ᐅ Solar Power System: Yes or No?

Hello,

our builder offers a solar thermal system from the company Junkers (A2/300/FKC-V2/ISM1) with 2 rooftop collectors totaling 4.74m² (51 ft²), Comfortline series, including an approximately 300-liter (79 gallons) hot water storage tank. Is this worthwhile for a single-family home of about 140m² (1,507 ft²)? Does anyone have experience with this system?

Thanks for your suggestions

Hello,

Exilhamburger schrieb:
....Is it worth it for a single-family home of about 140m2 (1,507 sq ft)? ...

It depends on how you define it. A solar thermal system does improve the primary energy profile (energy saving regulations, KfW certification), but with regard to final energy consumption in most cases it tends to be less cost-effective for a single-family house. The main issue is the challenge of storing thermal energy. However, if there is a relatively consistent hot water demand spread over the day, it makes more sense. This type of usage pattern is, however, more typical for commercial buildings. Additionally, it is often overlooked that the control system and circulation pump also consume several kWh per year.

Best regards

In my opinion, a solar power system always makes sense.
The systems are becoming more affordable and efficient over time.

You can also feed any excess electricity back into the grid and receive compensation.
Although feed-in tariffs unfortunately decrease year by year, it is still profitable.
Just take a look around and it’s best to get advice from a professional.

Regards
Matze

Matze66 schrieb:
In my opinion, a solar thermal system always makes sense.
These systems are becoming more affordable and efficient over time.

You can also feed surplus electricity back into the grid and receive compensation.
Although the feed-in tariff unfortunately decreases year by year, it is still profitable.
Just have a good look around and ideally get advice from a professional.

Regards
Matze

Here we are talking about solar thermal systems, not photovoltaic systems.
In my view, a solar thermal system is uneconomical in most cases because hot water is usually only available when it is not needed or needed in small amounts.
If I want to shower in the morning, the water has to be heated by my heating system.
It is only really interesting for meeting a specific primary energy target or to achieve the required share of renewable energy.
However, such examples show how unrealistic the lawmakers are.
In my opinion, a good alternative is an air-to-water heat pump for domestic hot water. It is affordable to install and has very low electricity consumption. Plus, the heating system can be completely turned off during summer.

Regards

Hello,

S.D. schrieb:
We are talking about solar thermal systems here, not photovoltaic systems.

In my opinion, solar systems is the broader term and includes both solar thermal and photovoltaic systems.

S.D. schrieb:
..Only interesting for the purpose of meeting a specific primary energy value or to achieve the required share of renewable energy.

Correct. It’s just about “making it work.” The practical reality looks quite poor, though.

S.D. schrieb:
..However, these examples show that the legislators are completely out of touch with reality.

That’s the key question! One might even suspect it’s intentional. Just think about who benefits from this. Most likely not the homeowner!

S.D. schrieb:
..In my opinion, a good alternative is an air-to-water heat pump for domestic hot water. Cheap to buy and very low electricity consumption.

That’s a mistaken assumption because these heat pumps rely on the energy in the installation space. Where does that energy come from? Just run an energy balance calculation. Additionally, their coefficient of performance hardly exceeds a value of 2. “Standard” air heat pumps achieve > 3.5!

Best regards.

Whether a solar system is worthwhile depends on many factors. Keywords such as tilt angle, orientation, and the degree of shading are just a few examples. The construction method also affects efficiency. Ideally, your roof should receive full sunlight even on December 21st (the shortest day of the year). That way, you can generate a substantial surplus with a solar system. There are also many informative websites available online. If you are aware of your system’s efficiency, you can generate a good amount of electricity even with a small surface area.