ᐅ Different Statements from General Contractor / Construction Supervisor Regarding Heating
Created on: 25 Apr 2018 08:21
Y
YoschiHello 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
H
HilfeHilfe25 Apr 2018 08:32Regarding the air source heat pump, it operates according to demand (heating or hot water). I believe it can also be set to run only in the mornings and evenings. However, if a family of four wants to take long showers around 2 p.m. (14:00), it may happen that only cold water is available...
Basically, energy costs money regardless of the form it comes in.
Basically, energy costs money regardless of the form it comes in.
Basically, these are all generalizations and therefore completely incorrect statements.
If you want to build with radiators, which I strongly advise against, I would recommend gas. Although the supply temperature (not preheating time) is important for efficiency, it matters much less for gas than for a heat pump.
I would always operate heat pumps (in new construction) only with underfloor heating. However, the underfloor heating must be designed for this. Supply temperatures of 38°C (100°F) are too high to remain efficient.
Gas, on the other hand, is very undemanding, and with current prices, you might break even compared to a heat pump. This is because costs such as connection fees, maintenance, standing charges, and chimney sweeping have a relatively high impact on the total cost calculation when consumption is low.
Additionally, many companies charge substantial extra costs for heat pumps, although this is unnecessary.
Specifically, for me in new construction, if the heat pump is offered at a much higher price than the gas heating system, I would choose gas.
What is important for all types is the underfloor heating. A room-by-room heating load calculation is required. The underfloor heating is then designed accordingly. Future-proof values would be, for example, 30/26/21. This means a 30°C (86°F) supply temperature, 26°C (79°F) return temperature at 21°C (70°F) room temperature. You can set these within certain limits for each room; at least the room temperature.
For your information: I am also an amateur but have been dealing quite intensively with building services engineering for 8 years.
All suggestions assume no personal labor involved. If some personal work were desired, there would be one or two additional options.
If you want to build with radiators, which I strongly advise against, I would recommend gas. Although the supply temperature (not preheating time) is important for efficiency, it matters much less for gas than for a heat pump.
I would always operate heat pumps (in new construction) only with underfloor heating. However, the underfloor heating must be designed for this. Supply temperatures of 38°C (100°F) are too high to remain efficient.
Gas, on the other hand, is very undemanding, and with current prices, you might break even compared to a heat pump. This is because costs such as connection fees, maintenance, standing charges, and chimney sweeping have a relatively high impact on the total cost calculation when consumption is low.
Additionally, many companies charge substantial extra costs for heat pumps, although this is unnecessary.
Specifically, for me in new construction, if the heat pump is offered at a much higher price than the gas heating system, I would choose gas.
What is important for all types is the underfloor heating. A room-by-room heating load calculation is required. The underfloor heating is then designed accordingly. Future-proof values would be, for example, 30/26/21. This means a 30°C (86°F) supply temperature, 26°C (79°F) return temperature at 21°C (70°F) room temperature. You can set these within certain limits for each room; at least the room temperature.
For your information: I am also an amateur but have been dealing quite intensively with building services engineering for 8 years.
All suggestions assume no personal labor involved. If some personal work were desired, there would be one or two additional options.
Yoschi schrieb:
Gas vs. Geothermal
Company 1: Geothermal would not be cost-effective. Gas costs are around 70 to 80 € per month.
Electricity costs for heating are around 50 to 60 € per month.
This results in a difference of about 20 €.
However, since the initial investment for the geothermal heat pump is too high, it would not be worthwhile to install one. Geothermal energy takes a very long time to pay off, if at all. The main motivation here is usually environmental concerns, or if you want to achieve a specific energy efficiency standard like KfW, which is difficult to reach with gas without many additional measures. Since Company 1 handles the trades themselves and argues this way, they are primarily focused on selling gas heating systems.
Yoschi schrieb:
Company 2 also told me that gas heating should only be operated with underfloor heating, because the new gas heaters have an extremely low “preheat temperature” (I hope you know what I mean) of 38 degrees,
so my radiators would never get properly warm. Complete nonsense. Of course, gas heating systems can be operated with higher flow temperatures if you want to have radiators throughout the house. Unlike an air-source heat pump, gas heating is less inefficient at higher flow temperatures.
Yoschi schrieb:
Company 2 offered me an air-source heat pump, which would be cheaper in the end since I would save on the gas connection and the pump or the fan outside would only run in the morning and evening. Also nonsense. It’s true that hot water demand is often higher in the morning or evening, so the system works most then. However, a heat pump operates more efficiently when it runs more evenly. Especially during the day, when outside temperatures are highest, it can operate more efficiently than during the cooler night or morning hours.
If a photovoltaic system is installed, it can even make sense to heat more during the day to increase self-consumption.
Joedreck schrieb:
All suggestions are without any personal labor. If some degree of personal work was desired, there would be one or two additional options.I would be interested in those 🙂
Specki schrieb:
I would be interested in those 🙂My tip: trench collector
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