Retrofit explained

Generally, ‘retrofit’ means to add a component to something that didn’t have it when it was first made.

When we talk about retrofitting, it usually refers to installing improvements in an existing building for improving its energy efficiency and lowering its carbon footprint. But it can also be things like:

• Improving ventilation and air quality
• Installing upgrades to generate and store electricity

This contrasts with new build homes that should be designed with energy efficiency in mind from the start. It’s possible to retrofit homes, business premises, and even cars, but here we’ll focus on homes.

Retrofit upgrades are usually the responsibility of the homeowner or landlord. But some aspects of retrofit may still be relevant for tenants. There may also be grants or other support available for eligible tenants to retrofit their homes depending on where you live.

As one of the most intensive uses of energy in UK homes is heating, many retrofit improvements are intended to make heating your home more efficient. A home retrofit may include:

• solar panels
• heat pumps
• loft insulation
• wall insulation (either for cavity walls or solid walls)
• floor insulation
• energy efficient windows

The main benefit of home retrofitting is the improved energy efficiency of your home, which leads to lower energy bills.

Also, installing renewable energy technologies in particular help to protect against rising energy costs. For example, you can generate your own electricity from solar panels.

In older homes where insulation is poor, the benefits of retrofit include:

• Making the building easier to heat for less money.
• Keeping your home comfortably warm.
• Improving issues such as damp and condensation, helping to make your home a healthier place for people to live.

In addition to the financial and health benefits, home retrofit plays a major role in reducing carbon emissions in the UK. This is crucial for the UK moving towards net zero and addressing the climate emergency.

These are the average costs to install the most common retrofit improvements in a semi-detached home. Costs may be lower if you make multiple changes at the same time.

These costs don’t include potential discounts from funding, for example the Boiler Upgrade Scheme.

As a first step, check whether your home has an energy performance certificate (EPC). If you’re not sure, you can look up your property’s EPC If there is an EPC for your home and you live in England, Wales, or Northern Ireland, you can find it at the GOV.UK website. For a property in Scotland, check Scottish EPC Register.

The EPC will give you information about what kinds of retrofit measures would be best suited to your property. Note that EPCs expire after ten years, so it’s worth checking your EPC is still valid to ensure the retrofit recommendations are up to date.

When you change something in your home, it can affect how heat, air and moisture move around the building. Even small changes can have knock‑on effects.

Some improvements, like topping up loft insulation or changing heating controls, are usually low risk. Others, especially insulation and heating changes, can have a bigger impact on how the whole home works.

Because everything in a home is connected, it helps to think about the whole building, not just one bit at a time. This can reduce the risk of problems like damp or poor ventilation.

That’s why it’s a good idea to have a whole‑house plan. This doesn’t have to be complicated.

A whole‑house plan means you reduce the risk of unintended problems later by:

• Understanding how your home works now.
• Thinking about what changes you might want to make in the future.
• Making sure different improvements will work well together.

You can still do the work in stages, over time. That’s normal and often the only realistic option. But even if you only make one change now, knowing how it fits into the bigger picture can help you make better decisions.

It’s about good planning and design, not about having to do everything at once.

A qualified retrofit assessor can help you think through your options and develop a whole‑house plan. It can be helpful to get more than one assessment, so you can compare different approaches and recommendations before deciding what’s right for your home.

Depending on your circumstances and where you live, you may be able to get free or partly funded retrofit advice. We recommend using TrustMark to find a qualified retrofit assessor.

Whether you can get financial help for retrofitting your home depends on several factors including:

• where you live
• your financial situation
• whether you own or rent your home
• and the type of property you have

There are some programmes offering free retrofit improvements for eligible homeowners and tenants, usually based on income or benefits. Other programmes offer grants and zero interest loans for retrofit improvements.

You can find the latest information about getting help with the cost of home retrofit in our guide to financial support for home energy efficiency.

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