Air source heat pump & solar thermal & water softening system? Experiences?

Dear forum members,
after consulting some experts and receiving several answers, I also want to gather one (some) opinion(s) here:
We are building a detached single-family house with a developer. A air-to-air heat pump (Rotex HPSU 300) is included in the purchase price. So far so good. Now we have met with the responsible installer, who additionally recommends the following:
1. Instead of the 300-liter storage tank, we should take the 500-liter storage tank (additional cost: 500 €). Household consists of 2 adults and 2 children.
2. He also recommends installing a water softening system, since the water in our area is hard (over 14° dH) and thus, among other things, the warranty on the heat pump would be void (additional cost approx. 3000 €, exact price is yet to be determined).
3. Lastly, he recommends installing solar thermal for the heat pump. He is actually not a fan of it but would recommend it for this model (additional cost approx. 1500 €, exact price to be calculated as well).

So, altogether that would be additional costs of approx. 5000 €. What do you think about this? Does anyone have experience with similar situations?
Hope someone can help & many thanks in advance.

Hello,

...We are building a detached single-family house with a developer. A air-to-water heat pump (Rotex HPSU 300) is included in the purchase price. So far so good.

According to which criteria was it selected? What is the heating load? Has the actual energy demand for heating and hot water been determined? Has controlled residential ventilation/heat recovery been considered?

...Now we have met with the responsible installer, who additionally recommends the following:
1. Instead of the 300-liter storage tank, we should take the 500-liter storage tank (extra cost: 500 €). Household consists of 2 adults and 2 children ..

I can hardly imagine that 500 liters will be necessary here, unless there are bathing orgies. The hot water preparation is planned according to the demand just as carefully as the heating area!
However, when using a heat pump as a heat generator, "heat pump suitable" storage tanks should be used. Standard storage tanks are rather less suitable.

...2. Furthermore, he recommends installing a water softening system because the water in our area is hard (over 14° dH) and thus, among other things, the warranty of the heat pump would be void (additional cost about 3000 €, exact price still to be checked).

At best, the filling water of the heating system must meet certain requirements.

...3. Lastly, he recommends installing solar thermal for the heat pump. He is actually not a fan of it, but with this model he would recommend it (additional cost about 1500 €, exact price to be calculated as well).

I have a completely different opinion on that.

The builder is extremely business-minded and very focused on his turnover! Hopefully, he has also done his homework in the planning/dimensioning area just as thoroughly.

Best regards

Hello,

What is to be made of this?

It shows that the installer is business-minded; otherwise, nothing really


Best regards from the Rhineland

Oh dear, I already suspected that the main goal here is to sell. But the water softening system is still something to consider, isn’t it? I’m also thinking about household appliances, protection of the pipes, and so on. Maybe later on, so it would be cheaper. Just a quick question about solar thermal energy. A price of €1500 is not insignificant, but wouldn’t it pay off over the years? What exactly speaks against it? Thank you very much for the suggestions!

A water softening system is definitely good and saves a significant amount of cleaning effort. We have a hardness level of 18, so you almost have to do it. However, with softening systems, it is important to ensure that the sodium level in the drinking water does not become too high if an ion exchanger is installed. Possibly have the kitchen faucet installed separately. I don’t know if a descaling system is financially worthwhile, since scaled-up heating systems also consume more energy, but generally, the heating system should be filled with softened water anyway. I consider 500 liters to be too much, depending on how large your bathtub and habits are. 300 liters should be enough, that’s what we have too. (With a standard bathtub and eventually 4 people. But the gas boiler produces enough hot water again in 10 minutes if the 300 liters ever run out.)