Evaluation of temperature differentiation on a room-by-room basis in passive house apartments
Starting point / motivation
A differentiation of the temperature in particular rooms in passive houses does not make sense currently. This is often criticised by inhabitants and is documented in many sociological studies.
Contents and goals
During this research project the technology for room by room temperature differentiation for passive houses, which is used in 11 flats in the "Building of Tomorrow" - project "passive residential neighbourhood 1140 Vienna Utendorfgasse" should be evaluated by measurement techniques.
Methods of treatment
- Survey amongst residents about their behavior concerning the opening of windows and their satisfaction with the climatic conditions in the apartment.
- Monitoring of air flow between rooms with open/closed doors or open/tilted windows respectively in different weather conditions.
- Calibration of the virtual building model in order to display the actual air flow conditions.
- Detailed monitoring of two apartments for the purpose of validation of the virtual building model (room temperatures, humidity, window positions, air parameters etc. )
- Validation of the virtual building model by comparison of the calculated values with the monitoring results.
- Establishment of the desired climatic conditions through monitoring of room temperatures and humidity in bedrooms of apartments with/without room-by-room temperature control as well as interrogating the residents concerning their satisfaction.
- Calculation of the impact of room-by-room temperature control on heating demand and room climate through simulation of different scenarios with the validated virtual building model.
Results / conclusions
The result of the survey was that 90 % were satisfied with the room temperature regardless whether they had they had room-by-room temperature differentiation or not. 52,2 % of residents without and 14,3 % of residents with room-by-room temperature differentiation still used manual ventilation by leaving the windows open constantly to achieve the desired room temperature. Throughout the course of the survey residents of 30 out of the 39 flats have participated (77 % range).
The energy savings achieved by a reduction in the bedroom when using the bypass are small. When using manual ventilation, where windows are generally closed, when the temperature drops below 20°C, the heat energy demand for the flat itself and the adjacent flats rises by 9 %.
Since 52,2 % of residents without temperature differentiation on a room-by-room basis use constant manual ventilation in the bedrooms, the heat energy demand for the entire building rises by 4,7 %, if none of the residents have temperature control on a room-by-room basis.
Since 14,3 % of the residents surveyed, who have temperature control on a room-by-room basis, use constant ventilation in the bedrooms, the heat energy demand for the entire building rises by 1,3 %, if all residents have temperature control on a room-by-room basis.
Outfitting the whole passive house with room-by-room temperature control or flat-by-flat temperature control therefore results in a difference in heat energy demand of 3,4 %.
Out of those facts the results can be summarized as follows:Energy wise the room-by-room temperature differentiation has an adverse cost-benefit ratio. The room-by-room temperature differentiation should not be standard equipment but should only be installed on special request.
Since the investigations were done on a passive house heated by a supply air system, it would be advisable to do further investigation on a passive house heated by radiators room-by-room, where data about both the frequency of the manual ventilation as well as the frequency of radiators being turned on or off is recorded.
DI Helmut Schöberl
Schöberl & Pöll GmbH
Project or cooperation partner
- TU Wien, Forschungsbereich für Bauphysik und Schallschutz