ᐅ Heating Concept Air-to-Water Heat Pump for Single-Family Home with 2 Occupants – Quote from Heating Contractor?
Created on: 24 Apr 2022 10:40
E
Elias_dee
Good morning,
from October 2022, we will be building a turnkey single-family house for 2 people. The basic conditions are:
- Air-to-water heat pump
- Possibly a photovoltaic system (not yet confirmed)
- Central ventilation system with heat recovery
- The house will be occupied by 2 people
- Ground floor + upper floor + basement (partly used as living space)
- No KFW funding, standard build according to the Building Energy Act, 36.5 cm (14 inches) brickwork
The general contractor sent me the calculation and planned circuits from the heating engineer; see attachment. The calculation was based on 205 m² (2206 sq ft) living area x 0.035 -> 7.17 kW + 0.8 kW for hot water --> 8 kW
Safety factor 1.2 --> 9.6 kW
Based on this plan, the heating engineer offered through the general contractor the following:
- Weishaupt Biblock WBB 12-A-RMD-AI
- Combined storage tank WKS 300/100LE / Unit / Bloc / C, 300-liter (79 US gallons) domestic hot water tank and 100-liter (26 US gallons) buffer storage
- 12 room thermostats
I have done some reading here and elsewhere and understand that individual room regulation is pointless and that the circuits should be designed for the corresponding temperature from the start (at least that’s how I understood it; please correct me if I’m wrong).
Also, opinions appear divided on the topic of buffer storage tanks, but the tendency is that they are rather unnecessary. Honestly, I haven’t yet fully understood why. I keep reading that this kind of design can cause an air-to-water heat pump to wear out quickly and lead to high electricity consumption. The safety factor seems to have been set quite high by the heating engineer as well.
Without solid expertise in this area, I would prefer not to get into a debate with the heating engineer. Could you advise me on how the system concept for our single-family house could be better designed?
Thank you very much in advance!
Best regards,
Elias
from October 2022, we will be building a turnkey single-family house for 2 people. The basic conditions are:
- Air-to-water heat pump
- Possibly a photovoltaic system (not yet confirmed)
- Central ventilation system with heat recovery
- The house will be occupied by 2 people
- Ground floor + upper floor + basement (partly used as living space)
- No KFW funding, standard build according to the Building Energy Act, 36.5 cm (14 inches) brickwork
The general contractor sent me the calculation and planned circuits from the heating engineer; see attachment. The calculation was based on 205 m² (2206 sq ft) living area x 0.035 -> 7.17 kW + 0.8 kW for hot water --> 8 kW
Safety factor 1.2 --> 9.6 kW
Based on this plan, the heating engineer offered through the general contractor the following:
- Weishaupt Biblock WBB 12-A-RMD-AI
- Combined storage tank WKS 300/100LE / Unit / Bloc / C, 300-liter (79 US gallons) domestic hot water tank and 100-liter (26 US gallons) buffer storage
- 12 room thermostats
I have done some reading here and elsewhere and understand that individual room regulation is pointless and that the circuits should be designed for the corresponding temperature from the start (at least that’s how I understood it; please correct me if I’m wrong).
Also, opinions appear divided on the topic of buffer storage tanks, but the tendency is that they are rather unnecessary. Honestly, I haven’t yet fully understood why. I keep reading that this kind of design can cause an air-to-water heat pump to wear out quickly and lead to high electricity consumption. The safety factor seems to have been set quite high by the heating engineer as well.
Without solid expertise in this area, I would prefer not to get into a debate with the heating engineer. Could you advise me on how the system concept for our single-family house could be better designed?
Thank you very much in advance!
Best regards,
Elias
E
Elias_dee24 Apr 2022 21:49Benutzer200 schrieb:
Energy consultant:
Can only calculate energy needs but cannot size the heating system. For demand calculation and system design, you obviously need to specify temperatures – the standard everywhere is 20 degrees (68°F). However, it’s better to use 22 degrees (72°F) for living areas and 24 degrees (75°F) for the bathroom.
Also, aim for the lowest possible flow temperature – a good standard is 30 degrees (86°F) with 26 degrees (79°F) return temperature. With top insulation, even lower temperatures are possible. Heating pipes come in different sizes as well. A heat pump requires high flow rates, so use at least a 16mm (5/8 inch) pipe. Pipe spacing is also important; it should not exceed 10cm (4 inches). The length of heating circuits matters too.
An energy consultant cannot provide you with all this.
Therefore, I recommend searching online for Ing. Heckmann. He is highly recommended in another community focused on building services (you can find it quickly…).
He is basically THE expert for do-it-yourselfers (who often choose a Panasonic Aquarea, but that’s just a side note) who want to engage deeply with proper planning.
He can also provide you with a customized letter for waiving the ERR.
The total cost is transparent and only a few hundred euros (a few hundred €). That’s incomparable to the possible savings on heating costs and, of course, less material effort for the ERR (no materials, no installation, no additional electrical work). Thanks, those are very good tips. I’m happy to spend a few hundred euros for the engineering office. I’ll contact him early next week.
Elias_dee schrieb:
As mentioned, the floor plan is finalized, The basement stairs are drawn the wrong way around!
H
Hausbau 5525 Apr 2022 05:43Tolentino schrieb:
Be careful: bothering the heating technician with many questions and external planning can lead to them quitting. This happened to me.
However, under certain circumstances, this might not be the worst outcome. I can only support this opinion. I also did a lot of research and went to the heating installer of my general contractor with many arguments. The result was that he became overwhelmed and informed the general contractor that he could not carry out our construction project. In such a situation, you quickly reach your limits. Fortunately, the relationship normalized again after a three-way conversation. And I did not have a heating load calculation from the engineering office Heckmann—for that reason, the collaboration probably would have failed. Forget the suggestion from the "user"; it is not helpful in the current situation. Try to get in personal contact with the heating installer and work with him to implement your key points. But you must also be prepared for additional costs. You can find many tips online regarding the design of the heat pump and especially the underfloor heating system. One small example: for your entire house, you only have 12 heating circuits so far; we have 13 heating circuits in our small bungalow with 90 sqm (970 sq ft). A “somewhat unsuitable” heat pump can at worst still be replaced later. A poorly designed underfloor heating system stays in place forever. But take both seriously.
Similar topics