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
Hello,
Please feel free to send me a private message or direct email for this. Asking does not cost anything!
Best regards
CharlieBrown schrieb:
Hello,
specific question: Where can I find a good designer for heating, hot water, and ventilation for a single-family house to be built in 41812 Erkelenz?
Please feel free to send me a private message or direct email for this. Asking does not cost anything!
Best regards
An old topic, but in my opinion still very relevant.
It has been mentioned several times that a decision between a gas condensing boiler or an air-to-water heat pump can only be made based on a specific energy demand calculation. However, some people don’t have this yet, for example because their planning is not that far along.
But this is not an insignificant cost factor in building services engineering, and in my opinion, it ultimately also influences the overall planning.
So, it’s a dilemma. You don’t want to spend money on planning without knowing what you will end up with. On the other hand, others can’t provide planning either without that information.
What many of you should be able to provide, however, is your current status:
- What type of heating do you have (gas condensing boiler, air-to-water heat pump, other)?
- What were the initial acquisition costs?
- Do you have mechanical ventilation with heat recovery and/or underfloor heating?
- How much heated floor area do you have in square meters (sqm)?
- What is your average annual consumption (in kWh and currency)?
I’ve already read the following examples in this thread. Here’s my subjective evaluation:
- €600-800 per year for air-to-water heat pump (based on some research, this sounds quite low)
- At least €1000 per year for air-to-water heat pump (seems to be the most common opinion)
- €200 per month for gas (this sounds high)
- €200 per year more than for air-to-water heat pump (too low for a full year)
- €120-140 per month for gas (sounds reasonable)
- At least €1200 per year for air-to-water heat pump (sounds high)
If I try to roughly estimate an average, about €1000 per year in electricity costs just for the air-to-water heat pump (plus household electricity) sounds quite realistic.
Gas costs range around €1500 per year.
Over 20 years, that would be a saving of €10,000.
A Buderus Logamax Plus boiler (from a general contractor offer I received) costs about €1500, plus €2500 for connection costs and installation — so let’s say around €5000.
Therefore, the air-to-water heat pump must not cost more than €15,000 including purchase and installation, or no more than €10,000 more than the gas solution, to just break even.
According to an offer from a general contractor, the air-to-water heat pump costs about €5000 more, so it would be worthwhile.
But this calculation is a very general statement without specifying the floor area or other factors. I would estimate about 150sqm (1615 sqft) as a middle ground.
I would therefore ask you to simply share your costs (see the list above). As a very rough guideline to get a vague idea, this might help. Of course, it doesn’t replace proper planning, but people often look for reference points like this to avoid feeling taken advantage of by “experts.”
And I think real-world experience is exactly what many need.
It has been mentioned several times that a decision between a gas condensing boiler or an air-to-water heat pump can only be made based on a specific energy demand calculation. However, some people don’t have this yet, for example because their planning is not that far along.
But this is not an insignificant cost factor in building services engineering, and in my opinion, it ultimately also influences the overall planning.
So, it’s a dilemma. You don’t want to spend money on planning without knowing what you will end up with. On the other hand, others can’t provide planning either without that information.
What many of you should be able to provide, however, is your current status:
- What type of heating do you have (gas condensing boiler, air-to-water heat pump, other)?
- What were the initial acquisition costs?
- Do you have mechanical ventilation with heat recovery and/or underfloor heating?
- How much heated floor area do you have in square meters (sqm)?
- What is your average annual consumption (in kWh and currency)?
I’ve already read the following examples in this thread. Here’s my subjective evaluation:
- €600-800 per year for air-to-water heat pump (based on some research, this sounds quite low)
- At least €1000 per year for air-to-water heat pump (seems to be the most common opinion)
- €200 per month for gas (this sounds high)
- €200 per year more than for air-to-water heat pump (too low for a full year)
- €120-140 per month for gas (sounds reasonable)
- At least €1200 per year for air-to-water heat pump (sounds high)
If I try to roughly estimate an average, about €1000 per year in electricity costs just for the air-to-water heat pump (plus household electricity) sounds quite realistic.
Gas costs range around €1500 per year.
Over 20 years, that would be a saving of €10,000.
A Buderus Logamax Plus boiler (from a general contractor offer I received) costs about €1500, plus €2500 for connection costs and installation — so let’s say around €5000.
Therefore, the air-to-water heat pump must not cost more than €15,000 including purchase and installation, or no more than €10,000 more than the gas solution, to just break even.
According to an offer from a general contractor, the air-to-water heat pump costs about €5000 more, so it would be worthwhile.
But this calculation is a very general statement without specifying the floor area or other factors. I would estimate about 150sqm (1615 sqft) as a middle ground.
I would therefore ask you to simply share your costs (see the list above). As a very rough guideline to get a vague idea, this might help. Of course, it doesn’t replace proper planning, but people often look for reference points like this to avoid feeling taken advantage of by “experts.”
And I think real-world experience is exactly what many need.
Hello @Kaspatoo
I’m sharing my data here, although it doesn’t quite fit your list since we use geothermal heating (deep drilling).
Additionally, in my opinion, to make sense of the data, it should include the size of the building, how long it has been occupied (the first year usually requires more heating), and the building standard.
Size: 170 m² (1,830 sq ft)
Occupied since: 11/2014
Standard: KfW70 according to the old Energy Saving Ordinance (2009)
Consumption: < 3,500 kWh (to be safe, we informed the energy supplier of 4,000 kWh heat pump electricity for the next billing period = 72 Euros per month = 864 Euros per year including basic fees and without considering discounts).
(Electricity consumption for the heat pump heating and hot water without support from self-generated photovoltaic electricity)
I’m sharing my data here, although it doesn’t quite fit your list since we use geothermal heating (deep drilling).
Additionally, in my opinion, to make sense of the data, it should include the size of the building, how long it has been occupied (the first year usually requires more heating), and the building standard.
Size: 170 m² (1,830 sq ft)
Occupied since: 11/2014
Standard: KfW70 according to the old Energy Saving Ordinance (2009)
Consumption: < 3,500 kWh (to be safe, we informed the energy supplier of 4,000 kWh heat pump electricity for the next billing period = 72 Euros per month = 864 Euros per year including basic fees and without considering discounts).
(Electricity consumption for the heat pump heating and hot water without support from self-generated photovoltaic electricity)
E
ErikErdgas22 Sep 2016 09:53Hello Kaspatoo,
It is certainly interesting to compare consumption and cost values when evaluating cost-effectiveness. You are right that demand planning entails some financial effort. However, I believe this is essential for properly assessing the best option for each specific situation. In principle, you can certainly learn a lot from the current situation, but I would be cautious about what this means for system design or scenario evaluation.
A common problem is that the existing heat generator in older buildings is often oversized or incorrectly adjusted, or the radiators are not hydraulically balanced. Taking an average from the data presented in this thread is likely to distort the picture even further. Additionally, the often underestimated factor of domestic hot water production comes into play, especially in well-insulated buildings where its share is growing and certainly benefits condensing technology.
Best regards, Erik
It is certainly interesting to compare consumption and cost values when evaluating cost-effectiveness. You are right that demand planning entails some financial effort. However, I believe this is essential for properly assessing the best option for each specific situation. In principle, you can certainly learn a lot from the current situation, but I would be cautious about what this means for system design or scenario evaluation.
A common problem is that the existing heat generator in older buildings is often oversized or incorrectly adjusted, or the radiators are not hydraulically balanced. Taking an average from the data presented in this thread is likely to distort the picture even further. Additionally, the often underestimated factor of domestic hot water production comes into play, especially in well-insulated buildings where its share is growing and certainly benefits condensing technology.
Best regards, Erik
L
lars-steina22 Oct 2016 19:59Hello everyone,
I need your help or assessment. My architect has proposed an air-to-water heat pump with underfloor heating. I am now interested in a cost comparison (purchase/maintenance) with a gas boiler. The architect told me that the purchase costs take into account compliance with the Energy Saving Ordinance 2016 (for the gas boiler, a solar system for hot water as well as a heat network system would be required). The house is planned to be 150 sqm (1615 sq ft). The air-to-water heat pump is a Stiebel Eltron model WPL 10AC, including an 8.8 kW (8.8 kW) electric auxiliary heater.
I hope this information is enough to give an idea of the approximate monthly costs to consider.
I would appreciate hearing your opinions or experiences with an air-to-water heat pump.
Thank you!
I need your help or assessment. My architect has proposed an air-to-water heat pump with underfloor heating. I am now interested in a cost comparison (purchase/maintenance) with a gas boiler. The architect told me that the purchase costs take into account compliance with the Energy Saving Ordinance 2016 (for the gas boiler, a solar system for hot water as well as a heat network system would be required). The house is planned to be 150 sqm (1615 sq ft). The air-to-water heat pump is a Stiebel Eltron model WPL 10AC, including an 8.8 kW (8.8 kW) electric auxiliary heater.
I hope this information is enough to give an idea of the approximate monthly costs to consider.
I would appreciate hearing your opinions or experiences with an air-to-water heat pump.
Thank you!
There is simply too little information. It really depends on the specific house (insulation, energy standard, building design—e.g., windows, gables, bay windows, etc.). You can’t do more than guess—although I would already say that 8.8 kW is oversized, but I don’t know the design value, and you probably don’t have a heat load calculation yet. Until that is done, you shouldn’t commit to any system.
Since moving in during the first half of 2014, I have lived in a KfW-70 house built to the Energy Saving Ordinance (currently about standard) with roughly 180 m² (approximately 1,940 sq ft) of heated area (+ about 60 m² (approximately 645 sq ft) of unheated basement) and have used a total of 3,800 kWh for heating and hot water, although with a ground-source heat pump. But compared to F-pno (if his figure is for “per year”), you already see a big difference. How should anyone estimate your consumption that way?
Since moving in during the first half of 2014, I have lived in a KfW-70 house built to the Energy Saving Ordinance (currently about standard) with roughly 180 m² (approximately 1,940 sq ft) of heated area (+ about 60 m² (approximately 645 sq ft) of unheated basement) and have used a total of 3,800 kWh for heating and hot water, although with a ground-source heat pump. But compared to F-pno (if his figure is for “per year”), you already see a big difference. How should anyone estimate your consumption that way?
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