An the search for practical solutions, one sometimes finds them among relatives. The author’s brother-in-law is in the process of replacing his old gas heater with a new one these days. He is counting on the fact that natural gas will somehow come to Germany. He combines condensing heating with solar thermal energy, and then there are state subsidies for both.
The brother lives on Lake Constance, he has solar collectors on the roof, which he is not really happy with because of constant defects – that’s possibly atypical. They are currently being replaced by photovoltaics, but it was a difficult undertaking because there are hardly any solar installers who will install a system before winter. And if so, then at an outrageous price. It is to be combined with a heat pump. Only there is no craftsman who would like to install one.
Individual cases, for sure. But they show two things: First, there are free-rider effects, and because people are already frantically ordering solar cells and heating systems, demand does not need to be fueled by subsidies. The reduction in funding that has just taken place is understandable, but the political signal is devastating. And secondly, the government’s plans will fail because there are not enough craftsmen who are able to install the many heat pumps. There are significantly fewer subsidies, especially for wood pellets, for gas there are no longer any, and the lists with the new subsidy rates are even more confusing than before. Politically, there is a clear will to switch to electric heating, which is why there is still a relatively large amount of money waiting for the heat pump.
Electric does not mean carbon neutral
Electrical is considered clean. The fact that it is often pretended that an electrically operated heating system is climate-neutral is, of course, nonsense. In fact, the CO2 emissions result from the energy mix of electricity production, so in Germany not even half comes from renewables. If traffic and heating are added to the current consumption without corresponding expansion, it will not get any better. It is questionable whether the power plants and the grid are adequately equipped to cope with the increased consumption. In this respect, it is not good at all that electric fan heaters are doing the same as toilet paper recently, they are being ripped off the shelves in retail.
Generating heat with fan heaters, electric radiators and emitters is the worst of all options and only acceptable as occasional supplemental heating. In this way, one kilowatt hour of electricity is converted into around 0.8 to 0.9 kWh of heat output, and the heat pump creates several times that. This is not a mysterious creation of energy out of nowhere, but rather it brings the heat present in the air, the earth or the groundwater into the house. Since the air reaches sub-zero temperatures in winter, while the ground and the water do not at a frost-proof depth, the air heat pump has to work more in the cold season, so it is less efficient over the year. The fact that it still makes up the lion’s share of the installed systems is due to the costs, because the drilling and earthworks for a geothermal heat pump are expensive and in many places not even possible.
As a rule, heating water and service water are heated. Heat pumps that deliver hot air are cheap to buy, but only make sense if only one room is to be heated. In general, the heat pump works more effectively the smaller the temperature difference between the heat source and the heating system. New buildings are well insulated, the low heating requirement is covered by the heat pump. It becomes difficult when the oil or gas heating in the old building is to be replaced by an electric one. The central heating systems there are designed for high flow temperatures of the heating water, which special heat pumps that work with several stages or another refrigerant can provide, but this is not efficient. Normal heat pumps reach around 55 degrees, high-temperature heat pumps up to 75 degrees. If more is required or if the process water is to be heated to avoid legionella, a heating element that works like a kettle is switched on.
