Final Report

Energy demand of tumble driers with respect to differences in technology and ambient conditions

Tumble driers have a high ratio of and increasing impact on total electricity demand of households. In contrast to different other household appliances the market is not saturated yet and therefore growing selling rates can be expected.

Mainly two systems of tumble driers are currently available on the market: condenser tumble driers and air vented tumble driers, both powered by electricity. Tumble driers of both systems are mainly classified in the energy efficiency classes C and D.

The energy efficiency labelling of tumble driers takes into account the electricity demand of the different driers when used under standard conditions. Nevertheless under real life conditions in private households additional parameters influence the total energy demand of the two drying systems, like type of control (humidity or time control), type of fabric, loading of the drier, remaining water in the clothes after spinning in the washing machine, ambient temperature, energy demand for space heating or air humidity.

The crucial point is that some of these parameters have a different influence on the two drier systems. For example ambient temperature has a stronger influence on air-vented driers than on condenser driers. The drier systems themselves have an opposed effect on the energy demand for space heating.

Against this background the goal of this study was to compare the electricity demand of the two different drier technologies (air vented and condenser tumble driers) used under standard conditions with the energy demand when used under real life conditions especially with respect to the following effects:

  • differences in ambient temperature (relevant when driers are located outside heated rooms, directly influencing the electricity demand of the drier)
  • energy demand for space heating (relevant when driers are located inside heated rooms, causing an additional energy demand or energy demand substitution next to the direct electricity demand of the driers)