ᐅ Repair a heat pump for €5,000–7,500 or replace it with a new one?
Created on: 16 Feb 2024 16:32
J
jx7
Hello dear forum members,
we are facing the decision of "repair" or "new heat pump" and would appreciate your opinions.
Our 7.5-year-old heat pump has broken down after 68,000 starts in 7.5 years (25 starts per day).
Problem with the heat pump:
- The cause of the frequent cycling is unclear. (Most individual room valves are fully open.)
- The only available customer service is the German distributor (400 km (250 miles) away)
- The heat pump is oversized at 3-12 kW; 7-8 kW would be sufficient according to calculations
- The hot water tank is somewhat small at 165 liters (44 gallons) for 5 people
Possible repair appointment:
- Compressor replacement €5,000 (including installation)
- Fault diagnosis (dirt trap in the heating circuit/brine circuit?, temperature sensors?, bypass valve?)
- Possible control system optimization (improving speed regulation to enable lower speeds? possible speed limit? night setback? high hysteresis? possible blocking times?)
- Optional retrofit of a buffer tank (€2,000 plus installation, no combination buffer possible)
- Risk that the frequent cycling persists afterwards
Alternatively, we could install a new heat pump:
- Change to a larger manufacturer with a better service network
- Several weeks without hot water (the current electric heater only heats the water to 32°C (90°F)) until new installation
- New 5-year warranty
- Unknown costs, probably very expensive
(1) What do you think a new heat pump including installation would cost?
(2) How long do you think the installation would take?
(3) What are your thoughts on the repair vs. replace decision?
Additional data:
Location: Budenheim near Mainz
Current broken heat pump: Ecoforest geothermal heat pump (Model C3 3-12 kW HTR EH), modulating 3-12 kW, connected to underfloor heating and two 100-meter (330 feet) boreholes. Hot water tank 165 liters (44 gallons).
It was probably oversized at the time. The calculated optimal size is 7-8 kW.
The compressor failed after 68,000 starts in 7.5 years (25 starts per day). Two neighbors have the same heat pump in similar homes (same construction company) with 5 starts per day. Customer service at Ecoforest is poor.
The heat pump’s annual balance shows:
Heating 12,740 kWh
Cooling 1,850 kWh
Electricity 3,180 kWh
Annual performance factor (COP): 4.6
Additional data:
Energy standard: nearly KfW-55
Annual primary energy demand Qp according to energy-saving regulations: 34.5 kWh/(m²a)
Specific transmission heat loss H’T: 0.305 W/(m² K)
Heated building volume 920 m³ (32,480 ft³)
Living area: 220 m² (2,370 ft²)
Heated living area: 170 m² (1,830 ft²)
Household: 5 persons
Controlled mechanical ventilation installed
9.9 kW peak photovoltaic system installed
Desired heat pump:
- Modulating heat pump
- Capacity smaller than current (3-12 kW)
- Larger hot water tank than current (165 liters (44 gallons))
- Passive cooling function
- Electric backup heater for emergency operation
- Connection for 10,000-liter (2,600 gallons) basement pool (max 31°C (88°F)) possible (currently connected via low-temperature heat exchanger to heat pump)
we are facing the decision of "repair" or "new heat pump" and would appreciate your opinions.
Our 7.5-year-old heat pump has broken down after 68,000 starts in 7.5 years (25 starts per day).
Problem with the heat pump:
- The cause of the frequent cycling is unclear. (Most individual room valves are fully open.)
- The only available customer service is the German distributor (400 km (250 miles) away)
- The heat pump is oversized at 3-12 kW; 7-8 kW would be sufficient according to calculations
- The hot water tank is somewhat small at 165 liters (44 gallons) for 5 people
Possible repair appointment:
- Compressor replacement €5,000 (including installation)
- Fault diagnosis (dirt trap in the heating circuit/brine circuit?, temperature sensors?, bypass valve?)
- Possible control system optimization (improving speed regulation to enable lower speeds? possible speed limit? night setback? high hysteresis? possible blocking times?)
- Optional retrofit of a buffer tank (€2,000 plus installation, no combination buffer possible)
- Risk that the frequent cycling persists afterwards
Alternatively, we could install a new heat pump:
- Change to a larger manufacturer with a better service network
- Several weeks without hot water (the current electric heater only heats the water to 32°C (90°F)) until new installation
- New 5-year warranty
- Unknown costs, probably very expensive
(1) What do you think a new heat pump including installation would cost?
(2) How long do you think the installation would take?
(3) What are your thoughts on the repair vs. replace decision?
Additional data:
Location: Budenheim near Mainz
Current broken heat pump: Ecoforest geothermal heat pump (Model C3 3-12 kW HTR EH), modulating 3-12 kW, connected to underfloor heating and two 100-meter (330 feet) boreholes. Hot water tank 165 liters (44 gallons).
It was probably oversized at the time. The calculated optimal size is 7-8 kW.
The compressor failed after 68,000 starts in 7.5 years (25 starts per day). Two neighbors have the same heat pump in similar homes (same construction company) with 5 starts per day. Customer service at Ecoforest is poor.
The heat pump’s annual balance shows:
Heating 12,740 kWh
Cooling 1,850 kWh
Electricity 3,180 kWh
Annual performance factor (COP): 4.6
Additional data:
Energy standard: nearly KfW-55
Annual primary energy demand Qp according to energy-saving regulations: 34.5 kWh/(m²a)
Specific transmission heat loss H’T: 0.305 W/(m² K)
Heated building volume 920 m³ (32,480 ft³)
Living area: 220 m² (2,370 ft²)
Heated living area: 170 m² (1,830 ft²)
Household: 5 persons
Controlled mechanical ventilation installed
9.9 kW peak photovoltaic system installed
Desired heat pump:
- Modulating heat pump
- Capacity smaller than current (3-12 kW)
- Larger hot water tank than current (165 liters (44 gallons))
- Passive cooling function
- Electric backup heater for emergency operation
- Connection for 10,000-liter (2,600 gallons) basement pool (max 31°C (88°F)) possible (currently connected via low-temperature heat exchanger to heat pump)
180 liters (48 gallons) of hot water storage is integrated; the Daikin unit is not available without the built-in hot water tank.
The offer includes a buffer tank for €815 plus installation. I asked if it could be removed. With the smaller heat pump and with individual room controllers that will remain open in the future, it should work without the buffer tank. It only adds cost and reduces efficiency.
Regarding performance:
The output ranges from 0.85 to 9.1 kW. Ecoforest was 3 to 12 kW.
The crucial factor for startups is the lower value; the Daikin can regulate down much smaller before it has to shut off completely.
For a heating demand of 6.3 kW, 9.1 kW is more than sufficient. I asked if they would install the smaller model with 0.85 to 7.5 kW, which might be around €1,500 cheaper. I also mentioned that it’s acceptable if the pool can’t be heated on the coldest days (in the worst case, the electric heater would activate).
I hope that with these two changes to the offer, the price will be around €19,500, which after a 35% subsidy would be €13,000.
So the decision is between a €4,800 repair and a €13,000 new installation.
Is the switch from Ecoforest worth the additional cost?
Or do we believe that after the compressor repair, with the new knowledge about heating operation (all individual room controllers open, heat pump power limited to 3–6 kW, night shutdown, 30-minute pool program, etc.), the Ecoforest heating system will run trouble-free for the next 12 years? Based on the information I found online in the past few days, I have actually become more optimistic about the Ecoforest heat pump and had already accepted that no decent new offer would come.
The offer includes a buffer tank for €815 plus installation. I asked if it could be removed. With the smaller heat pump and with individual room controllers that will remain open in the future, it should work without the buffer tank. It only adds cost and reduces efficiency.
Regarding performance:
The output ranges from 0.85 to 9.1 kW. Ecoforest was 3 to 12 kW.
The crucial factor for startups is the lower value; the Daikin can regulate down much smaller before it has to shut off completely.
For a heating demand of 6.3 kW, 9.1 kW is more than sufficient. I asked if they would install the smaller model with 0.85 to 7.5 kW, which might be around €1,500 cheaper. I also mentioned that it’s acceptable if the pool can’t be heated on the coldest days (in the worst case, the electric heater would activate).
I hope that with these two changes to the offer, the price will be around €19,500, which after a 35% subsidy would be €13,000.
So the decision is between a €4,800 repair and a €13,000 new installation.
Is the switch from Ecoforest worth the additional cost?
Or do we believe that after the compressor repair, with the new knowledge about heating operation (all individual room controllers open, heat pump power limited to 3–6 kW, night shutdown, 30-minute pool program, etc.), the Ecoforest heating system will run trouble-free for the next 12 years? Based on the information I found online in the past few days, I have actually become more optimistic about the Ecoforest heat pump and had already accepted that no decent new offer would come.
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