Case Study

Heat Pump Installation in Victorian Terrace - Bournemouth

How we successfully installed a heat pump in a 140-year-old Victorian terrace, achieving 18% energy cost savings while preserving period features.

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Property Type
3-Bed Victorian Terrace
Built 1885, 110m²
Installation Date
April 2025
4 days on-site
Total Cost
£11,500
After up to £9,000 BUS grant
Annual Savings
£240/year
18% reduction

The Challenge: Victorian Property Retrofit

Key Challenges Identified

  • 1.
    Limited Outdoor Space:

    Narrow courtyard garden (3m × 4m) shared boundary wall with neighbors, requiring careful unit placement to avoid noise complaints and visual impact.

  • 2.
    Solid Wall Construction:

    9-inch solid brick walls (U-value 2.1 W/m²K) with no cavity insulation. Heat loss calculations showed 45% of heat escaping through walls.

  • 3.
    Original Cast Iron Radiators:

    Period radiators designed for high-temperature boiler systems (70-80°C flow temperature) incompatible with heat pump lower temperatures (40-50°C).

  • 4.
    Aging Gas Boiler:

    20-year-old Worcester boiler with declining efficiency (estimated 75-80%), requiring replacement within 2-3 years.

  • 5.
    Conservation Area Restrictions:

    Property located in Boscombe conservation area requiring planning sensitivity for external alterations.

Homeowner Goals

  • Replace aging boiler with future-proof renewable heating
  • Reduce carbon footprint and contribute to net zero targets
  • Lower long-term energy costs despite higher initial investment
  • Preserve Victorian character and avoid major structural changes

Our Solution: Tailored Victorian Retrofit

1

Comprehensive Heat Loss Survey

Conducted detailed room-by-room heat loss calculation using actual wall U-values, window types, and air infiltration rates. Total heat demand: 8.2kW @ -3°C design temperature.

Outcome: Specified 8kW Mitsubishi Ecodan heat pump with 10% oversizing buffer for Victorian thermal characteristics.
2

Strategic External Wall Insulation

Rather than whole-house insulation (cost-prohibitive at £12,000+), we targeted the rear elevation only (not visible from street, not subject to conservation restrictions). Installed 70mm EPS insulation reducing rear wall U-value from 2.1 to 0.35 W/m²K.

Outcome: 25% reduction in overall heat loss for £3,200 investment. Improved heat pump efficiency by 15% vs uninsulated scenario.
3

Selective Radiator Upgrades

Retained original cast iron radiators in hallway and dining room (period features visible to guests). Replaced radiators in bedrooms and living room with larger K2 double-panel convectors sized for 45°C flow temperature.

Outcome: Cost-effective compromise: £1,800 for 3 new radiators vs £4,500 for whole-house replacement. Period features preserved where visible.
4

Discrete Outdoor Unit Placement

Positioned 8kW outdoor unit on rear wall corner (3.2m from neighbor boundary), mounted on anti-vibration pads with acoustic barrier screen. Painted in "Anthracite Grey" to match existing garden wall color.

Outcome: Noise level 41dB @ 1m (quieter than background garden noise). No neighbor complaints. Minimal visual impact from house or neighboring properties.
5

Hot Water Cylinder Installation

Replaced old copper tank with 210L unvented cylinder in airing cupboard. Integrated immersion heater backup for summer-only hot water (avoiding heat pump operation in warmest months).

Outcome: Excellent hot water performance. Family of 3 reports never running out of hot water. Summer immersion use adds only £35/year to costs.

Installation Timeline

Day 1

Removed old boiler, prepared pipework, installed outdoor unit bracket, mounted heat pump, and drilled refrigerant pipe penetration.

Day 2

Installed hot water cylinder, connected heating pipework, replaced 3 radiators, and completed electrical connections.

Day 3

System pressure testing, refrigerant charging, commissioning, and initial system balancing. Temporary heating available by evening.

Day 4

Final commissioning, homeowner training session, MCS documentation, BUS grant redemption, and site cleanup.

Results After 12 Months

4.1
Actual SCOP
(Seasonal Performance)
£1,090
Annual Energy Cost
(vs £1,330 previously)
48 years
Simple Payback
(vs gas boiler replacement)

Energy Cost Comparison

Old gas boiler (2024/25)£1,330/year
Heat pump (2025/26)£1,090/year
Annual Savings£240 (18%)

Homeowner Testimonial - 12 Months Later

"Initially skeptical about a heat pump working in our Victorian house, but we're absolutely delighted. The house is warmer and more comfortable than it ever was with the old boiler - no more cold spots in the bedrooms. Running costs are lower, and knowing we've reduced our carbon footprint gives us real satisfaction.

The installation was professional and respectful of our period property. The team worked around our daily schedule and left everything spotless. We barely notice the outdoor unit, and it's definitely quieter than the old boiler ever was.

Would highly recommend to anyone with a Victorian or Edwardian property wondering if heat pumps can work in older homes. Ours definitely does!"

— Sarah M., Homeowner, Boscombe

Key Lessons for Victorian Properties

✓ What Worked Well

  • Targeted insulation (rear wall only) was cost-effective compromise
  • Selective radiator upgrades preserved period features
  • Mitsubishi Ecodan performed excellently in solid-wall property
  • Weather compensation controls optimized efficiency automatically

⚠ Challenges & Solutions

  • Challenge: Neighbour noise concerns. Solution: Anti-vibration mount + acoustic screen
  • Challenge: Limited pipework routes. Solution: Careful planning using existing floorboards access
  • Challenge: Learning curve for homeowners. Solution: Extended training + follow-up visits

Planning a Heat Pump for Your Victorian Home?

We specialize in sensitive retrofits for period properties across Dorset. Get expert advice tailored to your specific property.

Call 01202 985350