Specific Latent Heat of Vaporisation
The specific latent heat of of a substance
is the amount of heat energy needed to change one of that substance
from a to a gas without a change in (i.e. at its boiling point.)

Unit of Specific Latent Heat
The unit of specific latent heat of fusion and of vaporisation is the per .

Conduction
Conduction is the of heat energy through a substance
by the passing on of molecular from molecule to molecule.
There is no overall of the substance.

U-Value
The U-value of a structure is the amount of energy conducted per
through one metre of that structure
when a temperature of one degree celcius is maintained between its .

Radiation
Radiation is the of heat energy from one place to another in the form of waves.

Solar Constant (Solar Irradiance)
The average amount of the Sun's energy falling per
on one squared of the Earth's atmosphere
is the solar constant.
Its value is about 1.35 kW m^-2.

Convection
Convection is the transfer of heat through a by means of circulating caused by the heat.