Insulation
Internal Wall Insulation (IWI)
IWI adds insulation to the inside face of solid external walls — ideal when you want to keep the original exterior untouched.
At a glance
Why people enquire
- Reduces heat loss through solid external walls
- Preserves the original exterior of the property
- Can be carried out room by room to suit your schedule
- Suits listed buildings and conservation areas
- Pairs well with redecoration projects
Internal Wall Insulation (IWI) is fitted to the inside of a property's external solid walls, either with insulated plasterboard or a stud-and-mineral-wool build-up. It's a strong choice for properties where the outside cannot be altered — such as listed buildings, conservation areas, or homes with attractive original brickwork. IWI is usually carried out room by room, so the work can be staged to suit the household.
Benefits
- Reduces heat loss through solid external walls
- Preserves the original exterior of the property
- Can be carried out room by room to suit your schedule
- Suits listed buildings and conservation areas
- Pairs well with redecoration projects
Is it suitable for your home?
- Solid-wall homes where the exterior must remain unchanged
- Listed buildings and properties in conservation areas
- Rooms that feel persistently cold against external walls
- Walls free from untreated damp or penetrating moisture
How it works
01
Friendly conversation
Tell us about your home and what you'd like to improve.
02
Property assessment
We discuss what may suit your property and circumstances.
03
Survey if appropriate
A surveyor confirms suitability and technical details.
04
Clear next steps
You receive straightforward guidance and ongoing support.
Funding & scheme context
Schemes can change. We help you understand the picture.
Internal wall insulation has historically been supported under ECO4 for eligible households. Solid-wall measures are expected to remain relevant under the Warm Homes Plan. We'll help you understand what may currently apply.
Eligibility and availability depend on current scheme rules, property circumstances and household details. Emerald Green Energy does not guarantee funding.
Why choose Emerald Green Energy
Friendly UK-based team that listens before recommending anything.
Experience across insulation, heating and renewables.
Clear, no-pressure guidance from first contact to completion.
Recommendations tailored to your property, not a script.
Aware of how government-backed schemes actually work in practice.
Focused on warmer, more comfortable homes, not pushy sales.
Frequently asked questions
Slightly — the insulation adds thickness to the inside of external walls. The exact reduction depends on the system used and is confirmed during the survey.
Yes. Skirtings, sockets and finishes on insulated walls are reworked as part of the install, and the new surfaces are finished ready for decoration.
Often yes. IWI lends itself to phased, room-by-room installation, which can be useful for occupied homes.
Ready to talk about your home?
Whether you're exploring insulation, heating, solar or future scheme support, our team is here to help.