ᐅ Allegro-Haus Ltd. Experiences

That’s exactly what I mean. That’s how it was offered to us; we even received some documents about it. I’m also familiar with the other houses—you know, the ones with the bay window were already all taken back then. There were still several city villas and detached houses with pitched roofs available. Do you remember which plots were offered to you at Leutewitzer Park?

BratacDD schrieb:
Do you still remember which plots were offered to you near Leutewitzer Park?

Unfortunately, I can’t recall exactly, but I think it was plots 1, 9, or 13. At least, they were relatively close to the street; it was quite some time ago.

€uro schrieb:

As you can see, everything has certain advantages as well as disadvantages. Proper evaluation and assessment can only be done with a solid and precise preliminary analysis and overall planning.

I am currently deciding between a ground-source heat pump and a Viessmann gas boiler with integrated solar water heating. Although I had initially committed to the ground-source heat pump, I was advised to choose the gas boiler instead. Now, I’m not so sure and wanted to bring the issue to the forum. Does anyone have experience with Viessmann gas boilers? How large should the gas tank ideally be?

Thanks in advance for any helpful advice.

Condor schrieb:
....I was advised to go with a gas heating system even though I had decided on a ground source heat pump.

Who advised you? Unless there are specific figures from the initial energy assessment behind these "recommendations," they are fairly meaningless.

Condor schrieb:
....How large should the gas tank be?

Why a gas tank? Is natural gas not available? With propane, among other things, it should be noted that the lowest modulation level is significantly higher than when using natural gas. This is a clear disadvantage => frequent cycling in mostly partial load operation.

Best regards

€uro schrieb:
Who exactly is "one"? As long as there are no specific figures from the initial assessment behind the "advice," it is relatively worthless. Why use a propane tank; is there no natural gas available? With liquefied petroleum gas (LPG), it should also be noted, among other things, that the lowest modulation level is significantly higher than when using natural gas. This is a clear disadvantage => cycling during mostly partial load operation.

"One" refers to the house sales department itself. The argument given is that with a solar-assisted gas heating system, it is possible to save energy and also operate panel radiators. Why a gas tank? You need an energy storage container if you are not connected to the municipal gas grid. Excuse me, could you explain in simpler terms? What is meant by the modulation level and cycling during partial load operation?

Condor schrieb:
..."The house sales team themselves say this. They argue that a gas heating system supported by solar energy can save energy and also operate panel radiators."

This is not an argument in favor of gas, as it can also be achieved with other heat generators. Additionally, solar thermal systems in single-family homes are usually uneconomical.

Condor schrieb:
...Why a gas tank? I need an energy storage container if I’m not connected to the municipal grid."

So natural gas is not possible or not available in this case?

Condor schrieb:
...Sorry, could you explain in simpler terms? What is meant by modulation performance level and cycling at partial load?"

Every heat generator is sized according to the calculated standard heating load. This considers the worst-case scenario, because you don’t want to be cold even under unfavorable conditions. However, this scenario only applies to a small fraction of the annual heating energy demand. Most of the time, a heat generator operates at partial load, meaning that as the outside temperature increases, the heating demand decreases. A device with wide modulation capability can adapt to this to some extent. If not, it cycles on and off. This negatively affects overall efficiency and service life, sometimes significantly. For liquid gas, the lowest performance level is higher due to the greater energy content, making it noticeably less favorable compared to natural gas.