ᐅ Which heating system is best for a newly built single-family home in 2011?
Created on: 27 Jul 2010 08:42
B
Bulla2000B
Bulla200027 Jul 2010 08:42After making progress in finding a building plot, we are now facing the challenge of choosing the right heating system. The representative from Ambiente Massivhaus said that only once the plot and house are finalized will they perform a heating surface calculation and heating demand calculation (or whatever it’s called). A floor heating system will definitely be installed.
He recommends an air-source heat pump system with a direct expansion evaporator. The residential area is connected to natural gas.
Now my question is: based on what I read, there seems to be no solid reason to install an air-source heat pump. Very low performance in winter (maybe global warming will help), poor annual performance factor compared to ground collectors and probes, and high noise levels due to the large air volume movement. Additionally, there are high electricity costs in winter because of the backup heater/electric heating element. The alternatives mentioned above would be better. Only, a heat pump with ground collectors also costs significantly more, mainly due to the excavation work. Our house will have a living area of about 125-130 m² (1.5 floors), so about 260 m² of space would be needed. This area is available on the plot. What would a rough estimate for such work be? For example, excavation and groundworks.
Furthermore, I am considering heating with gas, meaning installing a condensing gas boiler. Plus, hot water preparation on the roof (solar thermal system). That would be relatively inexpensive at first. Since houses today are well insulated (energy saving regulations 2009), and a condensing boiler can heat very efficiently compared to older systems, the heating costs should stay reasonable, right? I mean, solar thermal covers hot water demand for three-quarters of the year, so no gas is needed for that, the house is well insulated, and the burner is efficient… three factors supporting this. Or am I completely wrong?
In 10 years or later, it would still be possible to switch from gas to something else.
He recommends an air-source heat pump system with a direct expansion evaporator. The residential area is connected to natural gas.
Now my question is: based on what I read, there seems to be no solid reason to install an air-source heat pump. Very low performance in winter (maybe global warming will help), poor annual performance factor compared to ground collectors and probes, and high noise levels due to the large air volume movement. Additionally, there are high electricity costs in winter because of the backup heater/electric heating element. The alternatives mentioned above would be better. Only, a heat pump with ground collectors also costs significantly more, mainly due to the excavation work. Our house will have a living area of about 125-130 m² (1.5 floors), so about 260 m² of space would be needed. This area is available on the plot. What would a rough estimate for such work be? For example, excavation and groundworks.
Furthermore, I am considering heating with gas, meaning installing a condensing gas boiler. Plus, hot water preparation on the roof (solar thermal system). That would be relatively inexpensive at first. Since houses today are well insulated (energy saving regulations 2009), and a condensing boiler can heat very efficiently compared to older systems, the heating costs should stay reasonable, right? I mean, solar thermal covers hot water demand for three-quarters of the year, so no gas is needed for that, the house is well insulated, and the burner is efficient… three factors supporting this. Or am I completely wrong?
In 10 years or later, it would still be possible to switch from gas to something else.
Hello,
At least it’s commendable that he plans to do this. I would like to check the results then. 😉
How can he recommend that when the necessary parameters haven’t even been calculated yet? 😉
Well, he’s a salesperson after all!
Believing, assuming, and guessing is a tricky business. I wouldn’t make any significant investment based on that!
Correct, any type of ground source system costs considerably more than air source! That’s why people like to save here, trying to keep costs as low as possible. The builder ends up paying the price later. Direct evaporators have specific characteristics, which is one reason they are rarely used.
That can’t be answered reliably since the key parameters are unknown. What does the general contractor offer compared to other options?
No, not entirely. In my economic assessments, gas condensing boilers and air-source heat pumps often perform neck and neck when considering just heating and domestic hot water preparation. The deciding factors are always the specific numbers.
However, gas boilers lose ground significantly when indoor temperatures/cooling loads during the summer heat become so high that removing heat (cooling load) needs to be considered. Gas systems offer no real solutions here.
The reason is that energy regulations primarily address heating and hot water supply from a primary energy perspective, while summer heat protection is heavily neglected. This leads to higher indoor temperatures, particularly in top floor rooms, making heat removal necessary. Controlled ventilation systems are generally not suitable for this!
A tip: Have your indoor temperatures and cooling loads during summer heat calculated (VDI 2078 software method).
Make sure the results are guaranteed in the contract with penalties for non-compliance. 😉
At this point, your salesperson will start to get uncomfortable and fidget!
Retrofitting is usually much more expensive, unless the system is designed and prepared for this from the start. In that case, it’s better to do it right the first time.
Best regards
Bulla2000 schrieb:
...The representative from Ambiente Massivhaus said that only once the plot and the house are finalized will he carry out a calculation of the heating surfaces and heating demand (or whatever it’s called).
At least it’s commendable that he plans to do this. I would like to check the results then. 😉
Bulla2000 schrieb:
...
He recommends an air-source heat pump system with direct evaporator. The residential area is connected to natural gas supply.
How can he recommend that when the necessary parameters haven’t even been calculated yet? 😉
Well, he’s a salesperson after all!
Bulla2000 schrieb:
...The above-mentioned alternatives would be better.
Believing, assuming, and guessing is a tricky business. I wouldn’t make any significant investment based on that!
Bulla2000 schrieb:
...But such a heat pump with ground collectors costs significantly more, mainly due to earthworks.
Correct, any type of ground source system costs considerably more than air source! That’s why people like to save here, trying to keep costs as low as possible. The builder ends up paying the price later. Direct evaporators have specific characteristics, which is one reason they are rarely used.
Bulla2000 schrieb:
...What would something like that roughly cost? Excavation/earthworks etc.?
That can’t be answered reliably since the key parameters are unknown. What does the general contractor offer compared to other options?
Bulla2000 schrieb:
...
Also, I’m considering heating with gas, installing a gas condensing boiler... Or am I completely off here?
No, not entirely. In my economic assessments, gas condensing boilers and air-source heat pumps often perform neck and neck when considering just heating and domestic hot water preparation. The deciding factors are always the specific numbers.
However, gas boilers lose ground significantly when indoor temperatures/cooling loads during the summer heat become so high that removing heat (cooling load) needs to be considered. Gas systems offer no real solutions here.
The reason is that energy regulations primarily address heating and hot water supply from a primary energy perspective, while summer heat protection is heavily neglected. This leads to higher indoor temperatures, particularly in top floor rooms, making heat removal necessary. Controlled ventilation systems are generally not suitable for this!
A tip: Have your indoor temperatures and cooling loads during summer heat calculated (VDI 2078 software method).
Make sure the results are guaranteed in the contract with penalties for non-compliance. 😉
At this point, your salesperson will start to get uncomfortable and fidget!
Bulla2000 schrieb:
...
In 10 years or later, you could still switch from gas to whatever else.
Retrofitting is usually much more expensive, unless the system is designed and prepared for this from the start. In that case, it’s better to do it right the first time.
Best regards
B
Bauexperte27 Jul 2010 11:38Hello,
You are mistaken, as many homeowners are, by prioritizing energy efficiency over the expected costs – the annual consumption is what matters first.
It is true that on paper the annual performance factor of geothermal or ground collectors is better, but these come with high installation costs; depending on soil conditions and the number of boreholes, costs can reach five figures. With ground collectors, you can only use your garden as a lawn, nothing more. You should also consider how long you plan to heat before the invested costs pay off.
With all due respect, that is nonsense. The outdoor unit of an air-to-water heat pump is not a high-powered turbine; it only operates when needed and is no louder than normal conversation, if that.
No heating system works _without_ electricity, that is clear first. Recent experience with these heating technologies has shown that heating costs range around €600-800/year, depending on the occupants’ heating and showering habits. Last winter likely increased these costs by about €50-100, but this applies to any heating system.
It is undeniable that gas currently offers the best price/performance ratio overall; however, with a condensing gas boiler you accept a service life that is about 5 years shorter (ask a trusted plumbing and heating contractor). Conclusion: fairly and all things considered, there are as many advantages as disadvantages among the heating systems currently on the market.
Still, if you want to play it safe, you should consider installing a condensing gas boiler. There are many innovations being developed in the alternative heating energy sector, all compatible with underfloor heating systems. For example, pilot projects are running in Bavaria with small wind turbines mounted on the roofs of single-family homes, a project – in my opinion in the Eifel region – where ground collectors are being tested extensively, as well as a fuel cell system for future use in single-family homes – in my opinion sponsored by VW.
What you should keep in mind is that the installation shaft in your new build – housing the service lines – should allow enough space for future technologies, as described above, to be integrated when the service life of the condensing gas boiler comes to an end.
Best regards
Bauexperte
Bulla2000 schrieb:
Now my question: when I read all this, there seems to be no valid reason to install an air-source heat pump. Very low performance in winter (maybe global warming will help), poor annual performance factor compared to ground collectors and probes,
You are mistaken, as many homeowners are, by prioritizing energy efficiency over the expected costs – the annual consumption is what matters first.
It is true that on paper the annual performance factor of geothermal or ground collectors is better, but these come with high installation costs; depending on soil conditions and the number of boreholes, costs can reach five figures. With ground collectors, you can only use your garden as a lawn, nothing more. You should also consider how long you plan to heat before the invested costs pay off.
Bulla2000 schrieb:
and high noise levels due to the massive air circulation.
With all due respect, that is nonsense. The outdoor unit of an air-to-water heat pump is not a high-powered turbine; it only operates when needed and is no louder than normal conversation, if that.
Bulla2000 schrieb:
Additionally, high electricity costs in winter due to auxiliary heaters/heating rods. The above alternatives would be better.
No heating system works _without_ electricity, that is clear first. Recent experience with these heating technologies has shown that heating costs range around €600-800/year, depending on the occupants’ heating and showering habits. Last winter likely increased these costs by about €50-100, but this applies to any heating system.
Bulla2000 schrieb:
In 10 years or later, one could still switch from gas to whatever.
It is undeniable that gas currently offers the best price/performance ratio overall; however, with a condensing gas boiler you accept a service life that is about 5 years shorter (ask a trusted plumbing and heating contractor). Conclusion: fairly and all things considered, there are as many advantages as disadvantages among the heating systems currently on the market.
Still, if you want to play it safe, you should consider installing a condensing gas boiler. There are many innovations being developed in the alternative heating energy sector, all compatible with underfloor heating systems. For example, pilot projects are running in Bavaria with small wind turbines mounted on the roofs of single-family homes, a project – in my opinion in the Eifel region – where ground collectors are being tested extensively, as well as a fuel cell system for future use in single-family homes – in my opinion sponsored by VW.
What you should keep in mind is that the installation shaft in your new build – housing the service lines – should allow enough space for future technologies, as described above, to be integrated when the service life of the condensing gas boiler comes to an end.
Best regards
Bauexperte
B
Bulla200027 Jul 2010 13:13Thank you for your valuable insights. So, should the air-to-water heat pump not be viewed so critically? Despite the expensive supplementary heating in winter, does it usually pay off in most cases?
@€uro: So the weak point is the lack of cooling capability in summer, okay. But couldn’t you just open the windows like usual then? Do rooms really heat up that much from solar radiation?
We live in an old clay house with walls about 60 cm (24 inches) thick. It stays warm in winter and cool in summer, precisely because of the good insulation. Is this no longer the case with today’s well-insulated walls? Is air conditioning therefore mandatory?
Is it possible to combine domestic hot water preparation on the roof with an air heat pump? That would be good since you would probably need to draw in considerably less air if the water heating were eliminated.
@€uro: So the weak point is the lack of cooling capability in summer, okay. But couldn’t you just open the windows like usual then? Do rooms really heat up that much from solar radiation?
We live in an old clay house with walls about 60 cm (24 inches) thick. It stays warm in winter and cool in summer, precisely because of the good insulation. Is this no longer the case with today’s well-insulated walls? Is air conditioning therefore mandatory?
Is it possible to combine domestic hot water preparation on the roof with an air heat pump? That would be good since you would probably need to draw in considerably less air if the water heating were eliminated.
Hello,
Basically, everything should be looked at critically because every solution has both advantages but unfortunately also disadvantages. There is no one-size-fits-all ultimate solution, although sellers like to claim otherwise.
Whether and how much supplemental heating is needed in winter depends on a number of project-specific factors. Air-source heat pumps have gained a somewhat bad reputation because the actual performance often did not meet the forecasted values. This is partly due to the manufacturers, but in most cases it is the installers who are responsible. Instead of properly sizing and calculating the system as required, they estimate, assume, and speculate. The result is a rather inefficient system.
Example: For a defined climate location: From the design temperature point, for example, -14°C to about -4°C (7°F to 25°F), only about 6% of the total annual heating demand occurs. If a small portion of electric heating, for example via an electric heating element, is used—if it is even needed—this only has a minor impact on the overall annual balance.
Cooling is a weak point for gas heating, yes, but only if cooling is actually needed—otherwise not!
Ventilating by opening windows might work, but it is only sufficient if there is enough cooling potential available from the outside air and if the building has low cooling loads. This usually happens during night and early morning hours. Also, not every location is suitable for this (e.g., due to noise, dust, pollen, etc.). Who ventilates while on vacation? Indoor temperatures rise, and internal thermal masses (walls, ceilings) absorb this energy. At that point, window ventilation hardly has an effect, especially when outdoor temperatures are close to or above 20°C (68°F).
That is not due to good insulation but to the thermal mass. Insulation is mainly beneficial for winter heat protection. During summer heat periods, the solar radiation on the building components is decisive; insulation plays hardly any role. Modern buildings lack this thermal mass.
Example: Old churches or even barns with 40 to 50 cm (16 to 20 inches) thick walls made of fieldstones have a very poor insulation value, yet they stay pleasantly cool in summer—how is that?
No, it is not mandatory. It does not necessarily have to be a conventional air conditioner. You need to know the building’s cooling load first, only then can you say whether and what measures are required.
Yes, it can.
“Considerably” would need to be defined. I would say that with a solar thermal system you can harvest some kWh. Whether this is economical is another matter.
“Intake”??? I am not talking about an air-to-air heat pump! That would be a completely different topic.
Best regards.
Bulla2000 schrieb:
Thanks for your valuable insights. So, should we not view the air-to-water heat pump so critically? Despite the costly supplemental heating in winter, does it still pay off in most cases?
Basically, everything should be looked at critically because every solution has both advantages but unfortunately also disadvantages. There is no one-size-fits-all ultimate solution, although sellers like to claim otherwise.
Whether and how much supplemental heating is needed in winter depends on a number of project-specific factors. Air-source heat pumps have gained a somewhat bad reputation because the actual performance often did not meet the forecasted values. This is partly due to the manufacturers, but in most cases it is the installers who are responsible. Instead of properly sizing and calculating the system as required, they estimate, assume, and speculate. The result is a rather inefficient system.
Example: For a defined climate location: From the design temperature point, for example, -14°C to about -4°C (7°F to 25°F), only about 6% of the total annual heating demand occurs. If a small portion of electric heating, for example via an electric heating element, is used—if it is even needed—this only has a minor impact on the overall annual balance.
Bulla2000 schrieb:
@€uro: So the weak point is the lack of cooling capability in summer, okay. But couldn’t you just open the windows like today, and that’s fine, right? Do rooms really heat up so much from solar radiation?
Cooling is a weak point for gas heating, yes, but only if cooling is actually needed—otherwise not!
Ventilating by opening windows might work, but it is only sufficient if there is enough cooling potential available from the outside air and if the building has low cooling loads. This usually happens during night and early morning hours. Also, not every location is suitable for this (e.g., due to noise, dust, pollen, etc.). Who ventilates while on vacation? Indoor temperatures rise, and internal thermal masses (walls, ceilings) absorb this energy. At that point, window ventilation hardly has an effect, especially when outdoor temperatures are close to or above 20°C (68°F).
Bulla2000 schrieb:
... We live in an old clay house with certainly 60cm (24 inches) thick walls. It stays warm in winter and cool in summer, precisely because of the good insulation.
That is not due to good insulation but to the thermal mass. Insulation is mainly beneficial for winter heat protection. During summer heat periods, the solar radiation on the building components is decisive; insulation plays hardly any role. Modern buildings lack this thermal mass.
Example: Old churches or even barns with 40 to 50 cm (16 to 20 inches) thick walls made of fieldstones have a very poor insulation value, yet they stay pleasantly cool in summer—how is that?
Bulla2000 schrieb:New energy saving regulations for buildings are focused on winter heat protection.
... Isn’t that the case with today’s well-insulated walls anymore?
Bulla2000 schrieb:
... So, is air conditioning mandatory?
No, it is not mandatory. It does not necessarily have to be a conventional air conditioner. You need to know the building’s cooling load first, only then can you say whether and what measures are required.
Bulla2000 schrieb:
... Can domestic hot water preparation on the roof be combined with an air-source heat pump?
Yes, it can.
Bulla2000 schrieb:
... That would be good, then you would certainly need considerably less air intake if hot water heating was eliminated.
“Considerably” would need to be defined. I would say that with a solar thermal system you can harvest some kWh. Whether this is economical is another matter.
“Intake”??? I am not talking about an air-to-air heat pump! That would be a completely different topic.
Best regards.
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