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
RotorMotor schrieb:
Isn't that what is usually done? I believe that’s the main issue. It deviates from the standard and is new—similar to the heating load calculation. You don’t make money dealing with tedious details, especially when, like in our case, it has to be done twice.
Additionally, our general contractor is worried about cracks in the plaster and the resulting warranty claims.
Hello everyone,
we are currently in the process of choosing an air-to-water heat pump as well, but I’m a bit overwhelmed because the offers vary widely.
Our single-family house (KfW55) plus a secondary apartment and heated basement will have a total heated area of about 290m² (3120 sq ft). According to the Energy Saving Ordinance, the heating demand is 0.276 W/(m²K). By my calculation, that would be 8kW. If I assume 6 people x 0.25kW for domestic hot water, that adds another 1.5kW, so a heat pump with 9.5 – 10kW should be sufficient.
Where is my mistake? One supplier offered me a 14kW Daikin 3M heat pump. Did they simply ignore my Energy Saving Ordinance values and assume too high a heating requirement, or am I missing something?
My second question concerns the buffer tank:
One supplier says that 100 liters (26 gallons) of buffer tank is enough because the underfloor heating already stores a lot of water, while another insists that 500 liters (132 gallons) are needed to keep the cycling frequency low. I would really appreciate your assessment.
Good luck
we are currently in the process of choosing an air-to-water heat pump as well, but I’m a bit overwhelmed because the offers vary widely.
Our single-family house (KfW55) plus a secondary apartment and heated basement will have a total heated area of about 290m² (3120 sq ft). According to the Energy Saving Ordinance, the heating demand is 0.276 W/(m²K). By my calculation, that would be 8kW. If I assume 6 people x 0.25kW for domestic hot water, that adds another 1.5kW, so a heat pump with 9.5 – 10kW should be sufficient.
Where is my mistake? One supplier offered me a 14kW Daikin 3M heat pump. Did they simply ignore my Energy Saving Ordinance values and assume too high a heating requirement, or am I missing something?
My second question concerns the buffer tank:
One supplier says that 100 liters (26 gallons) of buffer tank is enough because the underfloor heating already stores a lot of water, while another insists that 500 liters (132 gallons) are needed to keep the cycling frequency low. I would really appreciate your assessment.
Good luck
R
RotorMotor7 Jul 2021 10:4714 sounds way too large.
500l (130 gallons) buffer tank anyway.
It's best to calculate yourself using the heat pump consumption database Energy Saving Ordinance - heating load.
500l (130 gallons) buffer tank anyway.
It's best to calculate yourself using the heat pump consumption database Energy Saving Ordinance - heating load.
N
nordanney7 Jul 2021 11:28mete111 schrieb:
What should I do regarding the buffer tank? We have planned for individual room control. How large should the buffer tank be sized? Normally, a buffer tank is not installed.
What you need is a hot water storage tank for potable/shower water supply (in whatever form). That is completely different from a buffer tank.
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