Operational and maintenance costs in passive houses and low energy houses
Starting point / motivation
In addition to the building costs, the costs of operation are an important basis for strategic and planning decisions for the developer. Older studies like the simplified operating cost evaluation of the CEPHEUS projects represent experiences from five years ago and aren‘t sufficient for a profound evaluation.
Therefore, the project „Operational and maintenance costs in passive houses and low energy houses“ focuses on a systematic acquisition, evaluation and comparison of the yearly additional and reduced costs of operation and maintenance.
Contents and goals
Ten passive houses and eight low energy buildings, partly apartment blocks, partly single detached houses, were compared. The aim was a comparison of the costs of operation and maintenance in passive houses and low-energy buildings.
The first step was to determine the relevant operational cost groups of the yearly additional and reduced costs of a passive house compared to a low energy building. In the next step all comparable operational costs were acquired. Actual consumption and operation costs were gathered for the objects as follows:
- heating (without losses),
- warm water,
- power consumption,
- maintenance (ventilation system) and
- inspection (chimney sweep and heat consumption readings).
The collected data was then compared to the values calculated in the building‘s energy pass or the PHPP calculation. Finally, a cost comparison was performed.
Results and conclusions
After careful evaluation of the collected data, the operating costs of a passive house for multiple families are 50% lower than the costs of operation in a low energy building. In terms of a direct comparison, no difference was made between the costs paid by the occupants (e.g. energy consumption of the exhaust air unit in the apartment) and the costs of operation (e.g. the central ventilation system) which are passed on to the occupants.
The total reduction of the operational costs of 2,10 Euro/m².a in single family passive houses compared to single family low energy houses are a pinpoint match to the savings in houses for multiple families with 2,10 Euro/m².a. For single family passive houses the percental savings are around 25 to 40 %.
DI Helmut Schöberl
Schöberl & Pöll OEG
DI Richard Hofer
Schöberl & Pöll GmbH