ᐅ Roof with photovoltaic system or alternative investments – experiences?
Created on: 7 Aug 2017 21:21
R
RumpelHumpel
Hi,
I am currently planning to renovate our 29-year-old house. Apart from recurring maintenance work, no major modernization measures have been carried out so far. We have insulated the walls ourselves in the past, but nothing else.
This means the house:
- still has the original roof
- the original gas heating system
- the original windows on the ground floor
What is already decided and will be done in late summer/early autumn is a roof renovation according to KFW standards. The roof will be completely rebuilt and insulated.
Additionally, I have budgeted around 13,000 euros for a photovoltaic system. However, I am still unsure how practical installing a photovoltaic system really is. The company I am in contact with recommended using the electricity ourselves and feeding the surplus into the grid. My initial thought was to include a storage system to use electricity at night or during bad weather. The location would actually be ideal for a photovoltaic system, as our roof faces southeast.
That’s why I am now considering whether I should invest the money in a new heating system instead. Our heating has been in use since the house was built and has never caused any problems. However, I believe that new gas boilers operate more efficiently and should reduce gas consumption (hopefully). I would probably also have a bit of extra money left over to possibly replace some radiators, if that can contribute to better efficiency...
Maybe you have some advice or would like to share what you would do.
Regards
I am currently planning to renovate our 29-year-old house. Apart from recurring maintenance work, no major modernization measures have been carried out so far. We have insulated the walls ourselves in the past, but nothing else.
This means the house:
- still has the original roof
- the original gas heating system
- the original windows on the ground floor
What is already decided and will be done in late summer/early autumn is a roof renovation according to KFW standards. The roof will be completely rebuilt and insulated.
Additionally, I have budgeted around 13,000 euros for a photovoltaic system. However, I am still unsure how practical installing a photovoltaic system really is. The company I am in contact with recommended using the electricity ourselves and feeding the surplus into the grid. My initial thought was to include a storage system to use electricity at night or during bad weather. The location would actually be ideal for a photovoltaic system, as our roof faces southeast.
That’s why I am now considering whether I should invest the money in a new heating system instead. Our heating has been in use since the house was built and has never caused any problems. However, I believe that new gas boilers operate more efficiently and should reduce gas consumption (hopefully). I would probably also have a bit of extra money left over to possibly replace some radiators, if that can contribute to better efficiency...
Maybe you have some advice or would like to share what you would do.
Regards
R
RumpelHumpel8 Aug 2017 18:45Thank you for the responses so far.
After discussions and further considerations with my household, we have concluded that the money should first be invested in insulation and heating.
Photovoltaic systems can be added later, once storage solutions become more affordable and electric cars reach more accessible price ranges.
After discussions and further considerations with my household, we have concluded that the money should first be invested in insulation and heating.
Photovoltaic systems can be added later, once storage solutions become more affordable and electric cars reach more accessible price ranges.
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Bau-Schmidt8 Aug 2017 19:19ares83 schrieb:
Could you explain why you come to that different conclusion? There are certainly some who are considering this, so reliable figures would be very helpful. What exactly do you want to know? My plan includes a photovoltaic system with battery storage and an air source heat pump with underfloor heating. Additionally, an electric car is being planned.
Well, your payback calculation. Purchase costs, expected savings, etc. We also prepared for photovoltaic solar panels and are now considering investing the remaining buffer into that. But when I look at the average monthly yields and then compare them to the average monthly consumption of a heat pump of the same model as mine, there is a gap. How did you solve that?
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Bau-Schmidt10 Aug 2017 10:39My first decision was based on my original profession as an electrician: I do not want to use gas. That leaves very few options for heating. The next consideration was the cost of switching systems. In my case, it meant nearly €6,000 (about $6,600) in additional expenses. Then I decided I wanted a photovoltaic system. I considered options with or without a battery storage system and requested quotes. With nearly the same energy output, the difference was another €9,000 (about $9,900). Switching from a conventional gas heating system with radiators to an air-source heat pump with underfloor heating, plus a photovoltaic system with battery storage, cost me around €30,000 (about $33,000).
The payback period for the photovoltaic system is approximately 13 to 14 years, depending on whether it includes storage or not. However, I did not focus on the payback period. It’s like buying a car: electric windows and air conditioning just come as standard—you either want them or you don’t.
Where I looked more closely was the forecast for consumption versus self-generation. It is often said that with a simple battery system, you can achieve up to an 80% degree of self-sufficiency. My system has a calculated generation of about 7,000 kWh. I hope to consume roughly 4,500 to 5,000 kWh of that myself. I estimate the total energy consumption of my house will be under 8,000 kWh. Currently, the feed-in tariff is 12.21 cents per kWh, while the cost for electricity supply is about 18 to 22 cents per kWh. I understand that in the winter months I will have higher electricity demand and need to account for that.
One note: the system should stay below 10 kWp. Self-consumed solar electricity from small systems up to 10 kilowatts peak remains exempt from the Renewable Energy Sources Act surcharge.
The payback period for the photovoltaic system is approximately 13 to 14 years, depending on whether it includes storage or not. However, I did not focus on the payback period. It’s like buying a car: electric windows and air conditioning just come as standard—you either want them or you don’t.
Where I looked more closely was the forecast for consumption versus self-generation. It is often said that with a simple battery system, you can achieve up to an 80% degree of self-sufficiency. My system has a calculated generation of about 7,000 kWh. I hope to consume roughly 4,500 to 5,000 kWh of that myself. I estimate the total energy consumption of my house will be under 8,000 kWh. Currently, the feed-in tariff is 12.21 cents per kWh, while the cost for electricity supply is about 18 to 22 cents per kWh. I understand that in the winter months I will have higher electricity demand and need to account for that.
One note: the system should stay below 10 kWp. Self-consumed solar electricity from small systems up to 10 kilowatts peak remains exempt from the Renewable Energy Sources Act surcharge.
B
Bieber081510 Aug 2017 11:25Bau-Schmidt schrieb:
Then I said I want to have a photovoltaic system. Of course, that’s one way to do it ;-). The original post mentions “investing” in the text. So I see the question more like this: I have 10,000 euros (or amount X) that I want to invest. What should I do:
- Photovoltaics
- Shipping container
- Closed-end real estate fund
- Savings account
- Professional training
- Sports betting
- …
Photovoltaics might very well be the choice in the end, but in any case, you should consider your overall financial situation. And you need to set a goal, which can simply be return on investment, but it can also be something like producing your own electricity. Some people also make investment decisions to “save on taxes”…
For our new build, we initially planned to include photovoltaic panels and a battery storage system. These generally complement a heat pump well, and I was hoping for subsidies.
Since photovoltaic systems do not provide additional comfort, I calculated it as a standard investment. It quickly became clear that the battery storage would never pay off, and the photovoltaic system (considering maintenance costs of 2%, electricity meter fees, taxes on self-consumption, etc.) would likely only break even after about 18 years—and that only if the inverter "lasts." If this investment is financed through a construction loan, the outlook is rather bleak.
The calculation naturally depends on electricity costs, self-consumption (and associated taxes), and feed-in tariffs. The fact is that wholesale electricity prices are very low and probably won’t return to previous levels in the next 10 years. Consumer prices are mainly driven by taxes. Political directions have also been set toward capping the Renewable Energy Act charges. This means that taxes may rise further in the short term but probably not in the medium term.
A brief addendum: In the end, I installed two conduits with a diameter of 40mm (1.5 inches) on the roof to allow for possible retrofitting in 10 years. I also think it makes sense to install empty conduits in the garage.
Since photovoltaic systems do not provide additional comfort, I calculated it as a standard investment. It quickly became clear that the battery storage would never pay off, and the photovoltaic system (considering maintenance costs of 2%, electricity meter fees, taxes on self-consumption, etc.) would likely only break even after about 18 years—and that only if the inverter "lasts." If this investment is financed through a construction loan, the outlook is rather bleak.
The calculation naturally depends on electricity costs, self-consumption (and associated taxes), and feed-in tariffs. The fact is that wholesale electricity prices are very low and probably won’t return to previous levels in the next 10 years. Consumer prices are mainly driven by taxes. Political directions have also been set toward capping the Renewable Energy Act charges. This means that taxes may rise further in the short term but probably not in the medium term.
A brief addendum: In the end, I installed two conduits with a diameter of 40mm (1.5 inches) on the roof to allow for possible retrofitting in 10 years. I also think it makes sense to install empty conduits in the garage.
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