ᐅ New single-family house construction, gas heating or heat pump, target KfW55 energy efficiency standard
Created on: 15 Aug 2013 20:51
E
Elektrofuzzi
Hello Forum,
I have been reading here for some time and am very impressed by the quality of some of the answers, so I hope to get the right guidance for myself as well.
I am currently planning my single-family house with 171m2 (1840 sq ft) of living space to KfW 70 standard.
Through the developer, I would get a gas condensing boiler with solar hot water and a Zehnder ComfoAir residential ventilation system.
Through a heating installer friend, I could get an Ochsner air-to-water heat pump GMLW9 plus VX with split outdoor unit Millennium MSV 14 for heating,
and an Ochsner Europa 323DK air-to-water heat pump with integrated residential ventilation. This pump would be installed in the utility room and extract warm air from the hallway and bathroom; fresh air would be supplied back to the rooms via membrane flaps on the window.
I would get both options at the same price.
About the house:
Setback floor, 171m2 (1840 sq ft) living space
Underfloor heating with supply temperature approx. 35°C (95°F)
2-layer wall construction: 17.5cm (7 inches) Ytong, 14cm (5.5 inches) insulation, brick veneer
10cm (4 inches) perimeter insulation
Triple glazing, 6-chamber profile, Ug value 0.7
Results of the energy assessment according to DIN 4108-6 and DIN 4701-10
Annual primary energy demand 56.92 kWh/m2
Transmission heat loss 0.27 W/(m2K)
Building envelope area 534.65m2 (5752 sq ft)
Building volume 705.65m2 (7598 sq ft)
Heated air volume 536.29m2 (5772 sq ft)
Usable building area 225.81m2 (2430 sq ft)
A/V ratio 0.76 1/m
Window area 39.36m2 (424 sq ft)
Ground slab U-value 0.23 W/(m2K)
Exterior wall U-value 0.17 W/(m2K)
Wood beam ceiling U-value 0.19 W/(m2K)
Ceiling to outside air above U-value 0.23 W/(m2K)
Ceiling to outside air below U-value 0.22 W/(m2K)
Absolute heating demand 10,704 kWh/year
Absolute hot water demand 2,823 kWh/year
I hope this is enough for now.
My questions:
Which of the above heating systems makes more sense?
Are these values reasonable?
Would I possibly reach KfW 55 with the heat pump system combined with a 5 kWp photovoltaic system?
I look forward to your answers.
Thank you
Elektriker
I have been reading here for some time and am very impressed by the quality of some of the answers, so I hope to get the right guidance for myself as well.
I am currently planning my single-family house with 171m2 (1840 sq ft) of living space to KfW 70 standard.
Through the developer, I would get a gas condensing boiler with solar hot water and a Zehnder ComfoAir residential ventilation system.
Through a heating installer friend, I could get an Ochsner air-to-water heat pump GMLW9 plus VX with split outdoor unit Millennium MSV 14 for heating,
and an Ochsner Europa 323DK air-to-water heat pump with integrated residential ventilation. This pump would be installed in the utility room and extract warm air from the hallway and bathroom; fresh air would be supplied back to the rooms via membrane flaps on the window.
I would get both options at the same price.
About the house:
Setback floor, 171m2 (1840 sq ft) living space
Underfloor heating with supply temperature approx. 35°C (95°F)
2-layer wall construction: 17.5cm (7 inches) Ytong, 14cm (5.5 inches) insulation, brick veneer
10cm (4 inches) perimeter insulation
Triple glazing, 6-chamber profile, Ug value 0.7
Results of the energy assessment according to DIN 4108-6 and DIN 4701-10
Annual primary energy demand 56.92 kWh/m2
Transmission heat loss 0.27 W/(m2K)
Building envelope area 534.65m2 (5752 sq ft)
Building volume 705.65m2 (7598 sq ft)
Heated air volume 536.29m2 (5772 sq ft)
Usable building area 225.81m2 (2430 sq ft)
A/V ratio 0.76 1/m
Window area 39.36m2 (424 sq ft)
Ground slab U-value 0.23 W/(m2K)
Exterior wall U-value 0.17 W/(m2K)
Wood beam ceiling U-value 0.19 W/(m2K)
Ceiling to outside air above U-value 0.23 W/(m2K)
Ceiling to outside air below U-value 0.22 W/(m2K)
Absolute heating demand 10,704 kWh/year
Absolute hot water demand 2,823 kWh/year
I hope this is enough for now.
My questions:
Which of the above heating systems makes more sense?
Are these values reasonable?
Would I possibly reach KfW 55 with the heat pump system combined with a 5 kWp photovoltaic system?
I look forward to your answers.
Thank you
Elektriker
K
kein name26 Aug 2013 11:11Hello,
what I’m still wondering is how you can install a gas condensing boiler system with a solar thermal system or a heat pump solution for the same price. Either the gas condensing boiler system tends to be relatively expensive, or the heat pump solution is really affordable. Usually, the gas condensing boiler is the cheapest heating option to purchase. The heat pump, on the other hand, has the advantage that its often significantly higher initial investment costs are offset by lower operating costs over a relatively long evaluation period, especially if, as Euro suggests, a total investment calculation is done.
If, however, you can get a heat pump system with the same performance and at the same price, then it would certainly be worth examining the expected operating costs in order to make an economic decision for a system based on a total cost calculation.
On the other hand, if gas is already connected on site, then the otherwise typical additional costs for gas condensing boiler systems should be limited.
Since you already mentioned an economic decision, I would really recommend performing a comparative calculation.
Best regards
what I’m still wondering is how you can install a gas condensing boiler system with a solar thermal system or a heat pump solution for the same price. Either the gas condensing boiler system tends to be relatively expensive, or the heat pump solution is really affordable. Usually, the gas condensing boiler is the cheapest heating option to purchase. The heat pump, on the other hand, has the advantage that its often significantly higher initial investment costs are offset by lower operating costs over a relatively long evaluation period, especially if, as Euro suggests, a total investment calculation is done.
If, however, you can get a heat pump system with the same performance and at the same price, then it would certainly be worth examining the expected operating costs in order to make an economic decision for a system based on a total cost calculation.
On the other hand, if gas is already connected on site, then the otherwise typical additional costs for gas condensing boiler systems should be limited.
Since you already mentioned an economic decision, I would really recommend performing a comparative calculation.
Best regards
E
Elektrofuzzi26 Aug 2013 11:54You forgot the controlled ventilation system, which is already integrated with the heat pump system. That is why the price is the same.
kein name schrieb:
.... Because typically, a gas condensing boiler is the most affordable heating option to purchase.... This should be put into perspective, as the initial investment for an air source heat pump and a gas condensing boiler plus connection costs usually are comparable at the same capacity! With gas, you can cook; with an air source heat pump, you can cool! ;-) kein name schrieb:
.... Since you already mentioned making an economic decision, I would strongly recommend performing a comparison calculation. Correct, everyone should do this. However, knowing the actual energy demand for heating and hot water is necessary for this. Best regards.
M
merlin66728 Aug 2013 14:45Do you have a rough idea of the heating load you need, what your climatic conditions are, and so on?
A 230m² (2,475 sq ft) house can have a heating load of about 5 kW as a passive house, or around 25 kW as a conventional house. Maybe more if it is located at an altitude of around 1500m (4,920 feet) and has very long heating periods.
A 230m² (2,475 sq ft) house can have a heating load of about 5 kW as a passive house, or around 25 kW as a conventional house. Maybe more if it is located at an altitude of around 1500m (4,920 feet) and has very long heating periods.
Best regards, we want to build a detached single-family house with solid construction, 230 sqm (2,475 sq ft), using Ytong or prefabricated walls made of aerated concrete.
merlin667 schrieb:
Do you have an approximate idea of the heating load you will need, what your climatic conditions are, etc.?
230 sqm (2,475 sq ft) as a passive house might require about 5 kW, as a conventional house around 25 kW, maybe more if located at around 1,500 m (4,920 ft) above sea level with very long heating periods.
M
merlin66728 Aug 2013 20:27Okay, the term "solid construction" is clear, but which insulation you use, and so on, is another question. Fundamentally, it always comes down to personal preference:
If you have your own forest and enough space, you could install a wood chip system or a wood gasifier combined with some solar collectors. If you have the option of a gas connection on your property, a gas condensing boiler can make good sense. If groundwater is accessible, you can use a groundwater heat pump. A deep geothermal heat pump is almost always possible, and if you have a sufficiently large property, a horizontal or trench collector can also work. I would generally recommend an air-source heat pump only if it is supported by photovoltaic panels and has very good energy efficiency. In terms of cost, ground-source and air-source heat pumps are comparable. Deep drilling is more expensive and not always possible everywhere. In my opinion, a gas boiler only makes sense if there is a gas connection near the property—external tanks, etc., are generally not practical.
The less heating power you need, the cheaper it is, no matter which system you choose, because a heating system with lower capacity costs less to purchase (comparing apples to apples) and has lower operating costs. For example, a 14 kW (kilowatt) gas condensing boiler costs about €1700 (approx. 1700 USD) on Amazon, a ground-source heat pump of the same size costs around €10,000 (about 10,000 USD) — though additional drilling or excavation costs apply — and an air-source heat pump costs about €13,000 (around 13,000 USD). Buffer tanks, etc., are not included and come as extra. The 9 kW (kilowatt) split air-source heat pump with all accessories (domestic hot water buffer, separation tank, electric heating element, etc.) that we install has a list price of €20,007 (about 20,000 USD). These are just material costs.
I hope this helps you understand better that it’s not easy to choose the right concept from the right provider, and there is no "one-size-fits-all" solution. Every system on the market is designed for a specific application. Heat pumps make sense when the flow temperatures are low (such as with underfloor heating).
Honestly, I get the impression that you have very little knowledge about what is available on the market and what might be suitable. Therefore, I strongly recommend having a conversation with former homeowners in your circle of friends and potential installation companies to get up to speed.
If you have your own forest and enough space, you could install a wood chip system or a wood gasifier combined with some solar collectors. If you have the option of a gas connection on your property, a gas condensing boiler can make good sense. If groundwater is accessible, you can use a groundwater heat pump. A deep geothermal heat pump is almost always possible, and if you have a sufficiently large property, a horizontal or trench collector can also work. I would generally recommend an air-source heat pump only if it is supported by photovoltaic panels and has very good energy efficiency. In terms of cost, ground-source and air-source heat pumps are comparable. Deep drilling is more expensive and not always possible everywhere. In my opinion, a gas boiler only makes sense if there is a gas connection near the property—external tanks, etc., are generally not practical.
The less heating power you need, the cheaper it is, no matter which system you choose, because a heating system with lower capacity costs less to purchase (comparing apples to apples) and has lower operating costs. For example, a 14 kW (kilowatt) gas condensing boiler costs about €1700 (approx. 1700 USD) on Amazon, a ground-source heat pump of the same size costs around €10,000 (about 10,000 USD) — though additional drilling or excavation costs apply — and an air-source heat pump costs about €13,000 (around 13,000 USD). Buffer tanks, etc., are not included and come as extra. The 9 kW (kilowatt) split air-source heat pump with all accessories (domestic hot water buffer, separation tank, electric heating element, etc.) that we install has a list price of €20,007 (about 20,000 USD). These are just material costs.
I hope this helps you understand better that it’s not easy to choose the right concept from the right provider, and there is no "one-size-fits-all" solution. Every system on the market is designed for a specific application. Heat pumps make sense when the flow temperatures are low (such as with underfloor heating).
Honestly, I get the impression that you have very little knowledge about what is available on the market and what might be suitable. Therefore, I strongly recommend having a conversation with former homeowners in your circle of friends and potential installation companies to get up to speed.
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