The biggest problem with renovating existing buildings, as I see it, is in big cities. Where to put the large heat pumps? Not to mention the heritage protection in cities like Munich, Hamburg, etc.
I think district heating is likely the better idea in big cities. On the one hand, because a very large heat storage allows better buffering (keyword sector coupling, also surface area grows quadratically but volume cubically). On the other hand, because of economies of scale. And also because not everything will work everywhere. But, for example, geothermal fields could be drilled under parks and other green spaces (provided there’s no subway line running there) or the air-water heat pump could be installed on the flat roof of the neighboring block. Heritage protection is one of the points that belongs on my list from earlier as well. We won’t be able to preserve every old facade exactly as it is. Some things may not really be worthy of protection, some can perhaps be faked, some will have to be solved with internal insulation. There should be some flexibility here.
Yes, right, but those are also political issues whose costs should only partly be passed on to the end customer. Everyone cares most about their wallet. That’s why an affordable heat pump tariff and subsidies for the investment are a very good lever to motivate people to participate. Investments and subsidies in the past were more like a watering can approach, if I think about Baukindergeld alone :rolleyes: An affordable heat pump tariff would be targeted and by far not a watering can principle.
The state is all of us together. In that respect, this dichotomy does not exist. On the other hand, it is simply the case that heat pumps are not sensible for everyone in the foreseeable future. As described earlier...the big environmental gain is when a house’s heating demand is reduced from 300kWh to 80kWh. That step is achievable even without a full renovation and while people are living in the house. The switch to low temperature heating can then be done later, or when it fits well, or simply omitted for some houses. We don’t have to tackle two problems at once. The issue of habitability is also an underestimated aspect; here in the forum we mainly talk about single-family houses where a few months of construction work can be managed when the owner changes. But with a block of 90 units, you can’t just evict everyone for months. And heat pump electricity is a watering can principle. The wealthy person in the 250 sqm new build with a heated fitness room in the basement (used one hour per week ;) ) benefits just as much from subsidized electricity as the tenant in the 20 sqm shoebox apartment. Every subsidy creates incentives and thus inevitably also misaligned incentives. I’ll just point to the BAFA-eligible ventilation + air-water heat pump monster units that everyone wanted to sell me. Or to the fact that we now have a geothermal borehole that will never pay off according to normal calculations, but was subsidized back then by BAFA (although we pay everything ourselves now due to system change).