Hello everyone,
I have the following situation: After receiving an offer from a developer to build a house with district heating and KfW Standard 55, it now turns out that this standard cannot be achieved with district heating because the local district heating system is reportedly rated poorly.
Here is the issue: The developer was not aware of or did not check this beforehand and now says that we need to include additional measures, such as photovoltaic panels for electricity generation, to meet the standard. This will cause us extra costs. We now have the following questions:
a) Is it possible that the house can no longer meet the KfW 55 standard based solely on the district heating rating? According to the developer, using something like an air-to-water heat pump would make it feasible again, but we are required to use the city’s district heating system (possible exemption to clarify)?
b) Do we have to share the extra costs? It was clearly communicated that we must use district heating. Based on that, we received a construction offer with KfW 55. However, the developer can no longer deliver this.
c) What would be a reasonable addition now? In my opinion, photovoltaic panels for electricity generation are the best option. Using solar thermal for hot water production probably makes little sense with district heating. The developer proposes to install 5sqm (54 sqft) of solar panels to comply with the KfW standard again.
We are somewhat overwhelmed by this topic. Does anyone have any ideas or suggestions?
Thank you
I have the following situation: After receiving an offer from a developer to build a house with district heating and KfW Standard 55, it now turns out that this standard cannot be achieved with district heating because the local district heating system is reportedly rated poorly.
Here is the issue: The developer was not aware of or did not check this beforehand and now says that we need to include additional measures, such as photovoltaic panels for electricity generation, to meet the standard. This will cause us extra costs. We now have the following questions:
a) Is it possible that the house can no longer meet the KfW 55 standard based solely on the district heating rating? According to the developer, using something like an air-to-water heat pump would make it feasible again, but we are required to use the city’s district heating system (possible exemption to clarify)?
b) Do we have to share the extra costs? It was clearly communicated that we must use district heating. Based on that, we received a construction offer with KfW 55. However, the developer can no longer deliver this.
c) What would be a reasonable addition now? In my opinion, photovoltaic panels for electricity generation are the best option. Using solar thermal for hot water production probably makes little sense with district heating. The developer proposes to install 5sqm (54 sqft) of solar panels to comply with the KfW standard again.
We are somewhat overwhelmed by this topic. Does anyone have any ideas or suggestions?
Thank you
BenutzerPC schrieb:
-> Sorry, do you mean a central ventilation system here? At the moment we have planned a decentralized system without heat recovery?Yes, a central system with heat recovery. First, read up a bit on decentralized systems and consider whether you really want that...
BenutzerPC schrieb:
Our builder alternatively suggested installing a 5sqm (54 sqft) photovoltaic system for electricity generation. What do you think of that? By the way: When talking about photovoltaic systems, how do you distinguish the terminology between using it for hot water generation versus electricity production?Photovoltaic = electricity
Solar (thermal) = hot water
A 5sqm (54 sqft) photovoltaic system is economically nonsensical; it will never pay off. But presumably, the idea was to address the renewable share with a minimal investment. However, as I mentioned above, I’m not at all sure that a photovoltaic system can really cover that share and not just be positively accounted for in the primary energy demand. As far as I know, this only works if the generated electricity is also used for heating (→ heat pump or heating element in the hot water tank). You don’t have the first option, and the latter is extremely inefficient. For heating support, solar thermal makes more sense, except when using a heat pump.
B
BenutzerPC22 Jan 2017 18:05Yes, you are right. The 5 sqm (54 sq ft) photovoltaic system is probably just to meet the criteria for KfW55. We are currently at the point where we are considering whether
a) we should most likely switch to a central ventilation system. The additional costs would then need to be clarified as to who will cover them and to what extent. As mentioned, KfW55 was assured to us according to the contract.....
b) we waive KfW55. If it only fails at this small point, then we just have "KfW55+X." It’s all just calculation anyway. I think the standard is only relevant for maintaining the loan. In a few years, no one will ask whether it’s KfW75, 55, or 40 anymore. Then there will be completely new requirements again, right?
a) we should most likely switch to a central ventilation system. The additional costs would then need to be clarified as to who will cover them and to what extent. As mentioned, KfW55 was assured to us according to the contract.....
b) we waive KfW55. If it only fails at this small point, then we just have "KfW55+X." It’s all just calculation anyway. I think the standard is only relevant for maintaining the loan. In a few years, no one will ask whether it’s KfW75, 55, or 40 anymore. Then there will be completely new requirements again, right?
BenutzerPC schrieb:
a) we are most likely switching to a central ventilation system. The additional costs would then need to be clarified regarding who will cover them and to what extent. As mentioned: KfW55 was guaranteed to us according to the contract.....If it is contractually agreed, that initially looks good for you. However, your contracting partner will surely prefer solutions that are economically viable for them. Meet halfway. At least you get something from the controlled residential ventilation with heat recovery. Present it as an upgrade to the decentralized ventilation, which can be offset, and if in the worst case you contribute 2-3k€ (about 2,200-3,300 USD), everyone benefits. Otherwise, your general contractor will recover the sunk costs during the next price adjustment.
BenutzerPC schrieb:
b) we give up on KfW55. If only this small point is missing, then we have "KfW55+X". It’s all just accounting anyway. I think the standard is only relevant to maintain the loan. In a few years, no one will ask whether it was KfW75, 55 or 40. Then there will be completely new regulations again, right?The financial benefit of the KfW55 loan through interest advantage and repayment subsidy (5,000€ (about 5,500 USD)) is around 10,000€ (about 11,000 USD). Of course, this varies depending on the loan term compared and your individual bank conditions. Not a huge amount, but nice nonetheless. However, the renewable energy share is required by the Energy Saving Ordinance and has nothing to do with KfW. Just to state it clearly again: your problem must be solved, otherwise, there will be no house! Check whether the city requires KfW55 as a minimum standard. In our area, it is a recent trend to demand this in new development zones — for the green conscience of the authorities.
B
BenutzerPC22 Jan 2017 20:03Alex85 schrieb:
According to the energy saving ordinance, you are required to have a renewable energy share. This has nothing to do with KfW Yes, apparently before 04/01/2016, the requirements as currently planned were sufficient. However, as far as I know, building to KfW55 standard is not mandatory in our area. That choice is up to us.
Alex85 schrieb:
Your general contractor will recover the lost money with the next upgrade You are right there as well. Therefore, there is concern that possibly the cheapest mechanical ventilation with heat recovery will be chosen just to meet the requirement. Tomorrow, I will contact the general contractor to have him present his alternative.
B
BenutzerPC23 Jan 2017 17:48To revisit the topic: When the general contractor suggests a solution involving a solar system with a buffer tank, do they mean photovoltaic or solar thermal? Since we get our hot water through the district heating connection, the latter wouldn’t make sense, right?
This is likely a solar thermal system that heats water when exposed to sunlight. That explains the (large) buffer tank.
The idea is… well, if you assume solar thermal systems are effective, it should reduce your hot water costs. Whether it’s a game changer, I would personally doubt that.
Also consider that a large buffer tank requires floor space, and the underlying structure must be able to support the increased load (I wonder if the general contractor has factored that in…). Since it’s typically installed in the basement or utility room, it might not be a huge issue, but without the buffer tank, you could have room for an additional shelf there.
Personally, I see the greatest benefit in controlled mechanical ventilation with heat recovery. But that’s probably already been made clear.
The idea is… well, if you assume solar thermal systems are effective, it should reduce your hot water costs. Whether it’s a game changer, I would personally doubt that.
Also consider that a large buffer tank requires floor space, and the underlying structure must be able to support the increased load (I wonder if the general contractor has factored that in…). Since it’s typically installed in the basement or utility room, it might not be a huge issue, but without the buffer tank, you could have room for an additional shelf there.
Personally, I see the greatest benefit in controlled mechanical ventilation with heat recovery. But that’s probably already been made clear.
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