ᐅ Baden-Württemberg Photovoltaic Requirement for Existing Buildings – Replacing Roof Tiles
Created on: 11 Feb 2024 11:28
B
bloodyscorpion
Hello dear forum,
maybe some of you have faced the same situation or have the same question.
I couldn’t find anything clear on the internet regarding this.
Here is the initial situation:
- Solid brick house built in 1970
- Heating system with storage heaters running on 100% green electricity tariff, plus a tiled stove
- Roof insulated with insulation between rafters, attic insulated with XPS boards, plastic double-glazed windows,
so definitely not a modern insulation standard
- Annual energy consumption – daytime electricity (peak) 2,500 kWh (2,500 kWh) – nighttime electricity (off-peak) 7,400 kWh (7,400 kWh)
- Most of the living areas are heated with the tiled stove
In the coming years, the roof tiles will need to be replaced. From what I understand, in Baden-Württemberg, I would then have to install a photovoltaic system.
This raises the following questions for me:
- How am I supposed to finance this with the current high interest rates? The monthly cost, including the mortgage, would simply be too high.
- We can’t afford a complete renovation (insulation, new windows, heat pump, etc.).
- As far as I know, you can’t power storage heaters with a photovoltaic system, even with a battery storage, because they consume too much electricity. Plus, in winter, when we need the most electricity, too little electricity is generated...
- So, at most, a small photovoltaic system would make sense to cover our daytime consumption (about 2,500 kWh (2,500 kWh) per year).
- I have concluded that such a system is not yet economically viable for us, especially with the high purchase costs and high interest rates. Is it possible to avoid the photovoltaic installation requirement if you don’t have the financial means and only need to replace your roof tiles?
Has anyone been in a similar situation? What approach did you take or what are your plans?
Thank you very much!
maybe some of you have faced the same situation or have the same question.
I couldn’t find anything clear on the internet regarding this.
Here is the initial situation:
- Solid brick house built in 1970
- Heating system with storage heaters running on 100% green electricity tariff, plus a tiled stove
- Roof insulated with insulation between rafters, attic insulated with XPS boards, plastic double-glazed windows,
so definitely not a modern insulation standard
- Annual energy consumption – daytime electricity (peak) 2,500 kWh (2,500 kWh) – nighttime electricity (off-peak) 7,400 kWh (7,400 kWh)
- Most of the living areas are heated with the tiled stove
In the coming years, the roof tiles will need to be replaced. From what I understand, in Baden-Württemberg, I would then have to install a photovoltaic system.
This raises the following questions for me:
- How am I supposed to finance this with the current high interest rates? The monthly cost, including the mortgage, would simply be too high.
- We can’t afford a complete renovation (insulation, new windows, heat pump, etc.).
- As far as I know, you can’t power storage heaters with a photovoltaic system, even with a battery storage, because they consume too much electricity. Plus, in winter, when we need the most electricity, too little electricity is generated...
- So, at most, a small photovoltaic system would make sense to cover our daytime consumption (about 2,500 kWh (2,500 kWh) per year).
- I have concluded that such a system is not yet economically viable for us, especially with the high purchase costs and high interest rates. Is it possible to avoid the photovoltaic installation requirement if you don’t have the financial means and only need to replace your roof tiles?
Has anyone been in a similar situation? What approach did you take or what are your plans?
Thank you very much!
Good insulation is always better than no insulation at all.
But I recently read somewhere that there are chest-type split air conditioners, which can be installed in exactly the same place as the old storage heaters, and many houses have been somewhat modernized this way.
So split air conditioners are definitely better than storage heaters.
But I recently read somewhere that there are chest-type split air conditioners, which can be installed in exactly the same place as the old storage heaters, and many houses have been somewhat modernized this way.
So split air conditioners are definitely better than storage heaters.
W
WilderSueden12 Feb 2024 17:48bloodyscorpion schrieb:
When we bought the house, there was no talk about a photovoltaic mandate yet.
And anyone who has purchased a house in the greater Stuttgart area in recent years knows what price range we are talking about here. You are contradicting yourself a bit. The photovoltaic mandate has been in place for almost 4 years, and such things don’t just appear out of nowhere in a democracy. So either you haven’t bought a house in recent years or you weren’t paying attention. And if you bought before the photovoltaic mandate, your chances for additional financing back then would have been less than 1%.
mayglow schrieb:
I don’t have specific experience, but I quickly googled a bit. It seems that with storage heaters only about 30-40% of electrical energy is converted into heat energy. With electric direct heating (including infrared and electric surface heating), it is apparently close to 100%. I also quickly googled and found an article claiming the low efficiency of storage heaters. To me, this isn’t physically plausible. Heat from electricity is basically always 100% efficient; with storage heaters, the heat just doesn’t arrive when you need it. What really has about 30-40% efficiency is electricity generation from fossil fuels. But that affects all electric heating systems.
The lower efficiency of storage heaters is due to their design. They are highly insulated, meaning the actual heat storage is inside and reaches temperatures of several hundred degrees. The heat transfer through convection is technically a heat loss; ideally, the heat should be distributed by a fan. The fan consumes additional electricity. Essentially, it is a heat storage unit with an integrated fan heater. Whether this leads to only 30-40% efficiency, I am not sure, but it is definitely less efficient than infrared panels—which provide direct radiant heat—or even air-to-air heat pumps (split system air conditioners).
Tolentino schrieb:
They are highly insulated, so the actual heat storage is on the inside and reaches several hundred degrees.Although I still don't quite understand what exactly happens there. At first, it sounds to me like you would use significantly more energy to heat something to such a high temperature. But the energy shouldn’t just be "lost." Some comments also suggest that they always release heat, even when you don’t want them to. However, when I think of modern heating concepts—they are no longer designed for heating only during the day (but rather to maintain a constant temperature)—then that might not matter so much anymore?No, the high heat is not the problem since you want it to be warm anyway. But if you want to heat effectively with it, you have to use the fan, which consumes additional electricity. As I mentioned, I can’t imagine it uses about 50% more power, but that at least explains why infrared panels can be more efficient.
And yes, the thermal inertia is more of an issue—so in situations like now, when it’s around -2°C (28°F) at night but +10°C (50°F) during the day, you have to decide at night whether to charge the storage tank for the next day or not.
The operation used to be confusing, too. You had one controller for heating, which set how hot the storage tank should get, and then a thermostat that controlled the fan. We didn’t understand this back then, and no one explained it to us, so the fan kept running constantly (because the thermostat was set to 21°C (70°F), but the heat wasn’t being stored). So cold air would come out. Or the opposite would happen.
The electricity bill for heating was almost bankrupting.
Unfortunately, I was just an 11-year-old kid back then, and my interest in heating technology was very limited.
And yes, the thermal inertia is more of an issue—so in situations like now, when it’s around -2°C (28°F) at night but +10°C (50°F) during the day, you have to decide at night whether to charge the storage tank for the next day or not.
The operation used to be confusing, too. You had one controller for heating, which set how hot the storage tank should get, and then a thermostat that controlled the fan. We didn’t understand this back then, and no one explained it to us, so the fan kept running constantly (because the thermostat was set to 21°C (70°F), but the heat wasn’t being stored). So cold air would come out. Or the opposite would happen.
The electricity bill for heating was almost bankrupting.
Unfortunately, I was just an 11-year-old kid back then, and my interest in heating technology was very limited.
W
WilderSueden12 Feb 2024 19:43Such a blower uses almost no power, and I would be surprised if it draws more than 10 watts. Even if it uses twice that, compared to the heating function, it is negligible. In a system with a night storage apartment, a night storage heater also has about 100% efficiency.
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