Publication - Research and analysis

Renewable and zero emissions heating systems in affordable housing projects: evaluation

An evaluation of renewable and zero emissions heating systems in 21 Scottish affordable housing projects. This study assesses the estimated, actual, and counterfactual costs of the projects’ heating systems and determines the drivers behind decision making.

Renewable and zero emissions heating systems in affordable housing projects: evaluation
Appendix B. Individual project data

Appendix B. Individual project data

B0. Overview

In this appendix, the information collected for each project is presented in two tables – an overview and then a per-unit cost breakdown. The second table has not been included if insufficient data was provided, and this is explained in the project's overview. If data is not available but it has been possible to estimate a value, cells are marked with a (B) and the estimation is explained underneath. Where information is yet to be established because the project is at an early stage, cells are marked (P).

An example overview table is provided below, which lists and explains the metrics considered for each of the projects.

Table 21: Example project overview
Metric Information
Location The project's local authority area
Unit count The number of affordable housing units included in the project
Unit types The number of different affordable housing unit types included in the project
Progress Whether the project is in the pre-construction phase, under construction or complete
On-gas grid Whether the project is situated on or off the gas grid
Section 75 Whether or not the project forms the Section 75 affordable housing obligation for a larger development
Sustainability target The energy demand target that the project is designed to achieve
Heating system The technology (or technologies) that are included in the project's heating and hot water generation and storage system
Capex extent The components and services included in the capital expenditure (capex) cost provided
Capex source The source of the capex figure
Opex Whether the project estimated an operational cost (opex) to the occupants to run the heating system
Counterfactual Whether the project has costed an alternative (counterfactual) heating system

B1. Solar PV (individual)

Project 1

An overview of Project 1 is provided in Table 22. A per-unit table has also been provided.

Table 22: Project 1 overview
Metric Information
Location North Ayrshire
Unit count 34
Unit types 7
Progress Under construction
On-gas grid No
Section 75 No
Sustainability target Aspect Silver Level 1 and 2
Heating system Rooftop solar PV modules, electric boiler
Capex extent Installed costs of PV, boiler
Capex source Averaged actual costs
Opex Estimates provided
Counterfactual None considered
Table 23: Project 1 costs per unit
Unit 1 2 3 4 5 6 7
Description 2-bed mid (A) 2-bed mid (B) 2-bed end 2-bed bungalow 2-bed WC bungalow 3-bed det. 4-bed WC det.
Count 3 6 8 8 2 3 4
Footprint (m2) 88 84 83 63 63 119 112
Heat demand 3598 3523 3902 3485 3561 5227 5000
Heat demand per m2 41.0 41.7 47.1 55.4 56.6 44.0 44.6
Installation capex £5,538 £5,538 £5,538 £5,538 £5,538 £5,538 £5,538
PV capex £1,870 £1,870 £1,870 £1,870 £1,870 £1,870 £1,870
Network capex Not considered
Total capex £7,408 £7,408 £7,408 £7,408 £7,408 £7,408 £7,408
Capex per m2 £84.4 £87.8 £89.5 £117.8 £117.8 £62.4 £66.0
Est. opex £475 £465 £515 £460 £470 £690 £660
Est. opex per m2 £5.4 £5.5 £6.2 £7.3 £7.5 £5.8 £5.9

Project 2

An overview of Project 2 is provided in Table 24. A per-unit table has also been provided.

Table 24: Project 2 overview
Metric Information
Location North Ayrshire
Unit count 18
Unit types 7
Progress Under construction
On-gas grid No
Section 75 No
Sustainability target Aspect Silver Level 1 and 2
Heating system Rooftop solar PV modules, electric boiler
Capex extent Averaged actual costs
Capex source Actual costs
Opex Estimates provided
Counterfactual None considered
Table 25: Project 2 costs per unit
Unit 1 2 3 4 5 6 7
Description 3-bed end 3-bed terrace 2-bed end 2-bed mid 2-bed WC bungalow 3-bed WC det. 4-bed WC det.
Count 1 2 7 2 3 2 1
Footprint (m2) 96 93 63 63 63 119 143
Heat demand 4205 3712 3598 3333 3598 5152 6606
Heat demand per m2 44.0 39.9 57.2 53.3 57.2 43.4 46.3
Installation capex £4,675 £4,675 £4,675 £4,675 £4,675 £4,675 £4,675
PV capex £1,603 £1,603 £1,603 £1,603 £1,603 £1,603 £1,603
Network capex Not considered
Total capex £6,278 £6,278 £6,278 £6,278 £6,278 £6,278 £6,278
Capex per m2 £65.7 £67.5 £99.8 £100.4 £99.8 £52.9 £44.0
Est. opex £555 £490 £475 £440 £475 £680 £872
Est. opex per m2 £5.8 £5.3 £7.6 £7.0 £7.6 £5.7 £6.1

Project 3

An overview of Project 3 is provided in Table 26. A per-unit table has also been provided.

Table 26: Project 3 overview
Metric Information
Location North Ayrshire
Unit count 2
Unit types 1
Progress Complete
On-gas grid No
Section 75 No
Sustainability target Gold
Heating system Rooftop solar PV modules, Sunamp heat battery
Capex extent Sunamp and PV installation
Capex source Actual costs
Opex Estimates provided
Counterfactual Gas boilers and PV to meet Silver Aspects 1 and 2
Table 27: Project 3 costs per unit
Unit 1
Description 2-bed terrace
Count 2
Footprint (m2) 85
Heat demand 3462
Heat demand per m2 40.5
Installation capex £4,950
PV capex £1,603
Network capex Not considered
Total capex £3,520
Capex per m2 £8,470
Est. opex £99.2
Est. opex per m2 £269
Alt capex 3.1
Alt capex per m2 £4,180
Est. alt opex 48.9
Est. alt per m2 309

Project 4

An overview of Project 4 is provided in Table 28, and per-unit data in Table 29. A partial data set has been provided for this project, so the units' heat demand has been estimated.

Table 28: Project 4 overview
Metric Information
Location North Lanarkshire
Unit count 2
Unit types 1
Progress Complete
On-gas grid Yes
Section 75 Yes
Sustainability target Gold
Heating system Rooftop solar PV modules, Sunamp heat battery
Capex extent Heating system installation, including electrician costs
Capex source Developer
Opex Not provided – estimated from maximum Gold heat demand
Counterfactual Not costed
Table 29: Project 4 costs per unit
Unit 1
Description 2-bed semi
Count 2
Footprint (m2) 83
Heat demand 2502 (B)
Heat demand per m2 30 (B)
Installation capex £4,132
PV capex £4,794
Network capex Not considered
Total capex £8,926
Capex per m2 £107.0
Est. opex £246 (B)
Est. opex per m2 £2.9 (B)

B2. Air Source Heat Pumps (Individual)

Project 5

An overview Project 5 is provided in Table 30, and per-unit data in Table 31. All available information is included, although a counterfactual has not been costed.

Table 30: Project 5 overview
Metric Information
Location Perth & Kinross
Unit count 4
Unit types 3
Progress Pre-construction
On-gas grid No
Section 75 Yes
Sustainability target Silver
Heating system ASHPs only
Capex extent Heating system installation
Capex source Developer's estimates
Opex Developer's estimates
Counterfactual Direct electric heaters (costs not provided)
Table 31: Project 5 costs per unit
Unit 1 2 3
Description 3-bed semi 2-bed GF flat 2-bed 1F flat
Count 2 1 1
Footprint (m2) 99 60 70
Heat demand 5639 3656 4321
Heat demand per m2 57.0 60.9 61.7
Installation capex £5,500 £5,500 £5,500
Network capex Not considered
Other heating capex N/A
Total capex £5,500 £5,500 £5,500
Capex per m2 £55.6 £91.7 £78.6
Est. opex £437 £366 £400
Est. opex per m2 £4.4 £6.1 £5.7

Project 6

An overview of Project 6 is provided in Table 32, and per-unit data in Table 33. All available data has been shared.

Table 32: Project 6 overview
Metric Information
Location Argyll & Bute
Unit count 300
Unit types 8
Progress Under construction
On-gas grid No
Section 75 No
Sustainability target Silver
Heating system ASHPs only
Capex extent Heating system installation
Capex source Developer's estimates
Opex Developer's estimates
Counterfactual Shared biomass (costed in feasibility study)
Table 33: Project 6 costs per unit
Unit 1 2 3 4 5 6 7 8
Description 2-bed terrace 2-bed WC semi 3-bed semi 4-bed semi 1-bed flat 1-bed WC flat 2-bed flat 2-bed flat
Count 111 16 81 18 27 13 31 3
Footprint (m2) 89 95 106 122 52 69 77 97.5
Heat demand 2790 3047 3045 3125 2309 2431 2601 2707
Heat demand per m2 31.3 28.7 25.0 40.6 44.4 35.2 26.7 28.5
Installation capex £4,944 £4,944 £5,933 £5,933 £5,933 £5,933 £5,933 £5,933
Network capex Considered negligible
Total capex £4,944 £4,944 £5,933 £5,933 £5,933 £5,933 £5,933 £5,933
Capex per m2 £55.6 £46.6 £48.6 £77.0 £114.1 £86.0 £60.8 £62.4
Est. opex £368 £402 £404 £412 £305 £321 £345 £357
Est. opex per m2 £4.1 £3.8 £3.3 £5.4 £5.9 £4.7 £3.5 £3.8
Alt capex £3,093,400 for whole site (approx. £10,300 per unit)
Alt capex per m2 £115.7 £97.2 £84.4 £133.8 £198.1 £149.3 £105.6 £108.4
Est. alt opex £310 (B) £338 (B) £340 (B) £347 (B) £257 (B) £270 (B) £290 (B) £300 (B)
Est. alt per m2 £3.5 (B) £3.6 (B) £3.2 (B) £2.8 (B) £4.9 (B) £3.9 (B) £3.8 (B) £3.1 (B)

Project 7

An overview of Project 7 is provided in Table 34, and per-unit data in Table 35.

Table 34: Project 7 overview
Metric Information
Location Angus
Unit count 10
Unit types 1
Progress Completed
On-gas grid No
Section 75 Yes
Sustainability target SAP: 81 (Project set up before the introduction of current standards)
Heating system ASHPs only
Capex extent Heating system installation
Capex source Contractor's actual costs
Opex Estimates provided
Alternative Gas boilers
Table 35: Project 7 costs per unit
Unit 1
Description 3-bed semi
Count 10
Footprint (m2) 100m2
Heat demand 3571 (B)
Heat demand per m2 35.7 (B)
Equipment capex £10,738
Labour capex
Network capex Not considered
Other heating capex N/A
Total capex £10,738
Capex per m2 £107
Est. opex £500
Est. opex per m2 £5.0
Alt capex £2,944
Alt capex per m2 £29
Est. alt opex £421 (B)
Est. alt per m2 £4.2 (B)

Project 8

An overview of Project 8 is provided in Table 36. A per-unit table has not been provided because the project is at an early stage and has not been costed in detail yet.

Table 36: Project 8 overview
Metric Information
Location Scottish Borders
Unit count 4
Unit types Not yet established (P)
Progress Preconstruction
On-gas grid Yes
Section 75 No
Sustainability target Silver with Gold aspects
Heating system ASHPs and MVHR
Capex extent Heating system installation
Capex source Housing associations' previous projects
Opex Not yet established (P)
Alternative No alternative considered

Project 9

An overview of Project 9 is provided in Table 37. A per-unit table has not been provided because the project contact was not able to share any cost data.

Table 37: Project 9 overview
Metric Information
Location Highland
Unit count 14
Unit types 5
Progress Pre-construction
On-gas grid No
Section 75 No
Sustainability target Bronze
Heating system Air to Water heat pumps; Air to Air heat pumps
Capex extent Not provided
Capex source Not provided
Opex Not provided

Project 13

An overview of Project 13 is provided in Table 38, and per-unit data in Table 39. Notably, this project is the only one to date to have considered the impact of heating systems on network costs. The alternative capex in Table 39 includes an equal share of the £107k cost for the LPG system infrastructure.

Solar PV has been included as part of the heating system in the tables because the project's opex and capex figures include the impact of this technology. (This is included in the 'Other Capex' row in Table 39.)

Table 38: Project 13 overview
Metric Information
Location Highland
Unit count 117 (87 with individual ASHP systems)
Unit types 9
Progress Pre-construction
On-gas grid No
Section 75 No
Sustainability target Silver
Heating system ASHPs, rooftop PV and Sunamp heat batteries
Capex extent Installation of heating system
Capex source Contractor's quotation
Opex Estimates provided
Alternative LPG
Table 39: Project 13 costs per unit
Unit 1 2 3 4 5 6 7 8
Description 2-bed semi (A) 2-bed semi (B) 3-bed semi (A) 3-bed semi (B) 4-bed det. 2-bed bungalow 3-bed bungalow 2-bed cottage flat
Count 20 10 24 8 7 4 2 12
Footprint (m2) 92.1 92.1 103 103 117 89 108.0 80.3
Heat demand 2570 2570 2730 2750 3580 3064 3914 2230
Heat demand per m2 27.9 27.9 26.5 26.7 30.6 34.4 36.2 27.8
Installation capex £6,672 £6,672 £6,672 £6,672 £6,672 £6,672 £6,672 £6,672
Network capex Additional £79,806 (£682 per home)
Sunamp + PV capex £4,346 £4,346 £4,728 £4,346 £5,603 £4,728 £4,728 £3,955
Total capex £11,700 £11,700 £12,082 £11,700 £13,119 £12,082 £12,082 £11,309
Capex per m2 £127.0 £127.0 £117.3 £113.6 £112.1 £135.7 £111.9 £140.8
Est. opex £244 £244 £239 £241 £352 £287 £298 £170
Est. opex per m2 £2.7 £2.7 £2.3 £2.3 £3.0 £3.2 £2.8 £2.1
Alt capex £9,875 £9,875 £10,235 £10,375 £11,835 £11,235 £11,735 £11,015
Alt capex per m2 £107.2 £107.2 £99.4 £100.7 £101.1 £126.2 £108.7 £137.2
Est. alt opex £371 £371 £389 £389 £588 £501 £466 £323
Est. alt per m2 £4.0 £4.0 £3.8 £3.8 £5.0 £5.6 £4.3 £4.0

Project 14

An overview of Project 14 is provided in Table 40. A per-unit table has not been provided as this project contact was not able to share any cost data.

Table 40: Project 14 overview
Metric Information
Location Glasgow City
Unit count 2
Unit types 1
Progress Complete
On-gas grid Yes
Section 75 No
Sustainability target Platinum
Heating system ASHPs, MVHR and Sunamp heat batteries
Capex extent Not provided
Capex source Not provided
Opex Not provided
Alternative Gas

Project 15

An overview of Project 15 is provided in Table 41, and per-unit data in Table 42. Notably, this is the only project to include solar thermal hot water generation, which has been denoted as the 'Other Capex' costs in Table 42.

Table 41: Project 15 overview
Metric Information
Location Dumfries & Galloway
Unit count 5
Unit types 3
Progress Under construction
On-gas grid No
Section 75 No
Sustainability target Silver
Heating system ASHPs, MVHR and solar thermal hot water generation
Capex extent Heating and hot water system installation
Capex source Quantity surveyor's estimates
Opex From SAP reports
Alternative None considered
Table 42: Project 15 cost per unit
Unit 1 2 3
Description 2-bed semi 3-bed semi 2-bed amenity bungalow
Count 2 2 1
Footprint (m2) 87.0 101 69
Heat demand 1215 1044 1120
Heat demand per m2 14.0 10.3 16.2
Equipment capex £10,457 £10,457 £10,457
Labour capex
Network capex Not considered
Other heating capex £3,680 £3,680 £3,680
Total capex £14,137 £14,137 £14,137
Capex per m2 £162 £140 £205
Est. opex £199 £171 £183
Est. opex per m2 £2.3 £1.7 £2.7

B3. Air Source Heat Pumps (shared)

Project 16

An overview of Project 16 is provided in Table 43. A per-unit table has not been provided because the project is at an early stage and has not been costed in detail yet.

Table 43: Project 16 overview
Metric Information
Location Scottish Borders
Unit count 21
Unit types Not yet established (P)
Progress Pre-construction
On-gas grid Yes
Section 75 No
Sustainability target Silver with Gold aspects
Heating system Shared ASHPs with heat interface units in each flat
Capex extent Not yet established (P)
Capex source Not yet established (P)
Opex Not yet established (P)
Alternative No alternative considered

Project 17

An overview of Project 17 is provided in Table 44. A per-unit table has not been provided because the project is at an early stage and has not been costed in detail yet.

Table 44: Project 17 overview
Metric Information
Location City of Edinburgh
Unit count 41
Unit types Not yet established (P)
Progress Pre-construction
On-gas grid Yes
Section 75 No (although development will have non-social let flats)
Sustainability target 100% improvement versus Silver (considered to define 'Net Zero')
Heating system Shared ASHPs with heat interface units in each flat
Capex extent Not yet established (P)
Capex source Not yet established (P)
Opex Not yet established (P)
Alternative Alternatives considered but these will not be costed

Project 13 (1-bed flats)

An overview of Project 13 is provided in Table 38, within the individual ASHP section, as the majority (87 of 117 units) incorporate individual systems. However, the development has 30 one-bed flats which are served by five separate communal ASHP systems, one per block.

Costs for these systems are presented in Table 45 below.

Table 45: Project 13 (1-bed flats) project costs per unit
Unit 1
Description 1-bed flats, 5 blocks of 6
Count 30
Footprint (m2) 48.6
Heat demand 1532
Heat demand per m2 31.5
Installation capex £8,857
Network capex £682
Sunamp + PV capex £4,017
Total capex £13,556
Capex per m2 £278.9
Est. opex £150
Est. opex per m2 £3.1
Alt capex £11,015
Alt capex per m2 £226.6
Est. alt opex £251
Est. alt per m2 £5.2

B4. Ground Source Heat Pumps (Shared)

Project 18

An overview of Project 18 is provided in Table 46, and per-unit data in Table 47. The capex for the GSHP system was provided as a single cost for the whole development.

Table 46: Project 18 overview
Metric Information
Location West Lothian
Unit count 16 (plus one staff building)
Unit types 1
Progress Pre-construction
On-gas grid Yes
Section 75 No
Sustainability target Silver
Heating system Shared GSHPs loop with individual heat pumps, underfloor heating
Capex extent Shared GSHPs loop and individual heat pump installation
Capex source Quantity Surveyor's estimates
Opex Estimated by Mechanical Consultants
Alternative Direct electric heaters (with solar PV to pass SAP)
Table 47: Project 18 costs per unit
Unit 1
Description 1-bed terrace
Count 16
Footprint (m2) 47.7
Heat demand 2,857
Heat demand per m2 60
Installation capex £10,871
Network capex Not considered
Other heating capex N/A
Total capex £10,871
Capex per m2 £228
Est. opex £400
Est. opex per m2 £8.4
Alt capex £4,659 (inclusive of solar PV)
Alt capex per m2 £97.7
Est. alt opex £1,400
Est. alt per m2 £29.4

Project 19

An overview of Project 19 is provided in Table 48, and per-unit data in Table 49.

Table 48: Project 19 overview
Metric Information
Location City of Edinburgh
Unit count 84
Unit types 5
Progress Under construction
On-gas grid Yes
Section 75 Yes
Sustainability target Aspect Silver Levels 1 and 2
Heating system Shared GSHPs loop with individual heat pumps, underfloor heating
Capex extent Shared GSHPs loop and individual heat pump installation
Capex source Actual costs
Opex Estimated by developer
Alternative Gas boilers
Table 49: Project 19 costs per unit
Unit 1 2 3 4 5
Description 2-bed terrace 2-bed end 3-bed terrace 3-bed end 4-bed semi
Count 16 16 34 10 8
Footprint (m2) 82 82 97 97 125
Heat demand 1674 (B) 1674 (B) 1980 1980 (B) 2552 (B)
Heat demand per m2 20.4 (B) 20.4 (B) 20.4 20.4 (B) 20.4 (B)
Equipment capex £11,500 £11,500 £11,500 £11,500 £11,500
Labour capex
Network capex Not considered
Other heating capex N/A
Total capex £11,500 £11,500 £11,500 £11,500 £11,500
Capex per m2 £140 £119 £119 £92 £92
Est. opex £88 (B) £88 (B) £104 £104 (B) £135 (B)
Est. opex per m2 1.1 (B) 1.1 (B) 1.1 1.1 (B) 1.1 (B)
Alt capex £4,000 £4,000 £4,000 £4,000 £4,000
Alt capex per m2 49 41 41 32 32
Est. alt opex £118 (B) £118 (B) £139 £139 (B) £180 (B)
Est. alt per m2 1.4 (B) 1.4 (B) 1.4 1.4 (B) 1.4 (B)

B5. Biomass (shared)

Project 20

An overview of Project 20 is provided in Table 50, and per-unit data in Table 51. Rather than a purpose-built biomass plant for the housing development, the heat source for this project is an industrial scale biomass combined heat and power plant. The capex for the system in this project was provided as a single cost for the whole development, so the figures presented below assign an equal portion of the total cost to each of the units.

Table 50: Project 20 overview
Metric Information
Location Fife
Unit count 85
Unit types 11
Progress Under construction
On-gas grid Yes
Section 75 Yes
Sustainability target Silver
Heating system Shared biomass heating from Markinch biomass plant
Capex extent District heating network and heat interface units in each property
Capex source Actual costs
Opex Central estimates provided
Alternative Gas boilers – not costed
Table 51: Project 20 costs per unit (A)
Unit 1 2 3 4 5
Description 2-bed terrace 3-bed terrace (A) 3-bed terrace (B) 2-bed WC semi 2-bed semi
Count 28 15 11 4 2
Footprint (m2) 83.2 93 116.8 79.8 95.3
Heat demand 5,410 (B) 6,047 (B) 7,594 (B) 5,189 (B) 6,196 (B)
Heat demand per m2 65 (B) 65 (B) 65 (B) 65 (B) 65 (B)
Installation capex £8,837 £8,837 £8,837 £8,837 £8,837
Network capex Inherent to above costs
Other heating capex N/A
Total capex £8,837 £8,837 £8,837 £8,837 £8,837
Capex per m2 £106 £95 £76 £111 £93
Est. opex £139 (B) £155 (B) £195 (B) £133 (B) £159 (B)
Est. opex per m2 £1.67 (B) £1.67 (B) £1.67 (B) £1.67 (B) £1.67 (B)
Table 52: Project 20 costs per unit (B)
Unit 6 7 8 9 10 11
Description 4-bed det. 4-bed WC semi 4-bed semi 5-bed detached 2-bed cottage flat 2-bed WC cottage flat
Count 2 4 2 5 6 6
Footprint (m2) 112.8 98.1 122.2 120 83.8 79
Heat demand 7,334 (B) 6,378 7,945 (B) 7,802 (B) 5,449 (B) 5,137 (B)
Heat demand per m2 65 (B) 65 65 (B) 65 (B) 65 (B) 65 (B)
Equipment capex £8,837 £8,837 £8,837 £8,837 £8,837 £8,837
Labour capex
Network capex Inherent to above costs
Other heating capex N/A
Total capex £8,837 £8,837 £8,837 £8,837 £8,837 £8,837
Capex per m2 £78 £90 £72 £74 £105 £112
Est. opex £188 (B) £164 £204 (B) £200 (B) £140 (B) £132 (B)
Est. opex per m2 £1.67 (B) £1.67 £1.67 (B) £1.67 (B) £1.67 (B) £1.67 (B)

Project 21

An overview of Project 21 is provided in Table 53. A per-unit table has also been provided.

Table 53: Project 21 overview
Metric Information
Location North Ayrshire
Unit count 123
Unit types 15
Progress Under construction
On-gas grid Yes
Section 75 No
Sustainability target Aspect Silver Levels 1 and 2
Heating system Shared biomass heating
Capex extent DHN installation costs (inc. back-up system)
Capex source Actual costs (averaged from development total)
Opex Estimates Provided
Alternative Gas DHN
Table 54: Project 21 costs per unit (A)
Unit 6 7 8 9 10
Description 2-bed bungalow (A) 2-bed bungalow (B) 2-bed WC bungalow 2-bed house (A) 2-bed house (B)
Count 5 7 4 13 13
Footprint (m2) 63 63 63 88 84
Heat demand 4,111 3,889 4,111 4,778 4,222
Heat demand per m2 65 62 65 54 50
Installation capex £11,355 £11,355 £11,355 £11,355 £11,355
Network capex Inherent to above costs
Other heating capex N/A
Total capex £11,355 £11,355 £11,355 £11,355 £11,355
Capex per m2 £245 £177 £206 £237 £183
Est. opex £110 £150 £160 £145 £175
Est. opex per m2 £2.38 £2.34 £2.91 £3.02 £2.81
Alt capex £3,015 £3,015 £3,015 £3,015 £3,015
Alt capex per m2 65.1 47.0 54.8 62.8 48.5
Est. alt opex £110 £150 £160 £145 £175
Est. alt per m2 £2.38 £2.34 £2.91 £3.02 £2.81
Table 55: Project 21 costs per unit (B)
Unit 6 7 8 9 10
Description 2-bed bungalow (A) 2-bed bungalow (B) 2-bed WC bungalow 2-bed house (A) 2-bed house (B)
Count 5 7 4 13 13
Footprint (m2) 63 63 63 88 84
Heat demand 4,111 3,889 4,111 4,778 4,222
Heat demand per m2 65 62 65 54 50
Installation capex £11,355 £11,355 £11,355 £11,355 £11,355
Network capex Inherent to above costs
Other heating capex N/A
Total capex £11,355 £11,355 £11,355 £11,355 £11,355
Capex per m2 £245 £177 £206 £237 £183
Est. opex £110 £150 £160 £145 £175
Est. opex per m2 £2.38 £2.34 £2.91 £3.02 £2.81
Alt capex £3,015 £3,015 £3,015 £3,015 £3,015
Alt capex per m2 47.9 47.9 47.9 34.1 35.7
Est. alt opex £185 £175 £185 £215 £190
Est. alt per m2 £2.94 £2.78 £2.94 £2.43 £2.25
Table 56: Project 21 costs per unit (C)
Unit 11 12 13 14 15
Description 3-bed house 3-bed WC house 4-bed house (A) 4-bed house (B) 4-bed bungalow
Count 20 1 3 1 2
Footprint (m2) 96 119 108 112 130
Heat demand 4,667 5,778 5,556 5,778 6,444
Heat demand per m2 49 49 51 52 50
Installation capex £11,355 £11,355 £11,355 £11,355 £11,355
Network capex Inherent to above costs
Other heating capex N/A
Total capex £11,355 £11,355 £11,355 £11,355 £11,355
Capex per m2 £135 £119 £96 £105 £101
Est. opex £190 £210 £260 £250 £260
Est. opex per m2 £2.25 £2.20 £2.19 £2.31 £2.32
Alt capex £3,015 £3,015 £3,015 £3,015 £3,015
Alt capex per m2 31.5 25.4 27.9 26.9 23.2
Est. alt opex £210 £260 £250 £260 £290
Est. alt per m2 £2.20 £2.19 £2.31 £2.32 £2.23

Contact

Email: 2024heatstandard@gov.scot