Hello everyone,
For our planned new build, we have received two offers regarding a heating system.
The prices are almost identical. I do not want to post the complete technical descriptions yet.
Both are air-to-water heat pumps.
Offer A:
iPump A 2-7 heat pump, split system with inverter-controlled rolling piston compressor
The iPump A 2-7 includes a domestic hot water tank with a 200-liter (53-gallon) capacity
Heating performance at A2°/W35°C: Performance range (min/max): 2.06–7.55 kW
Nominal power / CoP: 3.90 kW / 4.42
Offer B:
Stiebel air-to-water heat pump WPL 17 ACS
Classic Flex Set
Heating capacity at A-7/W35 (EN 14511) 7.8 kW
Heating capacity at A2/W35 (EN 14511) 5.73 kW
Inverter-controlled air-to-water heat pump for outdoor installation
Stiebel buffer tank SBP 100, 100 liters (26 gallons)
Can anyone share any information about these two products? Any experience? The manufacturer iDM is completely unknown to me so far.
What surprises me a bit is the size comparison of the outdoor units. The iPump is almost twice as large as the Stiebel.
I would be very grateful for any feedback.
For our planned new build, we have received two offers regarding a heating system.
The prices are almost identical. I do not want to post the complete technical descriptions yet.
Both are air-to-water heat pumps.
Offer A:
iPump A 2-7 heat pump, split system with inverter-controlled rolling piston compressor
The iPump A 2-7 includes a domestic hot water tank with a 200-liter (53-gallon) capacity
Heating performance at A2°/W35°C: Performance range (min/max): 2.06–7.55 kW
Nominal power / CoP: 3.90 kW / 4.42
Offer B:
Stiebel air-to-water heat pump WPL 17 ACS
Classic Flex Set
Heating capacity at A-7/W35 (EN 14511) 7.8 kW
Heating capacity at A2/W35 (EN 14511) 5.73 kW
Inverter-controlled air-to-water heat pump for outdoor installation
Stiebel buffer tank SBP 100, 100 liters (26 gallons)
Can anyone share any information about these two products? Any experience? The manufacturer iDM is completely unknown to me so far.
What surprises me a bit is the size comparison of the outdoor units. The iPump is almost twice as large as the Stiebel.
I would be very grateful for any feedback.
T
T_im_Norden9 Nov 2020 12:50It’s always about the design temperature, or natural temperature.
If the heating system is calculated for a 30°C (86°F) supply temperature, the rooms have to be arranged accordingly.
In most cases, this means covering a larger surface area than at 35°C (95°F). As a result, the supply temperature in actual operation will naturally also drop accordingly.
I spoke with a tradesperson today who can operate their Nibe heat pump with a 23/24°C (73/75°F) supply temperature.
If the heating system is calculated for a 30°C (86°F) supply temperature, the rooms have to be arranged accordingly.
In most cases, this means covering a larger surface area than at 35°C (95°F). As a result, the supply temperature in actual operation will naturally also drop accordingly.
I spoke with a tradesperson today who can operate their Nibe heat pump with a 23/24°C (73/75°F) supply temperature.
N
neo-sciliar9 Nov 2020 13:22T_im_Norden schrieb:
It always comes down to the design temperature, meaning the outdoor design temperature.
If the heating system is calculated for a supply temperature of 30°C (86°F), the rooms must be equipped accordingly.
This usually means covering a larger floor area than with 35°C (95°F). As a result, the actual supply temperature during operation naturally decreases accordingly.
I just spoke today with a technician who can run his Nibe heat pump at 23/24°C (73/75°F) supply temperature. That sounds logical: the closer the underfloor heating pipes are spaced, the larger the area covered, the lower the supply temperature. But try explaining that to a homeowner as a layperson. Especially one who is set on certain things because the general contractor hired them.
Of course, you can remove the heating system from the general contractor’s package. Consequences: no warranty, no overall package management (an independent energy consultant is necessary for KfW), risk of not finding a tradesperson quickly, and so on.
This just happened to me. The (only!!!) HVAC and plumbing subcontractor working under my general contractor dropped out because I wanted an efficient design and installation plan. I was even willing to provide a new plan from the building services engineer myself, but without any explanation, he informed me that he will not be carrying out my project.
Also see here:
https://www.hausbau-forum.de/threads/heizlastberechnung-verlegeplan-din-neue-berechnung-notwendig.36961/post-445657
https://www.hausbau-forum.de/threads/lage-stadtvilla-oder-efh-auf-500-m2-rechteck.33505/post-446544
Also see here:
https://www.hausbau-forum.de/threads/heizlastberechnung-verlegeplan-din-neue-berechnung-notwendig.36961/post-445657
https://www.hausbau-forum.de/threads/lage-stadtvilla-oder-efh-auf-500-m2-rechteck.33505/post-446544
T
T_im_Norden9 Nov 2020 14:24As Tolentino already mentioned, it depends on the general contractor (GC) and the homeowner builder (HB).
My HB also hinted at being a bit of a “difficult customer” for the GC but still did everything the way I wanted, although he was well prepared from the start.
Since I have a direct contractual relationship, even though everything is organized and scheduled through the GC, it was easier for me.
The price was simply adjusted according to the additional work, and then everything proceeded smoothly.
My HB also hinted at being a bit of a “difficult customer” for the GC but still did everything the way I wanted, although he was well prepared from the start.
Since I have a direct contractual relationship, even though everything is organized and scheduled through the GC, it was easier for me.
The price was simply adjusted according to the additional work, and then everything proceeded smoothly.
T
T_im_Norden9 Nov 2020 14:30For the heat pump, I would ask about that. 9 kW is a lot, and a minimum capacity of 5 kW is also quite high.
T_im_Norden schrieb:
Can operate at a flow temperature of 23/24 degrees.I believe @Ötzi Ötztaler is running 24.5 with a hysteresis of 1, from what I have read. I am personally running my on-off heat pump at 27/22.Similar topics