Hello everyone,
We just had a conversation with the company responsible for our heating and plumbing installation.
First of all – we are building a large single-family house with a basement, two full floors, and a hipped roof with a 22° (22 degrees) pitch. Wall construction is 17.5 cm (7 inches) sand-lime brick, insulation with mineral wool, plus a brick façade.
We are building according to the 2012 Energy Saving Ordinance (EnEV 2012) and are not aiming to achieve a higher standard.
Our original plan was:
- Gas heating with underfloor heating on all levels, no wall-mounted radiators, and a central mechanical ventilation system with heat recovery.
Now, after the discussion, I’m totally confused. The company recommends:
- Heating via an air-to-air heat pump, solar thermal for hot water, plus gas to support hot water
- Underfloor heating only on the ground floor and first floor, excluding children’s rooms and bedrooms (to avoid overheating during sleep), with the rest heated by wall-mounted radiators on a second heating circuit
- No mechanical ventilation system with heat recovery due to noise issues
I can understand reconsidering the mechanical ventilation system because of potential constant noise and airflow, so we might want to think that over.
But I’ve never heard of combining a heat pump, gas, and solar thermal in one system!
Solar thermal is said to be uneconomical anyway, especially with a roof pitch of only 22° (22 degrees), right? We also don’t have a direct south-facing roof orientation. Does anyone have links or information about the economic viability?
Our main priorities are comfort; cost and economic efficiency are not the primary focus, but I don’t want to end up building something completely pointless either. The problem is, we need some sort of renewable energy source to comply with the Energy Saving Ordinance. The thermal protection report is not available yet, but I definitely need some concrete information for the next meeting. It would be great if someone could help!
We just had a conversation with the company responsible for our heating and plumbing installation.
First of all – we are building a large single-family house with a basement, two full floors, and a hipped roof with a 22° (22 degrees) pitch. Wall construction is 17.5 cm (7 inches) sand-lime brick, insulation with mineral wool, plus a brick façade.
We are building according to the 2012 Energy Saving Ordinance (EnEV 2012) and are not aiming to achieve a higher standard.
Our original plan was:
- Gas heating with underfloor heating on all levels, no wall-mounted radiators, and a central mechanical ventilation system with heat recovery.
Now, after the discussion, I’m totally confused. The company recommends:
- Heating via an air-to-air heat pump, solar thermal for hot water, plus gas to support hot water
- Underfloor heating only on the ground floor and first floor, excluding children’s rooms and bedrooms (to avoid overheating during sleep), with the rest heated by wall-mounted radiators on a second heating circuit
- No mechanical ventilation system with heat recovery due to noise issues
I can understand reconsidering the mechanical ventilation system because of potential constant noise and airflow, so we might want to think that over.
But I’ve never heard of combining a heat pump, gas, and solar thermal in one system!
Solar thermal is said to be uneconomical anyway, especially with a roof pitch of only 22° (22 degrees), right? We also don’t have a direct south-facing roof orientation. Does anyone have links or information about the economic viability?
Our main priorities are comfort; cost and economic efficiency are not the primary focus, but I don’t want to end up building something completely pointless either. The problem is, we need some sort of renewable energy source to comply with the Energy Saving Ordinance. The thermal protection report is not available yet, but I definitely need some concrete information for the next meeting. It would be great if someone could help!
B
Bauexperte12 May 2015 22:03bortel schrieb:
Wouldn't a domestic hot water heat pump also work in the case of the original poster? In a new build? I know, it's the latest "gadget" from plumbing and heating companies.
Regards, Bauexperte
Thank you all again!
Tomorrow we have a meeting with the architect, which should help us a lot. Also, I just came across the comment from Bauexperte about the 15% requirement, where the heating specialists apparently referred to a 2016 energy-saving regulation house, because one of them said we need 30% renewable energy.
So everything is quite confusing and not properly coordinated. We still need to clarify a lot.
@Bauexperte
A few more remarks, I’ll get to the other issues tomorrow, I’m too tired now...
- What do you mean by children “evaporating” at 22°C (72°F) with underfloor heating? Do you think that’s too warm? That’s very subjective. We currently have a very poorly adjusted underfloor heating in our rental apartment with tiles that get really, really warm (definitely above 30°C (86°F), maybe even 35°C (95°F)). The room temperature in winter is usually around 24°C (75°F), and I wouldn’t want it any colder. I like to walk around in a thin shirt even during winter. I don’t even own regular sweaters.
- Regarding the basement: you said it would be costly to keep the underfloor heating permanently at 17–18°C (63–64°F). Is underfloor heating really that much more expensive than individual radiators during construction?
- Construction time – we are currently planning 10 to 12 months (I would prefer 10, the architect and others want 12 or more). The shell construction should not stay unfinished all winter. The screed definitely needs 28 days to dry, and then the heating-up phase will start.
One silly question – in a well-insulated house with a heat pump, no gas, and solar panels, how is the domestic hot water heated? The underfloor heating has a supply temperature of only about 30°C (86°F), which is reached by the heat pump, right? Does the rest come from regular electricity?
Tomorrow we have a meeting with the architect, which should help us a lot. Also, I just came across the comment from Bauexperte about the 15% requirement, where the heating specialists apparently referred to a 2016 energy-saving regulation house, because one of them said we need 30% renewable energy.
So everything is quite confusing and not properly coordinated. We still need to clarify a lot.
@Bauexperte
A few more remarks, I’ll get to the other issues tomorrow, I’m too tired now...
- What do you mean by children “evaporating” at 22°C (72°F) with underfloor heating? Do you think that’s too warm? That’s very subjective. We currently have a very poorly adjusted underfloor heating in our rental apartment with tiles that get really, really warm (definitely above 30°C (86°F), maybe even 35°C (95°F)). The room temperature in winter is usually around 24°C (75°F), and I wouldn’t want it any colder. I like to walk around in a thin shirt even during winter. I don’t even own regular sweaters.
- Regarding the basement: you said it would be costly to keep the underfloor heating permanently at 17–18°C (63–64°F). Is underfloor heating really that much more expensive than individual radiators during construction?
- Construction time – we are currently planning 10 to 12 months (I would prefer 10, the architect and others want 12 or more). The shell construction should not stay unfinished all winter. The screed definitely needs 28 days to dry, and then the heating-up phase will start.
One silly question – in a well-insulated house with a heat pump, no gas, and solar panels, how is the domestic hot water heated? The underfloor heating has a supply temperature of only about 30°C (86°F), which is reached by the heat pump, right? Does the rest come from regular electricity?
The comment about 22 degrees and evaporation was meant as a joke, since that’s what your family mentioned.
A heat pump can produce water up to 60°C (140°F) hot, but it is effectively limited to a maximum of 50°C (122°F).
If your insulation isn’t especially good, choose a brine-to-water heat pump with trench or surface collector if you decide not to use a gas condensing boiler.
But all of this should become clearer after the HLB...
A heat pump can produce water up to 60°C (140°F) hot, but it is effectively limited to a maximum of 50°C (122°F).
If your insulation isn’t especially good, choose a brine-to-water heat pump with trench or surface collector if you decide not to use a gas condensing boiler.
But all of this should become clearer after the HLB...
B
Bauexperte12 May 2015 23:09Good evening,
Nowadays, installing underfloor heating is hardly more expensive; if at all.
Regards, Bauexperte
Panama17 schrieb:No – that is correct. Compared to the 2007 energy saving regulation, the 2009 regulation requires the annual primary energy demand to be 30% lower; the new building components must achieve energy performance values that are 30% better than those required by the 2007 energy saving regulation.
Also, I came across Bauexperte’s 15% comment where the heating guys apparently referred to a 2016 energy saving regulation house, because one of them said we needed 30% renewable energy.
Panama17 schrieb:I have to disagree with the previous poster – “22° and boiling” was not a joke. With tightly spaced heating coils, that is already quite a lot. You will find out yourself; supply temperature. It may be (even for you, with your heat requirements) too warm. It is, as mentioned, no comparison to how it used to be.
- What do you mean by “at 22°C (72°F) with underfloor heating the kids would be boiling”? Do you mean it would be too warm? That’s quite subjective. Currently, in our rental flat, the underfloor heating is set very poorly, with the tiles getting really, really hot (definitely over 30°C (86°F), maybe even 35°C (95°F)). The room temperature in winter is usually 24°C (75°F), and I wouldn’t want it much colder. I like to walk around in a thin shirt even in winter. I don’t even own regular sweaters.
Panama17 schrieb:An example: if you want to keep a water boiler at a constant temperature, what do you do? Right, you heat it up and then turn the control down so that your desired temperature is maintained; the water simmers. This is the same for heated rooms, no matter where in the house. It is much more cost-effective to hold a set temperature than to reheat from cold. Why? When the water has cooled down, it costs significantly more electricity to get back up to the desired temperature.
- About the basement: they said it would be expensive to keep the underfloor heating constantly at 17-18°C (63-64°F). Is underfloor heating really so much more expensive to install than individual radiators?
Nowadays, installing underfloor heating is hardly more expensive; if at all.
Panama17 schrieb:That long? The screed drying time is (almost) right; in my opinion, 21 days is sufficient.
- Construction time – we are currently planning for 10-12 months (I would prefer 10, the architect and others say 12 or more), and the shell should not stand through the entire winter. The screed should definitely dry for 28 days, and then there is apparently a heating-up program.
Panama17 schrieb:Either by a closed system – the domestic hot water tank and the indoor unit of the heat pump form a unit – or by a separate domestic hot water storage tank. In both cases, the "hot" water rises to the top (physics) and supplies the warm water for the tub/shower.
One more silly question – in a house with very good insulation, a heat pump without gas, and solar – how is the hot water heated then? The underfloor heating only has a supply temperature of about 30°C (86°F), which is reached by the heat pump, correct? And the rest is from regular electricity?
Regards, Bauexperte
Bauexperte schrieb:
In new construction? I know, it’s the latest "gadget" in plumbing and heating companies.
Regards, BauexperteWhat do you mean by that?
Would you prefer solar over an air-to-water heat pump?
D
Doc.Schnaggls13 May 2015 09:07Hello,
In our house, we have an air-to-water heat pump combined with a controlled mechanical ventilation system.
The upper floor, ground floor, guest room in the basement, and the hallway are heated using a hydronic underfloor heating system. Our hot water is also produced by the air-to-water heat pump.
I consider solar water heating or even an additional gas heater for water heating completely unnecessary.
Instead, we installed a 4.25 kWp photovoltaic system with surplus feed-in on the roof. So far (heating has been running since November 2014), we have drawn almost exactly as much electricity from the grid as we have fed in – and this includes the screed drying program and three months of interior construction work.
Therefore, in my opinion, a photovoltaic system makes much more sense than anything else.
I would never want to go without the controlled mechanical ventilation system – stale air, especially in the bedrooms, is a thing of the past. Yes, you can hear the system if you listen very closely and it is completely quiet in the house. But the quiet noise is not really disturbing. Nobody feels any drafts in our home either.
Regards,
Dirk
In our house, we have an air-to-water heat pump combined with a controlled mechanical ventilation system.
The upper floor, ground floor, guest room in the basement, and the hallway are heated using a hydronic underfloor heating system. Our hot water is also produced by the air-to-water heat pump.
I consider solar water heating or even an additional gas heater for water heating completely unnecessary.
Instead, we installed a 4.25 kWp photovoltaic system with surplus feed-in on the roof. So far (heating has been running since November 2014), we have drawn almost exactly as much electricity from the grid as we have fed in – and this includes the screed drying program and three months of interior construction work.
Therefore, in my opinion, a photovoltaic system makes much more sense than anything else.
I would never want to go without the controlled mechanical ventilation system – stale air, especially in the bedrooms, is a thing of the past. Yes, you can hear the system if you listen very closely and it is completely quiet in the house. But the quiet noise is not really disturbing. Nobody feels any drafts in our home either.
Regards,
Dirk
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