Blog>Expert Advice>Whole house retrofit: Save energy and cut your bills
Last updated: 4 July 2025
Whole house retrofit: Save energy and cut your bills
New, modern homes are designed with energy-efficiency in mind, in line with current building regulations. However, this wasn't always the case, meaning that millions of homes across the UK are harder and more expensive to heat. The solution? Retrofitting. Read on to find out more.
According to TrustMark, around 24 million homes in the UK need retrofitting to meet modern energy standards. So if you're cranking up the thermostat in an older home and are still feeling the chill, you're not alone.
Our homes use 35% of the UK's energy and emit 20% of the UK's total CO2 emissions (TrustMark).
Therefore improving the energy efficiency of UK homes is a key part of the government's commitment under the Climate Change Act 2008. That is, to achieve net-zero carbon emissions by 2050.
In this post, we look at what retrofitting involves, the benefits it offers, and the process of having it done in your home. Checkatrade member Josh Raffo from Thrift Energy also gives us his advice.
What is retrofitting?
Retrofitting (a property) is the process of making upgrades to a building to improve aspects such as safety, sustainability, or energy efficiency.
With fluctuating energy prices and the UK's commitment to reduce carbon emissions, retrofitting is becoming more common.
Since many UK homes were built before modern energy regulations (we have the oldest housing stock in Europe), they often suffer from poor insulation, cold draughts, and inefficient heating systems.
What does a retrofit include?
A whole house retrofit addresses key areas, including:
Insulation: Walls, floors, loft/roof
Windows and doors: Upgrading to double or triple glazing
Reviewing services: Heating (including renewable heating systems), hot water, and lighting
What are the benefits of a whole house retrofit?
Improving your home's energy efficiency via a whole house retrofit offers several benefits:
Improved home comfort
Enhanced indoor air quality (better for your health)
Reduced damp and mould
Reduced carbon emissions
How to retrofit your home
Your home's energy efficiency can be improved in several ways, either by upgrading different parts of your home or replacing them entirely.
The most common renovations for retrofitting your home include:
Loft insulation - to reduce heat loss from the roof
Wall insulation - either internal, external, or cavity wall insulation
Draught-proofing - to seal gaps in floors, doors, and chimneys
Double or triple-glazing - to minimise heat loss through windows and doors
Heating systems - upgrading to a more efficient boiler, installing a renewable system such as a heat pump, or incorporating smart controls
Checkatrade member Josh Raffo from Thrift Energy says:
"Proper ventilation is essential in any whole house retrofit to prevent damp, mould, and poor air quality.
"At Thrift Energy, we take a comprehensive approach, ensuring that insulation upgrades, double or triple glazing, and heating system improvements don’t compromise airflow.
"That’s why hiring certified installers is crucial. Getting it right the first time means a healthier, more energy-efficient home with lower carbon emissions for years to come."
Whole house retrofit: understanding the process
There are two options for embarking on a house retrofit:
1. Use our free search tool to find tradespeople
Find tradespeople covering your local area to fulfil the energy-efficient home improvements you require.
Whether you need help with insulation, heat pumps, or double-glazing, you can find checked and reviewed tradespeople on Checkatrade.
Our members work to the Checkatrade Standard and are covered by the Checkatrade Guarantee.
2. Contact a Retrofit Assessor
Alternatively, search for a Retrofit Assessor. This route is often a requirement if your energy-efficient retrofits are funded by a government initiative such as ECO4 or the Great British Insulation Scheme.
In this instance, you must hire an installer certified with TrustMark to retrofit homes in accordance with PAS 2035 compliance.
Here's how the retrofit process works:
A Retrofit Assessor conducts a home energy assessment to identify weak points in insulation, ventilation, and heating efficiency, i.e. the measures that are needed to improve your home's energy efficiency
A Retrofit Coordinator then uses this assessment to create an Improvement Plan tailored to your home. This is broken down into stages so you can choose the work you wish to undertake depending on your budget
Retrofit Installers will then provide quotes for the energy efficient upgrades you wish to go ahead with. Once you've made your selection, your Retrofit Coordinator will start planning the work schedule
Final assessment and monitoring then takes place to ensure the work meets all required quality standards
How much do retrofit services cost?
A Retrofit Assessment tends to cost in the region of £400 - £600
Retrofit companies typically charge between £1,500–£3,900 + VAT , depending on the scope of the services you require
See the tradespeople we've checked for your job
How much does it cost to retrofit a house?
The cost of a whole house retrofit will vary depending on the energy-efficient home improvements you choose to undertake.
Our guide to retrofitting house costs contains further information.
What grants are available for retrofitting UK homes?
The UK government has committed to reducing climate change. So, they want to encourage homeowners to make their homes more energy-efficient to help reach the net-zero target by 2050.
As such, there are several government initiatives and schemes to help with the cost of making homes more energy efficient, including the ECO4 Scheme, the Great British Insulation Scheme, the Boiler Upgrade Scheme, and the Warm Homes Local Grant.
Find out which green homes grants are available.
Who should you contact for retrofitting services?
It depends on what retrofit measures you wish to undertake. You may need multiple tradespeople to cover all angles. From insulation installers to double glazing companies and heating and ventilation contractors.
See the tradespeople we've checked for your job
FAQs
What is a whole house retrofit?
A whole house retrofit is the process of upgrading key areas of the home to improve overall energy efficiency. These areas typically include insulation, windows and doors, and reviewing services such as the heating system, hot water, and lighting.
How much does a whole house retrofit cost in the UK?
It's hard to put a figure on the cost of a whole house retrofit without undertaking a retrofit assessment — your property size, the scope of the works, and the cost of local contractors will largely determine the cost you're quoted.
Draught proofing can cost as little as £85 - £275 for an entire property as this energy-efficiency home improvement can normally be tackled as a DIY project. However, something like a boiler upgrade or installing wall insulation carries a higher cost and must be done by a checked tradesperson.
Do I need a PAS 2035-certified professional for a retrofit?
If your energy-efficient home improvements are being funded by a government-backed scheme, such as ECO4, it's often a requirement to must use a PAS 2030-certified installer and have a PAS 2035-accredited Retrofit Coordinator oversee the project.
PAS 2030 applies to installers who carry out retrofit work
PAS 2035 refers to the compliance that applies to the whole retrofit process
See the tradespeople we've checked for your job