6 - Summer comfort and cooling

Stimulation of better summer comfort and reduced energy consumption for cooling by EPBD implementation

During the last decades, a continuous increase in the penetration of Air Conditioning (A/C) systems in the Member States (MS) is taking place, a phenomenon which gives serious peak electricity problems. Whereas in the past a major challenge was to keep our buildings sufficiently warm, recently and in new buildings the challenge is to guarantee reasonable comfort conditions in summer with no, or at least minimum, cooling energy. At the same time, article 4 of the Energy Performance of Buildings Directive (EPBD) and its annex, require special attention for indoor climate conditions ('These requirements shall take account of general indoor climate conditions, in order to avoid possible negative effects'). This means that buildings have to consume less energy, but have to provide good indoor climate, including good summer comfort (without overheating).

For this reason:

  • MS should take concrete measures to reduce the penetration of A/C.
  • It is important that building designers and other stakeholders have a reasonable indication in the framework of the EPBD implementation, whether or not a building has a serious risk of overheating. The availability of (draft) CEN standards is an important support but will not automatically guarantee an effective implementation at the level of each MS.
  • Building designers and users should become aware of the various alternative cooling techniques that improve substantially the summer comfort without (or very limited) increasing the energy consumption. These techniques refer both to the city and the building level. For example solar and thermal control techniques, heat amortisation and heat dissipation techniques have been proven to be extremely efficient and capable of decreasing the cooling load of buildings by up to 80 %.
  • It is extremely important that such techniques are foreseen by the national calculation methods and that alternative calculation methodologies are being proposed. 

Consequently, the main objectives of ASIEPI were to create or increase awareness of the MS around available alternative techniques and technologies that improve thermal comfort without increasing the energy consumption and to provide guidance on how to assess the energy performance of such techniques.

The activities within ASIEPI allowed to collect information about the practical experiences from MS who already have, for a while, specifications regarding summer comfort and A/C. To what extend is summer comfort directly or indirectly taken into account and which are the key parameters? Actually, in many cases regulations are limited in the calculation of the cooling load and, in a limited number of countries, in the definition of a maximum allowed energy consumption for cooling. However, when the summer performance of a building is evaluated in terms of the ‘cooling load’, the message given is that the building needs air conditioning, which is in most cases not true. The use of alternative methodologies to express the summer performance of buildings, like the balance point temperature of a building, would be fairer, more environment friendly and better understood.

It is then also important to collect information on past developments in the MS regarding summer comfort, e.g.:

  • Summer comfort was in some countries like the Netherlands and France not a specific issue of concern. Why was this? How has it progressed? What has changed? What are the developments? What are the difficulties?

In parallel, evaluation has take place on the existing situation regarding the implementation and the impact of the existing methods to achieve summer comfort in the MS. Then, the alternative cooling techniques and the respective advanced calculation methodologies used in some MS and other countries has been identified and assessed to show their overall benefits, while at the same time it has been examined how it is possible to best integrate alternative cooling assessment methods into the existing calculation methods.