Heat Pump for End-of-Terrace House UK 2026

Heat pump end-of-terrace UK 2026: exposed side wall, side passage outdoor unit, single-aspect heat loss penalty.

UK end-of-terrace house exterior showing exposed side wall

Updated 17 June 2026 How we review →

By Rob Griffiths17 June 2026 · 5 min read

Quick answer

End-of-terrace houses present specific heat pump install considerations vs mid-terrace: exposed side wall increases heat loss by 20-35% compared to mid-terrace (one extra exterior wall = ~10-12m2 of additional surface area). Typical end-of-terrace UK heat load: 7-9 kW (vs 5-7 kW mid-terrace of equivalent size). Outdoor unit siting advantage: side passage (typical 800-1500mm) gives easier outdoor unit placement than mid-terrace - acoustic baffles less critical since one side faces neighbour-free space. Priority upgrades: exposed side wall insulation (external wall insulation EWI or internal wall insulation IWI = GBP 4,000-9,000); cavity wall fill if cavity present + unfilled (GBP 400-800); standard heat pump install GBP 10,000-13,500. SCOP: 3.2-3.6 typical post-insulation (better than typical mid-terrace because outdoor unit easier to site optimally). Net cost: GBP 2,500-7,500 net of BUS grant for typical 3-bed end-of-terrace install.

End-of-terrace houses make up about 15% of UK housing stock (~3.5 million properties). They present a mix of advantages + disadvantages for heat pump install vs mid-terrace. This guide covers the install path.

End-of-terrace heat loss characteristics

The exposed side wall premium.

Compared to mid-terrace homes of equivalent floor area:

Mid-terrace: 2 walls exposed (front + back), 2 walls party (left + right shared with neighbours). Party walls have ~0 heat loss (neighbours heat from other side).
End-of-terrace: 3 walls exposed (front + back + one side), 1 wall party (one shared with neighbour). The exposed side wall is typically 8-12m2 additional surface area.

Heat-loss impact:

Mid-terrace 3-bed: 5-7 kW peak heat load.
End-of-terrace 3-bed (equivalent floor area): 7-9 kW (20-35% higher).
Difference driven entirely by the exposed side wall.

Side wall construction varies by era:

Victorian / Edwardian (1850-1910): solid 9-inch brick walls. U-value 1.5-2.0. Very high heat loss.
1920s-1940s: solid 9-inch brick walls. U-value 1.5-2.0.
1950s-1970s: cavity walls (typically unfilled). U-value 1.0-1.4 unfilled, 0.55-0.65 filled.
1980s+: cavity walls (often filled at construction). U-value 0.55-0.65 typical.

Side wall insulation - priority upgrade

EWI vs IWI vs cavity fill.

For pre-1980s end-of-terrace homes, side wall insulation is the single biggest heat-loss reducer:

Option 1 - Cavity wall fill (most cost-effective if cavity exists):

Cost: GBP 400-800 typical for end-of-terrace single wall.
Reduces heat loss 50-70% from that wall.
Often free via ECO4 / Great British Insulation Scheme (GBIS) for eligible households.
Quick install (3-4 hours).

Option 2 - External Wall Insulation (EWI) - best heat loss reduction:

External wrap of insulation board (100mm PIR or PUR) + render finish.
Cost: GBP 4,000-7,000 for single side wall (8-12m2).
Reduces heat loss 80%+ from that wall.
Better than IWI because no internal disruption + protects existing brickwork.
Requires planning permission in conservation areas / sometimes listed buildings.

Option 3 - Internal Wall Insulation (IWI):

Internal insulation board (50mm PIR) + plasterboard finish.
Cost: GBP 2,500-5,000 for single side wall.
Reduces heat loss 60-75%.
Loses ~50mm of internal floor space per wall.
Use when EWI impractical (terrace street facade, listed building).

Outdoor unit siting - side passage is your friend

The end-of-terrace advantage.

The biggest end-of-terrace advantage over mid-terrace is outdoor unit siting:

Side passage placement (most common):

800-1500mm side passage between house + neighbouring fence/garden boundary.
Plenty of room for outdoor unit + servicing access.
Acoustic baffles less critical (one side opens to neighbour-free space, often a garden).
Easy refrigerant pipework routing into utility/kitchen via wall penetration.

Front garden or driveway placement:

For end-of-terrace with parking out front + no side passage.
Need visual screening (planting / acoustic enclosure).
Permitted development typically applies; planning rarely needed.

Rear garden placement:

Standard rear garden (8-12m depth typical for UK terrace).
Often the simplest option for end-of-terrace.
4m+ neighbour distancing usually achievable.

Heat pump sizing for end-of-terrace

7-9 kW typical.

Sizing framework based on age + side wall state:

Victorian/Edwardian end-of-terrace, side wall un-insulated: 9-12 kW.
Victorian/Edwardian end-of-terrace, side wall IWI or EWI fitted: 7-9 kW.
1950s-70s end-of-terrace, side wall cavity-filled: 7-9 kW.
1980s+ end-of-terrace: 6-8 kW.

Pre-install heat-loss calc should specifically itemise the exposed side wall - it's the variable that pushes sizing 1-2 kW higher than equivalent mid-terrace.

Cost framework

End-of-terrace install scenarios.

Scenario A - 1980s+ end-of-terrace with filled cavity:

Heat pump 7 kW + cylinder + install: GBP 10,000-12,500.
BUS grant: -GBP 7,500.
Net: GBP 2,500-5,000.

Scenario B - 1950s-70s end-of-terrace, cavity wall fill needed:

Cavity wall fill side wall: GBP 400-800.
Heat pump 8 kW + cylinder + install: GBP 10,500-13,500.
BUS grant: -GBP 7,500.
Net: GBP 3,400-6,800.

Scenario C - Victorian/Edwardian end-of-terrace, side wall EWI:

Side wall EWI: GBP 4,000-7,000.
Heat pump 9 kW + cylinder + install: GBP 11,000-14,500.
Window upgrade (if still single-glazed): GBP 4,000-8,000.
BUS grant: -GBP 7,500.
Net: GBP 11,500-22,000.

Realistic SCOP for end-of-terrace

Performance achievable.

Un-insulated Victorian end-of-terrace: SCOP 2.7-3.2. Mediocre.
1950s-70s end-of-terrace with cavity-filled side wall: SCOP 3.2-3.5. Good.
1980s+ end-of-terrace + double-glazed: SCOP 3.4-3.7. Solid.
EWI + selective radiator upgrades + envelope: SCOP 3.6-4.0.

End-of-terrace homes can match mid-terrace SCOP scores ONLY with side wall insulation done; without it, performance lags by 0.3-0.5.

Q01Is an end-of-terrace house good for a heat pump?

Yes, with side wall insulation. Heat-loss is 20-35% higher than mid-terrace due to exposed side wall; insulating it (EWI/IWI/cavity-fill) brings heat pump SCOP from 2.7-3.0 (uninsulated) to 3.4-3.7 (insulated). Outdoor unit siting easier than mid-terrace thanks to side passage access.

Q02What size heat pump for an end-of-terrace?

Typical 7-9 kW. Older end-of-terrace (Victorian/Edwardian, uninsulated side wall): 9-12 kW. 1980s+: 6-8 kW. Side wall insulation can reduce required size by 1-2 kW.

Q03Do I need to insulate the side wall before installing a heat pump?

Strongly recommended for pre-1980s end-of-terrace homes. Without insulation, heat pump operates at lower SCOP (2.7-3.0) due to high side-wall heat loss. Cavity-fill (GBP 400-800) is the cheapest fix; EWI (GBP 4,000-7,000) the most effective.

Q04Where should I site the heat pump outdoor unit on an end-of-terrace?

Side passage is usually best - 800-1500mm wide typical, easy refrigerant pipe routing, less acoustic concern (one side opens to neighbour-free space). Rear garden or front driveway are alternatives. Standard 4m+ neighbour distancing applies.