ᐅ Comparison of Groundwater, Ground Source, and Air Source Heat Pumps

Hello everyone,
I am planning a new build (two-story single-family house, approx. 140 m² (1507 sq ft) of living space) and definitely want to use a heat pump for heating. This will be combined with a photovoltaic system and a storage battery. I do not want cooling in the house; I only need the heat pump for heating and hot water. The house will not have a mechanical ventilation system. I have received many different opinions from various experts regarding the heat pump, so I have not reached a clear conclusion yet. Maybe you can help me get a better idea?

Here is a rough summary of the pros and cons I have gathered:

Water-to-Water Heat Pump

• Highest energy yield and efficiency
• High initial costs due to groundwater drilling
• Costs are difficult to estimate in advance; depend on groundwater level and soil conditions

Air-to-Water Heat Pump (recommended by the construction manager)

• Moderate costs
• Low space requirements
• Supposedly sufficient for the house (I am not sure about this)
• The fan is audible (although relatively quiet), which could potentially disturb neighbors or myself

Ground Source (Brine-to-Water) Heat Pump

• Longest lifespan (possibly irrelevant, since after 10–20 years newer technology may be worthwhile anyway)
• Lower initial costs
• High space requirement for ground collectors (not an issue; the garden is large enough)

Based on my non-expert assessment, I would choose the water-to-water heat pump and accept the additional cost of about €10,000. Are there any arguments I might have overlooked? What are the long-term experiences regarding maintenance work, repair, and upkeep costs?

Thanks in advance!

Domestic hot water requires suitable groundwater and approval from the water authority.
There is always a risk that the system may become clogged due to manganese or similar substances.

Brine-water system: deep drilling or horizontal ground collector.

Air-to-water heat pump is the easiest to implement and the most cost-effective option, and naturally, it is capable of heating a 140 m2 (1,507 sq ft) house.

As always, my advice is: more important than the heat source itself is the design of the underfloor heating system and its hydraulics.

First, investigate groundwater and soil conditions; it might not be that expensive. If it is, a brine system is also a good option. Air-to-water heat pumps would be my last choice from the options given.

Only the air-to-water heat pump makes economic sense here. The new systems are also very quiet. I would immediately rule out ground source and groundwater options, as they are very expensive and sometimes unreliable (especially groundwater).

For your home appliances, an air-to-water heat pump is ideal anyway. A gas connection would be even better.

Exactly this question was asked here just 2 weeks ago, but I can’t find the post anymore..

Thanks in advance for the answers! I haven’t found any comparable posts here either. The responses are very contradictory, which leads me to believe that the decision is not straightforward and depends on the specific circumstances. Would you try to commission an independent analysis and consultation? Who would be the best contact for that? There are “experts” everywhere.

I still need to look into ground source heat pumps more thoroughly, especially the advantages and disadvantages of a ground collector versus a deep borehole with probe.

If I understand correctly, a water-water heat pump requires a significant initial investment: test drilling, water analysis, etc. In the end, it might turn out that it’s not worthwhile. To me, that seems like the biggest risk. Unfortunately, no one in the neighborhood has installed a water-water heat pump yet, otherwise that would give a reference point.

@Bookstar : The suggestion about a gas connection wasn’t meant seriously, was it? 🙂

The design of the underfloor heating is important, I understand that. It must be matched to the heat pump. I still need to research exactly what that involves (tips/links are welcome).