Renovation of a 1960s house: Questionable expert recommendations?

Pellet heating? You are dependent on a supplier and you need more space in the house for storage as well as somewhat more complex service and repairs.

a heat pump is not worth it because of the significantly higher maintenance costs compared to, for example, a gas heating system

What maintenance costs? It is clear that a gas heating system has to be serviced every year including the chimney sweep. But a heat pump is as maintenance-intensive as a refrigerator.

The appraiser is either good (because he only does the bare minimum) or has not yet gotten beyond the year 1990.

A very fitting description :cool:. Until now I had rather thought the latter, but with your feedback I have somewhat corrected my opinion.

A heat pump only makes sense if you really insulate all around and also switch to underfloor heating. I wouldn’t do it, that’s not good for old houses. However, you are right about insulating the top floor ceiling/roof as well as the water pipes. You can leave the heating pipes inside. That is a closed circuit, so there is hardly any deposits/corrosion. I don’t believe that CO² will become so expensive so quickly that the additional costs would pay off within your lifetimes.

As I said, I am ambivalent about the heat pump. With an insulated roof and better windows, the demand would already be lower. All of that with some self-generated electricity consumption, possibly enlarged heating surfaces and slightly lowered system temperatures. Or do I immediately get some mold problems in the unchanged facade? I would actually find the self-consumption of solar power quite appealing, and then a heat pump would be the first choice. I don’t see the rise in CO2 costs as calmly as you do. I don’t see it as dramatically as nordanney, but I do expect a continuous increase and consider that at least a co-decisive criterion in the system selection.

What about a wood pellet heating system?

Yes, pellets are also worth considering. With that I would in any case achieve the same system temperatures. I would have to think about how much storage space is needed. I assume that usually dust-related sack silos are placed in the basement (e.g. old oil storage) and that pellets are not stored "open" in a walled storage room with a sloped floor? Is there some kind of standard in the single-family home area or does it depend on the local situation? Is there anything to consider regarding fire protection?

Pellet heating? You depend on a supplier and you need more space in the house for storage as well as somewhat more elaborate service and repairs.

Well, I am also dependent on a supplier for oil. That from time to time I have to pick up the phone and have my storage filled with oil or pellets I would not find inconvenient or annoying. Is maintenance really that much more elaborate for pellet boilers? What specifically has to be done and what does it cost? Thanks for your answers, that is really helpful for forming an opinion!

I actually find self-consumption of solar power quite appealing, and a heat pump would be the first choice for that.

This works very well in summer. But in winter, when you want to keep the house warm, hardly anything or nothing at all comes from the roof, meaning exactly when you need the self-generated electricity you have none and have to buy it.

The expert seems pragmatic to me. I like that. Insulating old buildings to the fullest extent can cause serious problems for the building fabric; there are plenty of examples of this. It is no coincidence that the mold remediation boom closely followed the insulation boom. Replace water pipes only if they are made of lead. The heating system can certainly remain. I would also do new electrical work. On the heating side, I find pellet and split wood gasifiers interesting. I like the idea of maintaining system temperatures and not insulating fully the best. There are also subsidies for this. Photovoltaics and heat pumps are often mentioned. There is sun in summer; heat is needed in winter. As writes: Photovoltaics usually provide energy at the wrong time. Nevertheless, photovoltaics are fundamentally useful.

The expert seems pragmatic to me. I like that. Insulating old buildings as tightly as possible can cause serious problems to the building fabric; there are plenty of examples for that. It’s no coincidence that the mold remediation boom closely followed the insulation boom. Only replace water pipes if they are made of lead. The heating system can certainly stay. I would also renew the electrical system. On the heating side, I also find pellet and split wood gasifiers interesting. The idea of maintaining the system temperatures and not fully insulating appeals to me the most. There are also subsidies for that.

I like that you basically support the expert’s opinion fairly uniformly. I had feared a belief conflict would break out here. The water pipes are not made of lead; those were rather installed in the 30s/40s. He opened several taps, and after the long standstill some brown brew naturally came out, nothing alarming. Nevertheless, I would replace the water pipes since they are 60 years old and the issue of wear/corrosion is probably different from dead heating water. When thinking of wood gasifiers – without having informed myself in detail – I immediately think of increased maintenance and “messiness.” I have heard of wood gasifier combined heat and power plants where problems with clogged heat exchangers or other deposits often occur depending on gas quality (which varies greatly depending on fuel).

Photovoltaics and heat pumps are often mentioned. There is sun in summer; heat is needed in winter. As writes: Photovoltaics usually deliver energy at the wrong time. Nevertheless, photovoltaics are fundamentally sensible.

In winter, for reasons of comfort/coziness, we want to additionally heat with the wood stove in the living room anyway, so we would not heat completely with the heat pump then. Although the roof is anything but photovoltaic-optimal (WSW orientation with an estimated 55° pitch), snow would quickly slide off in winter, and PVGIS still indicates a yield of almost 800 kWh/kWp. With appropriate buffer and/or electricity storage sizing, I would consider decent self-consumption through the heat pump feasible. Of course, not when it snows and rains for days on end... Attached are a few pictures of the roof structure and condition. The expert recommended external rafters insulation. During my research, I found estimated costs of up to €250/m², which would mean €40k for about 160 m² of roof area. I am not sure how old these values are (current cost explosion) and whether they are net or gross. The tiles are said to be 40 years old. Can they be reused? Are they even “gently” removed and reused, or is it cheaper (because faster) to throw the tiles directly into the scrap container and reroof with new ones?

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