Modern home with solar panels

Ready to retrofit?

Publication date: 23 April 2024
Reading time: Four minutes

Deciding whether to make your home or property portfolio more energy efficient (retrofitting) is an important and potentially expensive decision. We’ve highlighted some key considerations you should think about when you’re looking at your options as well as sources of financial help for your retrofit project.

What is retrofitting?

New build blocks

Retrofitting means making changes that improve an existing building’s energy efficiency, and bring it closer to modern standards. At Handelsbanken we’re committed to reaching net zero emissions by 2040 at the latest. As part of that, we’re also committed to helping our customers on their own net zero journeys. 

Buildings are the UK’s second-largest source of emissions Opens in a new window and we have the oldest and least energy-efficient housing stock in Europe. More than half of our homes were built before England last won the World Cup, and about a fifth were built over a century ago. More than 80% of homes in the UK use gas boilers, making them vulnerable to spikes in gas prices. That’s why if we’re going to meet our aim to reduce our carbon footprint, it’s important that we make our housing stock more energy efficient. 

An average home could potentially save over £500 Opens in a new window on its annual energy bills by taking basic energy efficiency measures, and thus energy efficient homes can be more attractive to tenants. Finally, estate agents Knight Frank Opens in a new window estimate that improving a residential building’s energy efficiency can raise its value over and above regular local house price growth.

Do you need to retrofit?

How energy efficient is your home already? Its Energy Performance Certificate (EPC) gives your home a rating from A to G, with A being the most efficient.

If it’s in England, Wales or Northern Ireland, you can find your property’s EPC here Opens in a new window – which includes not only its current rating, but the potential it could achieve with some upgrades. In Scotland, the process is slightly different and you can find out more about Scotland’s EPC register here Opens in a new window

If you don’t have an EPC or your current one has expired, ask for an assessment Opens in a new window. You need a valid EPC before you can sell your home or rent it out.

Sustainable loans

We’re here to help, by providing businesses with finance for a variety of sustainable purposes. Find out more via the link below.

Can you afford to retrofit?


Retrofitting is a long-term strategy, investing upfront to enjoy the benefits over the coming years and decades.

If you live in an older property or have older properties in your investment portfolio, improving their energy efficiency is not only important for the future of the planet, it can make economic sense - and is better for yours and your tenants’ health too. 

If you’re a landlord, you may be able to command higher rental levels for a more efficient property Opens in a new window, as tenants will expect to save money on their energy bills. 

It may be more than a ‘nice-to-have’

Wall insulation

At the time of writing (April 2024) the rules on EPCs mean that you can’t commence or continue renting out a domestic or non-domestic property with an EPC rating below E, although some exclusions apply. How that might change going forward is unclear at the moment, and the rules are different in England, Scotland and Wales (check out our guide to current EPC rules for more information). 

There is a suggestion that in order for the UK to meet its legally-binding decarbonisation commitments, stricter EPC limits than currently enforced may be necessary. That could mean a minimum EPC B rating for non-domestic property in England by 2030, and EPC C for domestic property from 2028.

How do I decide which retrofit measures to adopt?

These depend on your individual circumstances, not to mention your budget.

A deep retrofit is a comprehensive upgrade of the building, replacing or improving every item or system that contributes to energy efficiency. It can result in a 30-50% energy saving Opens in a new window and, in exchange for a higher initial outlay, can lead to a reduction of operating costs, improvement in air quality and a boost in the value of the property.

Many homeowners will opt for some of the individual elements of a retrofit, which can include:

Solar panels

In the UK, solar panel installations have been considered a “permitted development” since 2008 and planning permission is not generally needed unless homes are in a conservation area. In November 2023, rules were relaxed further meaning that homes with flat roofs in conservation areas do not need to apply for planning permission either. Speak to a professional to learn more. 

There has never been a better time to install solar panels, with prices having reduced approximately 90% in the past decade, and payback periods in many regions being eight years or fewer Opens in a new window.

What’s more, they may be able to generate income, in the shape of Smart Energy Guarantee (SEG) Opens in a new window payments, which in many cases will be tax free, if you’re feeding excess energy back into the grid. However, it’s worth checking with your supplier what your feed-in rate would be. 


If your home isn’t insulated, it may lose around a third of its heat through the walls Opens in a new window and a quarter through the roof Opens in a new window

Cavity wall insulation involves injecting material into the gap between your home’s inner and outer walls, if it has one (most homes built after the 1920s will). For walls without cavities, such as single skin walls, internal or external wall insulation may be possible. 

Loft insulation can take two main forms – either insulating the floor of the loft with a material like mineral wool or natural alternative such as hemp or sheep’s wool; or alternatively from fitting specialised boards between the rafters in your roof or using spray foam insulation. The latter is more expensive but may be suitable if you want to use your attic as a “room in roof” living space.

You may also want to draught-proof existing doors and windows.

Heat pumps

Ground or air source heat pumps extract heat from outside and can be up to four times more efficient than gas boilers Opens in a new window. The type you choose depends on your budget and available space but either way there’s no gas bill and fewer emissions. In England and Wales, you can claim up to £7,500 of government funding Opens in a new window towards installing one, and heat pumps have recently become VAT free.

Biomass boilers

These heating systems burn organic matter like wood, household waste or manure and can be used to generate central heating and hot water. Burning wood will release some carbon dioxide and particulate matter, but much less than fossil fuels.

Double or triple glazing

Aside from the obvious benefit of being warmer in winter and cooler in summer, your home will be quieter and less damp than if it’s single glazed (you will need to ensure you still have adequate ventilation however). You can choose wooden frames that complement your home’s appearance and even transfer the old panes into the new frames in some cases. If this isn’t possible, you may wish to consider secondary glazing. 


The Energy Saving Trust estimates that if the average UK household replaced all its bulbs with LED versions, it would take about £40 off its annual electricity bill Opens in a new window. The upfront cost of around £100 would easily be recouped by the energy savings combined with greater lifetime of the LED compared to a halogen bulb – five times longer.

Financial help to support your retrofit project:

The Energy Company Obligation Opens in a new window (ECO) is a government energy efficiency scheme in England, Scotland and Wales designed to tackle fuel poverty and help reduce carbon emissions, focused on supporting low-income households. ECO is an obligation, placed on energy suppliers with over 150,000 customers to deliver measures such as insulation, first time central heating, renewable heating, solar panels, and district heating connections to domestic premises.

The Great British Insulation Scheme Opens in a new window (GBIS) is a government energy efficiency scheme in England, Scotland and Wales formerly known as ECO+. It is designed to complement the ECO and boost help for those on the lowest incomes, as well as extending support to a wider range of households living in the least energy efficient homes and in the lower council tax bands.

The Home Upgrade Grant (HUG) Opens in a new window and the Local Authority Delivery (LAD) schemes provide funding for energy efficiency upgrades and low-carbon heating in low-income households in England. Funding for both schemes is available from local authorities who were successful in the 2021 Sustainable Warmth competition Opens in a new window and supported by government funding.

The Smart Export Guarantee (SEG) Opens in a new window supports small scale renewable power (electricity) generation. It does not offer upfront payments but households installing renewable power technologies will be paid by their energy supplier for each unit of electricity they supply to the grid (i.e. the excess to their domestic consumption). They will not be paid for electricity they use themselves.

Green Deal loans mean households may be able to access funding for home energy improvements (including energy efficiency measures and heating systems) through the Green Deal Opens in a new window. Unlike a previous scheme with the same name, these loans are not backed by the government and are instead backed by private investors. The loans are paid back over time with interest, through energy bills. The loan is attached to the property (rather than the constituent), so if a homeowner sells their home, the loan will pass to the new owner.