Hello,
My husband and I are currently trying to decide which heating system to install in our planned house.
I insist on having a ventilation system and a wood-burning stove in the living room. So the heating should be compatible with these.
Our chosen construction company has now offered us three heat pumps:
Air-to-water heat pump: Nibe F2040-8 with Nibe VVM320
Exhaust air heat pump: Nibe F750 P with supply air module SAM 40
Ground source heat pump: Nibe 1245-6 with deep drilling
My husband currently prefers the exhaust air heat pump because he thinks it works like the air-to-water heat pump but makes better use of the warm air from running computers... Everywhere I read, though, it says: "Avoid exhaust air heat pumps unless you are building a passive house."
Does the supply air module actually make it function somewhat like an air-to-water heat pump, but with better use of the warm indoor air?
The house is planned as a two-story timber frame construction with KfW 55 standard. To be honest, I am completely overwhelmed by this complicated heating topic. The more information I get, the more complex it seems.
My husband and I are currently trying to decide which heating system to install in our planned house.
I insist on having a ventilation system and a wood-burning stove in the living room. So the heating should be compatible with these.
Our chosen construction company has now offered us three heat pumps:
Air-to-water heat pump: Nibe F2040-8 with Nibe VVM320
Exhaust air heat pump: Nibe F750 P with supply air module SAM 40
Ground source heat pump: Nibe 1245-6 with deep drilling
My husband currently prefers the exhaust air heat pump because he thinks it works like the air-to-water heat pump but makes better use of the warm air from running computers... Everywhere I read, though, it says: "Avoid exhaust air heat pumps unless you are building a passive house."
Does the supply air module actually make it function somewhat like an air-to-water heat pump, but with better use of the warm indoor air?
The house is planned as a two-story timber frame construction with KfW 55 standard. To be honest, I am completely overwhelmed by this complicated heating topic. The more information I get, the more complex it seems.
Grym schrieb:
Oh, so with air-to-water heat pumps, the figures from the annual performance factor calculator are too optimistic, but for groundwater heat pumps they are too pessimistic? I see.
In another forum, users easily achieve values over 4 with the Panasonic units. The better the insulation, the higher the share of hot water demand. This occurs year-round, even in summer with 25°C (77°F) outdoor temperature and 5°C (41°F) ground temperature.
The differences in consumption are marginal, especially with good insulation. First, I never said anything about the annual performance factor of the groundwater heat pump. Second, this is not about THAT Panasonic heat pump. Third, the annual performance factor also depends on the location, and the one user with the good performance might be the exception.
My ground temperature in winter after long heating periods is around 5°C (41°F), while in summer it is significantly higher (this might be different with a shallow borehole or collector). There is a website where people upload their actual annual performance factors into a database; you might want to check the figures for air-to-water heat pumps there.
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I think most owners of air-to-water heat pumps understand that their energy consumption is a few hundred kWh higher compared to a ground-source (brine-to-water) heat pump. We're talking about 300-500 kWh. I’m not saying that an air-to-water heat pump is equivalent to a ground-source heat pump, but the principle is the same – you're heating with electricity. The ground-source heat pump is slightly more efficient.
There are plenty of ground-source heat pumps in the database with an annual performance factor (APF) below 3. There are also some air-to-water heat pumps with an APF above 4. It all comes down to good and bad designs on both sides. On average, the difference corresponds to a few hundred kWh.
You need to calculate, of course, about 60-120 EUR more costs annually versus an initial investment of 6,000 to 10,000 EUR. It’s generally not worth it—much more worthwhile is combining an air-to-water heat pump with a photovoltaic system. With just 10-20% self-consumption, the ground-source heat pump becomes outdated again, plus you get additional feed-in tariffs. Of course, if you want to go all the way: passive house, photovoltaic, ground-source heat pump. Everyone can decide for themselves.
With an air-to-water heat pump and a modern new build, ideally with KfW55 insulation standards and taking advantage of 20-year financing, no one will become poor. Yes, ground-source heat pumps save about 5-10 EUR per month.
A note on the database: it shouldn’t be taken too seriously. If the heating system doesn’t operate at low flow temperatures, the annual performance factor will drop significantly, whether it’s an air-to-water or a ground-source heat pump.
But as I said, the technically optimal solution is probably the ground-source heat pump combined with passive house standards, photovoltaic system, controlled ventilation with ground heat exchanger, photovoltaic battery storage, electric vehicle, and PV on the garage roof (or even more environmentally friendly, of course, bicycle and public transport instead of a car). You can always push it further…
There are plenty of ground-source heat pumps in the database with an annual performance factor (APF) below 3. There are also some air-to-water heat pumps with an APF above 4. It all comes down to good and bad designs on both sides. On average, the difference corresponds to a few hundred kWh.
You need to calculate, of course, about 60-120 EUR more costs annually versus an initial investment of 6,000 to 10,000 EUR. It’s generally not worth it—much more worthwhile is combining an air-to-water heat pump with a photovoltaic system. With just 10-20% self-consumption, the ground-source heat pump becomes outdated again, plus you get additional feed-in tariffs. Of course, if you want to go all the way: passive house, photovoltaic, ground-source heat pump. Everyone can decide for themselves.
With an air-to-water heat pump and a modern new build, ideally with KfW55 insulation standards and taking advantage of 20-year financing, no one will become poor. Yes, ground-source heat pumps save about 5-10 EUR per month.
A note on the database: it shouldn’t be taken too seriously. If the heating system doesn’t operate at low flow temperatures, the annual performance factor will drop significantly, whether it’s an air-to-water or a ground-source heat pump.
But as I said, the technically optimal solution is probably the ground-source heat pump combined with passive house standards, photovoltaic system, controlled ventilation with ground heat exchanger, photovoltaic battery storage, electric vehicle, and PV on the garage roof (or even more environmentally friendly, of course, bicycle and public transport instead of a car). You can always push it further…
120 € per year seems very optimistic to me... that would be just 10 € per month. In my circle of acquaintances, monthly heating costs with an air-to-water heat pump are usually over 70 € per month.
In general, though, I agree with you – the choice of heating system is not that crucial – one has higher investment costs, the other lower running costs. At the end of the day, the overall outcome is similar.
In general, though, I agree with you – the choice of heating system is not that crucial – one has higher investment costs, the other lower running costs. At the end of the day, the overall outcome is similar.
G
Goldi0911118 Aug 2016 21:41I can confirm the numbers as well; two colleagues are involved. €900 per year with a ground-source heat pump and one family at €500 for gas.
Goldi09111 schrieb:
I can confirm these numbers as well; two colleagues have it. €900 per year with a ground-source heat pump and one family pays around €500 for gas. These figures don't tell the whole story since it depends on the building size, electricity/gas prices, and user behavior (children, amount of showering, etc.). I pay less than €500 per year here with a ground-source heat pump, despite relatively high electricity costs (more details about my construction project can be found here in the forum).
Goldi, that’s nonsense... One kWh of heating from gas costs 7 cents – with a kWh from a brine-water heat pump having an annual performance factor of 4.5, it’s about 5.5 cents without a heat pump tariff, and with an air-water heat pump having an annual performance factor of, let’s say, 3.8, it’s 6.6 cents.
Are you seriously going to tell me that one kWh of heat from gas provides twice as much warmth?
Are you seriously going to tell me that one kWh of heat from gas provides twice as much warmth?
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