Heating choice, what makes sense

No, of course not - the sun doesn’t always shine when you have to heat up ;)

Hello! In my opinion, none of the currently offered systems are fundamentally bad. I find the religious wars in internet forums to be somewhat exaggerated at times. It always depends on the personal situation what is advisable, and in the end good planning and good installation of a heating system are more important than the type of heating system. With a gas heating system, you have low investment costs but high consumption. With certain measures such as insulation, better KfW level, solar thermal, photovoltaics, or heat pumps, you can reduce consumption but increase investment costs, so it ends up roughly the same. It should also be clear that the lower the consumption costs already are, the harder it is to save further investment costs through even lower consumption. Even a KfW-100 house built in 2015 already has significantly lower consumption costs than a house from the 80s or 90s. Gas is interesting again because electricity prices (relevant for electric heat pumps) have risen sharply, but the gas price has remained constant. In unfavorable constellations of heat pumps with high electricity consumption, the high electricity price can make quite a difference, for example a heat pump in a house in a colder region, which draws its heat from the very cold outside air during the heating period (down to -20 degrees?), combined with a high heating demand, for example because of poor insulation and because the area is rather cold. For heat pumps, therefore, highly efficient ground-source heat pumps, which extract heat from the ground (+5° Celsius), are becoming increasingly interesting, especially because since this year there is a subsidy of €4,500 from BAFA for ground-water heat pumps with a calculated annual performance factor of at least 4.5. There is a website on the topic "heating comparison," created by an energy consultant named Alois Zimmermann, which compares the investment, operating, and maintenance costs of various heating systems in an example calculation (under certain assumptions for house size, heating demand, and price increases). Maybe this site can help you a little. Otherwise, there is also the option of hiring an energy consultant who calculates the optimal heating variant for your personal situation. Best regards jx7 PS: We are currently planning a single-family house in the warm Rhine valley near Mainz with KfW-70 and ground-water heat pump (deep drilling/geothermal).

I quote the first post from the OP:

since we don't want gas/liquefied gas (gas isn't even available in the street), oil or pellets, an efficient and economical solution is needed.

There aren't really many options left to even carry on a "religious war"...

Hello Michael,

in addition to the many good previous contributions, here are the following notes:

- The installation of a controlled residential ventilation system is, especially in new buildings, a very sensible measure, as it is energetically very efficient and comparatively easy to implement.

- How is the heat transfer supposed to be carried out, underfloor heating (everywhere or only partially?) or radiators. Since a heat pump is basically a given, you should get the flow temperatures as low as possible in order to operate economically.

- How many people will live in the house, how is the hot water demand to be estimated? The higher the hot water consumption in the end, the less efficiently the heat pump will operate.

- Which type of storage is exactly planned, and how is the integration into the building technology/electrical installation in general supposed to take place? One should not forget the losses that occur during the charging/discharging as well as the operation of an electric storage.

Basically, in the planning phase, I would actually still allow options or alternatives to better compare them. Even if you don’t like pellets or liquid gas, arguments may arise during the discussion that might help me with the overall planning of the property or lead to an increase in knowledge. An important argument are and remain the investment costs for the heating system. If I can save here, I can possibly implement energy efficiency measures that were not considered with a capped budget.

Best regards, Erik

Hi discussion partner,

I am currently facing a similar problem. Semi-detached house with about 150 sqm, 3 floors plus basement, new build in Fahrenzhausen (postal code 85777). We are three people who shower daily. We have found insulation important so far - we want to achieve KfW 50 or below. The plot is about 340 sqm, the house has a footprint of 65-70 sqm (still unclear), a double garage will be added to the property and about 40 sqm will be paved (however, permeable to water). Now I have some questions: 1) Controlled ventilation with heat recovery: What is especially recommended? I had no idea there are so many variants. 2) We prefer a heat pump. Personally, I would like brine, my wife is worried about the investment costs - and my wife’s gut feeling has not been wrong so far. So it could also be an air heat pump. Our developer suggests one from Nibe (unfortunately it is not offered as such - whatever was really put together there (Nibe Split air/water heat pump F2030 AMS 10-12)) 3) Does it make sense to additionally use solar thermal? 4) Is it more sensible to use photovoltaics to supply the heat pump? 5) How large would a photovoltaic system have to be dimensioned to fully supply the heat pump? 6) How large would a photovoltaic system have to be dimensioned to also provide enough electricity for the household? The idea would be towards autonomy.

I am not interested in exact values yet, but more in an estimate whether something like this is possible and how expensive it would be.

Just a brief note about the photovoltaic system. It doesn’t work in winter – now at 4 p.m. with this crappy weather the production is close to zero. But you would need electricity for the heat pump, of course this also applies at night. So you need a power storage – which also costs more than pocket money. The size of the photovoltaic system and the power storage depend on your electricity consumption ;)

We have a 7,x kWp system on the roof. In spring and autumn we can consume the produced electricity well – depending on heating demand and in the evenings/nights of course also buy electricity. In summer most of it is fed in, in winter most of it is purchased.

Personally, I don’t think much of solar thermal for hot water because of the reasons mentioned above – too much hot water production in summer, too little in winter :(