ᐅ Final House Planning: Heating Components, What Makes Sense – No Air Source Heat Pump
Created on: 10 Feb 2016 10:37
V
Veltins
Hello everyone,
After spending the past few weeks figuring out what, how, with whom, and how big we want to build, we are now focusing on what I consider almost the most important part: choosing the right technology, especially the heating and cooling systems. We are planning a 144 sqm (1550 sq ft) house built to KfW 40 standard. It will have no basement, located in a low-altitude area in NRW, and will house four people.
Our general contractor (GC) typically installs the following components:
- Nibe Fighter 755 G air-source heat pump (variant of the 750 model) combined with a solar panel system with 2 kWp output
- Underfloor heating on the ground and upper floors
- 180-liter (48-gallon) domestic hot water tank
Optionally, the following components can be installed at an additional cost:
- Expansion of the photovoltaic system to 3.3 kWp
- 7.0 kWh home battery
- Inverter
Our requests regarding heating capacity and expected electricity consumption have yielded rather unsatisfactory results. In other words: too much marketing talk and too few answers to ease my concerns, which are as follows:
- Is the Nibe 755 G with the small solar panel, despite good insulation, even sufficiently sized to handle 144 sqm (1550 sq ft) without continuous supplemental heating? Are 180 liters (48 gallons) really enough, especially with two small children? And does it make sense to invest a five-figure amount in expanding the photovoltaic system with a battery relative to the cost?
- Is an optional stove worth it at all? With around 7,000 EUR for the chimney plus the stove itself, economically, it doesn’t add up. We are almost ruling it out.
- What other “combinations” besides an air-source heat pump would you consider?
Basically, I am not opposed to an air-source heat pump, but if a projected annual need of 6,000 kWh for hot water and heating is the standard for this setup, then I currently achieve comparable costs with my existing 1990 house that has poor insulation and a gas boiler. You can guess which GC we are dealing with. Replacing the standard components is not easy.
I am about to consult a heating expert, as I really don’t trust the GC on this point, and they mostly just hire their standard suppliers to install standard equipment. Therefore, I would be very grateful for any expert tips on this topic in advance.
Best regards
After spending the past few weeks figuring out what, how, with whom, and how big we want to build, we are now focusing on what I consider almost the most important part: choosing the right technology, especially the heating and cooling systems. We are planning a 144 sqm (1550 sq ft) house built to KfW 40 standard. It will have no basement, located in a low-altitude area in NRW, and will house four people.
Our general contractor (GC) typically installs the following components:
- Nibe Fighter 755 G air-source heat pump (variant of the 750 model) combined with a solar panel system with 2 kWp output
- Underfloor heating on the ground and upper floors
- 180-liter (48-gallon) domestic hot water tank
Optionally, the following components can be installed at an additional cost:
- Expansion of the photovoltaic system to 3.3 kWp
- 7.0 kWh home battery
- Inverter
Our requests regarding heating capacity and expected electricity consumption have yielded rather unsatisfactory results. In other words: too much marketing talk and too few answers to ease my concerns, which are as follows:
- Is the Nibe 755 G with the small solar panel, despite good insulation, even sufficiently sized to handle 144 sqm (1550 sq ft) without continuous supplemental heating? Are 180 liters (48 gallons) really enough, especially with two small children? And does it make sense to invest a five-figure amount in expanding the photovoltaic system with a battery relative to the cost?
- Is an optional stove worth it at all? With around 7,000 EUR for the chimney plus the stove itself, economically, it doesn’t add up. We are almost ruling it out.
- What other “combinations” besides an air-source heat pump would you consider?
Basically, I am not opposed to an air-source heat pump, but if a projected annual need of 6,000 kWh for hot water and heating is the standard for this setup, then I currently achieve comparable costs with my existing 1990 house that has poor insulation and a gas boiler. You can guess which GC we are dealing with. Replacing the standard components is not easy.
I am about to consult a heating expert, as I really don’t trust the GC on this point, and they mostly just hire their standard suppliers to install standard equipment. Therefore, I would be very grateful for any expert tips on this topic in advance.
Best regards
Hello building expert,
thank you for your detailed answers. Yes, your assumption about the supplier is correct, as well as the conclusion that if this option is not chosen, there will be no other alternatives offered by this supplier. I am still undecided whether this might become a deal-breaker... Friends of ours built with this supplier and the Nibe 750, but without a photovoltaic system, which is supported. They currently have an energy consumption of 4700 kWh in the same house type with 4 people, meeting KfW 55 standards.
Larina: How satisfied are you with the Stiebel Eltron system and the choice of technology? Do you already have initial consumption estimates or even actual consumption data?
thank you for your detailed answers. Yes, your assumption about the supplier is correct, as well as the conclusion that if this option is not chosen, there will be no other alternatives offered by this supplier. I am still undecided whether this might become a deal-breaker... Friends of ours built with this supplier and the Nibe 750, but without a photovoltaic system, which is supported. They currently have an energy consumption of 4700 kWh in the same house type with 4 people, meeting KfW 55 standards.
Larina: How satisfied are you with the Stiebel Eltron system and the choice of technology? Do you already have initial consumption estimates or even actual consumption data?
Thank you for your responses. Since this past weekend, we have completely moved away from using the Nibe 755 as the sole system for hot water and heating. We visited three houses by V.. and reviewed their heating cost breakdowns. It’s deceiving: last year, we hardly had a winter—extremely mild. When I consider just a moderately cold winter as a standard, the costs come to at least 130 euros per month, just for hot water and heating.
Visually, we also didn’t like the decentralized air inlets. Therefore, if we build with this general contractor, only an air-to-water heat pump will be considered. This would be another Nibe system, an F2040-8 outdoor unit combined with a VVM320. It includes centralized ventilation with a counterflow heat exchanger, a photovoltaic system, and a Tesla battery. This would comply with the 40 Plus Standard. From a purely economic standpoint, I know I won’t recoup the extra cost, but considering the disadvantages of decentralized ventilation and the benefits of a controlled residential ventilation system (is it one system or are there further distinctions?), I find it worthwhile. Including the 5,000-euro repayment subsidy, this upgrade costs me exactly 10,000 euros more. A stove is no longer an option.
I’m curious about the heating load calculation results. The above combination seems more sensible to me than a simple exhaust air heat pump. My only concern is the noise level of the outdoor unit. Are there any experiences with the Nibe air-to-water heat pump? Regardless of purchase costs, do you consider the combination of these components reasonable by comparison? And is the comfort gain from controlled residential ventilation, beyond just heating issues, also worth considering?
Visually, we also didn’t like the decentralized air inlets. Therefore, if we build with this general contractor, only an air-to-water heat pump will be considered. This would be another Nibe system, an F2040-8 outdoor unit combined with a VVM320. It includes centralized ventilation with a counterflow heat exchanger, a photovoltaic system, and a Tesla battery. This would comply with the 40 Plus Standard. From a purely economic standpoint, I know I won’t recoup the extra cost, but considering the disadvantages of decentralized ventilation and the benefits of a controlled residential ventilation system (is it one system or are there further distinctions?), I find it worthwhile. Including the 5,000-euro repayment subsidy, this upgrade costs me exactly 10,000 euros more. A stove is no longer an option.
I’m curious about the heating load calculation results. The above combination seems more sensible to me than a simple exhaust air heat pump. My only concern is the noise level of the outdoor unit. Are there any experiences with the Nibe air-to-water heat pump? Regardless of purchase costs, do you consider the combination of these components reasonable by comparison? And is the comfort gain from controlled residential ventilation, beyond just heating issues, also worth considering?
B
Bauexperte15 Feb 2016 11:02BeHaElJa schrieb:
Even if the photovoltaic system covers 100%, it would take 11 years to break even. It’s questionable whether the battery would still be functioning by then.Unless you are using some kind of Chinese mystery product, definitely. Panasonic® by the way guarantees 5,000 charge cycles, which roughly equals a battery lifespan of 20 years.Regards, Bauexperte
B
Bauexperte15 Feb 2016 11:03Veltins schrieb:
I am curious to see the heating load calculation results. Before signing the contract? This approach by the respected colleague competitor would indeed be new to me.
Regards, Bauexperte
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