Retrofitting older buildings with heat pumps: What facility managers need to know

Retrofitting older buildings with heat pumps is a challenge, but one worth tackling. With the UK pushing towards net-zero and energy costs fluctuating, facility managers are under pressure to find sustainable, cost-effective heating solutions. Commercial heat pumps offer a path forward if you know how to integrate them into existing structures effectively.

This guide walks through the key considerations, common pitfalls, and real-world solutions when retrofitting older buildings with heat pump technology.

What makes heat pumps a good fit for older buildings?

Heat pumps work by transferring heat rather than generating it, making them far more efficient than traditional gas boilers. For older buildings, however, it’s not always as simple as swapping one system for another.

The good news? Heat pumps are flexible—they can extract heat from the air (Air Source Heat Pumps, or ASHPs) or the ground (Ground Source Heat Pumps, or GSHPs). That means they can be adapted to different types of properties, whether it’s a Victorian office block, a 1960s council building, or a listed heritage site.

The challenge? Older buildings weren’t designed with heat pumps in mind. They often lack proper insulation, have space constraints, or rely on outdated heating infrastructure. These factors can all impact performance.

Key challenges when retrofitting a heat pump

1. Insulation and heat retention

Heat pumps work best in well-insulated buildings. That’s because they operate at lower temperatures than gas boilers, meaning heat loss needs to be minimised.

• If the building has solid brick walls or single-glazed windows, it may need additional insulation or secondary glazing before a heat pump can be effective.
• Listed buildings often come with restrictions on modifying walls or windows, meaning internal insulation might be the only option.

Without addressing insulation, you might find that a heat pump system struggles to keep up—leading to higher running costs and less comfort for occupants.

2. Space constraints

Older buildings weren’t designed with modern heating systems in mind. That can lead to two major issues:

• Lack of space for a heat pump unit – Air source heat pumps require an external unit, while ground source systems need space for boreholes or trenches. Not every property has that flexibility.
• Existing radiators may not be large enough – Since heat pumps work at lower temperatures, they require larger surface areas to distribute heat effectively. That could mean upgrading to larger radiators or even switching to underfloor heating.

3. Noise and aesthetics

In historic or densely populated areas, the external unit of an air source heat pump can raise concerns. Some councils have strict noise regulations, and for heritage properties, aesthetics matter too. Solutions include:

• Positioning the unit in a discreet location, such as behind a parapet or within a courtyard.
• Using acoustic enclosures to reduce noise impact.

4. Integration with existing heating systems

Many older buildings still rely on high-temperature heating systems, designed for gas or oil boilers. Heat pumps operate at lower temperatures, meaning the existing system might not be compatible.

Options include:

• Retrofitting with low-temperature radiators.
• Installing a hybrid system that pairs a heat pump with a backup boiler.

Hybrid systems are becoming more common for older buildings, as they allow a phased transition rather than an all-or-nothing approach.

Case Studies: Retrofitting in Action

🔹 Sutton Dwellings, Chelsea
 A great example of heat pump retrofitting in historic buildings. Here, Edwardian-era social housing was fitted with ground source heat pumps, with boreholes drilled discreetly in the courtyard. The project proved that even century-old buildings can be successfully decarbonised.
📖 Source: The Guardian

🔹 Greenhouse, Leeds
 Originally an old industrial building, this was converted into an eco-friendly residential complex. The developers installed solar thermal panels and ground source heat pumps, cutting energy use dramatically.
📖 Source: Financial Times

Cost & Funding Considerations

Upfront costs vs. Long-term savings

There’s no sugarcoating it: retrofitting a heat pump isn’t cheap. The average cost for an air source heat pump in a commercial setting is between £15,000 and £30,000, while ground source systems can be significantly higher. However, the long-term savings can be substantial.

For example:
 A 1960s office retrofit with an ASHP saw a 30% drop in heating bills within two years.
📖 Source: The Times

Government Incentives

Facility managers should take full advantage of government grants and incentives, including:

• Boiler Upgrade Scheme (BUS) – Offers up to £7,500 off the cost of installation.
• Salix Energy Efficiency Loan Scheme – Interest-free loans for public sector buildings.

These schemes help offset the initial investment, making heat pumps a more financially viable solution.

Regulatory & compliance considerations

Planning permissions

Not all buildings require planning permission for heat pumps, but:

• If the building is listed, you will need approval.
• If the heat pump exceeds a certain noise threshold, planning consent may be required.

It’s always worth checking local authority guidelines before installation.

Building regulations

New regulations are being introduced to phase out fossil fuel heating systems in commercial buildings. From 2025, gas boilers will no longer be permitted in new-builds, and by 2035, most existing buildings will need to transition to low-carbon heating solutions.

📖 Source: Gov.uk

Best practices for facility managers

1. Start with an Energy Audit – This helps determine if insulation upgrades are needed before installing a heat pump.
2. Work with Specialists – Retrofitting older buildings requires expert guidance. Find heat pump installers familiar with heritage properties.
3. Consider a Hybrid Approach – If full electrification isn’t viable immediately, a hybrid system with a backup boiler could be a practical step forward.
4. Monitor Performance Post-Installation – Smart metering can track efficiency and fine-tune settings.

Final thoughts

Retrofitting older buildings with heat pumps isn’t a one-size-fits-all process, but with careful planning, it’s absolutely doable. From energy audits to hybrid systems, facility managers have multiple options to decarbonise their properties without compromising performance.

And with government support, falling technology costs, and a push for net-zero compliance, there’s never been a better time to make the switch.