What is a U-value?
A U-value, also known as thermal transmittance, measures how easily heat passes through a building element such as a wall, roof, floor, window or door. U-values are expressed in W/m²K.
Lower U-values indicate better insulation and improved energy efficiency.
The database includes default U-values for walls, roofs, floors, windows, doors and other common building elements.
When are default U-values used?
These default U-values are used in energy assessment tools including SBEM, DSM and EPC software when the exact construction or insulation details of a building are unknown or cannot be confirmed during a site survey.
How to find the value you need
Use the filters above to narrow down the results by element type, construction type, country, or building regulation period.
You can also press Ctrl + F (or Cmd + F on Mac) to search this page directly.
Wall U-Values: NCM Defaults
Solid (Masonry) Wall
| Construction | Region | Year/Detail | Regulation | U-Value |
|---|---|---|---|---|
| Cast concrete wall | Not specified | Internal insulation | — | 0.83 |
| Cob wall | England & Wales | Pre-1982 | — | 0.8 |
| Cob wall | England & Wales | 1982 onwards | — | 0.6 |
| Cob wall | Not specified | External insulation | — | 0.39 |
| Cob wall | Not specified | Internal insulation | — | 0.41 |
| Heavy partition wall | Not specified | — | — | 3.5 |
| Masonry wall with rainscreen | Not specified | — | — | 1.7 |
| Solid brick wall, 110mm | England & Wales | Uninsulated | — | 3.1 |
| Solid brick wall, 110mm | England & Wales | Dry lined | — | 1.9 |
| Solid brick wall, 110mm | England & Wales | Insulated | — | 0.6 |
| Solid brick wall, 225mm | Not specified | Pre-1919 uninsulated | — | 1.7 |
| Solid brick wall, 230mm | England & Wales | Dry lined | — | 1.41 |
| Solid brick wall, 230mm | England & Wales | Insulated | — | 0.63 |
| Solid brick wall, 340mm | England & Wales | Pre-1919 uninsulated | — | 1.6 |
| Solid brick wall, 340mm | England & Wales | Dry lined | — | 1.2 |
| Solid brick wall, 340mm | England & Wales | Insulated | — | 0.5 |
| Solid concrete wall | Not specified | Uninsulated | — | 1.7 |
| Solid concrete wall | England & Wales | Dry lined | — | 1.2 |
| Solid no fines concrete wall | England & Wales | — | — | 1.63 |
| Solid stone wall – Granite or Whin | England & Wales | Uninsulated | — | 1.83 |
| Solid stone wall – Granite or Whin | England & Wales | Dry lined | — | 1.38 |
| Solid stone wall – Granite or Whin | England & Wales | Insulated | — | 0.83 |
| Solid stone wall – Sandstone | England & Wales | Uninsulated | — | 1.83 |
| Solid stone wall – Sandstone | England & Wales | Dry lined | — | 1.38 |
| Solid stone wall – Sandstone | England & Wales | Insulated | — | 0.83 |
| Solid wall | England & Wales | 1974–1980 | — | 1.7 |
| Solid wall | England & Wales | 1980/85 | Part L | 0.6 |
| Solid wall | England & Wales | 1990 | Part L | 0.45 |
| Solid wall | England & Wales | 1995 | Part L | 0.45 |
| Solid wall | England & Wales | 2002 | Part L | 0.35 |
| Solid wall | England & Wales | 2006/2010 | Part L | 0.35 |
| Solid wall | Northern Ireland | 2006 | Part F | 0.35 |
| Solid wall | Scotland | 1975–1981 | — | 1 |
| Solid wall | Scotland | 1982–1990 | — | 0.6 |
| Solid wall | Scotland | 1991–1996 | — | 0.45 |
| Solid wall | Scotland | 1997–2001 | — | 0.45 |
| Solid wall | Scotland | 2002 | Part J | 0.3 |
| Solid wall | Scotland | 2007 | Section 6 | 0.25 |
| Solid wall | Not specified | External insulation | — | 0.33 |
Cavity Wall (Clear)
| Construction | Region | Year | Regulation | U-Value |
|---|---|---|---|---|
| Clear cavity wall | England & Wales | Pre-1974 | — | 1.6 |
| Clear cavity wall | England & Wales | 1974–1980 | — | 1 |
| Clear cavity wall | Northern Ireland | 1977 or earlier | — | 1.7 |
| Clear cavity wall | Northern Ireland | 1978–1983 | — | 1 |
| Clear cavity wall | Scotland | Pre-1975 | — | 2.4 |
| Clear cavity wall | Scotland | 1975–1981 | — | 1 |
| Clear cavity wall | Scotland | 1982–1990 | — | 0.6 |
| Clear cavity wall | Scotland | 1991–1996 | — | 0.45 |
| Clear cavity wall | Scotland | 1997–2001 | — | 0.45 |
| Clear cavity wall | Scotland | 2002–2006 | — | 0.3 |
| Clear cavity wall | Scotland | 2007 | Section 6 | 0.25 |
Cavity Wall (Full Fill)
| Construction | Country | Year | Regulation | U-Value |
|---|---|---|---|---|
| Cavity wall | England & Wales | 1980/85 | Part L | 0.65 |
| Cavity wall | England & Wales | 1990 | Part L | 0.55 |
| Cavity wall | England & Wales | 1995 | Part L | 0.51 |
| Cavity wall | England & Wales | 2002 | Part L | 0.35 |
| Cavity wall | England & Wales | 2006/2010 | Part L | 0.27 |
| Fully filled cavity wall | Not specified | 50mm min. wool | — | 0.53 |
| Fully filled cavity wall | Not specified | 75mm min. wool | — | 0.41 |
| Fully filled cavity wall | Not specified | 100mm min. wool | — | 0.32 |
Cavity Wall (Partial Fill)
| Construction | Country | Year | Regulation | U-Value |
|---|---|---|---|---|
| Cavity wall retro insulation | England & Wales | Retrofit | — | 0.63 |
| Cavity wall | Northern Ireland | 1984–1991 | — | 0.6 |
| Cavity wall | Northern Ireland | 1992–1999 | — | 0.55 |
| Cavity wall | Northern Ireland | 2000–2005 | — | 0.45 |
| Cavity wall | Northern Ireland | 2006 | Part F | 0.27 |
| Cavity wall | Scotland | 1982–1990 | — | 0.6 |
| Cavity wall | Scotland | 1991–1996 | — | 0.45 |
| Cavity wall | Scotland | 1997–2001 | — | 0.45 |
| Cavity wall | Scotland | 2002–2006 | — | 0.3 |
| Cavity wall | Scotland | 2007 | Section 6 | 0.25 |
| Partially filled cavity wall | Not specified | 50mm min. wool | — | 0.57 |
| Partially filled cavity wall | Not specified | 50mm phenolic foam | — | 0.4 |
| Partially filled cavity wall | Not specified | 50mm polyurethane | — | 0.31 |
| Partially filled cavity wall | Not specified | 75mm min. wool | — | 0.43 |
| Partially filled cavity wall | Not specified | 75mm phenolic foam | — | 0.22 |
| Partially filled cavity wall | Not specified | 75mm polyurethane | — | 0.23 |
| Semi-exposed wall | Scotland | 1982–1990 | — | 0.7 |
| Semi-exposed wall | Scotland | 1991–1996 | — | 0.6 |
| Semi-exposed wall | Scotland | 1997–2001 | — | 0.6 |
Non-Structural Wall (Metal)
| Construction | Region | Year | Regulation | U-Value |
|---|---|---|---|---|
| Steel wall | Not specified | No insulation | — | 5.7 |
| Metal cladding plus internal block | England & Wales | Pre-1980 | Uninsulated | 2.3 |
| Metal cladding plus internal block | England & Wales | 1980/85 | Part L | 0.6 |
| Metal cladding plus internal block | England & Wales | 1990/95 | Part L | 0.45 |
| Metal cladding plus internal block | England & Wales | 2002 | Part L | 0.35 |
| Metal cladding plus internal block | England & Wales | 2006 | Part L | 0.35 |
| Metal cladding wall | England & Wales | Pre-1981 | — | 1.7 |
| Metal cladding wall | England & Wales | 1980/85 | Part L | 0.6 |
| Metal cladding wall | England & Wales | 1990 | Part L | 0.45 |
| Metal cladding wall | England & Wales | 1995 | Part L | 0.45 |
| Metal cladding wall | England & Wales | 2002 | Part L | 0.35 |
| Metal cladding wall | England & Wales | 2006/2010 | Part L | 0.35 |
| Metal cladding wall | Northern Ireland | 2006 | Part F | 0.35 |
| Metal cladding wall | Scotland | Pre-1975 | — | 1.7 |
| Metal cladding wall | Scotland | 1975–1981 | — | 1 |
| Metal cladding wall | Scotland | 1982–1990 | — | 0.6 |
| Metal cladding wall | Scotland | 1991–1996 | — | 0.45 |
| Metal cladding wall | Scotland | 1997–2001 | — | 0.45 |
| Metal cladding wall | Scotland | 2002–2006 | — | 0.3 |
| Metal cladding wall | Scotland | 2007 | Section 6 | 0.25 |
| Metal sheet wall | Not specified | Uninsulated | — | 5.7 |
Timber Frame Wall
| Construction | Region | Year | Regulation | U-Value |
|---|---|---|---|---|
| Log cabin wall | Not specified | Insulated | — | 0.4 |
| Log cabin wall | Not specified | Uninsulated | — | 0.76 |
| Stud wall to roof void | England & Wales | 1980/85 | Part L | 0.6 |
| Stud wall to roof void | England & Wales | 1990 | Part L | 0.45 |
| Stud wall to roof void | England & Wales | 1995 | Part L | 0.45 |
| Stud wall to roof void | England & Wales | 2002 | Part L | 0.35 |
| Stud wall to roof void | England & Wales | 2006/2010 | Part L | 0.35 |
| Stud wall to roof void | Not specified | Uninsulated | — | 1.2 |
| Stud wall to roof void | Not specified | 25mm quilt | — | 0.6 |
| Stud wall to roof void | Not specified | 50mm quilt | — | 0.37 |
| Stud wall to roof void | Not specified | 75mm quilt | — | 0.27 |
| Stud wall to roof void | Not specified | 100mm quilt | — | 0.21 |
| Stud wall to roof void | Not specified | 150mm quilt | — | 0.15 |
| Stud wall to roof void | Not specified | 200mm quilt | — | 0.12 |
| Stud wall to roof void | Not specified | 250mm quilt | — | 0.09 |
| Stud wall to roof void | Not specified | 300mm quilt | — | 0.08 |
| Thin lightweight partition wall | Not specified | — | — | 0.45 |
| Timber frame wall | England & Wales | 1980/1985 | Part L | 0.6 |
| Timber frame wall | England & Wales | 1990 | Part L | 0.45 |
| Timber frame wall | England & Wales | 1995 | Part L | 0.45 |
| Timber frame wall | England & Wales | 2002 | Part L | 0.35 |
| Timber frame wall | England & Wales | 2006/2010 | Part L | 0.3 |
| Timber frame wall | Northern Ireland | 1992–1999 | — | 0.45 |
| Timber frame wall | Northern Ireland | 2000–2005 | — | 0.35 |
| Timber frame wall | Northern Ireland | 2006 | Part F | 0.35 |
| Timber frame wall | Scotland | 1991 | Part J | 0.45 |
| Timber frame wall | Scotland | 1997 | Part J (S) | 0.45 |
| Timber frame wall | Scotland | 2002 | Part J | 0.3 |
| Timber frame wall | Scotland | 2006 | Section 6 | 0.3 |
| Timber frame wall | Not specified | 89mm studs | — | 0.42 |
| Timber frame wall | Not specified | 140mm studs | — | 0.3 |
| Timber frame wall | Not specified | 35mm PUR on sheathing | — | 0.26 |
| Timber frame wall | Not specified | 50mm phenolic foam | — | 0.13 |
| Timber frame wall | Not specified | Uninsulated | — | 1.14 |
| Timber framed (masonry inner leaf) | England & Wales | Uninsulated | — | 1.2 |
| Timber framed (masonry inner leaf) | England & Wales | Retrofit insulation | — | 0.45 |
| Timber framed (masonry inner leaf) | England & Wales | 1980/85 | Part L | 0.6 |
| Timber framed (masonry inner leaf) | England & Wales | 1990/95 | Part L | 0.45 |
| Timber framed (masonry inner leaf) | England & Wales | 2002 | Part L | 0.35 |
| Timber framed (masonry inner leaf) | England & Wales | 2006 | Part L | 0.35 |
| Timber framed (masonry outer leaf) | England & Wales | Retrofit insulation | — | 0.42 |
| Timber framed (no solid leaf) | England & Wales | Uninsulated | — | 1.6 |
| Timber framed (no solid leaf) | England & Wales | Retrofit insulation | — | 0.45 |
| Timber framed (no solid leaf) | England & Wales | 1980/85 | Part L | 0.6 |
| Timber framed (no solid leaf) | England & Wales | 1990/95 | Part L | 0.45 |
| Timber framed (no solid leaf) | England & Wales | 2002 | Part L | 0.35 |
| Timber framed (no solid leaf) | England & Wales | 2006 | Part L | 0.35 |
Light steel framing U-Values: NCM Defaults
| Category | Construction | U-Value |
|---|---|---|
| Light steel framing | Non-transpired solar panel, thickness 100mm | 0.25 |
| Light steel framing | Non-transpired solar panel, thickness 68mm | 0.35 |
| Light steel framing | Non-transpired solar panel, thickness 80mm | 0.3 |
| Light steel framing | Steel frame wall-50mm exp. polystyrene | 0.48 |
| Light steel framing | Steel frame wall-50mm polyurethane | 0.35 |
| Light steel framing | Steel frame wall-75mm exp. polystyrene | 0.38 |
| Light steel framing | Steel frame wall-75mm polyurethane | 0.27 |
Internal Wall Partition U-Values: NCM Defaults
| Category | Construction | U-Value |
|---|---|---|
| Partition wall | Lightweight party/partition wall | 0.48 |
| Partition wall | Internal wall – Stud partition – Insulated | 0.5 |
| Partition wall | Internal wall – Cavity – Insulated | 0.6 |
| Partition wall | Internal wall – solid- Insulated or dry lined | 0.9 |
| Partition wall | Internal wall – solid- Uninsulated (or unknown) | 1.4 |
| Partition wall | Internal wall – Cavity – Uninsulated (or unknown) | 1.5 |
| Partition wall | Internal wall – Stud partition – Uninsulated (or unknown) | 1.7 |
| Partition wall | Internal wall – Internal glazing as wall (not internal windo | 3.7 |
| Partition wall | Internal wall – light partitioning | 4.1 |
Roof U-Values: NCM Defaults
| Category | Construction | U-Value |
|---|---|---|
| Flat roof | Flat roof (E&W) 1980/85 Part L, concrete deck | 0.45 |
| Flat roof | Flat roof (E&W) 1980/85 Part L, light deck | 0.45 |
| Flat roof | Flat roof (E&W) 1990 Part L, concrete deck | 0.45 |
| Flat roof | Flat roof (E&W) 1990 Part L, light deck | 0.45 |
| Flat roof | Flat roof (E&W) 1995 Part L, concrete deck, non-resident | 0.45 |
| Flat roof | Flat roof (E&W) 1995 Part L, concrete deck, residential | 0.35 |
| Flat roof | Flat roof (E&W) 1995 Part L, non-residential, light deck | 0.45 |
| Flat roof | Flat roof (E&W) 1995 Part L, residential, light deck | 0.35 |
| Flat roof | Flat roof (E&W) 2002 Part L, concrete deck | 0.25 |
| Flat roof | Flat roof (E&W) 2002 Part L, lightweight deck | 0.25 |
| Flat roof | Flat roof (E&W) 2006/2010 Part L, concrete deck | 0.25 |
| Flat roof | Flat roof (E&W) 2006/2010 Part L, light deck | 0.25 |
| Flat roof | Flat roof (E&W) pre-1981 (lightweight) | 1.4 |
| Flat roof | Flat roof (E&W) pre-1981, concrete deck | 2.8 |
| Flat roof | Flat roof (E&W) pre-1981, with asbestos | 2 |
| Flat roof | Flat roof (E&W) with pavement or patio above | 0.42 |
| Flat roof | Flat roof (NI) 2006 Part F | 0.25 |
| Flat roof | Flat roof (SCO) 1975-1981 | 0.6 |
| Flat roof | Flat roof (SCO) 1982-1990 | 0.45 |
| Flat roof | Flat roof (SCO) 1991-1996 | 0.45 |
| Flat roof | Flat roof (SCO) 1997-2001 | 0.45 |
| Flat roof | Flat roof (SCO) 2002-2006 | 0.45 |
| Flat roof | Flat roof (SCO) 2007 Section 6 | 0.16 |
| Flat roof | Flat roof (SCO) pre-1975 | 1.14 |
| Flat roof | Flat roof, concrete deck, ext. insulated | 0.64 |
| Flat roof | Flat roof, concrete deck, uninsulated | 2.8 |
| Flat roof | Flat roof, insulated, metal deck | 0.64 |
| Flat roof | Flat roof, internal insulation | 0.53 |
| Flat roof | Flat roof, min. wool between 150mm joists | 0.3 |
| Flat roof | Flat roof, phenolic foam between 150mm joists | 0.22 |
| Flat roof | Flat roof, phenolic foam between 50-70mm joists | 0.42 |
| Flat roof | Flat roof, uninsulated, metal deck | 2.8 |
| Pitched roof, horizontal | Pitched roof (E&W) 1980/85 Part L | 0.35 |
| Pitched roof, horizontal | Pitched roof (E&W) 1990 Part L | 0.25 |
| Pitched roof, horizontal | Pitched roof (E&W) 1995 Part L | 0.25 |
| Pitched roof, horizontal | Pitched roof (E&W) 2002 Part L | 0.16 |
| Pitched roof, horizontal | Pitched roof (E&W) 2006/2010 Part L | 0.13 |
| Pitched roof, horizontal | Pitched roof (NI) 2006 Part F | 0.16 |
| Pitched roof, horizontal | Pitched roof (SCO) 1975-1981 | 0.6 |
| Pitched roof, horizontal | Pitched roof (SCO) 1982-1990 | 0.45 |
| Pitched roof, horizontal | Pitched roof (SCO) 1991-1996 | 0.25 |
| Pitched roof, horizontal | Pitched roof (SCO) 1997-2001 | 0.25 |
| Pitched roof, horizontal | Pitched roof (SCO) 2002-2006 | 0.16 |
| Pitched roof, horizontal | Pitched roof (SCO) 2007 Section 6 | 0.13 |
| Pitched roof, horizontal | Pitched roof (SCO) pre-1975 | 1.14 |
| Pitched roof, horizontal | Pitched roof, 100 mm quilt | 0.42 |
| Pitched roof, horizontal | Pitched roof, 150 mm quilt | 0.29 |
| Pitched roof, horizontal | Pitched roof, 200 mm quilt | 0.25 |
| Pitched roof, horizontal | Pitched roof, 25 mm quilt | 1.1 |
| Pitched roof, horizontal | Pitched roof, 250 mm quilt | 0.16 |
| Pitched roof, horizontal | Pitched roof, 300 mm quilt | 0.14 |
| Pitched roof, horizontal | Pitched roof, 50 mm quilt | 0.72 |
| Pitched roof, horizontal | Pitched roof, 75 mm quilt | 0.53 |
| Pitched roof, horizontal | Pitched roof, asbestos (insulated) | 1.2 |
| Pitched roof, horizontal | Pitched roof, asbestos (uninsulated) | 2.7 |
| Pitched roof, insulation | Pitched roof, ceiling at rafters-asbestos/cement sheet in | 0.55 |
| Pitched roof, insulation | Pitched roof, ceiling at rafters-asbestos/cement sheet un | 2.4 |
| Pitched roof, insulation | Pitched roof, insul at rafters (E&W) 1981-89 | 0.36 |
| Pitched roof, insulation | Pitched roof, insul at rafters (E&W) 1990 Part L | 0.36 |
| Pitched roof, insulation | Pitched roof, insul at rafters (E&W) 2006/2010 Part L | 0.16 |
| Pitched roof, insulation | Pitched roof, insul at rafters (SCO) 1975-1981 | 0.6 |
| Pitched roof, insulation | Pitched roof, insul at rafters (SCO) 1982-1990 | 0.45 |
| Pitched roof, insulation | Pitched roof, insul at rafters (SCO) 1991-1996 | 0.45 |
| Pitched roof, insulation | Pitched roof, insul at rafters (SCO) 1997-2001 | 0.45 |
| Pitched roof, insulation | Pitched roof, insul at rafters (SCO) 2002-2006 | 0.25 |
| Pitched roof, insulation | Pitched roof, insul at rafters (SCO) pre-1975 | 0.25 |
| Pitched roof, insulation | Pitched roof, insul at rafters, insulated | 0.75 |
| Pitched roof, insulation | Pitched roof, insul at rafters, uninsulated | 3.85 |
| Pitched roof, horizontal | Pitched roof, no insulation | 2.5 |
| Pitched roof, horizontal | Pitched roof, slate or tile, insulated | 1.1 |
| Pitched roof, insulation | Plywood and felt roof | 3.8 |
| Pitched roof, horizontal | Plywood and felt roof, flat ceiling uninsulated | 2 |
| Pitched roof, insulation | Roof with integral insulation (E&W) 2002 Part L | 0.25 |
| Pitched roof, insulation | Roof, insulation at rafters (E&W) 2002 Part L | 0.2 |
Floors U-Values: NCM Defaults
Solid Ground Floor
| Construction | Region | Year | Regulation | U-Value |
|---|---|---|---|---|
| Ground floor | England & Wales | 1980/85 | Part L | 0.58 |
| Ground floor | England & Wales | 1990 | Part L | 0.45 |
| Ground floor | England & Wales | 1995 | Part L | 0.45 |
| Ground floor | England & Wales | 2002 | Part L | 0.25 |
| Solid ground floor | England & Wales | 1990 | Part L | 0.45 |
| Solid ground floor | England & Wales | 1995 | Part L | 0.45 |
| Solid ground floor | England & Wales | 2002 | Part L | 0.25 |
| Solid ground floor | England & Wales | 2006/2010 | Part L | 0.25 |
| Solid ground floor | Scotland | 1992–2001 | — | 0.45 |
| Solid ground floor | Scotland | 2002–2006 | — | 0.25 |
| Solid ground floor | Scotland | 2007 | Section 6 | 0.22 |
| Solid ground floor | Not specified | Insulated | — | 0.45 |
| Solid ground floor | Not specified | Uninsulated | — | 0.58 |
| Floor type unknown | Not specified | Uninsulated | — | 0.58 |
Suspended Floor
| Construction | Region | Year | Regulation | U-Value |
|---|---|---|---|---|
| Exposed concrete floor | England & Wales | Pre 1980 | Uninsulated | 2.26 |
| Exposed concrete floor | England & Wales | 1980/85 | Part L | 1.6 |
| Exposed concrete floor | England & Wales | 1990 | Part L | 0.45 |
| Exposed concrete floor | England & Wales | 1995 | Part L | 0.45 |
| Exposed concrete floor | England & Wales | 2002 | Part L | 0.25 |
| Exposed concrete floor | England & Wales | 2006/2010 | Part L | 0.25 |
| Exposed timber floor | England & Wales | Pre 1980 | Uninsulated | 1.97 |
| Exposed timber floor | England & Wales | 1980/85 | Part L | 1.6 |
| Exposed timber floor | England & Wales | 1990 | Part L | 0.45 |
| Exposed timber floor | England & Wales | 1995 | Part L | 0.45 |
| Exposed timber floor | England & Wales | 2002 | Part L | 0.25 |
| Exposed timber floor | England & Wales | 2006/2010 | Part L | 0.25 |
| Exposed floor | England & Wales | 1995 | Part L | 0.45 |
| Exposed floor | England & Wales | 2002 | Part L | 0.25 |
| Exposed floor | England & Wales | 2006/2010 | Part L | 0.25 |
| Exposed floor | Scotland | 1997 | Part J | 0.45 |
| Exposed floor | Scotland | 2002 | Section 6 | 0.25 |
| Exposed floor | Scotland | 2007 | Section 6 | 0.22 |
| Semi-exposed floor | Scotland | 1982–1990 | — | 0.7 |
| Semi-exposed floor | Scotland | 1991–1996 | — | 0.6 |
| Semi-exposed floor | Scotland | 1997–2001 | — | 0.6 |
| Suspended concrete ground floor | England & Wales | Pre 1980 | Uninsulated | 0.51 |
| Suspended concrete ground floor | England & Wales | 1980/85 | Part L | 0.51 |
| Suspended concrete ground floor | England & Wales | 1990 | Part L | 0.45 |
| Suspended concrete ground floor | England & Wales | 1995 | Part L | 0.45 |
| Suspended concrete ground floor | England & Wales | 2002 | Part L | 0.25 |
| Suspended concrete ground floor | England & Wales | 2006/2010 | Part L | 0.25 |
| Suspended timber ground floor | England & Wales | Pre 1980 | Uninsulated | 3.07 |
| Suspended timber ground floor | England & Wales | 1980/85 | Part L | 0.58 |
| Suspended timber ground floor | England & Wales | 1990 | Part L | 0.45 |
| Suspended timber ground floor | England & Wales | 1995 | Part L | 0.45 |
| Suspended timber ground floor | England & Wales | 2002 | Part L | 0.25 |
| Suspended timber ground floor | England & Wales | 2006/2010 | Part L | 0.25 |
| Suspended ground floor | England & Wales | 1985 | — | 0.58 |
| Suspended ground floor | England & Wales | 1990 | Part L | 0.45 |
| Suspended ground floor | England & Wales | 1995 | Part L | 0.45 |
| Suspended ground floor | England & Wales | 2002 | Part L | 0.25 |
| Suspended ground floor | England & Wales | 2006/2010 | Part L | 0.25 |
| Suspended ground floor | Northern Ireland | 2006 | Part F | 0.22 |
| Suspended ground floor | Scotland | 1975–1981 | — | 0.58 |
| Suspended ground floor | Scotland | 1982–1990 | — | 0.58 |
| Suspended ground floor | Scotland | 1991–1996 | — | 0.45 |
| Suspended ground floor | Scotland | 1997–2001 | — | 0.45 |
| Suspended ground floor | Scotland | 2002–2006 | — | 0.25 |
| Suspended ground floor | Scotland | Pre-1997 | — | 0.58 |
Internal Floor / Ceiling
| Construction | Region | Detail | Regulation | U-Value |
|---|---|---|---|---|
| Intermediate floor (floor side, timber) | — | — | — | 1.4 |
| Intermediate floor/ceiling (concrete) | — | Uninsulated | — | 1 |
| Intermediate floor/ceiling (timber) | — | Insulated | — | 0.6 |
| Intermediate floor/ceiling (timber) | — | Uninsulated | — | 1.4 |
| Internal concrete floor | — | Conditioned space below | — | 1 |
| Internal tiled ceiling | — | Conditioned space above | — | 1.23 |
| Light plaster ceiling below non-timber floor | — | — | — | 1.4 |
| Suspended tiled ceiling below concrete floor | — | Insulated | — | 0.6 |
| Suspended tiled ceiling below concrete floor | — | Uninsulated | — | 1.4 |
| Suspended tiled ceiling below timber floor | — | Insulated | — | 0.6 |
| Suspended tiled ceiling below timber floor | — | Uninsulated | — | 1.4 |
Door U-Values: NCM Defaults
| Category | Construction | U-Value |
|---|---|---|
| Personnel door | Insulated personnel door (no date) | 0.81 |
| Personnel door | Personnel door (E&W) & (SCO) 2002/06 Part L | 2.2 |
| Personnel door | Personnel door, pre-1995 | 3 |
| Personnel door | Uninsulated personnel door (no date) | 3 |
| Vehicle access door | Vehicle access door (E&W) 1995 Part L | 1.5 |
| Vehicle access door | Vehicle access door (E&W) 2002/06 Part L | 1.5 |
| Vehicle access door | Vehicle access door (E&W) pre-1995 | 5.7 |
| Vehicle access door | Vehicle access door (NI) 2000-2005 | 1.5 |
| Vehicle access door | Vehicle access door (NI) 2006 Part F | 1.5 |
| Vehicle access door | Vehicle access door (NI) pre-2000 | 5.7 |
| Vehicle access door | Vehicle access door (SCO) 1997 Part J | 1.5 |
| Vehicle access door | Vehicle access door (SCO) 2002 Part J | 1.5 |
| Vehicle access door | Vehicle access door (SCO) 2007 Section 6 | 1.5 |
| Vehicle access door | Vehicle access door (SCO) pre-1997 | 5.7 |
| Vehicle access door | Vehicle access door pre 1995 – sandwich panel | 2.9 |
| Vehicle access door | Vehicle access door, insulated | 1.5 |
| Vehicle access door | Vehicle access door, uninsulated | 5.7 |
Curtain wall U-Values: NCM Defaults
| Category | Construction | U-Value |
|---|---|---|
| Curtain wall | Curtain wall (E&W) 1980/85 Part L | 0.6 |
| Curtain wall | Curtain wall (E&W) 1990 Part L | 0.45 |
| Curtain wall | Curtain wall (E&W) 1995 Part L | 0.45 |
| Curtain wall | Curtain wall (E&W) 2002 Part L | 0.35 |
| Curtain wall | Curtain wall (E&W) 2006/2010 Part L | 0.35 |
| Curtain wall | Curtain wall (SCO) 1991-1996 | 0.45 |
| Curtain wall | Curtain wall (SCO) 1997-2001 | 0.45 |
| Curtain wall | Curtain wall (SCO) 2002-2006 | 0.3 |
| Curtain wall | Curtain wall (SCO) 2007 Section 6 | 1.2 |
| Curtain wall | Curtain wall insulated no date | 1 |
| Curtain wall | Curtain wall, pre-1981 | 2.3 |
Glazing U-Values: NCM Defaults
How to find the default U-value for your window:
- Step 1: Identify the frame material
Check whether the window frame is hardwood, softwood, uPVC, metal, or another material. - Step 2: Identify the glazing type
Check whether the window is single glazed, double glazed, or triple glazed. - Step 3: Find the building regulation period
Use the construction date of the building to identify the relevant building regulation period. - Step 4: Match the table row
Find the row in the table that matches the frame material, glazing type, and building regulation period. - Step 5: Read the U-value
The U-value shown in that row is the applicable default U-value for that window type.
Hardwood -SINGLE -Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| Hardwood | SINGLE | 1985 Building Regulations (E&W) | 5.08 |
| Hardwood | SINGLE | 1990 Building Regulations (E&W) | 5.08* |
| Hardwood | SINGLE | 1995 Building Regulations (E&W) | 5.401 |
| Hardwood | SINGLE | 2002 Building Regulations (E&W) | 5.401 |
| Hardwood | SINGLE | 2006 Building Regulations (E&W) | 5.401 |
| Hardwood | SINGLE | 2010 Building Regulations (E&W) | 5.401 |
Hardwood -DOUBLE -Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| Hardwood | DOUBLE | 1985 Building Regulations (E&W) | 3.193 |
| Hardwood | DOUBLE | 1990 Building Regulations (E&W) | 3.193 |
| Hardwood | DOUBLE | 1995 Building Regulations (E&W) | 3.183 |
| Hardwood | DOUBLE | 2002 Building Regulations (E&W) | 3.183 |
| Hardwood | DOUBLE | 2006 Building Regulations (E&W) | 3.106 |
| Hardwood | DOUBLE | 2010 Building Regulations (E&W) | 3.106 |
| Hardwood | DOUBLE | no date (uninsulated) | 3.193 |
Hardwood -TRIPLE -Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| Hardwood | TRIPLE | 1985 Building Regulations (E&W) | 2.47 |
| Hardwood | TRIPLE | 1990 Building Regulations (E&W) | 2.47 |
| Hardwood | TRIPLE | 1995 Building Regulations (E&W) | 2.521 |
| Hardwood | TRIPLE | 2002 Building Regulations (E&W) | 2.521 |
| Hardwood | TRIPLE | 2006 Building Regulations (E&W) | 2.521 |
| Hardwood | TRIPLE | 2010 Building Regulations (E&W) | 2.521 |
| Hardwood | TRIPLE | no date (uninsulated) | 2.47 |
Metal -SINGLE –Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| Metal | SINGLE | 1985 Building Regulations (E&W) | 6.345 |
| Metal | SINGLE | 1990 Building Regulations (E&W) | 6.345 |
| Metal | SINGLE | 1995 Building Regulations (E&W) | 5.727 |
| Metal | SINGLE | 2002 Building Regulations (E&W) | 5.727 |
| Metal | SINGLE | 2006 Building Regulations (E&W) | 5.727 |
| Metal | SINGLE | 2010 Building Regulations (E&W) | 5.727 |
| Metal | SINGLE | no date (uninsulated) | 6.345 |
Metal -DOUBLE -Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| Metal | DOUBLE | 1985 Building Regulations (E&W) | 4.458 |
| Metal | DOUBLE | 1990 Building Regulations (E&W) | 4.458 |
| Metal | DOUBLE | 1995 Building Regulations (E&W) | 3.51 |
| Metal | DOUBLE | 2002 Building Regulations (E&W) | 3.51 |
| Metal | DOUBLE | 2006 Building Regulations (E&W) | 3.433 |
| Metal | DOUBLE | 2010 Building Regulations (E&W) | 3.433 |
| Metal | DOUBLE | no date (uninsulated) | 4.458 |
Metal -TRIPLE -Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| Metal | TRIPLE | 1990 Building Regulations (E&W) | 3.735 |
| Metal | TRIPLE | 1995 Building Regulations (E&W) | 2.848 |
| Metal | TRIPLE | 2002 Building Regulations (E&W) | 2.848 |
| Metal | TRIPLE | 2006 Building Regulations (E&W) | 2.848 |
| Metal | TRIPLE | 2010 Building Regulations (E&W) | 2.848 |
No frame -SINGLE -Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| No frame | SINGLE | 1985 Building Regulations (E&W) | 4.551 |
| No frame | SINGLE | 1990 Building Regulations (E&W) | 4.551 |
| No frame | SINGLE | 1995 Building Regulations (E&W) | 4.497 |
| No frame | SINGLE | 2002 Building Regulations (E&W) | 4.497 |
| No frame | SINGLE | 2006 Building Regulations (E&W) | 4.497 |
| No frame | SINGLE | 2010 Building Regulations (E&W) | 4.497 |
PVC -SINGLE -Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| PVC | SINGLE | 1985 Building Regulations (E&W) | 5.577 |
| PVC | SINGLE | 1990 Building Regulations (E&W) | 5.577 |
| PVC | SINGLE | 1995 Building Regulations (E&W) | 5.523 |
| PVC | SINGLE | 2002 Building Regulations (E&W) | 5.523 |
| PVC | SINGLE | 2006 Building Regulations (E&W) | 5.523 |
| PVC | SINGLE | 2010 Building Regulations (E&W) | 5.523 |
| PVC | SINGLE | no date (uninsulated) | 5.577 |
PVC -DOUBLE -Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| PVC | DOUBLE | 1985 Building Regulations (E&W) | 3.69 |
| PVC | DOUBLE | 1990 Building Regulations (E&W) | 3.69 |
| PVC | DOUBLE | 1995 Building Regulations (E&W) | 3.305 |
| PVC | DOUBLE | 2002 Building Regulations (E&W) | 3.305 |
| PVC | DOUBLE | 2006 Building Regulations (E&W) | 3.228 |
| PVC | DOUBLE | 2010 Building Regulations (E&W) | 3.228 |
| PVC | DOUBLE | no date (uninsulated) | 3.69 |
PVC -TRIPLE -Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| PVC | TRIPLE | 1985 Building Regulations (E&W) | 2.966 |
| PVC | TRIPLE | 1990 Building Regulations (E&W) | 2.966 |
| PVC | TRIPLE | 1995 Building Regulations (E&W) | 2.643 |
| PVC | TRIPLE | 2002 Building Regulations (E&W) | 2.643 |
| PVC | TRIPLE | 2006 Building Regulations (E&W) | 2.643 |
| PVC | TRIPLE | 2010 Building Regulations (E&W) | 2.643 |
| PVC | TRIPLE | no date (uninsulated) | 2.966 |
Softwood -SINGLE – Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| Softwood | SINGLE | 1985 Building Regulations (E&W) | 5.011 |
| Softwood | SINGLE | 1990 Building Regulations (E&W) | 5.011 |
| Softwood | SINGLE | 1995 Building Regulations (E&W) | 5.272 |
| Softwood | SINGLE | 2002 Building Regulations (E&W) | 5.272 |
| Softwood | SINGLE | 2006 Building Regulations (E&W) | 5.272 |
| Softwood | SINGLE | 2010 Building Regulations (E&W) | 5.272 |
Softwood -DOUBLE -Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| Softwood | DOUBLE | 1990 Building Regulations (E&W) | 3.124 |
| Softwood | DOUBLE | 1995 Building Regulations (E&W) | 3.054 |
| Softwood | DOUBLE | 2002 Building Regulations (E&W) | 3.054 |
| Softwood | DOUBLE | 2006 Building Regulations (E&W) | 2.977 |
| Softwood | DOUBLE | 2010 Building Regulations (E&W) | 2.977 |
| Softwood | DOUBLE | no date (uninsulated) | 3.124 |
Softwood -TRIPLE -Uncoated, clear
| Frame material | No. Panes | Building Regulation | U-value (W/m²K) |
|---|---|---|---|
| Softwood | TRIPLE | 1985 Building Regulations (E&W) | 2.401 |
| Softwood | TRIPLE | 1990 Building Regulations (E&W) | 2.401 |
| Softwood | TRIPLE | 1995 Building Regulations (E&W) | 2.392 |
| Softwood | TRIPLE | 2002 Building Regulations (E&W) | 2.392 |
| Softwood | TRIPLE | 2006 Building Regulations (E&W) | 2.392 |
| Softwood | TRIPLE | 2010 Building Regulations (E&W) | 2.392 |
| Softwood | TRIPLE | no date (uninsulated) | 2.401 |
How to select the right U-value
In practice, the general rule of thumb is to select the most conservative option available unless there is documented evidence to support a better value, for example, records confirming the construction date, wall type, or insulation specification of the building being assessed.
To download the NCM Databases visit the official website here: NCM: iSBEM for England.
To download files directly: https://www.uk-ncm.org.uk/filelibrary/NCM_Databases_v6.1.e.zip
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