Can You Install an Air Source Heat Pump in an Edwardian House?

Installing an air source heat pump felt like the responsible choice when we started exploring options for heating our Edwardian home. It aligns clearly with where UK Government policy and building standards are heading, particularly through initiatives such as the Boiler Upgrade Scheme. On paper it seems like the forward-looking decision.

We didn’t approach it casually. We’ve taken specialist advice and commissioned formal heat loss calculations. We reviewed radiator outputs. We looked carefully at what lower flow temperatures would mean in a solid-wall property.

On paper, it was viable - albeit with a number of upgrades to the fabric of the house in order for it to work well.

But we didn’t install one.

Not because it couldn’t work - but because, even after all our research, we didn’t feel confident it was the right decision for us at that moment.

What the Heat Loss Calculations Told Us

The numbers aren’t the issue.

Our heat loss calculations showed that, with upgraded radiators and improved insulation, the house could technically operate at the lower flow temperatures required by an air source heat pump.

But those upgrades had consequences.

Heat pumps perform best in well-insulated homes. Ours has no cavity walls. Preserving the original brickwork meant external insulation was never an option. Any improvements had to happen internally, and as we wrote in our piece on the compromises we didn’t expect when renovating an Edwardian house, insulation in solid-wall properties brings trade-offs. Room proportions are reduced, original cornice lost, not to mention condensation risks if not detailed correctly.

It isn’t a simple case of swapping a boiler for a heat pump.

It means rethinking the entire system.

The Solid Wall Reality

Edwardian houses were never designed for central heating as we understand it now.

They were built to breathe - solid brick, lime mortar, open fireplaces creating constant air movement. Retrofitting modern heating into that fabric is entirely possible, but it changes the balance of the building.

Radiator sizing becomes critical. Pipework needs reconsidering. Flow temperatures matter.

The heat pump itself is only one part of a much wider equation.

The Practical Risk No One Talks About

Our biggest hesitation isn’t the theory. It’s delivery.

Installing an air source heat pump in an older house requires coordination across the entire heating system:

• Resizing pipework

• Recalculating radiator outputs

• Allocating meaningful plant room space

• Ensuring the insulation strategy aligns with system performance

In a new build, that coordination is designed in from the outset. In a 1913 townhouse, it relies heavily on finding the right people who can work within the constraints of the existing structure.

We struggled to find a trade locally who felt confident taking ownership of the entire system - design, pipework upgrades and installation - end to end.

There were installers who could fit a unit. There were plumbers who could upgrade parts of the system. But very few who wanted responsibility for the whole strategy in a period retrofit. That’s not to say end-to-end providers don’t exist - but we struggled to find one in our area within our timeframe.

That fragmentation feels risky. Too many moving parts. Too much room for misalignment if performance didn’t meet expectations.

And perhaps most honestly - we underestimated how long sourcing the right person would take. We assumed it would be easier than it was, and we hadn’t built enough time into the renovation schedule to do it properly.

The Running Cost Question

Alongside delivery, the question of running costs hung over us.

In the UK, electricity is significantly more expensive per unit than gas. Heat pumps are far more efficient than traditional boilers, but real-world running costs depend heavily on insulation levels, system design and how the house is used.

We had heard mixed experiences. Some homeowners reported excellent efficiency. Others found that running costs were not dramatically lower than expected in older homes - and in some cases were higher.

The modelling suggested it could work.

But modelling and lived experience are not the same thing. And ours is a large house to get wrong.

The Halfway House We Chose

We haven’t rejected the idea. We’ve prepared for it.

We upgraded and optimised the pipework with lower flow temperatures in mind. We sized radiators carefully, so we can run the system at as low a temperature as possible. We designed a dedicated plant room with sufficient space for cylinders and associated equipment.

The house is now heat pump-ready if - and when - the timing, the local expertise and the economics make sense.

Would We Recommend an Air Source Heat Pump in an Edwardian House?

In the right circumstances - strong insulation, experienced installers, and time for careful coordination - an air source heat pump can absolutely work in a period property. But in a 1913 solid-brick Edwardian townhouse, it isn’t plug-and-play.

Heat pumps are often presented as a straightforward upgrade. In older homes, they are a whole-system decision.

Sometimes the most responsible choice isn’t committing immediately. It’s making sure the house - and the people delivering it - are truly ready.