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
A
Alessandro3 Nov 2021 12:57Hire an engineering firm. Just search online, send them the values (especially the desired room temperatures, otherwise everything will be calculated at 20°C (68°F)), pay 150 euros, and give it to the heating installer, done.
B
Benutzer2003 Nov 2021 13:01RotorMotor schrieb:
You can set it to 10, or you can leave it at 15,
That already makes a big difference – specifically in the supply temperature.
Alessandro schrieb:
Hire an engineering firm. Since I was banned from my previous accounts due to advertising and quoting, I will only say that you can easily search for IB Heck...mann. He is especially consulted in DIY communities (keyword Geisha). The DIYers really get into the topic.
Based on my own experience, I can recommend this engineering firm as well.
With my underfloor heating design, I can operate my old building with very moderate supply temperatures despite the lack of external thermal insulation composite system (ETICS).
A
Alessandro3 Nov 2021 13:03I hired this exact office myself and was very satisfied. It’s worth every cent.
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RotorMotor3 Nov 2021 13:42Benutzer200 schrieb:
That already makes a big difference – specifically in the flow temperature. I just tested it in one of our children’s rooms. Changing from 15 to 10cm (4 to 4 inches) reduces the flow temperature by 0.6 degrees.
However, the children’s room already has 100W too much heating capacity. Also, the loop length is 100m (330 feet). So the next question is, would it make sense to add another loop in that room? The tool gives no answer on this, and the installer thinks having 10 loops on the floor is already far too many...
Switching from parquet or carpet to vinyl or tiles lowers the flow temperature by 2.5 degrees!
No planner can beat physics.
Still, it’s definitely a worthwhile investment if you can convince the tradesperson to stick to it.
Unfortunately, compromises are often necessary, and you usually get quite far with general rules of thumb. :-)
H
Hausbau 553 Nov 2021 18:24RotorMotor schrieb:
Changing from parquet or carpet to vinyl or tiles results in a 2.5 degree lower supply temperature!
Your statement is interesting. I have a heating load calculation for our KfW Efficiency House 55 EE, which is being built as a bungalow (90 m² (970 sq ft)). Unfortunately, the desired supply temperature of 30°C (86°F) was not achieved. It ended up at 33°C (91°F). The temperature difference is 6 degrees, and by increasing the flow rate, I’m already getting a better supply temperature at 32/28°C (90/82°F).
In the heating load calculation, floor coverings were generally assumed to be parquet and thick tiles. We will now be using design vinyl throughout. According to your statement, should I be able to achieve the 30°C (86°F) supply temperature with this?
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RotorMotor3 Nov 2021 18:33Hausbau 55 schrieb:
Your statement is interesting. I have a heat load calculation for our KfW Efficiency House 55 EE, which will be built as a bungalow (90 m² (970 ft²)). Unfortunately, the desired supply temperature of 30°C (86°F) was not achieved. It ended up at 33°C (91°F). The temperature difference is 6 degrees, but by increasing the flow rate, I can already reach a better supply temperature at 32/28°C (90/82°F).
In the heat load calculation, floor coverings of parquet and thick tile were assumed as standard. Now we will be using design vinyl throughout. According to your statement, I should be able to achieve the supply temperature of 30°C (86°F) with that? Vinyl and tile are quite similar regarding thermal conductivity, but only if the vinyl is glued down without a carrier layer. Floating on a carrier, vinyl is more comparable to laminate.
Also, the supply temperature is not as fixed as it might seem, since it is always relative to the outdoor temperature.
It is quite possible that in your case 2 degrees less would suffice if you switch from parquet to glued vinyl!
However, this only applies if the room controlling the supply temperature is the one with the vinyl.
If, as is common, the bathrooms have the lowest heat output and are tiled, you don’t really gain anything by changing the other floors.
Because a radiant floor heating system is only as effective as its weakest link. 😉
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