Heat pump with photovoltaics vs gas and solar thermal

The consumption of the heat pump is from the first year, when everything was really dry; the consumption in the second year has dropped significantly (to the value I wrote). With us, electricity is 10C per kWh cheaper. That makes a big difference in the bills. The comparison of the amount of energy as you do is flawed both at the beginning and the end, because you do not take the efficiency into account. This is less than 1 for wood, gas, and oil (less heat energy obtained than chemical energy "put in"). Therefore, a heat pump can very well compete with other forms of energy. Apart from that, there is a suitable heat pump for every heating load; anyone who claims otherwise has not yet inquired at this point. So there is definitely a suitable one for 600 sqm. My brine heat pump had an annual performance factor of 6 last year (admittedly, above the average of about 5 for this technology), which means my kWh of heat cost less than 4C at my electricity price and beats wood, gas, and oil at my local prices. And that with absolutely no effort (chimney) and storage space, and an absolute minimum of maintenance (none). The higher the demand for heat energy, the more an efficient heating system pays off, and the better high investments can be recouped. What you wrote about photovoltaics is great; most people, however, do not have such large south-facing roof areas. And especially with photovoltaics, a heat pump would harmonize very well. It then produces cost-neutral hot water in summer and transitional periods and possibly also heats a little when a cold night comes. Definitely better than solar thermal.

Well, I have definitely informed myself and I did not write impossible but inefficient and not profitable within 30 years.

As far as electricity prices are concerned, since I feed in, I am tied to a supplier and cannot switch to a cheaper one.

I understand that I cannot calculate with an efficiency of 1, and if everything is weighed carefully here, then so be it. My stove has an efficiency of over 80%. I have a temperature of about 870 degrees in the combustion chamber and an exhaust gas temperature of < 160 degrees at the chimney outlet before the wall.

I have 7m of ceramic flue channels. The water tank has a specified heating capacity of 18kw.

When burning 10kg of wood (weighed before burning), the buffer tank heated up by about 10 degrees in approximately 3 hours. The stove also releases some of the heat directly through the glass and the surface into the room. (It is centrally placed as a room divider between kitchen/dining and living room). And there is nothing nicer than a warm tiled stove that 'radiates' warmth...

The investment costs for a heat pump instead of a gas condensing boiler would have been astronomical (at least a factor of 3-4 in my case).

The savings potential of a heat pump compared to a gas condensing boiler is not great enough to represent accordingly. That is why I made this statement for MYSELF.

Honestly, I do not understand why everyone is always against ST here. It is probably the cheapest and most proven way to generate heat (at least when the sun is shining).

Why should I invest additional costs in a heat pump if I do not benefit from it? Assuming the heat pump costs only half as much as it does today in 10 years, I will have already covered the costs for the gas condensing boiler twice and if it breaks down, I will just get a heat pump then.

Of course, I can only speak for my situation, but that is what such a forum is for: you can look at the experiences of different people and their motivations and then form an opinion for your own situation.

As long as the costs for primary energy are as they currently are, in my opinion a heat pump simply does not pay off. However, you should still design the heating installation for a heat pump (I have done that too). That means as small distances as possible in the underfloor heating and thus low flow temperatures.

When I read your numbers and look at your investment, I also do not believe you will have an ROI in the foreseeable future. I would be interested to know what comes out of it. Have you ever calculated that?

At 2000kwh / year, that is costs for oil/gas/wood of > 200€. How much cheaper would the heat pump be there, especially regarding the additional costs in the investment?

As far as electricity prices are concerned, since I feed in, I am tied to a supplier and cannot switch to a cheaper one.

I don’t know where you live and how old your system is, but what does feeding in have to do with consuming?

I have a system with surplus feed-in and I receive payment for the feed-in from the grid operator (not the supplier!) according to the Renewable Energy Act.

And the supply is taken over, as usual, by a supplier of my choice.

That I cannot calculate with an efficiency of 1 is clear to me, and if here everything is put on the gold scale, then so be it. My stove has an efficiency of over 80%.

You started by saying that my statements were simplistic, although yours were just as inaccurate and simplistic. Now I am trying the opposite and am precise and well-founded, and now you turn 180° and say it is too exact. Make up your mind! An 80% efficiency basically means something like a "coefficient of performance" of 0.8; from your heating output of 2000 kWh of your cubic meter of wood, you then get 1600 – that is already a significant difference (a simple kitchen scale is enough for that; you don’t need a gold scale).
If 10 kg of wood heats your buffer tank by 10°, that is an efficiency for hot water in the buffer tank of 63%. Of course, the total is higher if you largely utilize the remaining heat. I pay €0.20 for this amount of heat, and I have to do "nothing" (no fetching wood, storing, lighting, possibly cleaning, etc.). The radiant heat of a fireplace is a matter of taste. Personally, I am bothered by a "one-sided" very high radiant heat; I am extremely satisfied with the even warmth of underfloor heating, so I do not have a fireplace and will never get one (financially, it would not have been a problem). So that is a very subjective argument – to each his own.

There is no ROI when it comes to heating; it costs and costs... and money is not returned. Otherwise, you are making a calculation error:

At 2000 kWh/year, the costs for oil/gas/wood are > €200.

My heat pump, with last year's efficiency, required 1400 kWh of electricity but produced a bit more than 8400 kWh of heat for heating and hot water. In comparison, with wood or oil (your 80%) one would have to buy 10,500 kWh / with good gas condensing boiler about 9000 kWh of gas.
My investment would not have been much less with other heating technology, by the way, because I don’t have a gas line here (so gas tank or similar), and that would have caused space and additional costs. Also, a fireplace is not free either.

Why should I invest additional costs in a heat pump if I have no benefit in it? Assuming the heat pump only costs half as much in 10 years as it does today, then I will have paid for the gas condensing boiler twice by then and will just install a heat pump when it breaks down.

This statement is somehow illogical; I don’t know how to interpret it. How do you want to recoup the costs of the gas condensing boiler if the running costs are higher, only the investment is lower?

Otherwise, I think it is nice that you have also revealed something. Because without all this information, your statements were of course not understandable or reproducible (e.g., your electricity price / your photovoltaic amount). That really brings a benefit to other users here in the forum!

And about solar thermal, I still have to strongly disagree with you; especially if you always have finances in mind:
Look at how expensive your solar thermal system was and how little you produce with it! Just like with photovoltaics, you always have good yields when the sun shines nicely – but exactly then you need little hot water, especially in a single-family house only for showering (at least I only heat in winter, almost not at all in the transitional seasons). How many kWh from the thermal system do you really use (not just as waste heat that your buffer tank radiates unused in summer)? I need 1 kWh of electricity on average for hot water in summer. How long can I heat with the costs of a solar thermal system?

In contrast to photovoltaics, you cannot sell surpluses either... just imagine your photovoltaic surplus simply dissipated. Would it still be worth it then?

If you have an 8400 kWh heating load, that corresponds to about 850 liters of heating oil (if gas is not available, there would be liquefied gas with an underground tank). At current prices, that would be €400/year.

Why shouldn’t there be an ROI? I would have had to invest €60,000 in a heat pump solution versus €12,500 for a gas condensing boiler solution??? That’s €47,500 MORE COSTS, when do I get that back => ROI??

If now in 10 years I get the heat pump solution for €30,000, then I have the gas condensing boiler installed....

Where is my thinking error now???

I pay 0.2€ for this amount of heat

I don’t pay 20 cents like you but only 1.5 cents. Ok, I have to store the wood and I have to light the stove, but I would do that anyway because I like this warmth.

I don’t have a fireplace that ‘glows’; my stove is 2.5 m long and stands as a room divider between the living and cooking/dining area. It slowly releases the stored heat into the room. If I last put wood on at 6 p.m., then the next morning the surface temperature is about 30 degrees. If I sit on the stove bench in the morning with my coffee, I have a nice warm back....

For me, the supplier = the network operator (Bayernwerk AG formerly E.ON). I need to check if it’s actually possible to change the supplier. Although I don’t know what happens then to the 10% non-refundable yield. So far that has been offset with my consumption... We are talking about around 3000 kW.

60k € for a heat pump? Then with gold leaf, right? :x *duck*