ᐅ LWZ 8 CS Premium Combination Unit with Air-to-Water Heat Pump, Controlled Ventilation System, and Hot Water Storage Tank
Created on: 6 Jul 2020 20:56
B
Bauherr am L
Hello friends!
Originally, we were considering a ground-source heat pump because we thought that with an air-to-water heat pump we wouldn’t qualify for government subsidies.
However, during a discussion with our heating installer and a representative from Stiebel Eltron, we were told that we can meet the BAFA (Federal Office for Economic Affairs and Export Control) subsidy requirements even with an air-to-water heat pump, which would save us the significant extra costs for drilling.
We were now recommended the LWZ 8 CS Premium from Stiebel Eltron as a combined unit. Our heating load is 7.6 kW (calculated externally), so it would be suitable. What we like is that the LWZ 8 CS Premium does not require an outdoor unit.
Now my specific questions: In the conversation, the combined unit was strongly recommended. One argument was that the exhaust air from the integrated mechanical ventilation with heat recovery is also used for heating purposes, increasing energy efficiency. Additionally, everything is built into this one device, which supposedly reduces the installation effort and makes it easier for the technicians. From your point of view, is there any reason against choosing the combined unit?
The alternative would be three separate units (heat pump, whether ground-source or air-to-water / mechanical ventilation with heat recovery / hot water storage tank)...
Thanks
Originally, we were considering a ground-source heat pump because we thought that with an air-to-water heat pump we wouldn’t qualify for government subsidies.
However, during a discussion with our heating installer and a representative from Stiebel Eltron, we were told that we can meet the BAFA (Federal Office for Economic Affairs and Export Control) subsidy requirements even with an air-to-water heat pump, which would save us the significant extra costs for drilling.
We were now recommended the LWZ 8 CS Premium from Stiebel Eltron as a combined unit. Our heating load is 7.6 kW (calculated externally), so it would be suitable. What we like is that the LWZ 8 CS Premium does not require an outdoor unit.
Now my specific questions: In the conversation, the combined unit was strongly recommended. One argument was that the exhaust air from the integrated mechanical ventilation with heat recovery is also used for heating purposes, increasing energy efficiency. Additionally, everything is built into this one device, which supposedly reduces the installation effort and makes it easier for the technicians. From your point of view, is there any reason against choosing the combined unit?
The alternative would be three separate units (heat pump, whether ground-source or air-to-water / mechanical ventilation with heat recovery / hot water storage tank)...
Thanks
D
Daniel-Sp8 Jul 2020 09:50Bauherr am L schrieb:
Can you write a bit more? What is your heating load? What are the supply and return temperatures? What is the annual performance factor? Any subsidies?Supply and return temperatures as well as the annual performance factor do not depend solely on the device. Other factors include the outside temperature, the heat transfer coefficient (U-value) of the building envelope, and especially the often overlooked heat sink.B
Bauherr am L8 Jul 2020 11:35Daniel-Sp schrieb:
Supply and return temperatures as well as the annual performance factor do not depend solely on the device. Other factors include the NAT, the heat transfer coefficient (HT value) of the building envelope, and especially the often neglected heat sink. Is the heat sink the difference between supply and return temperatures?
But combined with the heat pump data, doesn’t that result in the annual performance factor?
What does NAT stand for and what exactly is the HT value?
D
Daniel-Sp8 Jul 2020 11:44In this context, the term heat sink refers to the underfloor heating system. NAT stands for the standard outside temperature, and HT ultimately describes the heat loss of the house to the outside, meaning how effective the overall insulation is.
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