A	Area	m2
c	Specific heat capacity	J kg−1 K−1
d	Thickness	m
Δ	Difference
E	Total energy transmitted through the sample	Wh
H	Heat loss	Wh
φ	Heat flow rate	W
λ	Thermal conductivity	W m−1 K−1
m	Weight	kg
ρ	Density	kg m−3
ψ	Linear thermal transmittance	W m−1 K−1
RH	Relative humidity	%
R	Thermal resistance	m2 K W−1
T	Temperature	K, °C
t	Time	h
τS	Response time	h
U	Thermal transmittance	W m−2 K−1