ᐅ Different Statements from General Contractor / Construction Supervisor Regarding Heating
Created on: 25 Apr 2018 08:21
Y
Yoschi
Hello dear forum,
I know this topic has been discussed many times, but due to differing statements, we are quite confused.
We are currently planning a single-family house, 120-130 sqm (1292-1399 sq ft) which is enough for us,
2 full floors, turnkey,
solid construction, no basement.
Now the topic of heating has come up.
A brief note about the companies:
Company 1: Does everything in-house or has the trades within the company.
Company 2: Works only with subcontractors from the region.
Which heating system should we choose?
We had a brief explanation about the options and how they work.
Gas vs. geothermal
Company 1: Said geothermal would not be worthwhile. Gas costs are about 70 to 80 euros per month (about $)
Electricity costs for heating about 50 to 60 euros per month (about $).
That makes a difference of about 20 euros.
But since the initial investment for the geothermal heat pump is too high, it would not be worth installing one.
Company 2: What kind of heating do you want?
Gas!
Why?
I explained to them what Company 1 told me.
They said that is wrong, often such statements are made because people don’t know better or are not allowed or able to install it.
Also, Company 2 told me that gas heating should only be used with underfloor heating because the new gas heating systems have an extremely low "supply temperature" (I hope you understand what I mean) of 38°C (100°F), so my radiators would never get properly warm.
And they would probably sell me an old technology system.
Company 1, for example, did not tell me that.
Company 2 offered me an air-source heat pump, which would be cheaper in the long run since I would save the gas connection, and the pump or the fan outside would only run in the mornings and evenings.
Is that correct?
Best regards
I know this topic has been discussed many times, but due to differing statements, we are quite confused.
We are currently planning a single-family house, 120-130 sqm (1292-1399 sq ft) which is enough for us,
2 full floors, turnkey,
solid construction, no basement.
Now the topic of heating has come up.
A brief note about the companies:
Company 1: Does everything in-house or has the trades within the company.
Company 2: Works only with subcontractors from the region.
Which heating system should we choose?
We had a brief explanation about the options and how they work.
Gas vs. geothermal
Company 1: Said geothermal would not be worthwhile. Gas costs are about 70 to 80 euros per month (about $)
Electricity costs for heating about 50 to 60 euros per month (about $).
That makes a difference of about 20 euros.
But since the initial investment for the geothermal heat pump is too high, it would not be worth installing one.
Company 2: What kind of heating do you want?
Gas!
Why?
I explained to them what Company 1 told me.
They said that is wrong, often such statements are made because people don’t know better or are not allowed or able to install it.
Also, Company 2 told me that gas heating should only be used with underfloor heating because the new gas heating systems have an extremely low "supply temperature" (I hope you understand what I mean) of 38°C (100°F), so my radiators would never get properly warm.
And they would probably sell me an old technology system.
Company 1, for example, did not tell me that.
Company 2 offered me an air-source heat pump, which would be cheaper in the long run since I would save the gas connection, and the pump or the fan outside would only run in the mornings and evenings.
Is that correct?
Best regards
B
Bieber081525 Apr 2018 11:54I find #3 very helpful! A few comments:
Since the questioner is talking to two companies, I assume he is the landowner. This means he is in the fortunate position of having a free choice. He decides which technology to use. After that, he looks for the right craftsman. Not the other way around: first the contractor, then the technology.
Roughly speaking, there are:
- Gas condensing boilers
- Air-to-water heat pumps
- Ground-source heat pumps (either deep borehole or horizontal trench collector)
- Groundwater heat pumps
- Exhaust air heat pumps
- Pellet heating systems
- District heating
- Combined heat and power units
- ...
In any case, I see (as already mentioned) a low-temperature underfloor heating system as the basis! In addition, the system should be designed according to the water demand (showers, etc.).
Besides investment and operating costs, legal requirements play a role, such as energy-saving regulations and renewable energy heating laws. This means the heating system is connected with measures like solar thermal systems, controlled ventilation with heat recovery, building envelope insulation, window quality, etc. And not only through technical dependencies (insulation – energy demand) but also through regulatory conditions. Additional requirements, such as those from KfW funding programs, may also apply.
In these matters, the heating installer is not the primary source of advice; rather, it is the architect or, better yet, the energy consultant who can help!
DIY work can be incorporated everywhere (for example, laying the heating loops). In my opinion, trench collectors are often brought into play for DIY because without self-labor they can quickly become very expensive.
Since the questioner is talking to two companies, I assume he is the landowner. This means he is in the fortunate position of having a free choice. He decides which technology to use. After that, he looks for the right craftsman. Not the other way around: first the contractor, then the technology.
Roughly speaking, there are:
- Gas condensing boilers
- Air-to-water heat pumps
- Ground-source heat pumps (either deep borehole or horizontal trench collector)
- Groundwater heat pumps
- Exhaust air heat pumps
- Pellet heating systems
- District heating
- Combined heat and power units
- ...
In any case, I see (as already mentioned) a low-temperature underfloor heating system as the basis! In addition, the system should be designed according to the water demand (showers, etc.).
Besides investment and operating costs, legal requirements play a role, such as energy-saving regulations and renewable energy heating laws. This means the heating system is connected with measures like solar thermal systems, controlled ventilation with heat recovery, building envelope insulation, window quality, etc. And not only through technical dependencies (insulation – energy demand) but also through regulatory conditions. Additional requirements, such as those from KfW funding programs, may also apply.
In these matters, the heating installer is not the primary source of advice; rather, it is the architect or, better yet, the energy consultant who can help!
DIY work can be incorporated everywhere (for example, laying the heating loops). In my opinion, trench collectors are often brought into play for DIY because without self-labor they can quickly become very expensive.
Yoschi schrieb:
@Bieber0815
So, you mean: underfloor heating with gas or air-to-water heat pumpSort of:
- Underfloor heating – can be implemented in all variations using the system temperatures mentioned above (30/26/21°C (86/79/70°F))
- Gas condensing boiler needs to be combined with a renewable energy source to comply with the energy saving regulations. Solar thermal for domestic hot water is often promoted because it’s usually the cheapest option. However, in your case, I would have the energy consultant compare photovoltaic or ventilation with heat recovery.
- Air-to-water heat pump: the next most affordable option after gas, but it absolutely requires proper sizing of the heating surfaces and correct dimensioning of the heat pump. Search online for "There is no fire burning in a heat pump." Unfortunately, very few HVAC installers truly understand this. Also, pay attention to noise levels and maintain adequate distances from bedrooms and neighbors!
- Geothermal: actually the "best" option, but usually the most expensive due to high costs of deep drilling. If interested and skilled, building a trench collector yourself can be cost-effective.
B
Bieber081525 Apr 2018 14:20The disadvantage of a trench collector is its space requirement and the associated usage limitations. For 450m² (4844 sq ft) plots, this would be a deal-breaker for me. For 1500m² (16146 sq ft) park areas, it is not an issue if planned well.
@Bieber0815 why should a trench collector be excluded for 450m² (4844 ft²)?
What kind of usage restriction are you referring to?
Or to put it another way... feel free to look up ring trench collectors and read through the related discussions in the forum you find... several collectors of this size have already been implemented there.
What kind of usage restriction are you referring to?
Or to put it another way... feel free to look up ring trench collectors and read through the related discussions in the forum you find... several collectors of this size have already been implemented there.
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