Insulation Costs

Insulating your home is one of the most effective ways for UK homeowners to save on energy costs while also making their homes more comfortable to live in. So what does insulation cost?

With a tendency for cool temperatures throughout much of the year, the UK climate means most homes could benefit from additional insulation to reduce heating demands.

Adding insulation creates a barrier between the warm air inside your home and the colder external temperatures outside. This improves the energy efficiency of your home, allowing you to retain heat better so less energy is required to heat your rooms to comfortable temperatures. With rising energy bills, this can mean considerable savings for most UK households. According to government statistics, an insulated home can reduce heating bills by an average of £405 per year.

Beyond cost savings, insulation enhances comfort by preventing draughts and cold spots within rooms. This allows you to heat rooms faster as less warmth gets lost to the outside. Many homeowners notice their homes simply “feel cosier” after insulation. Insulation can also prevent damp and mould issues by regulating internal moisture and temperatures. Investing in home insulation should be considered a priority for all UK homeowners. This guide covers the main types of insulation materials and methods to help you explore your options.

Types of Home Insulation

Loft Insulation

Loft insulation is critical for energy efficiency as heat rises in the home and most is lost through the roof. Government guidelines recommend installing 270-300mm thickness of insulation material in your loft space to prevent heat loss through the roof. Loft insulation is one of the most cost-effective home upgrades you can make when it comes to improving energy efficiency. According to Energy Saving Trust statistics, installing 200mm of insulation in the loft of a typical semi-detached UK home could lead to energy bill savings of £215 per year.

Loft insulation materials

• Mineral Wool – This traditional insulating material made from fibrous rock remains popular. Easy DIY install, costing about £800 to do a 1930s style semi-detached home.
• Sheep’s Wool Insulation – Made from 85% recycled wool, this sustainable option offers excellent heat retention. However, costs are higher with professional install around £1,500 for a semi-detached house.
• Other sustainable options like hemp fibre and cellulose insulation offer potential alternatives but can be pricier than rockwool or standard fiberglass rolls.

Overall loft insulation remains one of the smarter investments. As an example, a 1930s semi with no insulation could payback the £800 install cost in under 4 years through energy savings – then continue saving £215+ a year going forward.

Loft Insulation Materials Costs Comparison:

Material	Average Cost
Mineral Wool	£800
Sheep’s Wool Insulation	£1,500
Hemp Fibre	£900-£1,200
Cellulose	£850-£950

Cavity Wall Insulation

Cavity wall insulation involves filling the space or “cavity” between the inner and outer layers of external walls with an insulating material. Installing cavity wall insulation creates a thermal blanket between the walls, reducing heat loss through the walls and improving energy efficiency.

According to government statistics, cavity wall insulation could save the average semi-detached home £165 per year on energy bills. While savings vary based on existing wall insulation and home size, the installation costs are usually recouped in just a few years after install.

Cavity will insulation materials

• Polystyrene Beads – This budget option involves injecting small polystyrene balls into the cavity. A typical install costs around £500-£800.
• Mineral Wool – More commonly used as rolls or batts filled between wall cavities. This traditional fibrous insulation offers reliable performance, installed professionally from £800-£1,200.
• Other insulating materials like polyurethane foam are expanding options but currently more expensive. Homeowners should discuss options with installers to balance performance, cost and sustainability when selecting materials.

Overall cavity wall insulation offers homeowners another way to realise hundreds in annual energy bill savings after a moderate install investment. It also enhances comfort by stabilising internal wall temperatures.

Cavity Wall Insulation Materials Costs Comparison

Material	Average Cost
Polystyrene Beads	£500-£800
Mineral Wool	£500-£800
Polyurethane Foam	£1,000-£1,400

Solid wall insulation

Solid walls, often found in older homes, consist of a single wall of bricks or masonry without a cavity or gap. Insulating these walls can further prevent heat escaping compared to cavity walls. External or internal wall insulation boards/panels are installed depending on preference.

According to government reports, solid wall insulation can lower heating bills by £455 per year for a typical home. While pricier to install, payback periods are still usually under 10 years.

Solid wall insulation materials

• Internal Wall Insulation – Rigid insulation boards fixed to internal walls and covered in plaster or drywall offers simpler install around £5,500-£8,500 based on home size.
• External Wall Insulation (EWI) – Insulated render systems or cladding applied externally tends to be more expensive, averaging £10,000-£14,500 for a semi-detached home but can have added weatherproofing benefits.

Additional Considerations

• Installers should evaluate potential moisture risks in walls and ensure adequate ventilation.
• Ideal if walls require renovation already or if damp/mould issues present.
• Combining with roof insulation maximises potential savings.

With energy savings of up to £455 annually, solid wall insulation costs may seem high but can pay for itself over the long-term.

Solid Wall Insulation Materials Costs Comparison:

Type	Average cost
Internal Wall Insulation	£5,500-£8,500
External Wall Insulation	£10,000-£14,500

Floor Insulation

Heat loss through floors can account for 10-15% of a home’s heat loss. Insulating floors helps retain warmth and reduce energy demands. Floor insulation is important for houses with accessible sub-floors but also benefits homes with solid concrete floors.

For a typical semi-detached home, insured floor insulation could save about £90 annually on bills while enhancing comfort.

Floor insulation materials

• Rigid Foam Boards – Extended polystyrene or polyurethane boards fitted between joists underneath floorboards is a common DIY-friendly option. Costs around £800+ for materials.
• Insulated Plasterboards – Can be fitted underneath solid floors by lifting flooring to install sheets layered with insulating foam. Around £1,200+ for professional install.

Additional Considerations

• Perimeter insulation around the edge of floors should also be evaluated to prevent thermal bridges.
• Installing a moisture barrier might be recommended to prevent damp.
• Combining with underfloor heating systems can improve efficiency.

While the upfront costs are meaningful, floor insulation provides homeowners long-term energy savings and improved comfort underfoot.

Floor Insulation Materials Costs Comparison:

Material	Average cost
Rigid Foam Boards	£800+
Insulated Plasterboards	£1,200+

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