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 11:24I would go with a gas-solar system and be happy about the approximately 2000 euros saved in installation costs. It is important, of course, to size the heating system (flow temperature) so that a heat pump could be used in 20 years if the gas boiler needs or should be replaced.
R
R.Hotzenplotz6 Jan 2018 11:33Alright.
The only downside that just came to my mind... the intended cooling function, for which we specifically commissioned a glycol filling for the underfloor heating, would then be pointless. That only works with a geothermal pump or a water-to-water heat pump. It’s actually a shame because I now consider cooling in summer just as important as heating in winter.
@Bieber0815
I’ll keep that tip in mind. Thanks.
The only downside that just came to my mind... the intended cooling function, for which we specifically commissioned a glycol filling for the underfloor heating, would then be pointless. That only works with a geothermal pump or a water-to-water heat pump. It’s actually a shame because I now consider cooling in summer just as important as heating in winter.
@Bieber0815
I’ll keep that tip in mind. Thanks.
Well, everything that needed to be said has already been said, so why pay more than necessary?
That’s not really a drawback; you wouldn’t get more than a slightly cooler floor (a few degrees Celsius). However, a cold floor doesn't help much in summer since the air remains warm and humid. Cooling effects through underfloor heating systems with heat pumps are negligible. The house will still get warm anyway.
R.Hotzenplotz schrieb:
The only drawback I just thought of... the intended cooling function, for which we specifically commissioned a glycol filling for the underfloor heating, would then be useless.
That’s not really a drawback; you wouldn’t get more than a slightly cooler floor (a few degrees Celsius). However, a cold floor doesn't help much in summer since the air remains warm and humid. Cooling effects through underfloor heating systems with heat pumps are negligible. The house will still get warm anyway.
Furthermore, the efficiency of the air-to-water heat pump does not depend on the heating load but on the unit itself and other factors.
I won’t go into alternatives now because I think you have a certain tunnel vision on that.
So: have the controlled residential ventilation system checked to see if it’s sufficient. Whatever you save with solar, you can simply spend on extras or something like that.
I won’t go into alternatives now because I think you have a certain tunnel vision on that.
So: have the controlled residential ventilation system checked to see if it’s sufficient. Whatever you save with solar, you can simply spend on extras or something like that.
R
R.Hotzenplotz6 Jan 2018 11:39Okay, Mycraft. I suspected that it was nothing more than a pure marketing effect.
@Joedreck
Why tunnel vision? I don’t think so. I’m specifically asking here to get additional assessments and gladly other opinions and advice. I can’t claim to have a complete overview of the market, and I value what I read here more than what the installer tells me, who wants to sell me a particular product.
Therefore, it would be nice if you consider another alternative worth mentioning here at least once, so I can look into it.
@Joedreck
Why tunnel vision? I don’t think so. I’m specifically asking here to get additional assessments and gladly other opinions and advice. I can’t claim to have a complete overview of the market, and I value what I read here more than what the installer tells me, who wants to sell me a particular product.
Therefore, it would be nice if you consider another alternative worth mentioning here at least once, so I can look into it.
As a layperson, I don’t have a complete overview of the market either, nor do I fully understand all the technical details.
I find the price of the surface collectors quite outrageous. Generally, things like that seem to be expensive in your area.
I would seriously consider the trench collector. It’s important to have some patience, a good understanding, three friends on a weekend, and an excavator rented by the hour. Then you pay around 2000€ (about 2200 USD) for the heat source.
If that’s not an option at all, I would check how the underfloor heating is designed. If it is planned for a maximum of 35°C (95°F) at the standard outdoor temperature, an air-to-water heat pump is a real alternative. Was the region NRW?
Then I would calculate gas heating combined with the already planned mechanical ventilation with heat recovery and save on solar panels.
However, I don’t know what stage you are at or what else you are dealing with. Unfortunately, heating installers here are not always up to date or interested.
I find the price of the surface collectors quite outrageous. Generally, things like that seem to be expensive in your area.
I would seriously consider the trench collector. It’s important to have some patience, a good understanding, three friends on a weekend, and an excavator rented by the hour. Then you pay around 2000€ (about 2200 USD) for the heat source.
If that’s not an option at all, I would check how the underfloor heating is designed. If it is planned for a maximum of 35°C (95°F) at the standard outdoor temperature, an air-to-water heat pump is a real alternative. Was the region NRW?
Then I would calculate gas heating combined with the already planned mechanical ventilation with heat recovery and save on solar panels.
However, I don’t know what stage you are at or what else you are dealing with. Unfortunately, heating installers here are not always up to date or interested.
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