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
D
Daniel-Sp6 Aug 2020 23:43Hm, can you check that with the energy consultant?
D
Daniel-Sp6 Aug 2020 23:49I just read that it also has to be included in the energy performance certificate according to the Energy Saving Ordinance.
D
Daniel-Sp6 Aug 2020 23:51And then Google "Trenchplaner ring trench collector".
S
Strahleman7 Aug 2020 07:19Pixelsurium schrieb:
Building envelope area: 559.65 m2 (6019 ft2)
Building volume: 726.44 m3 (25643 ft3)
Heated air volume: 552.09 m3 (19497 ft3)
Desired temperature: 20-21°C (68-70°F)
Occupants: Currently: 2 + 1 child + possible granny flat (let's assume max. 5-6)
Ventilation: None Using this data in the Trenchplanner with a fairly conservative H,t-value of 0.3 W/m²K results in a heating load of 7.2 kW without a ventilation system and 6 kW with a central controlled residential ventilation system.
It is important that you determine the H,t-value of the house (best to consult an energy advisor and have the H,t-values of the individual building components as well as the overall H,t-value provided). An improvement of 0.05 W/m²K can already reduce the heating load by almost 1 kW. If you build without controlled residential ventilation, the H,t-value should be optimized as much as possible. As you can see, heating without controlled ventilation loses a significant amount of energy through uncontrolled air exchange (about 1.3 kW annually with regulation-compliant ventilation).
And an Ht value of 0.3 is really a very conservative assumption... Quite unworthy of a new build, it will definitely be better.
Even without a ventilation system, a 6 kW air-to-water heat pump should be able to keep a 180 sqm (1,938 sq ft) new build warm at all times. Also keep in mind that internal gains (from devices, occupants, etc.) are not considered in the calculations, so the actual heating load is even lower than calculated.
In the end, only a proper heating load calculation will help you, without safety margins. You will need this anyway for the correct sizing of the underfloor heating.
And a tip: if you still have the chance, install a central ventilation system. Regardless of the heating load, there is nothing that offers such a high increase in comfort in a new build. Fresh air after getting up, even in the middle of winter. No need to ventilate by opening windows... I don’t know anyone who has regretted the decision to install a controlled ventilation system, but many who later regret not having done so.
The only downside: once you’ve lived in a house with controlled ventilation, you won’t want anything else.
Even without a ventilation system, a 6 kW air-to-water heat pump should be able to keep a 180 sqm (1,938 sq ft) new build warm at all times. Also keep in mind that internal gains (from devices, occupants, etc.) are not considered in the calculations, so the actual heating load is even lower than calculated.
In the end, only a proper heating load calculation will help you, without safety margins. You will need this anyway for the correct sizing of the underfloor heating.
And a tip: if you still have the chance, install a central ventilation system. Regardless of the heating load, there is nothing that offers such a high increase in comfort in a new build. Fresh air after getting up, even in the middle of winter. No need to ventilate by opening windows... I don’t know anyone who has regretted the decision to install a controlled ventilation system, but many who later regret not having done so.
The only downside: once you’ve lived in a house with controlled ventilation, you won’t want anything else.
T
T_im_Norden7 Aug 2020 07:51If I have read it correctly, the ID assumes 5566 kW.
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