ᐅ Air source heat pump LWZ504 or ground source heat pump WPF10
Created on: 20 Jan 2016 13:02
F
Flose89Hello everyone,
I hope you can help me a bit.
Here are the key details:
New build from mid-2016 – solid construction KfW55 standard – in Bavaria, Augsburg
Roof: 45 degrees, south-facing, with 6 kWp photovoltaic system
260 m² (2,800 sq ft) underfloor heating
With controlled indoor ventilation system
Currently 2 people, later 4
From the energy consultant, I received the following:
Heating demand 16,760 kWh/year
Specific heating demand 41.3 kWh/(m²·year)
Specific final energy demand 9.7 kWh/(m²·year)
Specific primary energy demand 23.3 kWh/(m²·year)
Building volume 1,268 m³ (44,760 ft³)
Net floor area 405 m² (4,360 sq ft)
Thermal envelope 964.9 m² (10,380 sq ft)
Surface-to-volume ratio (A/V) 1/m 0.76
HT´ (thermal transmittance) W/(m²·K) 0.219
Standard heat load according to DIN 4108-6 (kW) 17.4
Which system would you prefer? Stiebel Eltron LWZ504 or WPF10 ground source heat pump combined with a Zehnder350 ventilation unit?
Currently, there is a price difference of about 7,000 € with the LWZ being cheaper.
There is a large garden available. A 500 m² (5,380 sq ft) surface collector with DIY work would be possible (excavation work free except for diesel fuel).
After deducting BAFA subsidies, the LWZ would be about 4,000 € cheaper.
Considering annual savings of 150–200 € per year, the WPF10 would pay off after about 20 years. Also, one needs to consider planting etc., as well as the additional work involved in installation.
What would you do?
Best regards,
Florian
I hope you can help me a bit.
Here are the key details:
New build from mid-2016 – solid construction KfW55 standard – in Bavaria, Augsburg
Roof: 45 degrees, south-facing, with 6 kWp photovoltaic system
260 m² (2,800 sq ft) underfloor heating
With controlled indoor ventilation system
Currently 2 people, later 4
From the energy consultant, I received the following:
Heating demand 16,760 kWh/year
Specific heating demand 41.3 kWh/(m²·year)
Specific final energy demand 9.7 kWh/(m²·year)
Specific primary energy demand 23.3 kWh/(m²·year)
Building volume 1,268 m³ (44,760 ft³)
Net floor area 405 m² (4,360 sq ft)
Thermal envelope 964.9 m² (10,380 sq ft)
Surface-to-volume ratio (A/V) 1/m 0.76
HT´ (thermal transmittance) W/(m²·K) 0.219
Standard heat load according to DIN 4108-6 (kW) 17.4
Which system would you prefer? Stiebel Eltron LWZ504 or WPF10 ground source heat pump combined with a Zehnder350 ventilation unit?
Currently, there is a price difference of about 7,000 € with the LWZ being cheaper.
There is a large garden available. A 500 m² (5,380 sq ft) surface collector with DIY work would be possible (excavation work free except for diesel fuel).
After deducting BAFA subsidies, the LWZ would be about 4,000 € cheaper.
Considering annual savings of 150–200 € per year, the WPF10 would pay off after about 20 years. Also, one needs to consider planting etc., as well as the additional work involved in installation.
What would you do?
Best regards,
Florian
With a ground-source heat pump, you improve the output per kilowatt-hour of electricity. You will need to use your own crystal ball to predict how electricity prices will develop in the future. This will help you better assess whether the extra cost is worth it for you.
You should also compare the energy consultant’s assumptions with your own usage habits. They usually assume a room temperature of 20°C (68°F); if you want it warmer, heating costs will increase.
Personally, I would choose a ground-source heat pump if it is technically feasible on your property, especially for a house this large.
You should also compare the energy consultant’s assumptions with your own usage habits. They usually assume a room temperature of 20°C (68°F); if you want it warmer, heating costs will increase.
Personally, I would choose a ground-source heat pump if it is technically feasible on your property, especially for a house this large.