Top Home Upgrades Covered by ECO4 in 2025

ECO4 funding covers a comprehensive range of energy efficiency improvements that can transform your home's comfort, running costs, and environmental impact. For eligible households, these upgrades are completely free—potentially saving you £10,000 to £30,000 or more.

This guide details every type of improvement covered under ECO4, what each involves, typical costs, and the benefits you can expect. Whether you need better insulation, a new heating system, or renewable energy, ECO4 might cover it.

1. Insulation Measures

Insulation is the foundation of home energy efficiency, and ECO4 covers all major types. Proper insulation can reduce heating bills by 20-40%.

Loft Insulation

What it is: Insulating material laid between and over ceiling joists
Typical cost saved: £300-£600
Annual savings: £200-£400 on heating bills
Installation time: 1 day

Loft insulation is one of the quickest wins for energy efficiency. Heat rises, and without adequate loft insulation, up to 25% of your home's heat escapes through the roof.

Cavity Wall Insulation

What it is: Insulation material injected into the gap between inner and outer walls
Typical cost saved: £500-£1,500
Annual savings: £150-£350 on heating bills
Installation time: 1-2 days

Most homes built between 1920 and 1990 have cavity walls. If yours aren't insulated, you're losing approximately 35% of your heat through the walls.

Solid Wall Insulation

What it is: Internal or external insulation boards applied to solid walls
Typical cost saved: £8,000-£20,000
Annual savings: £400-£600 on heating bills
Installation time: 1-3 weeks

Older homes (typically pre-1920) have solid walls without cavities. Solid wall insulation is more expensive but delivers significant improvements—this is where ECO4 funding becomes invaluable.

Underfloor Insulation

What it is: Insulation installed beneath ground floor
Typical cost saved: £1,000-£3,000
Annual savings: £100-£200 on heating bills
Installation time: 2-5 days

Particularly beneficial for homes with suspended wooden floors. Reduces drafts and heat loss through the floor, improving comfort significantly.

2. Heating System Upgrades

An efficient heating system is crucial for warmth and managing energy costs. ECO4 covers several heating improvements.

Boiler Replacement

What it is: Replacing old, inefficient boiler with modern A-rated condensing boiler
Typical cost saved: £2,500-£4,000
Annual savings: £300-£500 on heating bills
Installation time: 1-2 days

If your boiler is over 10 years old, it's likely inefficient. Modern boilers are 90%+ efficient compared to 60-70% for older models. ECO4 covers full replacement including all pipework and controls.

Air Source Heat Pumps

What it is: Renewable heating system extracting heat from outside air
Typical cost saved: £8,000-£14,000
Annual savings: £500-£800 compared to electric heating
Installation time: 2-3 days

Heat pumps are the future of home heating. They're 300%+ efficient and significantly reduce carbon emissions. ECO4 can fully fund installation for eligible households.

Smart Heating Controls

What it is: Smart thermostats and heating zone controls
Typical cost saved: £200-£500
Annual savings: £75-£150 on heating bills
Installation time: Half day

Modern controls let you program heating schedules, control temperature by room, and adjust settings remotely. Often included as part of boiler or heat pump installations.

3. Renewable Energy Systems

ECO4 extends beyond efficiency improvements to include renewable energy generation, helping you produce your own clean power.

Solar PV Panels

What it is: Photovoltaic panels generating electricity from sunlight
Typical cost saved: £5,000-£8,000
Annual savings: £400-£700 on electricity bills
Installation time: 1-2 days

Solar panels can cover 40-60% of your electricity needs. ECO4 covers full installation including panels, inverter, and wiring. You can also sell excess electricity back to the grid through the Smart Export Guarantee.

Solar Thermal Systems

What it is: Solar panels that heat water directly
Typical cost saved: £3,000-£5,000
Annual savings: £150-£300 on hot water heating
Installation time: 1-2 days

Solar thermal systems heat your hot water using the sun's energy, reducing boiler usage. Particularly effective when combined with efficient insulation.

4. Ventilation and Air Quality

Improving insulation and heating can affect air quality if ventilation isn't addressed. ECO4 covers ventilation measures to ensure healthy indoor environments.

Ventilation Measures Include:

Mechanical Ventilation with Heat Recovery (MVHR): Extracts stale air while recovering heat, ensuring fresh air without heat loss
Extractor fans: Bathroom and kitchen fans to remove moisture and cooking odors
Trickle vents: Small vents in windows allowing continuous background ventilation
Positive input ventilation: Systems that gently ventilate the home with filtered fresh air

These measures prevent condensation, mold, and poor air quality that can occur when homes are made more airtight. ECO4 assessments identify whether ventilation improvements are needed alongside insulation.

5. What's NOT Covered by ECO4

While ECO4 is comprehensive, there are some limitations to be aware of:

Not Covered:

Cosmetic improvements (decorating, new carpets)
Repairs to existing systems (unless part of a broader upgrade)
Improvements to outbuildings or non-residential spaces
Battery storage (though this may change)
Windows and doors (unless specifically required for energy efficiency)
Regular maintenance or servicing

ECO4 focuses specifically on measures that improve energy efficiency and reduce carbon emissions. However, necessary repairs required to enable these improvements (like roof repairs before loft insulation) may be included.

6. How Improvements Are Prioritized

Not every home needs every improvement. ECO4 assessors follow a "fabric first" approach to determine the best package for your property.

The Priority Order:

Insulation first: Stop heat escaping before upgrading heating systems
Heating efficiency: Once insulation is addressed, upgrade to efficient heating
Renewable energy: Finally, add renewable generation where beneficial
Ventilation: Included as needed to maintain air quality

This approach maximizes effectiveness. There's no point installing an expensive heat pump if heat is escaping through poor insulation. The home survey determines which improvements your property needs most.

7. Typical Improvement Packages

Here's what different homes typically receive through ECO4:

Basic Package (EPC E-G homes):

Loft insulation (if needed)
Cavity wall or solid wall insulation
Basic ventilation improvements
Total value: £3,000-£10,000

Standard Package (EPC D-E homes):

Full insulation (loft, walls, floors)
Boiler replacement or heat pump
Smart heating controls
Ventilation as required
Total value: £10,000-£18,000

Comprehensive Package (Lower income, EPC D-G):

Full insulation package
Heat pump or high-efficiency boiler
Solar PV panels
Advanced ventilation system
Smart controls
Total value: £18,000-£30,000+