Hello,
we are planning to build a detached house with about 200 sqm (2,150 sq ft) of living space.
The heating system will be a gas condensing boiler.
In the living and dining area, there will be a water-bearing stove.
And photovoltaic panels on the roof.
Our energy consultant said that if we want KfW 70 (a German energy efficiency standard), we need to install solar thermal panels on the roof instead of photovoltaic panels. But I would actually prefer not to do that.
Now to my question: Does solar thermal for hot water provide the same benefits as photovoltaic?
On the one hand for the KfW application,
and on the other hand from an energy perspective? And economically?
Thanks for your experience and input.
Best regards
we are planning to build a detached house with about 200 sqm (2,150 sq ft) of living space.
The heating system will be a gas condensing boiler.
In the living and dining area, there will be a water-bearing stove.
And photovoltaic panels on the roof.
Our energy consultant said that if we want KfW 70 (a German energy efficiency standard), we need to install solar thermal panels on the roof instead of photovoltaic panels. But I would actually prefer not to do that.
Now to my question: Does solar thermal for hot water provide the same benefits as photovoltaic?
On the one hand for the KfW application,
and on the other hand from an energy perspective? And economically?
Thanks for your experience and input.
Best regards
T
toxicmolotof16 Jul 2015 16:26So, once again:
What kind of water is inside the buffer tank? Heating water or potable water? Or are there two separate buffer tanks?
For example, we have one buffer tank for the heating system and a separate hot water tank for potable water.
If we had a water-circulating fireplace, it would only heat the heating water.
Please sketch the layout of all components and pipes.
What kind of water is inside the buffer tank? Heating water or potable water? Or are there two separate buffer tanks?
For example, we have one buffer tank for the heating system and a separate hot water tank for potable water.
If we had a water-circulating fireplace, it would only heat the heating water.
Please sketch the layout of all components and pipes.
chrischn schrieb:
By the way, he was also surprised that the heating system shows 0.0 for domestic hot water. Someone must have set up the system, so it should be easy enough to ask that person.
However, it still seems impractical to heat large amounts of water to high temperatures all year round when this is only cost-effective in certain cases where huge quantities can be produced at very favorable conditions. Otherwise, producing unnecessary amounts of hot water would require electricity.
The savings from the fireplace for heating water (meaning the piping, buffer tank, additional cost compared to a regular fireplace, etc.) I would rather invest in a central mechanical ventilation system with heat recovery.
With the relatively low additional investment, you could probably operate a central mechanical ventilation system economically soundly (Grym would be thrilled) and you wouldn’t have to cite only the luxury of not having to ventilate manually (and all the other benefits) as an advantage of the mechanical ventilation... 😉
Also, according to your earlier statement, there is even a favorable KfW loan available including a repayment subsidy...
M
Mr.Martin6 Aug 2015 11:23We have a 4 kW (5.4 hp) photovoltaic system and an approximately 4 kW (5.4 hp) solar water heating system on our roof.
I really wish I had installed an 8 kW (10.8 hp) photovoltaic system instead of this useless solar water heating system. The photovoltaic system generates electricity every day (even in winter), which translates into real savings (feed-in + self-consumption).
The solar water heater only produces hot water when the sun is shining strongly, which is about 98% of the time in midsummer—when you don’t really need hot water—or at most around 100 liters (26 gallons) for showering.
In autumn and winter, it supports the heating system, but only insignificantly.
Our solar water heating system cost about 4000 euros (approximately 4000 euros) extra, and if I save 50 euros (approximately 50 USD) per year in energy with it, that would be a lot.
This means it will take a very long time to pay off, and it will probably break down twice before then.
So, in my opinion... stay away from solar water heating on the roof.
I really wish I had installed an 8 kW (10.8 hp) photovoltaic system instead of this useless solar water heating system. The photovoltaic system generates electricity every day (even in winter), which translates into real savings (feed-in + self-consumption).
The solar water heater only produces hot water when the sun is shining strongly, which is about 98% of the time in midsummer—when you don’t really need hot water—or at most around 100 liters (26 gallons) for showering.
In autumn and winter, it supports the heating system, but only insignificantly.
Our solar water heating system cost about 4000 euros (approximately 4000 euros) extra, and if I save 50 euros (approximately 50 USD) per year in energy with it, that would be a lot.
This means it will take a very long time to pay off, and it will probably break down twice before then.
So, in my opinion... stay away from solar water heating on the roof.
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