ᐅ Split air-to-water heat pump

It would be interesting to know: approximately how many operating hours per day, how many kWh it consumes, is your hot water warm enough, does the electric heating element in the hot water tank need to assist, and for how long each day? I am currently deciding for the planned new build: ground loop heat pump or a split system? Including the ground loop, the first option is definitely significantly more expensive to install, and I wonder if the extra effort will really pay off compared to the split system within a maximum service life of 20 years? I am still quite uncertain.

I can't provide you with experience-based advice, but we are facing the same decision. Despite the significant price difference, we are leaning toward the ground probe. Keep in mind that the boreholes will still function in 20 years and won’t need to be replaced. The split unit might need to be replaced after 20 years. Additionally, we don’t like the idea of having to install the split unit outside somewhere.

You’re right, the borehole will probably still be fine after 20 years, but that’s just the heat source, and with a split system, the heat source is the outdoor air, which will still be there in 20 years 😉. My concern is more about the heat pump itself. Even a brine heat pump has a compressor, a filter dryer, and a heat exchanger, which don’t last forever and will eventually need replacement. The outdoor units for split systems are quite affordable, but their lifespan is probably closer to only 15 years. I don’t think there’s a huge difference in repair or replacement costs there. My question is more about the operating behavior of those split units when outdoor temperatures drop below 0°C (32°F)... at some point, the colder the outdoor air, the more they basically turn into pure electric heaters. Even if that’s only for a few weeks a year, that’s exactly what interests me...

I spoke with several HVAC installers, supervisors, and engineers. The clear consensus was: in the short and medium term, air source heat pumps are more cost-effective. In terms of comfort and long-term costs, ground source heat pumps remain the better and more economical choice.

The drilling for the ground source system is a major cost factor. The other components are only slightly more expensive than those of an air source heat pump.

It also depends somewhat on your plans and expectations. If you choose an air source heat pump, it’s advisable to set aside a larger reserve budget, as the split unit will likely need to be replaced sooner. But that is always somewhat uncertain.

I’m also interested in hearing about the experiences of air source heat pump users. So far, I only know of three ground source heat pump users among my friends, and they are all very satisfied.

Don’t forget the potential BAFA subsidy of €4500 (about $4800) for a ground source heat pump, which can significantly offset some of the additional costs.