Heat Loss - Floor

"The heat lost from the floor and outside door of an uninsulated house would typically be of the order of 11% of the total losses."

Floor Types

 Floor Type

 Insulation Method

 Solid  Below floor slab insulation. Above floor slab insulation.
 Suspended  -
 
"As a result (of heating from the sun), the ground temperature shows seasonal fluctuations to depths of about 15 m where the temperature is approximately equal to the mean annual air temperature (8 - 11° C in the UK)." - The British Geological Survey.
 
Therefore in practice the temperature beneath a building will be of the order of 8 - 11° C which is quite cool and so can represent a significant source of heat loss.
 

Insulation Methods

Below floor slab

Most traditionally built modern houses are built on a solid concrete floor. To reduce heat loss this encorporates insulation below the concrete. Obviously it is only practical to install this when the house is being built.
 

Above floor slab

Many older houses do not have insulated floors and so the only option is insulation above the concrete surface. Unfortunately, this is not easy to achieve because it has an impact on internal fittings such as skirting and doors. However, products are available.
 

Discussion

Under floor heating

Under floor heating is becoming more popular but it is easy to overlook the high running costs if there is insufficient insulation. The reasons are as stated above in that the heating system will be trying to warm the ground below which is at 8 - 11° C. It is therefore vital to include as much insulation as possible.