

Fig.
2 Consumption statistics for a lowenergy development: 41 lowenergy
homes in Niedernhausen, completed and occupied in 1992. Consumption measurements
by T. Loga and M. Grossklos [Loga 1997]. The average consumption of 65
kWh/(m²a) reasonably verifies the accuracy of the calculated heat requirement
of 68 kWh/(m²a) [PHPP] (The inserted curve is
the associated Gaussian distribution  note for those
familiar with the mathematics ^{2}). Fig. 3
Consumption statistics for the Passive House development in Wiesbaden:
The development of 22 Passive Houses was built in 1997. The average consumption
of 13.4 kWh/(m²a) matches very closely the calculated heat requirement
of 13 kWh/(m²a) [PHPP]. (Note for those familiar
with the mathematics ^{2}) Fig. 4 Consumption
statistics for the Passive House development Hannover Kronsberg: The development
of 32 passive houses was occupied in 1999. Average consumption during
the third year of operation (2001/2002) was 12.8 kWh/(m²a). The heat
requirement according to the [PHPP] calculations
amounts to
Fig. 5 Consumption statistics for the Passive House development Stuttgart/Feuerbach: The development of 52 passive houses was finished in the year 2000 (architect's office Rudolf). Average consumption was at 12.8 kWh/(m²a). The heat requirement calculations according to the [PHPP] amount to 13.5 kWh/(m²a) (note for those familiar with the mathematics ^{2}). ^{1}) Regarding the units: a kWh (kilowatthour) is an energy unit. A liter fuel oil (1 L) or 1 m³ natural gas has a heat energy value of 10 kWh. Here the annual heat requirement (q_{H}) is used for the comparison: q_{H} = Q_{H}
/ A_{TFA}.
This measurement includes distribution and heat delivery losses but not losses of the boiler. A_{TFA} is the energy reference area. For all results specified herein, this refers to the Treated Floor Area, that is a netfloorarea; selected as such in order to match the area that a standard heating bill and general heat consumption statistics are based on in Germany. It is important to note that the area A_{N}, based on the calculations prescribed by the EnEV, is approximately 20 to 30% larger than the actual inhabitable floor space. Therefore, energy consumption determined using the EnEV method will appear to be much lower than it actually is. For this reason, we consistently use only the actual usable net floor area for our calculations.
^{2})
Inserted into the diagrams are the associated Gaussian or
normal distributions: Additionally, n is the number
of buildings in a sample group. A closer look at the diagrams shows that
the heating consumption values of identically constructed objects are
approximated very well by a normal distribution. More details can be found
additionally in the CEPHEUS final report [ Schnieders/Feist 2001 ] Link to Basic informations about Passive Houses Passive House fundamentials. Link to the Passive House Conference Link to the site of the Passive House Institute:
This Internet information is based on published scientific reports. The sources are indicated and the reports are accessible to everybody. The associated field surveys were accomplished by three independent institutes: The Passivhaus Institut (PHI), Institut Wohnen und Umwelt (IWU) and the Fraunhofer Institut fuer Bauphysik (IBP). The results presented here are supported through further field surveys, which the Fraunhofer Institut fuer Solar Energy Systems (ISE) conducted. Beyond those field tests, everyone has the opportunity to inform himselve about actual experiences with living in Passive Houses. Because every year at the beginning of Novembre the IGPassivhaus organizes the "Day of the Passive House". During this day many Passive Houses open their doors for visitors. Interested individuals can then ask the inhabitants directly to share their experiences. The very remarkable energy savings of Passive Houses do not have any impact on the comfort in a home. To the contrary, the indoor air quality in a Passive House is excellent due to the constant supply of fresh air and there is a very steady indoor climate. To learn more about this please read the publication on Passive House comfort.
Many people think that a Passive House must be an expensive home because it achieves such high energy savings. However, that is not the case: the efficiency is improved in the areas of the building, where quality is already required if one wants to build a new home. Therefore it is possible, by designing a Passive House, to have lower lifecycle costs than with regular new construction. This is possible because the Passive House really achieves the promised energy savings  as we have shown for the developments documented here. 
When monitoring the energy
performance of identically constructed homes one will find that the measured
results are often very different from house to house, because homeowner
usage varies from family to family. Therefore, the energy consumption
of a sufficient number of identically constructed homes must be evaluated,
so that the varying conditions of operation average out and a true comparison
of the overall building energy performance becomes possible. Fig.1 on
the left side shows a diagram of measured results for 41 low – energy
homes and for a total of 106 Passive Houses. These actual results allow
further conclusions. LowEnergy Development in Niedernhausen
The standard deviation of the individual values is ±5.3 kWh/(m²a) and is also much lower than that of the lowenergy development. However, the variation due to user behavior is more pronounced relative to the significantly smaller average consumption. The standard deviation of the average value is statistically determined to be ±1.1 kWh/(m²a). The energy conservation by the Passive House standard is statistically determined to be 80%
±5% in savings compared to the low energy standard,
and
2. Heating season 2000/2001: 13,3 kWh/(m²a) 3. Heating season 2001/2002: 12,8 kWh/(m²a). Based on the measurement results, the extremely low heat consumption has also been statistically determined for the Passive House development in Hannover Kronsberg. The standard deviation of the individual values amounts to 6.6 kWh/(m²a), the average deviation is determined to be ±1.2 kWh/(m²a).
Fig. 6: This diagram summarizes the comparison of the energy consumption results of the lowenergy development (left, 65 kWh/(m²a)) with the three Passive House developments (approximately 13 kWh/(m²a) in each case). The consumption in Passive House developments by measured results is about 80% less than in already very energy efficient lowenergy homes. All fieldmeasured and averaged results match closely the apriori ( in advance) calculated heat requirements using the Passive House Planning Package (PHPP). Conclusions The measurements in the realized passive house developments show:
Summary Different users have, even if they live in identically constructed houses, frequently very different consumption results: Deviations of ±50% from the average consumption value are not exceptional. This is not only the case in houses constructed following the Passive House principles, but holds true for other construction types as well. This deviation is caused mainly by different thermostat settings during the heating season. Additionally, the maximum energy consumption in Passive Houses is still significantly lower than the lowest usage in average new buildings. As has been proven, the Passive House concept leads to very high energy savings, reproducibly, which amounts to more than 90% savings compared to existing buildings and to still on average 80% compared to the energy code requirements for new construction in Germany (which is quite good compared to other standards in the world).
Literature (small printed ones available only in German): [Ebel 2003] Ebel, W.; Großklos, M.; Knissel, J.; Loga, T. und Müller, K.: Wohnen in Passiv und Niedrigenergiehäusern – Eine vergleichende Analyse der Nutzungsfaktoren am Beispiel der „Gartenhofsiedlung Lummerlund“ in WiesbadenDotzheim, Endbericht / Energie; Institut Wohnen und Umwelt; Darmstadt 2003. [Feist/Loga/Großklos
2000] Feist, W.; Loga, T. und Großklos, M.: [Loga 1997] Loga,
Tobias; Müller, Kornelia; Menje, Horst: [Peper/Feist 2001] Peper, Sören; Feist, Wolfgang: Messtechnische Untersuchung und Auswertung  Klimaneutrale Passivhaussiedlung HannoverKronsberg; 1. Auflage, Proklima, Hannover 2001; this report can be orderes for free from proKlima. You may downlod an English version from this link: Passive Houses Kronsberg ( pdf, english, 4.5 MB big file) [Peper/Feist 2002] Peper, Sören;
Feist, Wolfgang: Klimaneutrale Passivhaussiedlung HannoverKronsberg
Analyse im dritten Betriebsjahr; [Reiß/Erhorn 2003] Reiß, Johann und Erhorn, Hans: Messtechnische Validierung des Energiekonzeptes einer großtechnisch umgesetzten Passivhausentwicklung in StuttgartFeuerbach, IBPBericht WB 117/2003, FraunhoferInstitut für Bauphysik, Stuttgart 2003. [Schnieders/Feist 2001] Schnieders,
Jürgen; Feist, Wolfgang; Pfluger, Rainer; Kah, Oliver: CEPHEUS
 Scientific Analysis, Final Report, Project Information Nr.
22, 1. edition, Passive House Institute, 2001
(updated: 20070510 author: Dr. Wolfgang Feist; thanks to Katrin Klingenberg for helping with we translation. © Passive House Institute; unchanged copy is permitted, please give reference to this page) 