Heating the Passive House in Darmstadt- Kranichstein efficiently during the winter of 2022/23
Since 2016, this home on the western side of the Passive House building in Darmstadt Kranichstein has been heated solely using what is referred to as a mini split unit. How this was installed is documented here: installation of a split unit. This device has been continuously monitored for 6 years and the published results can be found here: [Feist 2022] heating with a split unit air conditioner. In short: this works quite well, both in winter and in summer, and in a Passive House building the power consumption of the mini split unit is extremely low, so this is a very low cost heating variant.
In 2022, a worldwide natural gas crisis was triggered due to the war situation (in Europe!), which hit Germany especially hard as Germany was and still is highly dependent on natural gas for heating: about 50% of the heating energy demand is met through the fossil fuel gas; a very high percentage (about 66%) of this gas was pretty cheaply obtained from Russia - and in the course of 2022 this supply finally stopped completely. This explains a rather serious subsequent crisis, combined with extreme increases in the cost of fossil gas and also of other final energy sources. Simply because of the quantity structure, and also due to the costs, particularly economical use of energy was therefore required, especially for space heating. In the present case, the electricity consumption of this split unit is extremely low due to the low heat output in the Passive House building and the heat pump of the split unit: between 700 and 1100 kWh/year for the whole apartment equating to a cost of less than 400 € for the whole year.
That is around 5.5 kWh/(m²a) electricity consumption for heating. Of this, less than half is generated today using fossil fuels, less than one sixth from natural gas. This applies for average indoor temperatures of around 21.5 °C in winter, which were permanently maintained (in almost all rooms). Despite this, we took this year's situation as an opportunity for further investigation: if we also implemented particularly economical user behaviour in the Passive House building by systematically improving the standard of clothing, how far further could we reduce the electricity consumption of the heat pump? For this purpose, up-to-date records have been documented below - the following paragraphs are therefore written in the present tense and promptly reflect the situation arising in each case.
