Hello everyone,
we are planning a prefabricated house using timber frame construction. It will have 180 sqm (1,937 sq ft) of living space with underfloor heating, and about 230 sqm (2,475 sq ft) of usable area.
So far, the offer included an air-to-water heat pump from Daikin (Altherma 3R, formerly Rotex HPSU compact Ultra).
Now it seems that this unit might not have enough capacity (?) and as an alternative (additional cost around 4,000) we have been offered a "Wolf heat pump CHC Monoblock 10/300-35".
The Daikin is available in the 4-9 kW version—would that really be insufficient for this size? And what do you think about this offer?
I have the energy-saving regulation heat protection certification and a renewable energy heat law document available, if any information from those is needed.
Thank you very much!
Best regards
we are planning a prefabricated house using timber frame construction. It will have 180 sqm (1,937 sq ft) of living space with underfloor heating, and about 230 sqm (2,475 sq ft) of usable area.
So far, the offer included an air-to-water heat pump from Daikin (Altherma 3R, formerly Rotex HPSU compact Ultra).
Now it seems that this unit might not have enough capacity (?) and as an alternative (additional cost around 4,000) we have been offered a "Wolf heat pump CHC Monoblock 10/300-35".
The Daikin is available in the 4-9 kW version—would that really be insufficient for this size? And what do you think about this offer?
I have the energy-saving regulation heat protection certification and a renewable energy heat law document available, if any information from those is needed.
Thank you very much!
Best regards
Pixelsurium schrieb:
Thank you for the information. The installer is supposed to contact me on Monday, and I will have to make a decision... I will ask if Wolf also offers a "smaller" version... Ask, but don’t expect too much in response. He will probably give you some answer that sounds completely logical and leave you verbally stuck. However, be prepared that he will say it’s not sufficient, while in reality it probably is. The calculations are often rough estimates, including a large safety margin, and they rarely take into account internal gains or similar factors. I would immediately ask if only those two models are available or if you could choose another one from the Wolf range, for example.
Say you would like to have the calculated heating load. If that's not available, then ask for the HT value. Mention that you have an engineer friend who wants to review it or something like that.
Pixelsurium schrieb:
I find it odd that the Daikin 8kW is also listed in the Bafa list—does that mean the subsidy will definitely be approved? No. That only means the unit is generally eligible for funding. Whether you actually receive a subsidy is calculated individually based on data from your house, your heat pump, and your location. The determining factor is the (calculated) efficiency. It can happen that one heat pump qualifies and another does not, even if both are on the list.
The official BAFA calculator can be found via a search engine to run the calculation yourself. But for that, we would first need more specific data from you.
Has it already been confirmed whether you are building with controlled residential ventilation? I would argue that, unless you are constructing the worst timber-frame house in Germany for a new build, with your size and location, controlled residential ventilation will bring your heating load below 6kW.
D
Daniel-Sp7 Aug 2020 22:03Just as the heating engineer suspects that the Wolf unit is not sufficient, I also believe that 7 kW is too much.
Therefore, check the calculation carefully.
If you have a choice, select a heat pump that is as close to the required size as possible, without any oversizing. You won’t need any reserve capacity on about 98% of heating days because the design outdoor temperature (DOT) will not be reached for the whole winter.
That’s why it’s equally important to choose a heat pump that can modulate down to very low levels.
All the smart home integration is unnecessary fuss. It will take two or three heating seasons to optimize the heat pump settings, and then you will probably forget about it until it hopefully needs replacement in 20 years at the earliest. To me, that’s smart.
Very important: also ask for the floor heating calculation and review it thoroughly. You should not accept a supply temperature of 35°C (95°F) or even higher.
Have the planned hydraulics explained to you as well. There are still heating engineers who like to install a heat pump with a mixing buffer tank. This is a no-go!
Therefore, check the calculation carefully.
If you have a choice, select a heat pump that is as close to the required size as possible, without any oversizing. You won’t need any reserve capacity on about 98% of heating days because the design outdoor temperature (DOT) will not be reached for the whole winter.
That’s why it’s equally important to choose a heat pump that can modulate down to very low levels.
All the smart home integration is unnecessary fuss. It will take two or three heating seasons to optimize the heat pump settings, and then you will probably forget about it until it hopefully needs replacement in 20 years at the earliest. To me, that’s smart.
Very important: also ask for the floor heating calculation and review it thoroughly. You should not accept a supply temperature of 35°C (95°F) or even higher.
Have the planned hydraulics explained to you as well. There are still heating engineers who like to install a heat pump with a mixing buffer tank. This is a no-go!
S
Smirnoff19838 Aug 2020 11:30Daniel-Sp schrieb:
Make sure to have the planned hydraulic system explained to you. There are still heating engineers who like to install a heat pump with a mixing buffer tank. A big no-no!Just for clarification, why should no mixing buffer tank be installed anymore? What should be used instead?
P
Pixelsurium8 Aug 2020 12:32Hi,
thank you very much for the valuable tips. We are building without a ventilation system. I will ask about the HT value. I have now seen that the Wolf is a monoblock unit and the Daikin is a split system. Does this still make a difference?
thank you very much for the valuable tips. We are building without a ventilation system. I will ask about the HT value. I have now seen that the Wolf is a monoblock unit and the Daikin is a split system. Does this still make a difference?
Pixelsurium schrieb:
We are building without a ventilation system.That could turn out to be the biggest mistake in the construction... but it seems you already have several issues. First, the forgotten ring earth electrode. Then the confusion about the heat pump, and now you’re also revealing that no mechanical ventilation with heat recovery is planned...Similar topics