ᐅ KfW 70 energy standard with Poroton bricks, domestic hot water heat pump, gas heating, and decentralized ventilation system
Created on: 26 Jan 2014 22:12
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diefamilie1978D
diefamilie197826 Jan 2014 22:12Hello experts, homeowners, and friends of energy efficiency,
As a new homeowner (Stuttgart region), I have been focusing strongly on the topic of "energy" for the past few days.
Based on the latest calculations with the architect and structural engineer, a plastered Poroton T8 solid wall (Poroton T8) is fixed. According to the Schlagmann Poroton table, this option with 36.5 bricks meets the KfW 70 requirements.
Triple glazing is also confirmed. The house has a floor area of 220 sqm (2,368 sq ft).
The goal now is to create an optimum for the house’s energy efficiency to achieve KfW 70 without unnecessary financial loss. After the latest energy fair here in the region and initial consultations with building services providers, I see this home energy design as optimal:
1) Domestic hot water heat pump, also supported by photovoltaics, since I will have photovoltaic panels with self-consumption (about 5 kWp from the roof according to the plan)
2) For underfloor heating and peak load in winter, a gas boiler
3) Decentralized ventilation system with heat recovery
Is such a combination sufficient to meet the KfW 70 targets?
If not, where might the weak point in this setup be?
Thanks in advance for any answers or recommendations.
P.S. I removed solar thermal from the plan because, in my case, the payback calculation with photovoltaics and self-consumption is much more attractive.
As a new homeowner (Stuttgart region), I have been focusing strongly on the topic of "energy" for the past few days.
Based on the latest calculations with the architect and structural engineer, a plastered Poroton T8 solid wall (Poroton T8) is fixed. According to the Schlagmann Poroton table, this option with 36.5 bricks meets the KfW 70 requirements.
Triple glazing is also confirmed. The house has a floor area of 220 sqm (2,368 sq ft).
The goal now is to create an optimum for the house’s energy efficiency to achieve KfW 70 without unnecessary financial loss. After the latest energy fair here in the region and initial consultations with building services providers, I see this home energy design as optimal:
1) Domestic hot water heat pump, also supported by photovoltaics, since I will have photovoltaic panels with self-consumption (about 5 kWp from the roof according to the plan)
2) For underfloor heating and peak load in winter, a gas boiler
3) Decentralized ventilation system with heat recovery
Is such a combination sufficient to meet the KfW 70 targets?
If not, where might the weak point in this setup be?
Thanks in advance for any answers or recommendations.
P.S. I removed solar thermal from the plan because, in my case, the payback calculation with photovoltaics and self-consumption is much more attractive.
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diefamilie197826 Jan 2014 22:18Just as additional information: The plot is already prepared with a gas connection, so the gas issue is an advantage for me...
That doesn’t make much sense. You want a heat pump for the water and a gas boiler for heating? What kind of heat pump are you planning to install? A ground-source heat pump for nearly 20,000 euros? Plus the gas connection?
You should consult a qualified energy advisor. If there is a gas supply on the property, depending on the length of the internal installation, you will still pay between 2,500 and 5,000 euros for the connection.
A heat pump also costs money, requires a lot of equipment, separate boilers, and so on. Is it really worth it?
You should consult a qualified energy advisor. If there is a gas supply on the property, depending on the length of the internal installation, you will still pay between 2,500 and 5,000 euros for the connection.
A heat pump also costs money, requires a lot of equipment, separate boilers, and so on. Is it really worth it?
Hello,
I find it strange how the qp´´ bonus of the reference building with a gas condensing boiler is supposed to be matched!
If photovoltaic is used, it should be combined with a heat pump for heating and domestic hot water! This way, the share of self-consumption can be increased accordingly. Cooling might even be necessary in summer. With gas, you can cook and heat, but with a heat pump combined with photovoltaic, you can often heat, cool, and cook for almost no cost! ;-)
Which type of heat pump would be suitable can only be determined after the initial assessment, where the actual demand (capacity, energy) for heating and domestic hot water is established.
Generally, at mild locations, an air-source heat pump is more suitable, while in colder climates, a ground-source heat pump is preferable. The latter does not necessarily require expensive deep drilling. Often, a horizontal collector such as a trench collector suffices, where significant self-installation work can be done.
Best regards.
diefamilie1978 schrieb:Who can answer that without knowing the values of the reference building?
....Is such a combination sufficient to meet the KfW 70 targets?
diefamilie1978 schrieb:The basic concept, because it’s only halfway there!
...if not, where would the weak point be in the setup?
I find it strange how the qp´´ bonus of the reference building with a gas condensing boiler is supposed to be matched!
If photovoltaic is used, it should be combined with a heat pump for heating and domestic hot water! This way, the share of self-consumption can be increased accordingly. Cooling might even be necessary in summer. With gas, you can cook and heat, but with a heat pump combined with photovoltaic, you can often heat, cool, and cook for almost no cost! ;-)
Which type of heat pump would be suitable can only be determined after the initial assessment, where the actual demand (capacity, energy) for heating and domestic hot water is established.
Generally, at mild locations, an air-source heat pump is more suitable, while in colder climates, a ground-source heat pump is preferable. The latter does not necessarily require expensive deep drilling. Often, a horizontal collector such as a trench collector suffices, where significant self-installation work can be done.
Best regards.
D
diefamilie197827 Jan 2014 18:28Hello wastl,
this is not nonsense, because this combination comes directly from an energy consultant. There are also so-called "domestic hot water heat pumps." The price: less than 4,000 euros.
Take a close look at "domestic hot water heat pumps"—no ground loop, no air-to-air system, no probe.
Of course, I can gradually share the first concrete data, but this concept was presented to me by an energy consultant.
Since I was initially considering a split heat pump, this combination really made me think... which is the purpose of my thread here.
this is not nonsense, because this combination comes directly from an energy consultant. There are also so-called "domestic hot water heat pumps." The price: less than 4,000 euros.
Take a close look at "domestic hot water heat pumps"—no ground loop, no air-to-air system, no probe.
Of course, I can gradually share the first concrete data, but this concept was presented to me by an energy consultant.
Since I was initially considering a split heat pump, this combination really made me think... which is the purpose of my thread here.
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