Retrofitting Old Buildings With Heat Pumps Guide

Replacing an old boiler with a shiny new heating system might sound simple, but things rarely go to plan when dealing with older buildings.

Whether it’s a Victorian office block, a pre-war shopfront, a listed heritage site, or a home, chances are it wasn’t exactly built with heat pumps in mind.

With rising energy costs, stricter regulations, and the UK edging ever closer to its net-zero goals, heat pumps are the go-to. A Commercial Heat Pump is a seriously cost-effective option compared to traditional furnaces, which have higher operating costs.

The tricky part is making heat pumps work in buildings where energy efficiency wasn’t part of the original brief.

If you’re considering a retrofit, there’s a fair bit to consider—from poor insulation and awkward layouts to planning red tape and outdated systems.

This practical guide to retrofitting older homes and buildings with heat pumps explains the main obstacles, offers hands-on solutions, and shares real-life examples.

Why Consider Heat Pumps for Older Buildings?

Unlike boilers that burn fuel to generate heat, heat pumps move it, extracting warmth from the air or ground and transferring it inside. This makes them far more efficient than traditional gas or oil systems. It’s an appealing solution for older buildings—but there’s a snag.

Heat pumps work best in well-insulated environments. So if you’re dealing with draughty Edwardian windows or solid-brick Victorian walls, you’ll likely need to make a few upgrades to unlock their full potential.

Still, with the proper preparation, most older buildings can be brought up to scratch. It might not be as easy as plug-and-play, but it’s possible.

Common Challenges (and How to Tackle Them)

Three potential issues must be overcome when electing to heat older buildings with heat pumps, starting with heat loss.

1. Insulation and Heat Loss

This is the big one. Older buildings lose heat fast. Unlike boilers, which deliver intense bursts of warmth, heat pumps run consistently at lower temperatures. You’ll struggle to retain that steady heat if your building has gaps and rattly windows.

Before you install anything, it’s worth checking:

• Wall construction: If you have solid brick or stone, you might need to consider internal or external insulation.
• Windows: Still got single glazing? Even secondary glazing or some well-placed draught-proofing can work wonders.
• Air gaps: Seal wherever possible around windows, doors, and floorboards.

Your options may be limited if your building is listed or in a conservation area. A hybrid setup (heat pump + boiler) can offer a flexible alternative.

2. Space Constraints

Heat pumps aren’t exactly compact, and space in older buildings can be tight.

• Air Source Heat Pumps (ASHPs) require an external unit, which can be tricky if your property is in a dense, urban area.
• Ground-source Heat Pumps (GSHPs) require trenches or boreholes, which can be a non-starter in specific locations.

You can look at compact ASHP units that can be rooftop-mounted or installed in courtyards. Consider shared ground loop systems if you’re working across a campus or a cluster of buildings.

3. Noise and Visual Impact

Although heat pumps are much quieter than traditional systems, they are not silent. The outdoor units on ASHPs produce a constant hum, which can be an issue in urban or residential areas.

Things to remember include local authorities’ noise limits—always check what they are and that the heat pump noise is compliant before proceeding.

If you’re working with heritage properties, aesthetics matter. Acoustic enclosures or careful placement can reduce both sound and visibility.

4. Compatibility with Existing Systems

One of the biggest misunderstandings is that a heat pump can be installed in an old system and work immediately.

Most legacy setups are designed for high-temperature heating from gas or oil. Heat pumps, by contrast, run at lower temperatures, and performance will likely dip without changes.

To boost efficiency, consider taking these actions:

• Swapping in larger, low-temperature radiators.
• Adding underfloor heating is excellent with heat pumps, though it’s not a budget-friendly retrofit.
• Going with a hybrid system with a boiler to handle the colder days.

Real-World Example

Of course, proof is in the workings. A real-world example is an Edwardian social housing block in London.

Sutton Dwellings, Chelsea

This Edwardian social housing block had 27 boreholes drilled for a GSHP system. Compact units were installed in each flat, cutting energy bills and slashing emissions.

Upfront Costs vs. Long-Term Savings

There’s no getting around it — installing a commercial heat pump isn’t cheap. ASHP systems can cost anywhere from £15,000 to £30,000, while GSHPs are typically even more expensive. But the long-term savings can be significant.

There is a trade-off—invest in the upfront costs to get the long-term savings, like the savings achieved for a 1960s office block fitted with an ASHP. Heating bills dropped by nearly a third within two years. Source: The Times, UK.

Funding Support

The UK government offers several schemes to help ease property owners’ cost burdens. One is the Boiler Upgrade Scheme (BUS), which offers grants of up to £7,500, and the other is the Salix Energy Efficiency Loan Scheme, which provides interest-free loans for public sector buildings.

Please do your homework regarding funding support, which will dramatically affect your upfront spend.

Planning Permission and Regulations

If your building is listed or in a conservation area, you’ll almost certainly need planning permission to do anything, including installing heating systems.

Even for non-listed buildings, depending on the heating source, particularly if your installation affects the visual appearance or breaks local noise limits, you might still require approval.

Tips for Getting It Right

• Start with an energy audit — figure out the trouble spots before diving in.
• Bring in the experts — retrofitting older buildings isn’t straightforward. Work with contractors who’ve done it before.
• Phase the work — a hybrid setup can ease the transition if a complete installation isn’t practical.
• Keep an eye on performance. After the system is in place, use smart controls and data monitoring to tweak and improve.

Final Thoughts

Retrofitting a heat pump into an older building isn’t something you can do on a weekend, but with careful planning and the right team, it’s achievable.

The rewards? Lower energy bills, a reduced carbon footprint, and a building ready for the future. Plus, regular maintenance can extend the life of a heat pump.

For facility managers with an eye on long-term sustainability, it’s a sound and forward-thinking investment.