Hello,
We are starting to get really frustrated... every builder tells us something different...
We want to build a 130sqm (1,399 sq ft) KfW 70 house with the living room facing south, and we are unsure whether to choose gas or an air source heat pump. Some providers, at almost the same price level, offer us air source heat pumps and claim that the annual costs are significantly (30%) lower compared to gas, while others doubt this.
We understand that insulation with gas/solar systems is usually better because an air source heat pump boosts efficiency more towards KfW 70 standards compared to gas/solar, which might argue in favor of gas. An air source heat pump might fail somewhat sooner, and in case of problems, you can usually get quick and competent local support with gas. With air source heat pumps, there could be more difficulties. Additionally, the noise of air source heat pumps (in our case about 3 meters (10 feet) from the neighbor) is not insignificant. Some say that sooner or later, everyone ends up having issues with neighbors for this reason.
We are interested in air source heat pumps with storage tanks from these providers: Vaillant, Mitsubishi Zubadan, and Rotex.
What we are really curious about is the annual cost for heating and hot water with both systems.
We live near Kassel.
What should we choose, and what would be cost-effective TODAY? What is your opinion on Vaillant?
Regards
Gigi
We are starting to get really frustrated... every builder tells us something different...
We want to build a 130sqm (1,399 sq ft) KfW 70 house with the living room facing south, and we are unsure whether to choose gas or an air source heat pump. Some providers, at almost the same price level, offer us air source heat pumps and claim that the annual costs are significantly (30%) lower compared to gas, while others doubt this.
We understand that insulation with gas/solar systems is usually better because an air source heat pump boosts efficiency more towards KfW 70 standards compared to gas/solar, which might argue in favor of gas. An air source heat pump might fail somewhat sooner, and in case of problems, you can usually get quick and competent local support with gas. With air source heat pumps, there could be more difficulties. Additionally, the noise of air source heat pumps (in our case about 3 meters (10 feet) from the neighbor) is not insignificant. Some say that sooner or later, everyone ends up having issues with neighbors for this reason.
We are interested in air source heat pumps with storage tanks from these providers: Vaillant, Mitsubishi Zubadan, and Rotex.
What we are really curious about is the annual cost for heating and hot water with both systems.
We live near Kassel.
What should we choose, and what would be cost-effective TODAY? What is your opinion on Vaillant?
Regards
Gigi
Saruss schrieb:
Would you install a gas connection if you don’t have a gas heating system? Why would you?
Saruss schrieb:
That a gas connection plus maintenance, gas, heating, etc. incur ongoing costs So, an air-to-water heat pump is maintenance-free?
Saruss schrieb:
The synergy of an air-to-water heat pump with photovoltaics is greater than with gas Counterpoint: The synergy between gas and solar thermal systems is higher than with an air-to-water heat pump, since both are high-temperature systems.
As long as gas is available in the street and can be connected inexpensively, in my opinion this option must be evaluated objectively, since economically it is still very interesting at the moment.
MayrCh schrieb:
Why should he? You can also use gas, for example, for cooking. For this reason, despite having a different heating system, I would have had a gas line installed, but it was removed by the city due to lack of demand.
MayrCh schrieb:
Counter-argument: The synergy between gas and solar thermal is higher than with an air-to-water heat pump, as both are high-temperature systems. Unfortunately, solar thermal usually delivers energy mostly when you don’t need it, and unlike photovoltaics, you can’t sell the excess. Generally, it is not cost-effective—for example, during the non-heating period, which usually lasts at least 6 months, it can at most save costs for domestic hot water... Given the low prices of photovoltaics, solar thermal is generally not recommended.
Otherwise, feel free to present contrary figures; I’m genuinely interested in hearing how you justify the higher synergy. (In fact, solar thermal only replaces or supports the gas system, whereas an air-to-water heat pump can directly use electricity from the photovoltaic system.)
Ybias78 schrieb:
Our plot is fully developed and gas lines are available. That’s not the issue.
Is it possible to achieve a KfW55 standard house with a gas boiler and solar system including a battery? In principle, a professional should always perform a detailed calculation for the specific building, as many parameters are involved, and the technology/system is only one factor. With this combination, something like mechanical ventilation with heat recovery might also be necessary, since primary energy consumption is also taken into account.
Saruss schrieb:
You can also use gas for cooking, for example. Yes, but using an LPG cylinder in the utility room works for a fraction of the initial and ongoing costs of a gas connection. So, people might choose a gas connection just for cooking; whether that makes economic sense is another matter.
Saruss schrieb:
Unfortunately, solar thermal systems produce mostly when you don’t need it. Photovoltaic systems (without storage) also mostly generate electricity when you don’t need it.
Saruss schrieb:
But unlike photovoltaics, you can’t sell it. You can. Unfortunately, the “buyer” often has a surplus of electricity produced outside the market demand, which they frequently have to offload at negative prices.
MayrCh schrieb:
Yes, but using an LPG cylinder in the utility room is possible for a fraction of the one-time and ongoing costs of a natural gas connection. Therefore, getting a gas connection just for cooking is understandable; whether it makes economic sense is another matter. I already said, if you want to use it regardless of economic viability, and you already have a connection anyway, then the consideration for a gas heating system is a different issue...
MayrCh schrieb:
Photovoltaics (without storage) mostly produce power when you don’t need it.
Saruss wrote: but unlike photovoltaics, you can’t sell it.
You can. Unfortunately, the "buyer" has a lot of market-distorted surplus electricity that they often have to get rid of at negative prices. I now urgently request an explanation of how you sell the energy produced by solar thermal systems (otherwise, you have quite misunderstood and misquoted me – and at least for photovoltaic electricity in Germany, there is still a fixed sales price guaranteed for 20 years).
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