ᐅ Heating systems, insulation, government energy efficiency programs, photovoltaic panels – are these components worthwhile?
Created on: 20 Dec 2018 16:44
M
Menelaos
Hello everyone,
We are planning to build next spring. The building site is south of Bremen in Lower Saxony.
We are going to build a single-family house of 135 m² (1450 ft²). We have received a very detailed quote, and we have a few questions regarding the topics mentioned above.
The house is offered with options such as additional insulation, construction supervision, thermal bridge calculation, under-slab insulation, and a ventilation system. These were described as not necessary or financially neutral. The existing insulation for the exterior walls is 14 cm (5.5 inches), and the roof insulation is 20 cm (8 inches), which is considered sufficient. The ventilation system is also said to be a matter of personal preference.
For heating, we were recommended the Vitocal 200-S (air-to-water heat pump) with 6 kW heating capacity and a 300 L (79 gallons) hot water storage tank. Underfloor heating with individual room control and electric thermostats is planned. Our alternatives were a gas boiler, mainly due to concerns about potential noise from the outdoor unit, and a geothermal heat pump, which was discouraged because our project is too small to justify the investment and the costs of drilling.
We also brought up another air source heat pump option. The builder is willing to install it but would first need to familiarize themselves with the system to confirm they can support it. Maintenance and repair concerns were also mentioned, as technicians might not be familiar with “foreign” systems.
The air source heat pump is now planned to run together with a photovoltaic system, rated at 6 kWp and ready for operation. Installation will be on the side of the roof sloping toward the street, including an inverter and FRE control unit. No battery storage will be installed. Space will be reserved in the utility room for a battery if desired later.
So far, we feel well supported and competently advised. How does this situation sound to more experienced forum users, homeowners, builders, and technicians compared to our perspective?
Thank you in advance and best regards!
We are planning to build next spring. The building site is south of Bremen in Lower Saxony.
We are going to build a single-family house of 135 m² (1450 ft²). We have received a very detailed quote, and we have a few questions regarding the topics mentioned above.
The house is offered with options such as additional insulation, construction supervision, thermal bridge calculation, under-slab insulation, and a ventilation system. These were described as not necessary or financially neutral. The existing insulation for the exterior walls is 14 cm (5.5 inches), and the roof insulation is 20 cm (8 inches), which is considered sufficient. The ventilation system is also said to be a matter of personal preference.
For heating, we were recommended the Vitocal 200-S (air-to-water heat pump) with 6 kW heating capacity and a 300 L (79 gallons) hot water storage tank. Underfloor heating with individual room control and electric thermostats is planned. Our alternatives were a gas boiler, mainly due to concerns about potential noise from the outdoor unit, and a geothermal heat pump, which was discouraged because our project is too small to justify the investment and the costs of drilling.
We also brought up another air source heat pump option. The builder is willing to install it but would first need to familiarize themselves with the system to confirm they can support it. Maintenance and repair concerns were also mentioned, as technicians might not be familiar with “foreign” systems.
The air source heat pump is now planned to run together with a photovoltaic system, rated at 6 kWp and ready for operation. Installation will be on the side of the roof sloping toward the street, including an inverter and FRE control unit. No battery storage will be installed. Space will be reserved in the utility room for a battery if desired later.
So far, we feel well supported and competently advised. How does this situation sound to more experienced forum users, homeowners, builders, and technicians compared to our perspective?
Thank you in advance and best regards!
Two concepts are emerging:
Air-to-water heat pump and photovoltaic system is number one. I recommend going exactly with what is offered to you. Air-to-water heat pumps are not simple to configure, so please choose the model that the person who will also provide the service is most familiar with. The photovoltaic system makes sense because my son-in-law has a Junkers air-to-water heat pump without photovoltaics, and the whole system consumes quite a bit of electricity: 2000 euros per year compared to 800 euros for my wife and me with a gas heating system. It seems worthwhile to generate your own electricity for such a system—but we also had winters in 2017-2018 here where his air-to-water heat pump ran almost entirely on electricity, with nighttime temperatures of minus 10°C (14°F) or lower.
The other sensible concept is the traditional gas boiler with condensing technology. Its advantages: very robust, easy to operate and maintain, very space-saving, mature, efficient. The downside is the Energy Saving Ordinance: you must have a renewable component alongside. Here, not photovoltaics but solar thermal for hot water is recommended. The solar panels provide enough hot water from Easter to October that we can completely turn off the heating system for domestic hot water during that period. The system is cheaper to purchase than the heat pump concept, and in my opinion, not more expensive in operating costs at present. It depends on the gas price. However, the gas connection needs to be paid for, whereas it is not necessary with the heat pump. Karsten
Air-to-water heat pump and photovoltaic system is number one. I recommend going exactly with what is offered to you. Air-to-water heat pumps are not simple to configure, so please choose the model that the person who will also provide the service is most familiar with. The photovoltaic system makes sense because my son-in-law has a Junkers air-to-water heat pump without photovoltaics, and the whole system consumes quite a bit of electricity: 2000 euros per year compared to 800 euros for my wife and me with a gas heating system. It seems worthwhile to generate your own electricity for such a system—but we also had winters in 2017-2018 here where his air-to-water heat pump ran almost entirely on electricity, with nighttime temperatures of minus 10°C (14°F) or lower.
The other sensible concept is the traditional gas boiler with condensing technology. Its advantages: very robust, easy to operate and maintain, very space-saving, mature, efficient. The downside is the Energy Saving Ordinance: you must have a renewable component alongside. Here, not photovoltaics but solar thermal for hot water is recommended. The solar panels provide enough hot water from Easter to October that we can completely turn off the heating system for domestic hot water during that period. The system is cheaper to purchase than the heat pump concept, and in my opinion, not more expensive in operating costs at present. It depends on the gas price. However, the gas connection needs to be paid for, whereas it is not necessary with the heat pump. Karsten
B
boxandroof24 Dec 2018 11:02Nordlys schrieb:
Two concepts emerge:
Air-to-water heat pump and photovoltaic system are the first choice. I recommend taking it exactly as offered to you. Air-to-water heat pumps are not easy to configure properly, so please choose the model the service provider is most experienced with. The photovoltaic system makes sense alongside it because my son-in-law has a Junkers air-to-water heat pump without photovoltaics, and it consumes quite a bit of electricity: 2,000 euros per year compared to 800 euros for my wife and me with a gas heating system.I almost agree. But when it comes to heat pumps, you shouldn’t just choose the “standard” option; you really need to watch the provider closely, otherwise costs can quickly become higher than with gas. If in doubt, I would stick with gas, since mistakes are less critical there.
Photovoltaics pay for themselves financially, regardless of the heating system. During the heating season, there is no significant energy yield. Solar thermal systems almost never pay off financially, but they are often used because they are the cheapest way to meet regulations together with gas.
Hello everyone,
First of all, thank you for the many comments, opinions, and suggestions. Now I’m finally taking the time to respond.
We have told the builder that he can include the air-to-water heat pump with photovoltaics in his quotes. The specific model is still undecided. We want to visit the next home building fair, speak with the heating installer, and if possible, see and especially listen to the model while it’s running. At the moment, this is the biggest obstacle for us. To paint a worst-case scenario: the outdoor unit is humming so loudly in the front yard that you can’t sleep at night, and eventually, it just becomes a nuisance.
We are less concerned about the payback period. We are both young, and the purchase prices of the components are comparatively affordable, even including installation.
In advance, we wish you a Happy New Year 2019 and all the best for the year ahead.
First of all, thank you for the many comments, opinions, and suggestions. Now I’m finally taking the time to respond.
We have told the builder that he can include the air-to-water heat pump with photovoltaics in his quotes. The specific model is still undecided. We want to visit the next home building fair, speak with the heating installer, and if possible, see and especially listen to the model while it’s running. At the moment, this is the biggest obstacle for us. To paint a worst-case scenario: the outdoor unit is humming so loudly in the front yard that you can’t sleep at night, and eventually, it just becomes a nuisance.
We are less concerned about the payback period. We are both young, and the purchase prices of the components are comparatively affordable, even including installation.
In advance, we wish you a Happy New Year 2019 and all the best for the year ahead.
Menelaos schrieb:
To imagine the worst-case scenario: the outdoor unit hums so loudly in the front yard that you cannot sleep at night and it just becomes annoying over time. I only know these annoying devices from a passerby’s perspective – the homeowners place them in what they consider the best spot – and it’s the buzzing noise that bothers more often than the (less frequent) humming sound.
Menelaos schrieb:
We are both young Thanks, it’s good to hear someone finally say that 🙂
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