Ce71 Research Paper

78446 EST CE71 EcoBuild 4pp-V3:EST 20/08/2010 09:32 Page 1

CE71

Insulation materials chart
Thermal properties and environmental ratings

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Insulation materials chart
This chart details the thermal conductivities, environmental ratings and typical applications of insulation materials available in the UK. It is designed as an aid to specification. Note that the coloured cells indicate only the most common uses
– the fact a cell is blank does not necessarily mean that the type of insulation is not used for the application.
The properties of any selected product should be checked prior to final specification. When selecting an insulation material consideration should
be
given to the material’s fire, acoustic, moisture and environmental credentials along with the thermal performance of the product within the construction context.

Highest performance

Polyurethane (PU)

Polyisocyanurate (PIR)

Phenolic foam (PF)
Expanded Polystyrene
(EPS)
Extruded Polystyrene
(XPS)

Wool and fibre

Alternative

Vacuum Insulated Panels
Aerogel
Polyurethane with pentane up to 32kg/m3
Polyurethane soy-based
Foil-faced Polyurethane with pentane up to 32kg/m3
Polyurethane with CO2
In-situ applied Polyurethane (sprayed or injected)
Polyisocyanurate up to 32kg/m3
Foil-faced polyisocyanurate up to 32kg/m3
In-situ applied polyisocyanurate (sprayed)
Phenolic foam
Foil-faced phenolic foam
Expanded Polystyrene up to 30kg/m3
Expanded Polystyrene with graphite (grey)
Extruded Polystyrene with CO2
Extruded Polystyrene with HFC 35kg/m3
Glass wool [up to 48kg/m3]
Glass wool [equal/greater than 48kg/m3]
Stone wool [less than 160kg/m3]
Stone wool [160kg/m3]
Sheep’s wool [25kg/m3]
Cellulose fibre [dry blown 24kg/m3]
Hemp fibre
Polyester fibre
Wood fibre (WF)
Hemp lime (monolithic)
Cotton
Cork [120kg/m3]
Vermiculite
Perlite (expanded) board
Celular glass (CG)
Flexible thermal linings
Strawboard [420kg/m3]
Straw bale (monolithic)

A
A
A
A
A+
E
A+
B to A+
C
A
A+
A
C-D
C
A

Range of Thermal Conductivities4 (W/mK)
Lower numbers indicate better thermal performance

30
0.008
50-55
105-115
100-145
755
130
80-100
95-105
80-855
80-100
80-95
75-855
115-165
115-120
95-140
110-120
135-180
155
150-160
160-170
150-215
150-190
165
150-180
145-225
2606
165-170
155-200
235
190
140-185
n/a7
295
175-2356

0.013
0.014

0.027 0.03
0.026 0.038
0.02
0.035
0.023
0.028
0.025
0.028
0.022
0.023
0.023
0.028
0.020
0.025
0.020
0.023

0.03 0.045
0.03

0.032

0.025 0.037
0.029 0.031
0.03 0.044
0.036
0.034
0.038

0.037 0.040
0.034
0.054
0.035 0.046
0.039
0.035 0.044
0.039
0.061
0.067
0.039 0.04
0.041 0.055
0.039
0.06
0.051
0.038
0.05
0.04
0.063

Monolithic

0.081
0.047

0.063

Monolithic

Suspended timber

0.08

Suspended beam & block 0.07

Solid concrete

0.06

Panel

0.05

Steel frame

0.04

Floors

Timber frame

0.03

European Commission).

5. The effect of low emissivity surfaces has been included in
U-value calculations.
6. Monolithic insulant thicknesses quoted exclude external render and internal plastered finish.
7. Flexible thermal linings are thin layers designed to be applied directly to a solid wall, prior to finishes. A solid wall with 10mm flexible thermal lining will achieve a U-value of approximately 1.5W/m2K.

Cavity (partial fill)

0.02

Thermal Values Group (March 1999) submitted to DG XII of the

Walls

Cavity (full fill)

0.01

Roofs
External insulation

0.00

Insulation materials chart

Typical Applications

Internal insulation

Insulant thickness (mm) to achieve U-value =
0.25W/m2/k3

The domestic insulation market has recently seen the development of innovative high performance aerogel and vacuum panel insulants, as well as multifoil products1. Alongside these developments more traditional products have continued to evolve, with grey EPS and soy-based Polyurethane offering higher thermal performance and greater environmental sustainability respectively.
Monolithic insulants such as hemp-lime or straw bale construction offer alternative options to those wishing to meet the heightened thermal requirements of national building regulations.

Insulation Materials Chart

(BRE Green Guide)

The performance of insulation materials is key to any low energy homes strategy, whether designing, specifying and building a new house, or refurbishing an existing dwelling. Fabric insulation measures should always be considered before services and renewable energy generation.

Environmental Rating2

Domestic insulation materials

as ‘embodied impacts’ – have been evaluated. The comparison between materials is on the basis of similar thermal resistance, rather than mass or volume.
3. U-values calculated based on 9” solid brick wall, internally applied insulation (with battens and/or air gap where appropriate) and 12.5mm plasterboard. Fixings and air movement accounted for in calculated figures. All thicknesses rounded to nearest 5mm.
4. The thermal conductivity ranges are the minimum and maximum obtained from the thermal conductivity values declared by UK manufacturers (or suppliers) and those
given in the European Thermal Values publication. (Final report to the

Flat roof

1. Multifoil products work by reflecting radiated heat back into the internal space, and unlike other insulants are not assessed via a hot box test. For this reason their thermal conductivity is less crucial as a performance characteristic.
Total wall thickness to achieve U=0.25 W/m2K is 380mm and includes 85mm supplementary PU (pentane) insulation.
2. The environmental ratings of different types of insulation
(with A+ being the best) have been taken from the latest assessments in BRE’s Green Guide to Specification. Using Life
Cycle Assessment, the impacts associated with extraction, manufacture, transport and disposal – sometimes referred to

Ceiling insulation

Key: coloured cells indicate common uses.

Insulation on pitch

Insulation materials chart

78446 EST CE71 EcoBuild 4pp-V3:EST 20/08/2010 09:32 Page 4

CE71
Technical terms explained
Thermal
Conductivity
Also known as
Lambda [λ], or as k-value

A standardised measure of how easily heat flows through any specific material, which is independent of material thickness. • The lower the number, the better the thermal performance.
• Provides a quick way to easily compare to thermal performance of different insulants.
• Units are Watts per metre Kelvin W/mK.

Example • The thermal conductivity of Aerogel insulation is 0.013 W/mK.
• The thermal conductivity of brick is 0.077 W/mK.

Thermal
Resistance
Also known as
R-value

A measure of how much heat loss is reduced through a given thickness of any specific material.
• The thermal resistance of a l l is the thickness in metres and material is calculated from:
R = where λ λ is the thermal conductivity in W/mK
• To compare two insulants with different thicknesses and thermal conductivities, calculate the R-value for each.
• The higher the number, the better the thermal performance.
• For materials in series, these thermal resistances (unlike conductivities) can simply be added to give a thermal resistance for the whole.
• Units are metres squared Kelvin per Watt (m2K/W).

Example • The thermal resistance of 9mm Aerogel insulation is 0.0009/0.013 = 0.69m2K/W.
• The thermal resistance of a 220mm solid brick wall is 0.022/0.077 = 0.29m2K/W.
• The total thermal resistance of the two materials together is 0.69 + 0.29 = 0.98m2K/W.

U-value
Also known as thermal transmittance

A measure of how much heat is lost through a given thickness of any specific material, which includes conduction, convection and radiation.
• The U-value of a material (or several materials in series, e.g. brick and insulation in a wall) is calculated by taking the reciprocal of the R-value (i.e. 1/R-value), and adding convection and radiation heat losses.
• Repeating thermal bridging (e.g. wall ties) is also included.
• In practice this is a complex calculation, and so using U-value calculation software (most SAP software packages,
e.g. Build Desk, have a U-value calculator included within them) is recommended.
• The lower the number, the better the thermal performance.
• Units are Watts per metre squared Kelvin (W/m2K).

Example • The thermal transmittance of 9mm of Aerogel insulation on a 220mm solid brick wall is 1/0.98 + convection and radiation losses + repeating thermal bridging losses from fixings.
• Using U-value calculation software, the thermal transmittance was calculated as 0.94 W/m2K.

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CE71 © Energy Saving Trust April 2004. Revised August 2010. E&OE
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