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
B
Bieber08156 Jan 2018 22:39R.Hotzenplotz schrieb:
The price difference between solar and gas also seems quite small to me. In typical example calculations, there is usually a difference of many thousands of euros in favor of gas & solar, but for me it is only about €2,100 - €2,600.In our case, the air-to-water heat pump was cheaper than the gas option. Influencing factors: purchase from the developer, relatively inexpensive air-to-water heat pump, and additionally a high volume order by the developer.With the air-to-water heat pump, the gas connection and solar thermal system are not needed (which are usually installed together with gas due to legal requirements). Otherwise, everything else is the same (underfloor heating). If you have your energy consultant recalculate (and think it through!!), it may turn out that you are allowed to use gas without(!) solar thermal(!). The most important factor is your controlled residential ventilation system (which you want anyway). If that works, in my opinion gas is definitely cheaper than an air-to-water heat pump. Then you have to decide what matters most to you (investment costs, operating costs, ...).
R.Hotzenplotz schrieb:
The offer says air heat pump.If underfloor heating is included, then it is an air-to-water heat pump (air-to-water heat pump).R
R.Hotzenplotz6 Jan 2018 23:03Alex85 schrieb:
Energy from groundwater is a water-to-water heat pump and the most efficient option available. Very good!The groundwater level can be found in the attached document. Which authority should I contact on Monday to clarify whether we are allowed to do something like this? If this is the best solution, I should at least check if it’s feasible.
Alex85 schrieb:
It’s a shame that the general contractor charges so much for the horizontal collector (or trench collector). Both the collector costs and the earthworks are way overpriced.He just gave an estimate for the earthworks. As the property owner, I have to arrange the earthworks myself. But even with the €35,000 he calculated for earthworks to prepare the site, he was quite close to the actual cost.
We heat about 250m² (2,690 sq ft) of living space. From what I’ve read online, you need about twice the area for the collector surface. It can’t be asphalted, and no trees, pools, or other structures can be placed there. That would be 500m² (5,380 sq ft). I can imagine that a lot of digging would be required. But with such a large area, it doesn’t seem reasonable to limit yourself so much.
Bieber0815 schrieb:
In our case, the air-to-water heat pump was cheaper than the gas option. Influencing factors: purchase from the builder, relatively affordable air-to-water heat pump, and additionally high volume orders by the builder.Our builder also buys Waterkotte units in high volumes. You can get any other type of heat pump as well, but at different prices.
Because of the area required for the collectors, I had just suggested the trench collector. Apart from building over it, there are no restrictions. But this topic is off the table now.
Water-to-water heat pumps are very rarely used in relation.
You need two wells. Water is extracted from the first well, passes through the heat pump where energy is extracted, and then it is discharged back into a second well.
So, the first well must have sufficient yield, and the second one must be able to receive the water again.
This means you will also face drilling costs.
Furthermore, the water must have a certain quality. Otherwise, there can be significant issues with the heat pump.
In addition, (I’m not sure) the local water authority at the lowest level has to approve it. Whether they will, I have no idea.
I don’t want to offend you, but could it be that the general contractor is overcharging you? Obviously, you are taking everything from one source, and they are making a hefty profit from you.
The earthworks for shallow collectors might be around 2 x 5 hours, provided the excavated material can be stored on site. The quote is quite overpriced. You can surely find your own excavator and operator.
Water-to-water heat pumps are very rarely used in relation.
You need two wells. Water is extracted from the first well, passes through the heat pump where energy is extracted, and then it is discharged back into a second well.
So, the first well must have sufficient yield, and the second one must be able to receive the water again.
This means you will also face drilling costs.
Furthermore, the water must have a certain quality. Otherwise, there can be significant issues with the heat pump.
In addition, (I’m not sure) the local water authority at the lowest level has to approve it. Whether they will, I have no idea.
I don’t want to offend you, but could it be that the general contractor is overcharging you? Obviously, you are taking everything from one source, and they are making a hefty profit from you.
The earthworks for shallow collectors might be around 2 x 5 hours, provided the excavated material can be stored on site. The quote is quite overpriced. You can surely find your own excavator and operator.
R
R.Hotzenplotz7 Jan 2018 09:53Joedreck schrieb:
I don’t mean to offend you, but could it be that the general contractor is overcharging you? Obviously, you’re getting everything from one source, and they are making a good profit from you.You always have to be careful with general contractors. I had several offers for this project, and this one was the most attractive, plus our construction consultant said it was a very fair offer at a good price. Questioning and discussing individual items here and there is a different matter. Even the credit amounts for subcontracted trades are fair, and the consultant is aware of significantly lower prices elsewhere.
Two independent architects we consulted also said that at that price, we wouldn’t be able to build our house with them; they recommended we go with the general contractor specialized in single-family houses instead.
Joedreck schrieb:
The earthworks for flat collectors take possibly 2x5 hours, provided the excavated material can be stored. The offer is considerably overpriced.The general contractor estimated the costs for the earthworks. They don’t make any profit on that, not a single euro, because I have to contract the earthworks myself; they are not part of the main contract. They tell me what they need, and I have to request quotes accordingly. The same applied to the “normal” earthworks. In that case, the estimate was quite accurate, and there were also significantly more expensive offers.
I generally think an air-to-water heat pump is a good option. The heating demand isn’t very large (and even if it were, devices are basically available for any heating load), and with modulation, the overall system efficiency can be achieved with the right configuration. A trench collector offers advantages (especially in DIY projects) financially, as it requires less excavation compared to a horizontal collector.
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