worst-case condition).
It is calculated using the system design heat loss methodology set out in the CIBSE Domestic Heating Design Guide 2020, taking into account building geometry, construction of the premise, ventilation heat loss and building fabric heat loss.
More specifically, the total fabric heat loss flow rate (peak heating load), will be the sum of all the U-values of the individual elements of the external fabric (walls, roof, floor, windows, doors, flues and chimneys) multiplied by their respective areas, plus heat loss from ventilation, multiplied by the inside-outside temperature difference.
Building characteristics are collected from Energy Performance Certificate data and Ordnance Survey’s National Geographic Database. If the relevant building characteristics are not available, domestic housing archetypes are used. Archetypes are modelled around property type and property age, using Ordnance Survey data.
Premise Construction Assumptions
Building geometry is assumed to be square, so external wall dimensions can be calculated from the floor area. The length of all walls in the premise is therefore equal to the square root of the floor area.
Other general premise assumptions:
One external door per premise
All external walls have glazing which is apportioned equally. The area of glazing is determined from the housing archetypes using a glazing-to-wall ratio
Detached houses have 4 external walls (one with a door)
Semi-detached houses have 4 external walls (one with a door) and 1 party wall
Terraced houses have 2 externals walls (one with a door) and 2 party walls
Flats are assumed to be middle-floor and one-storey. They have 2 external walls, 1 party wall and 1 internal wall (with a door). Internal floors/ceilings replace solid floors/roofs. Floor-to-ceiling height is calculated using the building height divided by number of floors in the building
Whenever multiple UPRNs can be associated with a single building, the premise height and area are adjusted accordingly. These are taken primarily from Energy Performance Certificates or calculated from the building total area and height (measured to the eaves) if the EPC record is abnormal or not available.
Sources
Fields
Field Display name | Field Description |
UPRN | Unique Property Reference Number |
Parent UPRN | Unique Property Reference Number of the premise above in the building hierarchy |
Premise Area (m²) | Floor area of the premise |
Building Height (m) | Premise height. Matches the building height measured to the eaves in standalone buildings and shells. |
Peak Heating Load (kWp) | Maximum heating load for premise |
Annual Heat Demand (kWh) | Annual Heat Demand |
Annual Heat Demand per m² (kWh/m²) | Annual Heat Demand per m² of floor area |
Heat Demand Banding | Category based on the annual heat demand of the property (very low, low, medium, high, or very high) |
Building ID | Ordnance Survey National Geographic Database identifier |
Type | Category based on the building hierarchy (child, parent, or shell) |
Representative of building | A marker used to identify UPRNs that represent the heat demand of a complete building. |