Do Air Source Heat Pumps Work In Old Houses?

Last Updated on June 5, 2025

If you own an older home or manage a rental property, you’ve probably asked yourself at some point: Do air source heat pumps work in old houses? 

With energy bills rising and the push for greener alternatives gaining momentum, air source heat pumps (ASHPs) have become a popular choice for heating solutions.

While air source heat pumps are a well-known option for modern, energy-efficient homes, many older properties in the UK come with their own unique challenges, like solid walls, draughts, and older radiators. 

But the good news is, yes, air source heat pumps can work in old houses, as long as the right measures are in place.

In this guide, we’ll discuss how viable air source heat pumps are for older UK properties, including insulation requirements, planning permissions, and system sizing. 

If you’re a homeowner or landlord considering upgrading to a more efficient, low-carbon heating system, we will help you understand what’s involved, and why now is the time to act.

Can You Put An Air Source Heat Pump in An Old House?

Yes. Older homes in the UK can absolutely benefit from air source heat pumps, but their success depends heavily on factors such as insulation, system sizing, and compatibility with existing heating infrastructure.

Since older houses were not designed with energy efficiency in mind, retrofitting them for ASHPs requires careful planning.

One of the key challenges is heat retention. Unlike new-builds, many period properties have solid walls with poor insulation and single-glazed windows, making heat loss a serious issue. 

For an air source heat pump to perform efficiently, the building envelope must be improved. This often includes:

• Upgrading insulation in walls, lofts, and floors
• Installing double or triple glazing
• Ensuring airtightness to minimise draughts

Before installing an ASHP, it’s also essential to assess the existing heating system. Many older homes use high-temperature systems and smaller radiators, which may not deliver enough heat at the lower temperatures typical of heat pumps. In such cases, upgrading to larger radiators or underfloor heating may be necessary.

Our guide on “will heat pumps work with my radiators” sheds more light on this and helps clarify what changes, if any, might be necessary for your home.

What Size Air Source Heat Pump Do You Need for an Older Home?

Choosing the correct size air source heat pump is crucial. An undersized unit will struggle to heat the home, while an oversized one may cycle on and off inefficiently. The size depends on several factors, including property age, insulation levels, and floor area.

Here’s a helpful table to estimate the right ASHP size for older UK homes:

These are ballpark figures. For an accurate assessment, request a professional heat loss survey. 

Planning Permission and Legal Requirements For Air Source Heat Pumps

In most cases, installing an air source heat pump on a domestic property in the UK falls under Permitted Development Rights. However, older homes, especially listed buildings or those in conservation areas may require planning permission.

You should check with your local planning authority before installation, especially if:

• Your property is listed or in a conservation area
• The unit is to be placed within one metre of the property boundary
• The external unit will be mounted on the roof or wall facing a highway

An MCS-certified installer will typically assist with the application and ensure your installation is compliant. For a step-by-step overview, read our air source heat pump installation guide.

Preparing an Old House for an Air Source Heat Pump

To make air source heat pumps viable in older homes, the following upgrades are recommended:

1. Improve Insulation

Solid wall insulation (internal or external), loft insulation, and floor insulation dramatically reduce heat loss. To make things more accessible, heat pump grants such as the Boiler Upgrade Scheme (BUS) are available to help cover the cost of both the heat pump installation and, in some cases, the necessary insulation improvements.

2. Upgrade Windows and Doors

Switch to double or triple glazing to prevent drafts and retain heat.

3. Conduct a Heat Loss Survey

An accurate heat loss survey helps determine the ideal size of the heat pump and identifies insulation weak spots.

4. Consult a Professional Installer

An experienced installer will assess your property and determine whether your home is suitable for a heat pump. 

Why Air Source Heat Pumps Make Sense for Older Homes

Despite the necessary upgrades, air source heat pumps are an excellent choice for older properties, offering:

• Reduced carbon emissions and a greener heating solution.
• Lower long-term energy costs, especially with rising gas prices.
• Eligibility for government-backed grants to offset costs.
• Increased home value and EPC rating, which is vital for landlords and property investors.

It’s also worth weighing the air source heat pump pros and cons to decide if it’s the right solution for your property.

Ready to Future-Proof Your Old Home? Get Your Free Air Source Heat Pump Quote Today!

If you’re wondering whether an air source heat pump is right for your older property, the best next step is to get a tailored quote. At Eco Happy, our MCS-certified experts assess your home’s unique requirements to ensure maximum efficiency and comfort.

Don’t let an old house stop you from embracing a cleaner, greener future. Take control of your heating costs and improve your property’s efficiency today.

Request your free air source heat pump quote now — no obligation, just expert advice you can trust.

FAQs

Are heat pumps expensive to run?

Heat pumps are generally cheaper to run than traditional electric or oil heating systems and can offer savings compared to gas, depending on energy prices and your home’s insulation. 

They work by transferring heat rather than generating it, which makes them highly efficient, often producing 3 to 4 units of heat for every unit of electricity used. To keep running costs low, it’s important to ensure your home is well-insulated and that the system is correctly sized and installed.

What is the best heating system for an old house?

For older properties in the UK, the best heating system depends on factors like insulation, available space, and fuel type. If the home is well-insulated or can be upgraded, a heat pump can be a great long-term solution. 

For homes where insulation upgrades are limited, a modern condensing gas boiler might be more practical in the short term. It’s worth speaking with a heating specialist to explore options that balance comfort, energy efficiency, and cost.

Do you still need a boiler with a heat pump?

Not necessarily. Most air source and ground source heat pumps are fully capable of providing both heating and hot water on their own, especially in well-insulated homes. 

However, in some cases, particularly in older or larger properties, a hybrid system that combines a heat pump with a traditional gas boiler may be recommended to ensure sufficient heat output during very cold weather or to meet high hot water demand. Your installer will help determine the best setup for your needs.