Options for replacing compact heat pump units when renewal is necessary in Passive House buildings
Since the late 1990s, compact heat pump units have been used in passive single-family homes for ventilation, heating and providing hot water. If a compact unit can't be repaired, for example due to a defective compressor or unavailable spare parts, the whole unit usually needs to be replaced. On behalf of the proKlima Energy Fund (enercity-Fonds), the Passive House Institute researched the available options and how they can be assessed from technical and economic perspectives using a terraced house in Hanover as an example.
The study shows that, over its life cycle, replacing a compact unit is the most economical option for the example house. Another alternative is to use a simple, cost-efficient air-to-air heat pump (split unit) in combination with a continuous-flow water heater or a separate heat pump for preparing domestic hot water. Purely electric systems, such as infrared heaters, ultimately offer the least economical solution.
The study can be found here