Air-to-water or ground source heat pump – Which is best for your home? (And which isn't!)

Are you looking for an efficient way to heat your home and make it more sustainable? You'll quickly come across two popular options: the air-to-water heat pump and the ground-source heat pump. But which one is best suited for your situation?

What is an air-to-water heat pump?

An air-to-water heat pump is a sustainable heating system that extracts heat from the outside air and converts it into usable energy for heating your home and heating tap water.

This is how it works in short:

1. Heat from the outside air – The heat pump extracts energy from the air even at low outside temperatures.

2. Refrigerant and compressor – This heat is upgraded to a usable temperature via a refrigerant and compressor.

3. Transfer to water – The heat generated is transferred to the water in your central heating system and possibly to your hot water storage boiler.

Key Benefits

• Energy efficient – ​​Extracts 70–80% of the energy from the outside air, so you need less electricity.

• Sustainable – Reduces CO₂ emissions and often uses environmentally friendly refrigerants.

• Comfortable – Can heat your home, cool it (with some models), and provide hot water.

• Subsidies – In many countries there are subsidies or tax benefits available.

Application

An air-to-water heat pump is usually connected to underfloor heating, low-temperature radiators, or a buffer tank. It's therefore ideal for both new-build homes and well-insulated existing homes.

What is a ground source heat pump?

A ground source heat pump (also called a geothermal heat pump ) is a heating system that extracts heat from the ground or groundwater to heat your home and tap water – and in some cases also cool it.

How does it work?

1. Heat from the earth – At a depth of a few metres, the ground temperature is fairly constant all year round (around 10–12 °C in the Netherlands/Belgium).

2. Source – This heat is extracted via a closed ground loop (pipes filled with a liquid) or an open source (groundwater is pumped up and returned).

3. Compressor – The heat pump increases the temperature using a refrigerant and compressor.

4. Heating and hot water – The upgraded heat is used for underfloor heating, low-temperature radiators and hot tap water.

Advantages

• Constant efficiency – Because the ground temperature is stable, a ground source heat pump delivers a very high efficiency, often higher than an air-to-water heat pump.

• Energy-efficient and sustainable – Up to 80% of the required energy comes from the ground.

• Cooling option – Can provide passive cooling in summer by utilizing the cooler ground temperature.

• Long lifespan – The ground loop often lasts 50+ years.

Disadvantages

• Higher investment – ​​Installation is more expensive than with an air-to-water heat pump, mainly due to the drilling required.

• Permits required – A permit is often required for deep drilling or open source systems.

• Space and soil suitability – Not every plot is suitable, for example due to groundwater levels or limited space.

In short: a ground source heat pump is more expensive to purchase, but delivers the highest efficiency and the most comfort in the long term.

Comparison table

	Air-water	Soil
Purchase price	€8,000 – €12,000	€15,000 – €25,000
Yield (SCOP)	3.5 – 4.5	4.5 – 5.5
Installation time	1 – 2 days	4 – 7 days
Need space?	Few	Source needed in garden

Subsidy 2025

Both systems qualify for an attractive ISDE subsidy. In 2025, you can expect between €2,400 and €4,100, depending on the capacity and source type.

Conclusion

An air-to-water heat pump is ideal for renovation projects or when you want quick results. Choose a ground source heat pump if you're looking for maximum efficiency and are willing to invest for the long term.

ISDE Subsidy 2025: Up to €4,100 for Hybrid and All-Electric Heat Pumps

Good news for those who want to make their homes more sustainable: the ISDE subsidy will be further expanded starting in July 2025. For hybrid systems, you can expect an average of €2,100, while for all-electric systems, the subsidy can reach up to €4,100.

What is changing?

Starting July 1, 2025, heat pumps with higher efficiency will receive additional incentives. A bonus scheme will also be introduced for homes with an energy label of C or lower. Ground-source heat pumps will receive an additional €500 compared to 2024.

Terms and conditions in brief

• Installation by a certified installer
• Product must be on the RVO notification list
• Invoice date must be after July 1, 2025

Direct Current (DC) Heat Pumps: The Silent Revolution?

While most heat pumps currently run on alternating current (AC), a new generation is emerging: DC heat pumps. These systems connect directly to solar panels and avoid losses through inverters.

What are the benefits?

• Up to 10% less energy loss
• Less noise production
• Faster response to heat demand
• Better integration with home batteries

Who is this interesting for?

This is a logical next step for energy-neutral homes and smart grid solutions. Especially for new construction and project development, this can lead to even higher EPC scores.

Air-to-water vs. ground source heat pump – In-depth comparison

Below you'll find a clear, in-depth comparison of air-to-water and ground-source heat pumps. I cover operation, performance, costs, pros/cons, suitability, practical considerations, and decision-making (when to choose which).

1. Short summary

• Air-to-water heat pump : extracts heat from outside air. Lower investment costs, easier installation, slightly lower efficiency at low outdoor temperatures.

• Ground source heat pump (geothermal) : extracts heat from the ground or groundwater. Higher investment, higher and more stable efficiency (COP), longer lifespan, and better performance during cold periods.

2. How they work (briefly)

• Air to water : outdoor unit extracts heat from the air → refrigerant → compressor increases temperature → heat to water (central heating / buffer tank).

• Ground : closed ground loop or open source takes heat from ground/groundwater → heat exchanger → compressor increases temperature → heat to water.

3. Performance & efficiency

• Coefficient of Performance (COP)

  • Air-to-water ratio: typically 2.5–4.0 (depending on outside temperature and system). COP drops in very cold outdoor air.

  • Ground: typically 3.0 – 5.0+ due to stable source temperature. Consistently high efficiency, especially in winter.

• Seasonal yield (SCOP)

  • Air-to-water: Lower seasonal efficiency in colder climates.

  • Soil: higher SCOP due to a more consistent source; often more beneficial in cold winters.

4. Costs (indicative, highly dependent on region & project)

• Purchase & installation

  • Air-to-water: low → moderate (usually the cheapest alternative). No drilling, outdoor unit, or indoor module.

  • Soil: high (drilling/groundworks or groundwater wells cause high installation costs).

• Operation (annual energy costs)

  • Air-water: on average higher than soil for comparable heat demand.

  • Bottom: Lower due to higher efficiency.

• Payback period

  • Air-to-water: Often shorter in low-investment scenarios or when existing infrastructure is suitable; payback period can be 5–12 years (depending on subsidies and energy prices).

  • Soil: longer payback period due to higher investment, but lower annual costs; can be more profitable in the long term (10–20 years), especially with high energy costs and available subsidies.

Note: Exact amounts depend on location (soil type, drilling costs, subsidies). For a concrete calculation, you must request quotes.

5. Space & permits

• Air-to-water : minimal space requirements; outdoor unit mounted on a facade or ground. Usually no special drilling or deep-dive permits required, but local noise regulations must be observed.

• Ground : Space for horizontal loops or the ability to drill vertical probes is required. Permits and soil investigation are often required for open wells and deep drilling.

6. Installation complexity and impact

• Air-to-water : quick installation, minimal impact on garden/ground. Fewer specialist contractors required.

• Soil : Intensive (excavation/drilling), lengthy installation, possible temporary disruption to the garden/site. Requires specialized drilling companies and soil investigation.

7. Sound and aesthetics

• Air-to-water : The outdoor unit is noisy (varies by model). Positioning and distance from neighbors are important.

• Floor : Virtually no noise pollution; main unit indoors (quiet). The aesthetic impact of the outdoor unit is smaller or nonexistent.

8. Lifespan & maintenance

• Air-to-water : outdoor unit ~15–20 years, indoor hydraulics dependent; annual/periodic maintenance recommended (coolant level, fan).

• Ground : ground loop >50 years (closed loop systems), technical heat pump ~20–25 years; maintenance on heat pump, hydraulics and source (for open systems), but ground loop itself requires virtually no maintenance.

9. Environment & CO₂ impact

• Both systems significantly reduce fossil fuel consumption.

• Soil often has a slightly higher yield → lower indirect CO₂ (per kWh of heat).

• Choice of coolant and electricity mix influences overall environmental benefit.

10. When is which option attractive? (decision points)

Choose air-water if:

• You want lower initial costs.

• You have limited space for drilling or do not get permission.

• You want to install quickly or are moving within a short period of time.

• Existing installation (e.g. radiators, central heating boiler) can easily be adapted for low-temperature operation.

Choose a ground source heat pump if:

• You are willing to invest more for long-term savings.

• Your garden/plot and soil are suitable for loops or drilling.

• You want maximum efficiency and stability during cold periods.

• You plan to stay in the same place for a longer period of time (long payback period acceptable).

11. Practical checklist before selecting/requesting quotes

1. Insulation level of home (good insulation increases efficiency)?

2. Available space in the garden (for horizontal loops) or possibility of drilling?

3. Local permit requirements and soil conditions (have a soil survey carried out).

4. Noise restrictions and placement options for outdoor unit.

5. Heating system in the house (underfloor heating = ideal; older high-temperature radiators are less efficient).

6. Available subsidies or tax arrangements (can significantly influence financial choice).

7. Compare quotes from multiple installers including system design, COP/SCOP expectations, and references.

8. Replacement planning (do you want to invest now or wait until the end of your central heating system's lifespan?).

12. Common Misconceptions

• "Ground heat pumps always provide free hot water" — No; they provide heat efficiently but run on electricity. It's not a free source, but it is very efficient.

• Air-to-water heating doesn't work in severe frost — It can work, but efficiency drops; modern systems are suitable for low temperatures and can be supplemented with electric heating or a backup (or combined with solar thermal).

• “Ground is maintenance-free” — The ground loop itself is low-maintenance, but the heat pump installation does require regular maintenance.

13. Recommendation / final advice

• If budget, quick installation, and limited space are important to you, start with air-to-water and choose a quality model with a good COP and low-noise design.

• If you prioritize long-term costs, efficiency in cold periods, and sustainability , and your plot and budget allow for it, consider a ground source heat pump (have a soil survey and multiple quotes carried out).

• In both cases: first optimise insulation and low-temperature systems (underfloor heating or suitable radiators) — this will significantly increase efficiency.

ISDE 2025 – Much more in depth + sample calculation

Many clients don't fully understand subsidies. So have your agent explain this as if you were explaining it to your neighbor, but with technical precision.

Why this subsidy is relevant:

The government is contributing to your switch to a heat pump. Why? Because the Netherlands wants to get off gas by 2030. This scheme is called ISDE – and you can get up to €4,100 back with it in 2025.

Practical example:

Product: Haier HPM10 – 10kW air-to-water heat pump
Purchase price: €10,500
ISDE 2025 (estimate): €2,850
Net investment: €7,650
Payback period (average): 5–6 years

"And if you have solar panels, it will be even faster."

Main conditions:

• Heat pump is on the notification list (RVO.nl)

• Installation by a certified company (such as New Heating)

• Requested within 12 months of installation

• The home is privately owned (different rules apply for homeowners' associations)

Innovation: DC heat pumps – Smart explanation + visual power

The revolution of DC heat pumps

Most systems run on alternating current (AC). But with DC power—direct power from your solar panels—you get a direct connection. No conversion loss, faster response, and a quieter system.

What you as a customer need to know:

• You save 5% – 10% extra compared to AC

• No solar energy conversion required

• Perfect to combine with home batteries

• Ideal for off-grid or energy-positive homes

Use a comparison table like this:

We believe in the power of the air-to-water heat pump . And not just because it's a product we sell. No, because we see its impact in our customers' homes every day. Because we know how well this technology works, how accessible it is to families across the Netherlands, and how it offers the perfect balance between affordability, efficiency, and comfort.

At New Heating, we've installed hundreds of air-to-water heat pumps in recent years. Not just in new construction projects, but also in existing homes. Homes that once had an old central heating boiler , where now, after just one day's work, you'll find a modern system that runs silently, consumes minimal power, and provides the whole family with comfortable warmth and hot water. That's what makes these systems so powerful: they're versatile, scalable, and proven reliable.

We primarily work with Haier models—and that's no coincidence. Haier makes heat pumps that are truly tailored to the Dutch climate. The HPM08, HPM10, and HPM12 are all top-notch. Compact in size, quiet in operation, and highly efficient, even at low outdoor temperatures. What strikes us about the Haier series is its unparalleled price-quality-performance ratio. And our customers feel the difference. In the comfort, in the energy bill, in the noise level—and in the realization that they've become more independent of gas.

What makes air-to-water heat pumps so appealing is their simplicity combined with the enormous gains in energy efficiency. You simply use the always-present outside air as a source to heat your home. Installation requires no deep drilling or major structural changes, and fits perfectly with the existing infrastructure of many Dutch homes. You can combine this heat pump with underfloor heating, low-temperature radiators, and even with your existing pipework. And because we calculate and install everything custom-made, with New Heating you can be sure you'll receive a system that works optimally for your home.

We often hear from customers: "I thought I'd have to do a complete renovation." But the reality is that we can complete many homes in a single business day. Install the outdoor unit, connect the indoor unit, connect the buffer tank, fine-tune the settings—and you're done. After that, the system runs independently, quietly, and efficiently. And because we work with ISDE-certified products, you can apply for a subsidy immediately. The air-to-water heat pumps from Haier, SPRSUN, and Rotenso that we supply are all eligible for this program. This means you can sometimes receive a subsidy of up to €3,000 on an installation that is already surprisingly affordable.

And then there's the point many people wonder about: "Is it warm enough?" Yes, absolutely. Provided it's properly installed. And that's precisely where we make the difference. Our technicians ensure the correct coordination between the heat pump, the distribution systems in your home, and the settings of your controller. We don't leave you with a manual and good luck wishes. We ensure your system performs as promised. And we remain available for maintenance, questions, or expansions with, for example, solar panels or a home battery.

For us, the air-to-water heat pump is the ideal first step toward gas-free living . You don't need to undertake expensive renovations. You regain comfort and quiet. You immediately lower your energy costs. And you increase the value of your home. That's not a pipe dream—it's what our customers are already experiencing.

When you choose New Heating, you're choosing a company that not only understands this work but lives it. They know which models work, which systems make the difference, and invest in quality, service, and trust every day. We believe in the air-to-water heat pump. We install them with pride. And we see the results with families, homeowners' associations, business owners, and everyone who's tired of waiting and wants to start saving.

So don't be fooled by complicated diagrams or apprehension. Let us analyze your home, assess your needs, and immediately advise you on the best air-to-water heat pump for your needs. Chances are, we can show you that making your home more sustainable is simpler, faster, and more affordable than you thought. And once the system is up and running, you'll wonder why you didn't do it sooner.

At New Heating, we make sustainability achievable, understandable, and above all, tangible—every day, in every home, with every system. That's what we do. That's what we're proud of.

And precisely because we're seeing such a huge increase in demand for air-to-water heat pumps, we at New Heating have designed our entire installation process accordingly. Not as one of the options – but as the core of what we do. We've trained teams specializing in these systems, we only work with suppliers who deliver what they promise, and we've now completed hundreds of installations where customers are amazed by the peace, quiet, and comfort such a system provides.

Because let's be honest: people often still associate heat pumps with complicated issues. They think of noise, cold indoors, and technical details you don't understand. But when you see how a Haier HPM series performs, how stable it is – even in the dead of winter – you understand that it's simply a piece of modern technology that does its job quietly. No hissing, no heating, no noise. Just pleasant warmth you barely notice, except on your energy bill – which suddenly drops significantly. That's the difference. Not because we promise it, but because we see it happen every day with our customers.

Our air-to-water systems are also perfectly compatible with solar panels, something a growing number of people are requesting. Your heat pump then runs largely on your own generated electricity – meaning not only lower costs but also a much smaller carbon footprint. We regularly receive photos from customers sharing their energy bills: zero consumption, sometimes even feeding it back into the grid. People who once thought sustainability was unaffordable are now proud they took the plunge. And that's exactly what we want: solutions that aren't just good on paper, but actually work in everyday life.

It's also important to know that we don't just deliver a box of technology. We provide a system completely tailored to your home. You won't get a standard solution with us, no copy-paste installation. We consider your insulation level, your floor space, your heating needs, the location of your home, your family size, and your future plans. Based on that, we build a system that fits. Sometimes that's just a heat pump with a buffer tank. Sometimes we combine it with smart thermostats, additional zone control, or even a connection to your existing central heating boiler as a backup. We deliver what you need. We leave out what's unnecessary.

And we make it easy for you. From the initial orientation to the grant application. We've automated the entire process wherever possible – you can request a quote online, receive a clear overview of costs, grant amounts, expected savings, and payback period. And then we take care of the rest. We schedule the installation, deliver the system, install it professionally and neatly, and show you exactly how everything works. And if you have any questions afterward, we're available. Not just with a chatbot, but with real people. Because we believe in technology and service. That's what makes us different.

The air-to-water heat pump is no longer just for "the neighbors with a Tesla," or for new construction only. It's the solution for those who want to save money now, make their homes more sustainable now, and don't want to wait for legislation, rising gas prices, or vague climate promises. We make it feasible – even if you think your home might not be suitable. We've installed heat pumps in 1960s terraced houses, detached houses from the 1930s, apartments, and even old farmhouses. Each time, we find the right configuration, with the right capacity and settings, so your system does what it's supposed to: heat your home with minimal energy.

And then there's the quiet category. Our Haier heat pumps are ideal for people who are sensitive to noise. The outdoor unit is designed so that the noise level often doesn't exceed 35 to 45 dB—comparable to a gentle rustling sound or a distant refrigerator. And in many cases, we can position the outdoor unit so you'll barely hear or see it. We'll work with you to find the perfect solution. Do you have a narrow side garden, a spacious roof, or a shed where you'd like to install the indoor unit? We've seen it all and always found a solution.

We're also proud to be supporting a growing number of customers in combining air-to-water heat pumps with other energy technologies. Think of heat pump boilers, like our Haier HP200M7 series, or battery-powered energy storage. This isn't the future anymore – it's now. We build complete energy units where the heat pump seamlessly integrates with solar panels, smart meters, and new control systems that optimize your energy consumption. Not just to save money, but also to prepare for the future of the grid. Because the energy transition is coming, and we'll make sure you're ahead of the curve.

We see it as our mission to be not just an installer, but a knowledge partner. That's why we write blogs, create explainer videos, explain everything in plain language, and even use AI to generate new articles based on the latest legislation and trends. This way, you, as a customer, always stay informed about what's happening—without having to follow the news yourself or browse government websites. We filter the information and bring you the relevant information, every week, every month, directly from our practice.

You might have noticed: we're passionate. Not to sell anything, but because we believe in it. Every day, we see the changes in the homes, the lives, and the monthly expenses of people who have taken the plunge. And yes, it often starts with doubt. With the question: "Is this really for me?" But it almost always ends with: "I wish I had done this sooner."

So whether you have a detached house with underfloor heating, a terraced house with old radiators, or an apartment with limited space: don't wait any longer. Let us take a look with you, free of charge. Because where others think it's difficult, we make it easy. And where others wait, we make it happen. We are New Heating. And the air-to-water heat pump? We bring it to your door, with knowledge, care, experience—and a smile.

Let us handle it. That's what we do. Every day. With pride. With passion. With results.