Heat Loss and Insulation

Typical heat losses in an uninsulated home are:

  • 35% through the walls 
  • 25% through the roof
  • 15% lost as a result of draughts
  • 15% through floors
  • 10% through windows

The Fabric First approach

A fabric first approach prioritises the thermal performance of the building fabric (walls, roof, floors, windows and doors) before other building services such as heating or renewable energy. Taking this approach can have a number of benefits including:

  • Reduced energy consumption
  • Reduced running costs
  • Improved thermal comfort (in both winter and summer)
  • No ongoing maintenance costs

An Energy Performance Certificate will help you identify the most effective measures for your property. You may also be able eligible for up to £5,000 in Green Homes Grant funding that can help pay for insulation measures (£10,000 is available for those on certain benefits).

Once you’ve improved the fabric of your home, you could think about adding some energy generation capacity.

Wall Insulation

Depending on what sort of house you live in, different types of wall and roof insulation will be applicable to your house:

Cavity wall insulation can be injected into wall cavities and the drill holes ‘made good’. If your house was built from the 1930s onward, it’s likely you have some form of cavity wall.

Solid wall insulation can be fixed to the internal or external wall of the building. If your house is older than about 1930, you probably have solid walls.

Party wall insulation can be injected into the vented cavity between neighboring properties.

Roof and Loft Insulation

Loft insulation is laid between and over the joists to a recommended depth of 280mm. This method is commonly applied if you don’t use your loft space as a room.

Room in roof insulation – A layer of insulation can be added to the vertical and sloping surfaces of the roof space. This method is commonly applied if you use your loft space as a room.

Flat roof insulation – A layer of insulation can added above or below the flat roof. The work is usually carried out when some other part of the roof needs to be replaced.

Floor insulation

Solid floor insulation – A layer of rigid insulation can be laid on top of the existing floor with a layer of boarding on top of that. Some adjustments will be needed for skirting boards and other fittings.

Suspended timber floors – Rolls of mineral wool are laid between the joists and held in place with plastic meshing before the floorboards are re-laid.

Windows and Doors

Double or triple glazing – Fitting high performance windows can cut heat loss substantially, and make the room more comfortable by eliminating cold areas around windows. It’s worth noting that the payback period can be in excess of 20 years.

Secondary glazing – A secondary pane of glass can be installed from the inside without the need to remove or replace the existing window. Secondary glazing is most often applied in buildings where building restrictions apply. The method is just as effective as double glazing and can work out cheaper.

Draught Proofing

Fitting draught proofing materials around windows, doors, letterboxes and keyholes can be an effective way to cut heat loss at low cost. The materials can be purchased from most DIY stores.