ᐅ Heating System Concept for a New Single-Family Home of Approximately 190 m²: Split Heat Pump vs. Ground Source Heat Pump

Hello everyone,

We are currently working with our architect to prepare our building permit / planning permission application. To make good use of the time, I have already asked a heating company for a cost estimate regarding heating, bathrooms, and plumbing.

They proposed two different heating system options:

Split heat pump: Buderus Logaplus package WPLS.2 -8 (an equivalent ELCO unit could also be offered here)
Ground source heat pump: Buderus Logaplus package WPS 1-1 WPS 8K-1, 1HK E plus, buffer tank (an equivalent ELCO unit could also be offered here)

The price difference (after deducting the BAFA subsidy) is about €6,000 (approximately $6,500). According to the heating company, the ground source heat pump will not pay off in energy savings compared to the split system, although it has a slight advantage in efficiency. However, they estimate the ground source heat pump to be lower maintenance and more durable. They also openly admit to being more convinced by the ground source system. In the end, though, the conclusion is that both solutions are “solid” options.

In principle, I find the idea of geothermal energy convincing, but in practice I would like to be able to justify the additional €6,000 (about $6,500) cost rationally.

The system will be installed in a new single-family home without a basement, roughly 190m² (2,045 ft²), with underfloor heating.

So, is this partly a matter of personal belief? Or are there still many missing details I haven’t considered for a final evaluation? What other questions should I be asking myself to move forward in my decision-making?

Best regards from the Ruhr area
Christian

I saw a clear and informative graphic in this forum by a user comparing brine/water and air/water systems, which clearly shows that brine as a source only becomes cost-effective with large energy demands, which don’t occur in single-family homes.
In this respect, your heating installer is correct.

Regarding durability and maintenance, this should mainly concern the outdoor unit with a split system, since the heat pump itself is the same.
I don’t think this outweighs the other factors.

A major advantage of the brine system is that you don’t have a fan unit in your front yard, which can be justified purely from a comfort perspective.

We are currently facing the same problem.
The issue: Ground loop systems have a higher annual performance factor, but the material still needs to be installed underground somehow. For an area of about 150 m² (1,615 ft²), we need roughly 300 m² (3,230 ft²) of ground loop. At a soil depth of 1-2 m (3-6 ft), this would mean excavating approximately 500 m³ (17,660 ft³) of soil. Excavating that volume takes time and is extremely expensive (is this cost already included in the price mentioned above?). If you estimate about €7,000 for the excavation now, you could heat with an air-to-water heat pump for just over one generation before the higher costs of installing the ground loop are recouped through electricity savings.
In the next few weeks, we will be looking at several air-to-water heat pumps, mainly because of noise levels. However, newer units are reportedly much quieter and less noticeable than older models...
Our heating installer says: Ground loop is great and works fairly consistently.
The architect says: Air-to-water heat pumps are now almost as good – the extra cost isn’t worth it.
The energy consultant says: Ground loop is great and better than air-to-water heat pumps.
As always, you ask five people and get six different opinions.

I think this is more about ground probes rather than surface collectors. With current drilling costs – if permitted – that is definitely the more efficient solution compared to the elaborate setup of surface systems.

We haven’t made a decision yet. I want to look into both options more closely. At the moment, I’m leaning towards an air-to-water heat pump, mainly because of the cost. However, this is offset by the €3000 higher subsidy for the other option. So, it’s important to compare the current prices carefully.

Bau_Bambi schrieb:
We are currently facing the same issue.
The problem: Ground loop systems have a higher annual performance factor, but the loop needs to be installed in the ground somehow. For a property of about 150 m² (1,615 ft²), we would need around 300 m² (3,230 ft²) of ground loop area. With a soil depth of 1–2 m (3–6.5 ft), that means approximately 500 m³ (17,660 ft³) of soil needs to be excavated. Excavating this amount takes time and is extremely expensive (is this already included in the price above?). If we estimate about €7,000 for excavation work, you can heat with an air-to-water heat pump for just over a generation before the higher installation costs of the ground loop are recouped through electricity savings.
We will be looking at several air-to-water heat pumps in the next few weeks, mainly because of noise levels. However, newer devices are said to be much quieter and less noticeable than older models...
Our heating installer says: Ground loop systems are great and operate quite consistently.
The architect says: Air-to-water heat pumps are now similarly efficient – the extra cost is not worth it.
The energy consultant says: Ground loop systems are superior and better than air-to-water heat pumps.
As usual, you ask five people and get six different opinions.

According to our heating installer, a ground loop heat pump with horizontal loop fields is not feasible for us due to the size of the property and garden. This means my quoted price refers to geothermal boreholes with a drilling depth of 70 m (230 ft).

Bau_Bambi schrieb:
Our heating engineer says: Ground source is great, it always operates quite consistently.
The architect says: Air-to-water heat pump is now similarly good – the extra cost is not worth it.
The energy consultant says: Ground source is great and better than air-to-water heat pump.

Every opinion is valid.
Does the heating engineer say that air-to-water heat pumps are significantly worse?
I fully agree with the architect.
Does the energy consultant explain why ground source is better and when it pays off? That would quickly put his initial statement into perspective.

Bau_Bambi schrieb:
The problem: Ground source has a higher seasonal performance factor, but the system has to be installed in the ground somehow. Assuming about 150sqm (1600 sq ft) for us, we need approximately 300sqm (3200 sq ft) of ground source area. At 1–2m (3–6.5 ft) depth, that would mean removing around 500m³ (660 cubic yards) of soil.

I understood the original poster more as meaning drilling is planned. Not a horizontal ground collector (which could be installed quite easily by oneself).