ᐅ Energy Saving Regulation 2016 or KfW 55 Standard for a Bungalow with Air-to-Water Heat Pump and Controlled Mechanical Ventilation, Optional Photovoltaic System
Created on: 5 Jun 2019 08:25
M
micric3
Good morning,
We are currently in the preliminary planning phase and are being flooded with information from various builders.
The topic of the "Energy Saving Ordinance 2016 or KfW 55 standard" especially leads to additional discussions.
The current concept for a household of four is as follows:
- Underfloor heating + air-to-water heat pump / controlled mechanical ventilation system combo, for example Vaillant recoCOMPACT (alternative: Nibe 730/750)
- Photovoltaic system ready for later retrofitting
- No gas connection possible/available
Opinions from some builders:
- KfW 55 was only attractive because of the low interest rates compared to traditional bank loans
- Currently, few are building to KfW 55 standard; the Energy Saving Ordinance 2016 is 'back in trend'
Calculation from another builder:
30 cm (12 inches) exterior masonry instead of 24 cm (9.5 inches) exterior masonry (both according to Energy Saving Ordinance 2016) = (costs €3,750)
(Additional costs for KfW 55 with 36.5 cm (14 inches) exterior masonry, floor slab insulation, increased roof insulation, and KfW 55 calculations and documentation were (costs €14,680))
I would like to hear some opinions on this:
Good luck
Michael
We are currently in the preliminary planning phase and are being flooded with information from various builders.
The topic of the "Energy Saving Ordinance 2016 or KfW 55 standard" especially leads to additional discussions.
The current concept for a household of four is as follows:
- Underfloor heating + air-to-water heat pump / controlled mechanical ventilation system combo, for example Vaillant recoCOMPACT (alternative: Nibe 730/750)
- Photovoltaic system ready for later retrofitting
- No gas connection possible/available
Opinions from some builders:
- KfW 55 was only attractive because of the low interest rates compared to traditional bank loans
- Currently, few are building to KfW 55 standard; the Energy Saving Ordinance 2016 is 'back in trend'
Calculation from another builder:
30 cm (12 inches) exterior masonry instead of 24 cm (9.5 inches) exterior masonry (both according to Energy Saving Ordinance 2016) = (costs €3,750)
(Additional costs for KfW 55 with 36.5 cm (14 inches) exterior masonry, floor slab insulation, increased roof insulation, and KfW 55 calculations and documentation were (costs €14,680))
I would like to hear some opinions on this:
Good luck
Michael
B
boxandroof10 Jun 2019 20:51You are mixing up heating load with heat demand. Even if it makes financial sense, this measure won’t make you rich.
It depends on the overall concept and its objectives: which heating system, subsidies, threshold values to reach the next efficiency level, or whether to choose a smaller heating system. If you push insulation to the maximum, you might not need a conventional heating system anymore, so it could become cost-effective again.
You will insulate the slab either above or below the concrete; insulating below is better, but both options are possible.
It depends on the overall concept and its objectives: which heating system, subsidies, threshold values to reach the next efficiency level, or whether to choose a smaller heating system. If you push insulation to the maximum, you might not need a conventional heating system anymore, so it could become cost-effective again.
You will insulate the slab either above or below the concrete; insulating below is better, but both options are possible.
N
nix zu schwör23 Jun 2019 12:08@boxandroof
A consulting engineer is liable, as with any regulated profession.
Especially with the heating system, you save significant amounts over decades.
Where did you hear that nonsense? It’s complete nonsense. Neither condensing technology nor heat pump technology has a lifespan of several decades. You should be lucky to get 10 years.
The annual performance factor is close to 5, as we have planned the heating surfaces, hydraulics, and building accordingly.
You can only achieve an annual performance factor of 5 with expensive ground source heat pumps, so the investment is much higher and the consumption is often similar to gas, which will hardly be sustainable with rising electricity costs. With an air-source heat pump, you can only dream of half that. The test parameters are fixed, otherwise the figure would not make sense, so the COP is not considered.
@lesmue79
You cannot omit the insulation, as it must be demonstrated according to the Energy Saving Ordinance 2013 (EnEV 2013). You also forget the thermal bridge allowance, because with that you can no longer apply an optimized flat rate value for the building. This means not only is your calculation wrong, but no KfW house is achievable, no matter how poor the standard.
@boxandroof
Heating load calculation according to DIN EN 12831 using mhs software is already the right approach.
Many still do not understand that the sum of the room heating loads is generally significantly higher than the building heating load according to the Energy Saving Ordinance 2013 (EnEV 2013), which here is only estimated and does not take the parameters within the building into account.
A consulting engineer is liable, as with any regulated profession.
Especially with the heating system, you save significant amounts over decades.
Where did you hear that nonsense? It’s complete nonsense. Neither condensing technology nor heat pump technology has a lifespan of several decades. You should be lucky to get 10 years.
The annual performance factor is close to 5, as we have planned the heating surfaces, hydraulics, and building accordingly.
You can only achieve an annual performance factor of 5 with expensive ground source heat pumps, so the investment is much higher and the consumption is often similar to gas, which will hardly be sustainable with rising electricity costs. With an air-source heat pump, you can only dream of half that. The test parameters are fixed, otherwise the figure would not make sense, so the COP is not considered.
@lesmue79
You cannot omit the insulation, as it must be demonstrated according to the Energy Saving Ordinance 2013 (EnEV 2013). You also forget the thermal bridge allowance, because with that you can no longer apply an optimized flat rate value for the building. This means not only is your calculation wrong, but no KfW house is achievable, no matter how poor the standard.
@boxandroof
Heating load calculation according to DIN EN 12831 using mhs software is already the right approach.
Many still do not understand that the sum of the room heating loads is generally significantly higher than the building heating load according to the Energy Saving Ordinance 2013 (EnEV 2013), which here is only estimated and does not take the parameters within the building into account.
nichts zu schwör schrieb:
You can only achieve a seasonal performance factor (SPF) of 5 with expensive ground probes, so the investment is much higher and the energy consumption often ends up being comparable to gas, which will hardly be sustainable given the rising electricity costs.
With an air-source heat pump, you can only dream of half that.In practice, it’s different. We also have a seasonal performance factor well above 4, and that with an air-to-water heat pump. Your bias against the technology seems to cloud your view of reality.B
boxandroof23 Jun 2019 13:42nichts zu schwör schrieb:
Neither condensing technology nor heat pump technology has a lifespan of several decades.Of course not. The decision for a specific type of heating and its ongoing costs usually does not end with the replacement of the boiler or whatever system is used.nichts zu schwör schrieb:
You can only achieve an annual performance factor of 5 with expensive ground probes.An annual performance factor of 5 is not only achievable with costly ground probes. A performance factor of 4.5 for an air-to-water heat pump is a realistic target and would be my requirement for a new build; we are actually well above that. However, you won’t find anyone who takes responsibility for that. My planner also came to me with various “expert” opinions about the performance factor, which is why I had to take care of several details myself, out of necessity.By the way, the BAFA only subsidizes air-to-water heat pumps starting from a calculated annual performance factor of 4.5.
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nix zu schwör24 Jun 2019 12:57@ares83
There are standard values rather than real-world values, as the standards assume ideal and consistent conditions. Since the COP value is at least 1 point higher than the seasonal performance factor (SPF), this only confirms the poor SPF of the air source heat pump. Radiators and thus a higher flow temperature than 35°C (95°F) are excluded anyway.
@boxandroof
The BAFA subsidy applies from a COP of 3.1, which corresponds to an SPF of around 2.1, because an SPF of 2.5 has not been sustainable in the past, and temperatures below 7°C (45°F) are no longer taken into account.
Quote from BAFA:
...for the calculation of the subsidy for the heat source "air," the heating capacity at A-7/W35 is applied.
since hardly any air source heat pump could achieve such a value. Only with a reachable SPF above 4.5 for ground source heat pumps would the cost per kWh be lower than with gas. Currently, due to electricity prices, the trend is toward an SPF of around 5.0.
No ground source heat pump currently achieves an SPF higher than 5.5–6.0. Regarding the figure of 6.0, I only know of one research project. I don't know if it still exists.
Here, the politically and artificially increased primary energy factor for electricity does not apply, since the focus is on actual costs and not on making air source heat pumps attractive to homeowners through calculations.
This is also why the regulation to approve only passive houses for new builds from 2020/21 onward has been introduced. Because regardless of the current heating system chosen, all are significantly more expensive than the old systems, partly due to their much shorter service life.
There are standard values rather than real-world values, as the standards assume ideal and consistent conditions. Since the COP value is at least 1 point higher than the seasonal performance factor (SPF), this only confirms the poor SPF of the air source heat pump. Radiators and thus a higher flow temperature than 35°C (95°F) are excluded anyway.
@boxandroof
The BAFA subsidy applies from a COP of 3.1, which corresponds to an SPF of around 2.1, because an SPF of 2.5 has not been sustainable in the past, and temperatures below 7°C (45°F) are no longer taken into account.
Quote from BAFA:
...for the calculation of the subsidy for the heat source "air," the heating capacity at A-7/W35 is applied.
since hardly any air source heat pump could achieve such a value. Only with a reachable SPF above 4.5 for ground source heat pumps would the cost per kWh be lower than with gas. Currently, due to electricity prices, the trend is toward an SPF of around 5.0.
No ground source heat pump currently achieves an SPF higher than 5.5–6.0. Regarding the figure of 6.0, I only know of one research project. I don't know if it still exists.
Here, the politically and artificially increased primary energy factor for electricity does not apply, since the focus is on actual costs and not on making air source heat pumps attractive to homeowners through calculations.
This is also why the regulation to approve only passive houses for new builds from 2020/21 onward has been introduced. Because regardless of the current heating system chosen, all are significantly more expensive than the old systems, partly due to their much shorter service life.
B
boxandroof24 Jun 2019 13:11I agree with you on the policy and that lifespan is an important factor in the cost-effectiveness analysis, especially when the heat pump is purchased at a high price. However, it is impossible to make any general statements about this. Regarding the other generalized comments about standards and seasonal performance factors (SPFs), I have nothing constructive to add.
The BAFA provides an annual performance factor calculator. For new buildings, funding is available for air-to-water heat pumps including domestic hot water production with an annual performance factor of at least 4.5. This value is purely theoretical and, since the last update of the funding guidelines, has become difficult to achieve—but still not impossible. That’s the theory.
Enough has already been written about the practical side.
The BAFA provides an annual performance factor calculator. For new buildings, funding is available for air-to-water heat pumps including domestic hot water production with an annual performance factor of at least 4.5. This value is purely theoretical and, since the last update of the funding guidelines, has become difficult to achieve—but still not impossible. That’s the theory.
Enough has already been written about the practical side.
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