Soft Floor Finishes

Carpets laid over concrete slab floors tend to insulate the thermal mass of the slab from incoming heat. This delays its entry but also slows down its release. The net result is a temperature rise of 1"2C, which is good in winter, but not so good in summer. This effect partly offsets the winter disadvantage of increased heating energy requirements due to absorption of heat by the thermal mass.

While carpet lowers winter energy consumption, it increases summer energy requirements. Table 6.1 compares the effect on energy use of carpet and ceramic tiles on a concrete slab. Cork tiles are another soft floor finish with a similar insulating effect to carpet.

A ceramic tiled finish on a concrete slab floor increases the thermal mass of the floor and the ability to store heat. This can improve cooling in summer (providing the windows are shaded) and works best for rooms with good north solar access. Other hard floor finishes, such as slate and vinyl tiles, have a similar effect on thermal mass performance.

Colours Thermal mass that is coloured black absorbs more heat than white coloured material. Its effect on room temperature could be a 2"3C year-round temperature rise Textures Textured surfaces, such as brick walls, have more exposed surface area and absorb more heat, while shiny or glossy surfaces absorb less heat than dull surfaces.

Wall Surfaces

An exposed brick wall absorbs more heat than a smooth plastered wall. The improved thermal storage of dark, textured walls should be balanced against the negative effect of such walls on internal light levels. Light-coloured reflective surfaces maximise both daylight and artificial light, whereas dark surfaces absorb light.