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
The 100-year timeframe is, of course, not to be taken too literally. There are so many variables involved that any estimate is simply a rough guess.
What can be said:
Ground-source heat pumps are approximately 20-30% more efficient under the same conditions.
In a well-insulated new building, this saves about 200€ per year.
You can find these figures with a simple online search; there are databases and plenty of reading material available.
A ground-source system with deep boreholes typically costs around 12,000€ more than an air-to-water system (it can also be 10,000 or 20,000€, depending on the circumstances).
Assuming 12,000€, you would break even after about 60 years (without interest calculations, so just a back-of-the-envelope estimate).
For heating systems, however, it’s more common to calculate in 20-year periods — so after 20 years you would still be 8,000€ in the red.
And from there, it gets even more uncertain. A ground-source heat pump owner might argue that replacing the compressor is cheaper than for someone with an air-to-water heat pump. On the other hand, the air-to-water heat pump owner might say that in 20 years, equipment will cost only half as much, making the difference marginal.
A third, undecided person might say: Who knows what technology will be available in 20 years...
But simplified to the essentials, in 20 years you are financially worse off with a ground-source heat pump. From my perspective, a ground-source system only makes sense if you don’t have enough space for an air-source heat pump. Modern units are almost silent, but you still wouldn’t want to place one right next to the patio.
If you do the installation yourself, the calculation looks different. An efficient air-source heat pump can be installed with subsidies for about 2,000€, while a trench collector system costs about twice that. With such a low investment, you don’t have to worry as much about which option is better.
What can be said:
Ground-source heat pumps are approximately 20-30% more efficient under the same conditions.
In a well-insulated new building, this saves about 200€ per year.
You can find these figures with a simple online search; there are databases and plenty of reading material available.
A ground-source system with deep boreholes typically costs around 12,000€ more than an air-to-water system (it can also be 10,000 or 20,000€, depending on the circumstances).
Assuming 12,000€, you would break even after about 60 years (without interest calculations, so just a back-of-the-envelope estimate).
For heating systems, however, it’s more common to calculate in 20-year periods — so after 20 years you would still be 8,000€ in the red.
And from there, it gets even more uncertain. A ground-source heat pump owner might argue that replacing the compressor is cheaper than for someone with an air-to-water heat pump. On the other hand, the air-to-water heat pump owner might say that in 20 years, equipment will cost only half as much, making the difference marginal.
A third, undecided person might say: Who knows what technology will be available in 20 years...
But simplified to the essentials, in 20 years you are financially worse off with a ground-source heat pump. From my perspective, a ground-source system only makes sense if you don’t have enough space for an air-source heat pump. Modern units are almost silent, but you still wouldn’t want to place one right next to the patio.
If you do the installation yourself, the calculation looks different. An efficient air-source heat pump can be installed with subsidies for about 2,000€, while a trench collector system costs about twice that. With such a low investment, you don’t have to worry as much about which option is better.
R
R.Hotzenplotz9 Jan 2018 09:32Lumpi_LE schrieb:
But to put it simply, in 20 years you are worse off with a geothermal heat pump. In my opinion, a geothermal solution only makes sense if there is no space for an air source heat pump.I can’t see it that way. In our case, without geothermal energy, I save about 10,000 euros considering the subsidies compared to the air source heat pump, but since the additional cost for the air-to-water heat pump is over €9,000, I don’t really gain anything.
Our feedback regarding the geothermal heat pump:
1. Drilling is basically possible, and there is no limit on drilling depth.
2. The area is located in water protection zone WSG 3b.
3. Grouting of the borehole is required.
4. Application process:
a. For depths up to 100 m (330 feet), four copies of the application must be submitted via the Rhein-Erft district authority.
b. For depths over 100 m (330 feet), the application must be submitted simultaneously to both the NRW mining authority and the Rhein-Erft district authority.
5. The contractor needs a W120 certification.
Now I am still waiting for the drilling costs.
Lumpi_LE schrieb:
Well, a general contractor will push whatever suits them on you anyway or they will rip you off. My statement refers to the market price, meaning an independent quote from a heating engineer.I find that quite generalizing and shortsighted. If you have read the thread, you know for sure that this is not the case here.R
R.Hotzenplotz9 Jan 2018 11:45I don’t think it’s good either. You can work with a general contractor (GC) if you are aware of the specific challenges and pay attention to them. Still, both building with a GC and building with an independent architect will have plenty of cost traps that people often fall into. I don’t think anyone can claim to be completely free of that.
The GC doesn’t force anything on you either. You can remove parts of the contract and hire the heating system installer separately. You can get any type of heating system through a GC, but then the question really is at what price. For example, the GC has a plumber who exclusively works with Waterkotte heat pumps. This means that if you choose a heat pump from another manufacturer, a different installer would likely be hired, who, due to lower volume, would not be able to offer the same conditions as someone working together all year round.
The GC doesn’t force anything on you either. You can remove parts of the contract and hire the heating system installer separately. You can get any type of heating system through a GC, but then the question really is at what price. For example, the GC has a plumber who exclusively works with Waterkotte heat pumps. This means that if you choose a heat pump from another manufacturer, a different installer would likely be hired, who, due to lower volume, would not be able to offer the same conditions as someone working together all year round.
R
R.Hotzenplotz10 Jan 2018 20:38Today I spoke with a very experienced installer who has no interest in selling anything, as it is clear that we will not be hiring him. He said that, in principle, it is indeed difficult to compare gas/solar systems with ground-source heat pumps. Generally, most cases would lean towards a ground-source heat pump, but for us, it is different because a relatively high hot water demand is expected, which definitely puts the ground-source heat pump at a disadvantage. The electric backup heater is constantly in use because the heat pump only reaches around 25°C (77°F), if I remember correctly. In principle, he also recommended having a detailed calculation done.
Does anyone actually calculate this so precisely, looking at how many cubic meters of water are used annually and how often the ground-source heat pump relies on the electric backup heater? You would have to conduct a more or less detailed interview with each client about the household’s usage patterns. Who does that? I feel like I am going in circles.
Does anyone actually calculate this so precisely, looking at how many cubic meters of water are used annually and how often the ground-source heat pump relies on the electric backup heater? You would have to conduct a more or less detailed interview with each client about the household’s usage patterns. Who does that? I feel like I am going in circles.
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