How Much Are Retrofitting Costs?

The Retrofitting costs of homes across the UK are a rising priority, especially with new laws coming into place like Awaab’s Law and the Renters Rights Act, which introduces a mandatory EPC minimum that houses must adhere to, which many properties in the UK do not, as ONS shows;

“Homes in England had a median Energy Performance Certificate (EPC) score of 69 (Band C), while homes in Wales had a median EPC score of 68 (Band D)”

This means around half of properties in England and Wales need to improve their ratings to meet sustainability requirements, which can lower tenant bills, boost property values and diminish the health risks that come with poorly insulated or heated properties. 

Retrofitting costs that come from upgrading a building’s energy efficiency without a full rebuild are often a practical solution for social housing providers and landlords, especially when compared with the fines that could come from not meeting energy efficiency standards. But what exactly is retrofitting, and what are the retrofitting costs involved?

What is Retrofitting?

Retrofitting involves updating existing buildings with energy-efficient technologies and materials to reduce energy consumption and carbon emissions. This process can include structural improvements like insulation or modern technology such as heat pumps.

For housing providers, retrofitting offers a strategic way to improve property quality while aligning with environmental and regulatory standards, such as potential upcoming changes to EPC requirements. 

These upgrades help properties achieve a minimum EPC rating of C or higher, which is a requirement, and if they aren’t met by 2030, there are fines that can reach up to £15,000 per property, which, if you are a landlord with multiple properties or a housing developer, can add up fast.

Examples of Retrofitting Costs

Retrofitting costs can vary widely depending on the type of upgrade, property size, and location. Here’s a breakdown of some common retrofitting costs and their methods;

1. Insulation

• Cavity Wall Insulation: Costs are on average £2200 according to E.ON Energy, depending on wall conditions and property size, with a mid-floor flat being much cheaper than a larger detached property. Cavity wall insulation is one of the most cost-effective ways to enhance a property’s thermal efficiency.
• Internal Wall Insulation: Prices range from £8,000 to £10,000 per property according to Checkatrade. This option is ideal for properties with limited exterior space or aesthetic restrictions.
• External Wall Insulation: Ranging from £10,000 to £12,500, this type of insulation can be pricier but significantly improves thermal efficiency and reduces external noise.
• Loft Insulation: According to Checkatrade, it can be around £600 to £1,000; loft insulation can dramatically reduce heat loss in homes with attic spaces.
• Underfloor Insulation: Typically costing £2,500 to £5,000 for a professional job, according to the UK Home Energy Guide, this insulation is beneficial for properties with accessible floor voids.

2. Glazing

• Double Glazing Replacement: Costs vary, with full replacements (panes and frames) at an average of £8,000 to £15,000 for a three-bed property, according to Checkatrade. Double glazing is essential for reducing heat loss and improving indoor comfort, especially in colder climates.

3. Heating System Upgrades

• Gas Boiler Replacement: Replacing a gas boiler can cost between £1,800 and £3,500 for a like-for-likeswap, with newer, A-rated boilers saving tenants up to £580 per year on heating.
• Heat Pumps: Air-source heat pumps are a pricier option, between £8,000 and £14,000 according to Bosch, but they can save approximately £340 annually. This system is also eligible for certain government grants, offsetting initial costs.
• Heating Controls: Installing new controls costs around £119-£219 according to Checkatrade, allowing for better temperature management, improving energy efficiency, and potentially lowering utility bills.

4. Additional Measures

• Solar Panels: Installation costs anywhere from £4,900 for a 1-2 bed home to £9,800-£10,900 for a 4+-bed property, though the average UK cost is £8,677 with annual savings of up to £1,200 depending on location and sunlight exposure, according to SwitchTogether. Solar panels can also increase a property’s value by £1,350 to £5,400.
• Draught-Proofing: A more affordable retrofit option, draught-proofing costs about £250 for a property, according to Retrofit Planner, helping prevent heat loss and enhance occupant comfort.
• LED Lighting: Simple Lighting shows that switching to energy-efficient LED lighting can cost between £2.00 and £10.00 per bulb, providing substantial long-term savings on electricity.

With these measures combined into a full-scale Energiesprong retrofit overhaul, costs could total around £35,000 according to Green Alliance, but the expenses may vary. Retrofits can also lead to an increase in property value, with some reports showing an average boost of £10,000 when energy-efficient systems are installed.

Why Should You Retrofit Your Home?

There are several reasons why landlords and housing providers are investing in retrofit programmes, from reducing energy consumption to meeting evolving housing standards.

Lower Bills

 Improving insulation, heating efficiency and the building fabric can reduce the amount of energy required to heat a property. 

This can help lower household energy costs and improve thermal comfort for residents. The potential savings depend on the property, its starting EPC rating, the measures installed and how residents use energy.

Environmentally Friendly

Retrofitting can reduce energy consumption and associated carbon emissions. Measures such as insulation, heat pumps and solar panels can all contribute to improving the environmental performance of existing housing stock.

Meeting New Housing Standards 

Awaab’s Law came into force for the social rented sector in October 2025. From 30 November 2026, Phase 2 will extend the significant-hazard requirements to additional hazards including excess cold, excess heat, falls, structural collapse, fire and explosion, electrical hazards and domestic hygiene.

At the same time, the government has confirmed that social rented homes in England will need to meet EPC C or an equivalent standard by 1 April 2030 under the reformed Decent Homes Standard.

For private rented homes, the government has confirmed a 1 October 2030 compliance date for the new EPC C or equivalent standard, subject to valid exemptions.

These changes mean retrofit planning is increasingly connected to wider housing compliance, not simply energy efficiency.

Future-Proofing Properties 

Starting retrofit work early gives housing providers more time to assess their stock, prioritise properties and spread capital expenditure across planned programmes rather than responding to regulatory deadlines at the last minute.

It can also help providers understand which properties require relatively simple upgrades and which need more comprehensive intervention.

Boost Property Value

Energy efficiency can also influence property value. Rightmove’s analysis found that properties moving from EPC F to EPC C increased in value by an average of 15%, although this research reflects historical property transactions and should not be treated as a guaranteed return on retrofit investment.

How to Retrofit Your Home: Four Key Steps

Completing a successful retrofit involves a few essential steps. For housing providers, taking a planned, whole-house approach can help ensure that individual measures work together rather than creating unintended problems.

1. Assess Energy Efficiency: Start by reviewing the property’s EPC and identifying its current energy-efficiency weaknesses. For larger portfolios, housing providers should consider how properties can be grouped according to EPC rating, building type, heating system, construction and likely retrofit requirements. A professional retrofit assessment can then help determine which improvements should be prioritised.

2. Conduct a Home Survey: A detailed survey can identify problems with insulation, heating, ventilation and energy loss before work begins. This is particularly important because improving one part of a property can affect another. For example, making a home more airtight without considering ventilation can increase the risk of excess humidity and condensation. Monitoring factors such as temperature and humidity can also provide useful evidence of how properties perform before retrofit work begins.

3. Find Qualified Contractors: Retrofit work should be planned and delivered by suitably qualified professionals. For larger programmes, housing providers should consider the requirements of PAS 2035 and use appropriately certified contractors and installers.
Quality matters because poor installation can reduce the expected benefits of a retrofit and create new problems that may be expensive to resolve.

4. Explore Financing Options: Retrofit funding can help reduce the upfront cost of retrofit programmes. The government’s Warm Homes Plan, published in January 2026, aims to upgrade up to 5 million homes by 2030. For social housing providers, the Warm Homes: Social Housing Fund is a key funding route for energy-efficiency improvements and low-carbon heating.

For eligible households in privately owned homes, the Warm Homes: Local Grant can also fund measures such as insulation, heat pumps, smart controls and solar panels. Housing providers should assess available funding alongside their stock condition, EPC data and planned capital works so that funding opportunities can be matched to the properties that need them most.

Prove the Value of Your Retrofit with ResiSure

Retrofitting brings a host of potential benefits, but completing the work is only part of the process. Housing providers also need to understand whether retrofit measures are delivering the expected results in real homes.

An EPC provides a modelled assessment of a property’s energy efficiency. Post-retrofit monitoring provides measured evidence of how the property is actually performing.

ResiSure’s technology monitors temperature, humidity, mould risk and air quality before, during and after retrofit works. This provides housing providers with a clearer picture of whether properties are retaining heat, maintaining healthy humidity levels and delivering the expected improvements.

For providers managing large retrofit programmes, this evidence can also help identify properties that are underperforming and require further investigation.

ResiSure devices take readings every 30 minutes, with information presented through a central dashboard and regular reports; this data can help housing providers validate retrofit activities, identify performance gaps and build an evidence base for future funding and improvement programmes.

Retrofitting Costs a Small Price to Pay

Retrofitting costs vary considerably, but the cost of doing nothing can also become significant as energy-efficiency requirements and housing standards continue to develop.

The most effective approach is to understand the condition and performance of each property, prioritise the measures that will have the greatest impact and plan improvements around long-term regulatory and funding requirements.

With Awaab’s Law expanding in 2026, EPC C requirements approaching in 2030 and significant government investment through the Warm Homes Plan, retrofit is increasingly becoming a core part of property management rather than a standalone sustainability project.

For housing providers, monitoring the results of retrofit work can be just as important as completing it. ResiSure helps provide the real-world data needed to understand whether retrofit investments are delivering warmer, healthier and more energy-efficient homes.