Which heating? Gas or electric heating?

If you want to be independent and self-sufficient, build a passive house with proper photovoltaics, a garden for self-supply, a chicken coop

Love to do so :) but unfortunately there are no suitable plots for that here...

It all rather speaks in favor of a decent gas heating system...

Probably... but not certain.. The following should be considered. 1. 4000 liters of oil indicate a heating load of 14kW for a 4-person household. That is about 64W/m² and almost double what a house according to the Energy Saving Ordinance achieves today. Whether it is actually 14kW, I rather doubt. Presumably, the oil furnace has been operated very inefficiently until now. 2. For the efficient operation of a heat pump, the required flow temperatures are particularly decisive. With underfloor heating, the conditions are relatively good. There are heat pump users who operate a heat pump very efficiently even with radiators. With underfloor heating that achieves flow temperatures below 40°C, this should be possible without problems. However, you have to deal with the technology. That means no ERR, no buffer tank, hydraulic balancing, and an optimal heating curve. If a flow temperature <40°C cannot be achieved with the current underfloor heating, one should consider improving the insulation standard. This has two effects:

[*]Reduction of flow temperatures (thus suitable for heat pumps) [*]Reduction of heat demand.

3. If, due to the possible flow temperatures, a geothermal heat pump comes into question, it would be advisable to get information about the concept of the trench collector. In new buildings, this can be created unbeatable cheaply. After deducting subsidies, even better than an air heat pump. In existing buildings, it is somewhat more difficult but certainly possible. Getting information certainly does no harm. 4. Gas has the advantage that you do not really have to worry about the points mentioned earlier. On the other hand, you should ask yourself whether there is not a certain risk that fossil fuels will be burdened much more in the near future, e.g. in the form of a CO2 charge. Regards Nika

Probably... but not certain.. The following should be considered. 1. 4000 liters of oil in a 4-person household indicate a heating load of 14kW. That is about 64W/m² and almost double what a house achieves today according to the Energy Saving Ordinance. Whether it is actually 14kW, I tend to doubt. Presumably, the oil heater has been operated very inefficiently until now.

2. For the efficient operation of a heat pump, the required flow temperatures are decisive. With underfloor heating, you have relatively good conditions. There are heat pump users who operate a heat pump extremely efficiently even with radiators. With underfloor heating that achieves flow temperatures below 40°C, this should also be easily possible. However, you then have to deal with the technology. That means no ERR, no buffer, hydraulic balancing, and optimal heating curve. If with the current underfloor heating a flow temperature <40°C is not achievable, one should consider improving the insulation standard. This has two effects:

[*]Lowering the flow temperatures (thus suitable for heat pumps)
[*]Reducing the heat demand.

3. If then, due to possible flow temperatures, a geothermal heat pump is an option, it would be advisable to inform yourself about the concept of the trench collector. In new buildings, this can be created unbeatable cheaply. After deduction of subsidies, even better than an air heat pump. In existing buildings, it's somewhat more difficult but definitely possible. Getting information certainly doesn't hurt.

4. Gas has the advantage that you do not really have to worry about the points mentioned earlier. On the other hand, one should ask whether there is not a certain risk that fossil fuels will be significantly more burdened in the near future, e.g., in the form of a CO2 tax.

Regards, Nika

Thank you very much for the great feedback! (also to everyone else)

Our flow temperature is about 30 degrees – we also have radiators running at 60 degrees flow temperature, but we actually only have one in operation – it is in the bathroom.

Trench collector sounds totally interesting, but the garden is mostly built on and landscaped, so unfortunately this option is out.

4000 liters of oil is rather an estimate – but 3500 liters for sure.

Gas is certainly the cheapest, but somehow we don’t feel good about investing in this type of fuel.

Best regards

Our supply temperature is about 30 degrees – although we do have radiators running at 60 degrees supply, we actually only have one in operation – which is in the bathroom.

Are the 30 degrees independent of the outside temperature? Or do you have 30 degrees supply at 10°C outside, and rather 40-45 degrees supply at -10°C?

When switching the heating system to anything (gas condensing boiler, oil condensing boiler, pellet condensing boiler, or heat pump), lower the supply temperature in the bathroom to the level of the rest of the circuit. At the moment, due to the bathroom radiator, you always have 60°C (or whatever the highest temperature in the heating circuit currently is) supply for everything. The rest is then mixed down. With your old oil heating system this doesn't matter initially because it doesn't use condensing technology anyway. With a new one, however, the average heating medium temperature should be as low as possible, and 25/60 is obviously more than 25/35.

Are the 30 degrees independent of the outside temperature? Or do you have 30°C in the supply line at 10°C outside, and more like 40-45°C in the supply line at -10°C?

When changing the heating system to anything (gas condensing, oil condensing, pellet with condensing or heat pump), lower the supply temperature in the bathroom to the level of the rest of the circuit. At the moment, you always have 60°C (or whatever the highest temperature currently in the heating circuit is) in the supply line for everything because of the bathroom radiator. The rest is then just mixed down. With your old oil heater this does not matter anyway, because it does not have any condensing utilization. But with a new one, the average heating medium temperature should be as low as possible and 25/60 is clearly more than 25/35.

So the supply line is always around 30 degrees.

Thanks for the tip about the bathroom radiator – but it does not run constantly either, I have to check where you can adjust that in the heating system’s menu. It is certainly true that providing 60 degrees costs energy.

By the way, there was a mistake in my initial post – the heat pump should drill 3 x 90 or 2 x 135 m deep, not 3 x 45 m …

Is it actually possible to do without passive cooling? Or is the effect in summer so pleasant that the 900 euro extra cost (plus tax) would be worth it in our case?

Not a second thought, of course gas because it is much cheaper and more solid technology

Not a second thought. Of course without fossil fuel if it is technically reasonably possible.