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
Bauexperte11 Jul 2012 20:50Hello Gigi,
Regarding the topic itself – I’m sure €uro will also weigh in; I just want to quickly clear up some misconceptions.
This happens because very few companies train their sales staff on renewable technologies; mainly the contract is the focus, no matter what.
In my experience, that is not possible, and I would advise caution!
“That bread I eat, that song I sing” – usually neither side really knows. What’s important for both systems is an accurate demand analysis—and your preferences. Gas is not necessarily worse, and an air-to-water heat pump is not always the better choice; energy costs—whether oil, gas, or electricity—rise steadily anyway. Electricity might “maybe” become somewhat cheaper in the medium term—some are already talking about a renaissance of storage heaters because energy providers don’t know what to do with the surplus from wind turbines.
Based on feedback from our homeowners, energy consumption costs for air-to-water heat pumps for a family of four—assuming precise planning and dimensioning—amount to around €600-800 (about $650-870)/year for heating and hot water, depending on heating needs and shower habits. For gas, it is mostly about €200 (about $220) more per year. However, this cannot be transferred one-to-one; careful planning and calculation are essential.
Who says that?
You’ve mostly spoken to “gas enthusiasts” and “good” acquaintances, at least that’s how it reads...
It is true that the actual lifespan of an air-to-water heat pump has yet to be conclusively proven; on the other hand, an air-to-water heat pump (simply put) is nothing other than the reverse principle of a refrigerator—how often has your refrigerator needed repair? If a specialized company—trained on the chosen system—installs and commissions the unit (construction managers should usually keep their hands off the controls), I am not aware of any cases where problems arose and homeowners were left stranded. The gas folks are much more relaxed when it comes to having to adjust a system over the weekend!
That’s nonsense too—if a German hears any noise, he really hears it.
Anyway, here’s what I suggest: visit a new development and listen with your own ears to the “immense” noise generated by an air-to-water heat pump, then we can continue talking.
Have a proper calculation done and then talk to an expert—there are very good contacts at the energy agency (available in every federal state). Then decide based on the heating demand of the house and your hot water needs among the systems under consideration.
Best regards
Regarding the topic itself – I’m sure €uro will also weigh in; I just want to quickly clear up some misconceptions.
gigi schrieb:
We’re slowly starting to despair... every builder says something different...
This happens because very few companies train their sales staff on renewable technologies; mainly the contract is the focus, no matter what.
gigi schrieb:
Some providers manage to offer us an air-source heat pump at almost the same price level.
In my experience, that is not possible, and I would advise caution!
gigi schrieb:
They talk about significantly (30%) lower annual costs compared to gas, and others doubt that.
“That bread I eat, that song I sing” – usually neither side really knows. What’s important for both systems is an accurate demand analysis—and your preferences. Gas is not necessarily worse, and an air-to-water heat pump is not always the better choice; energy costs—whether oil, gas, or electricity—rise steadily anyway. Electricity might “maybe” become somewhat cheaper in the medium term—some are already talking about a renaissance of storage heaters because energy providers don’t know what to do with the surplus from wind turbines.
Based on feedback from our homeowners, energy consumption costs for air-to-water heat pumps for a family of four—assuming precise planning and dimensioning—amount to around €600-800 (about $650-870)/year for heating and hot water, depending on heating needs and shower habits. For gas, it is mostly about €200 (about $220) more per year. However, this cannot be transferred one-to-one; careful planning and calculation are essential.
gigi schrieb:
We understand that insulation is better with gas/solar because an air-source heat pump improves efficiency up to KFW70 compared to gas/solar, which would rather speak in favor of gas.
Who says that?
gigi schrieb:
Air-source heat pumps might break down more quickly, and with problems, of course, you have competent help on site quickly with gas. With air-source heat pumps, there could be difficulties.
You’ve mostly spoken to “gas enthusiasts” and “good” acquaintances, at least that’s how it reads...
It is true that the actual lifespan of an air-to-water heat pump has yet to be conclusively proven; on the other hand, an air-to-water heat pump (simply put) is nothing other than the reverse principle of a refrigerator—how often has your refrigerator needed repair? If a specialized company—trained on the chosen system—installs and commissions the unit (construction managers should usually keep their hands off the controls), I am not aware of any cases where problems arose and homeowners were left stranded. The gas folks are much more relaxed when it comes to having to adjust a system over the weekend!
gigi schrieb:
Furthermore, the noise from air-source heat pumps (in our case, 3 meters (10 feet) from the neighbor) is not insignificant. Some say that sooner or later everyone will have problems with neighbors because of this.
That’s nonsense too—if a German hears any noise, he really hears it.
Anyway, here’s what I suggest: visit a new development and listen with your own ears to the “immense” noise generated by an air-to-water heat pump, then we can continue talking.
gigi schrieb:
What should we choose, and what would be cost-effective TODAY?
Have a proper calculation done and then talk to an expert—there are very good contacts at the energy agency (available in every federal state). Then decide based on the heating demand of the house and your hot water needs among the systems under consideration.
Best regards
The great thing about the internet is that everyone will tell you something different: For us, only gas was an option because I am not convinced at all by those air circulation systems. They are fancy new technologies, but have too many drawbacks. Noisy, then you have an ugly fan on the property, and in winter you have to heat with electricity anyway because where should the warmth come from when it’s -15°C (5°F).
For me, gas condensing boilers have three advantages: They are inexpensive to replace, the technology is well-known, and I can use the gas in the house directly for cooking.
In well-insulated houses, hardly any heating is needed anyway. I have practical experience from a KfW 55 house (a two-family house with an additional wood stove). The family and my colleague’s parents paid 500 € in gas last year. I currently pay more than that in my rental apartment.
Be aware with gas… up to 2,500 € connection costs from the utility provider need to be added.
For me, gas condensing boilers have three advantages: They are inexpensive to replace, the technology is well-known, and I can use the gas in the house directly for cooking.
In well-insulated houses, hardly any heating is needed anyway. I have practical experience from a KfW 55 house (a two-family house with an additional wood stove). The family and my colleague’s parents paid 500 € in gas last year. I currently pay more than that in my rental apartment.
Be aware with gas… up to 2,500 € connection costs from the utility provider need to be added.
Hello,
Best regards,
NB: Forum posts do not replace the necessary planning and sizing of the system. Some "advice" from anonymous hobby experts lacks any foundation.
gigi schrieb:That is to be expected; everyone believes their concept is the best!
...we are slowly getting desperate... every developer tells a different story...
gigi schrieb:In terms of initial investment, air heat pumps and gas plus connection costs are usually comparable. To properly evaluate the investment in a technical solution, the actual demand (capacity, energy) for heating and hot water must be known.
...Some providers manage to offer us an air heat pump at almost the same price level. They claim significantly (30%) lower annual costs compared to gas, while others doubt this.
gigi schrieb:This is incorrect. Both the Energy Saving Ordinance and KfW require compliance with two parameters: Ht’ and qp’’. Who is the cause? Gas has the fundamental disadvantage that a solar thermal system must usually be installed unless you use the 15% rule. If you want to stick with gas, this should definitely be implemented to avoid an uneconomical solar thermal system.
...
It is clear to us that insulation is better with gas/solar, because an air heat pump improves efficiency to KfW 70 standard better than gas/solar, which would favor gas.
gigi schrieb:General statements without evidence are completely pointless! Hello,
...An air heat pump could fail somewhat faster...
gigi schrieb:This is where the problems begin. If choosing an air heat pump, it must offer full modulation! Unfortunately, these providers do not offer this!
...We are interested in air heat pumps with storage tanks by these providers: Vaillant, Mitsubishi Zubadan, and Rotex?
gigi schrieb:This is an essential criterion alongside financing costs. However, it can only be answered once the fundamental prerequisites are clear—meaning the actual demand. Until then, it is all guesswork, assumptions, and speculation. Overall, there is no reliable or solid basis for a major investment decision.
...What interests us very much is the annual € cost for heating and hot water with both systems.
Best regards,
NB: Forum posts do not replace the necessary planning and sizing of the system. Some "advice" from anonymous hobby experts lacks any foundation.
Der Da schrieb:
The family and the parents of my colleague paid 500 € for gas last year. What if they only had to pay 250 € for electricity with an air source heat pump, while saving on excessive insulation because the consumption is lower than the demand? Or, combined with a photovoltaic system, have no heating and hot water consumption costs at all (annual balance) and even cover the usual household electricity? Possibly even earning extra money by selling surplus energy? Best regards
Well, a photovoltaic system is generally a great option if you have the necessary budget or are willing to take out a loan for it. I would also agree that such a system eventually pays off. But as I said, every budget eventually runs out. There is always room for improvement.
What I wanted to express with my post is that gas doesn’t have to be as expensive as it is often said to be. We also spent a lot of time in the beginning considering which heating method to choose.
I have a bad experience with those air-source heat pumps because I know how annoying they can be. Maybe I’m too sensitive, or as with any product, there are some poor quality units. But I can hear those things.
What I wanted to express with my post is that gas doesn’t have to be as expensive as it is often said to be. We also spent a lot of time in the beginning considering which heating method to choose.
I have a bad experience with those air-source heat pumps because I know how annoying they can be. Maybe I’m too sensitive, or as with any product, there are some poor quality units. But I can hear those things.
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