Replace oil heating in a 60s house?

Hello,

It’s about my parents’ house. It dates from the 60s, very well maintained. A few years ago, my parents had additional seals installed on the double-glazed windows and insulated the roller shutter boxes. On the roof, my father added a layer of rock wool, I think a foil and then drywall, but I’m not sure about the details. There are radiators throughout the whole house, no underfloor heating. The house is divided into two apartments; the ground floor is rented out, my parents live on the first floor.

My father has been pestering me for years about the heating. At the moment they heat with oil. I estimate the heating system is about 15 years old, maybe a bit more. It works perfectly. My father always talks about how it will have to be replaced eventually and he doesn’t know whether he should tackle it now since he could get a good subsidy. If he waits until it breaks, he doesn’t know if there will still be a subsidy then. Would you replace a heating system that is actually fine already, now? I am skeptical about that. Now with the energy crisis, he’s even more eager.

The second question is, what kind of heating now or later. Heat pumps don’t work so well with radiators, do they? I’ve read that you can retrofit a ceiling heating system and then cover the ceiling with drywall. Does anyone know about that? There is no gas connection, and I would hesitate about that at the moment anyway. Pellets, well, they are also getting more expensive. It should also be mentioned that the orientation is not ideal for solar thermal or photovoltaics and that large trees cast shadows on the roof. Would solar thermal or photovoltaics be mandatory with a new heating system?

Many questions, maybe someone can give an assessment.

Regards,
Tobi

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Heat pumps don't work that well with radiators, do they?
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You can't really say that in general. There is a great video contribution on this from the Fraunhofer Institute, which can be found quite quickly.

I have a similar case in the family. Gas would work but is currently 40% more expensive in consumption. Pellets only 10% cheaper. Result: Do nothing, possibly optimize the system. Until proper insulation is done, switching the heating system makes no sense. Oil burner from 2005, has grandfathering until 2035.

I also believe in doing nothing. If the burner breaks, it can be replaced inexpensively within a few days. The subsidies actually only cover the additional costs due to craftsmen and material shortages and the often pointless energy consultant. The heat pump works better the lower the supply temperatures are. That means well-insulated house and large heating surfaces.

My parents are currently also looking (their oil heating system has had minor issues several times, and they expect that it's only a matter of time before they need something new). Sometimes there are recommendations like lowering the flow temperature on their current heating system for one winter (and keeping the radiators turned up) to see if a heat pump might still work somewhat efficiently. (We haven't tried that yet) There are also high-temperature heat pumps as an alternative, but there are practically no experience reports about them. The energy consultant also recommended a pellet heating system to my parents, but they are not convinced so far. Currently, their favorite is an air-to-water heat pump and possibly see if 1-2 other measures suggested by the energy person can be implemented. (Some things have already been done over the decades, e.g. insulated and clad facade, double-glazed windows (they were advised against more), the basement was at some point dried and insulated, etc.) The suggested measures apparently mainly concerned the basement and attic, but we’ll see. I'm a bit skeptical about their current consultant, but we’ll see. So far, as far as I can tell (from second hand and at a distance), there have been very few statements about the heating system itself and the potential challenges with it, but rather only general energy efficiency stuff and measures. What subsidies are necessary and what makes sense in general, but regarding heating and the feasibility of this, I still somehow feel there is quite a lot missing. But overall still work in progress.

55 degrees flow temperature can actually be done by everyone, it's just less efficient.

Pellets are a tricky thing. As mentioned, currently only about 10% cheaper in consumption than oil. Environmentally of course better than oil, but not as good as a heat pump. Additionally, very high investment and a heating system with a lot of mechanics, thus prone to malfunctions.

Insulate as much as possible and then heat pump.