Thinking of replacing your old boiler or reducing soaring energy bills? Air-to-water heat pumps are a cleaner, more efficient way to heat your home and water, even when it's cold. This guide shows you how to pick the best option for comfort, savings, and a greener future.
An air-to-water heat pump is an efficient and eco-friendly heating option. It works well for both homes and businesses. It takes heat from the outside air, even when it's cold, and moves that energy to water. The hot water moves through your radiators, underfloor heating, and hot water systems. This process offers dependable heating and hot water. It also cuts down on fossil fuel use compared to traditional boilers.
Air-to-water heat pumps help reduce your home's carbon footprint and increase energy efficiency. As experts in renewable energy systems, we understand their importance.
Air-to-water heat pumps operate using a proven vapor compression cycle. Here’s how the process works, step by step:
Heat Extraction: The outdoor unit takes in up to 3 units of free, renewable energy from the air, even when it’s cold.
Electric Drive: The compressor uses 1 unit of electricity from the grid or solar panels. It raises the temperature of the absorbed heat.
Heat Distribution: The total energy of 4 units goes to your water heating system. This can reach an efficiency of up to 400%.
For every unit of electricity you use, you get up to four units of heat energy. Heat pumps are among the most cost-effective and sustainable options available.
*Pro Tip: To boost performance, connect with solar PV. This can cut costs and reduce carbon emissions. Our team has helped many clients create custom solutions. If you need professional help, we’re here for you.
Monobloc Heat Pump: What is it? A monobloc air-to-water heat pump has all the main parts in one outdoor unit. This includes the compressor, evaporator, and condenser. This unit connects to the hot water tank and heating system inside the building. It uses only water pipes for this connection. This design makes installation easier. It also cuts down on complex refrigerant piping. This is great for places with little indoor space or tough access.
| Advantages | Disadvantages | Ideal Scenarios |
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Split Heat Pump: What is it? Split systems consist of an outdoor unit and an indoor unit. Refrigerant pipes link the two. Heat exchange happens indoors in the hydrobox. This setup provides more flexibility for system layout and maintenance. It works well for projects needing custom performance or complex installations.
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Only Domestic Hot Water ：
| Function | Ideal Application | Product |
Supplies domestic hot water only |
| Domestic Heat Pump Water Heater |
Space Heating and DHW Models:
| Function | Ideal Application | Product |
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| Heating and Cooling Heat Pump |
Heating and Cooling Swimming Pool :
| Function | Ideal Application | Product Example |
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| Swimming Pool Heat Pump |
Greenhouse Gas Reduction: The International Energy Agency (IEA) states that heat pumps generate 2 to 4 times more heat per kWh of electricity than standard electric heating. This makes them much more efficient and helps lower CO₂ emissions 1.
Key data: In 2022, record growth in heat pump sales was seen in both Europe and the United States. Although they have increased, heat pumps still provide only about 10% of global heating needs in buildings. To meet the IEA's Net Zero Emissions by 2050 goal, global heat pump capacity needs to almost triple by 2030. 2
Impact: Nearly half of the expected reduction in fossil fuel use for heating in buildings by 2030 is projected to come from heat pump adoption. 1.3.
Source:
Government Subsidies & Incentives: National and regional incentives are speeding up heat pump adoption.
1. European Union: The REPowerEU plan has raised almost €300 billion for energy transition. It funds big heat pump projects. Homeowners can get direct subsidies, often several thousand euros for each installation. 456.
2. United States: The Inflation Reduction Act (IRA) provides a tax credit up to $2,000 for eligible heat pumps. Also, there are state-level rebates for low- and middle-income homes. ENERGY STAR Most Efficient heat pumps can get these incentives until at least 2025. 789
| Country | Policy |
| Germany | Bundesförderung für effiziente Gebäude - BEG |
| France | MaPrimeRénov' |
| United Kingdom | Boiler Upgrade Scheme - BUS |
| Italy | Superbonus & Ecobonus |
| Netherlands | Investeringssubsidie duurzame energie en energiebesparing - ISDE |
| Austria | 'raus aus Öl und Gas' für Private |
Market Growth and Climate Targets:
1. In 2023, global heat pump sales exceeded 20 million units, reflecting a major trend shift in both Europe and China. 3
2.By 2030, the EU’s policies aim to double the deployment rate, supporting Paris Agreement and national climate commitments. 46.
Sources:
| Aspect | Heat Pumps | Boilers |
Initial Cost | Higher | Lower |
| Operating Cost | Lower (high efficiency) | Higher |
| Environmental Impact | Low (especially with renewable electricity) | High (fossil fuel dependent) |
| Performance in Cold Climate | Limited without supplementary systems | Reliable |
| Energy Efficiency | High in mild climates | Moderate to low |
Cost Comparison
| System | Initial Cost | Annual Operating Cost |
| Heat Pump | $8,000 - $15,000 | $500 - $1,200 |
| Gas Boiler | $4,000 - $8,000 | $1,500 - $3,000 |
| Oil Boiler | $6,000 - $9,000 | $1,800 - $3,500 |
*Actual costs vary by country, subsidy policy, energy prices, and equipment brand. Data sources: U.S. Department of Energy, IEA, Consumer Reports 2023–2024.
Sources:
Choosing the right air-to-water heat pump is key for comfort and energy efficiency. This is especially true in Europe. There, insulation and temperature changes can be quite significant. Correct sizing ensures optimal year-round performance.
Undersized: It can’t heat your home well in winter. This lowers comfort and may raise your electricity bills.
Oversized: It causes frequent cycling on and off. This reduces efficiency, increases wear, and adds extra upfront costs.
Consider key factors like home insulation, glazing, orientation, and local climate. It’s best to use a professional heat load calculation, such as EN 12831 or a Manual J equal for Europe.
| Home Size (m²) | Recommended Capacity (kW) | Recommended Capacity (BTU/hr) |
| Up to 90 | 4–6 | 13,600–20,500 |
| 90–140 | 6–8 | 20,500–27,300 |
| 140–180 | 8–10 | 27,300–34,100 |
| 180–230 | 10–12 | 34,100–40,900 |
| 230+ | 12–16 | 40,900–54,600 |
*These values apply to a modern European home that is well-insulated. It meets EPBD or Passivhaus standards. It is located in a moderate climate with average ceiling heights. Homes with less insulation or in colder areas need more output (ask a professional).
The compressor is the heart of a heat pump. It affects energy efficiency, comfort, and noise levels. Modern European heat pumps usually have variable-speed (inverter) compressors. These compressors are flexible and efficient, especially in changing weather. The three main types of compressors used in heat pumps are:
| Compressor Type | Efficiency | Comfort Stability | Noise Level | Initial Cost |
| Fixed-Speed | Moderate | Low | Moderate | Lower |
| Inverter (Variable-Speed) | Excellent | High | Low | Higher |
Explanations:
Fixed-speed compressors operate at a steady speed. They provide decent efficiency and comfort. Noise levels are moderate, and they also have a lower initial cost.
Inverter compressors adjust their speed at all times. This leads to better efficiency, steady comfort, and quieter operation. But they do need a bigger upfront investment.
(Based on EU Ecodesign Regulation 813/2013 & EN 14825)
| Climate Zone | Representative Location(s) | Test Conditions (Ambient Temp) | Minimum SCOP (Seasonal Coefficient of Performance) | Minimum SEER (Seasonal Energy Efficiency Ratio) |
| Mild | Mediterranean (e.g., Athens) | ~2°C (Heating season average) | ≥3.5 | ≥6.1 |
| Moderate | Central Europe (e.g., Strasbourg) | -7°C to -10°C | ≥3.2 | ≥5.9 |
| Cold | Northern Europe (e.g., Helsinki) | -20°C to -22°C | ≥2.8 | ≥5.7 |
Explanation:
SCOP (Seasonal Coefficient of Performance): It shows how well heating performs in winter. It takes outdoor temperature changes into account.
SEER (Seasonal Energy Efficiency Ratio): Measures how well a system cools during the cooling season.
These values show the minimum rules set since 2015. Many premium heat pump models go beyond these standards.
HSPF (Heating Seasonal Performance Factor) is mainly used in North America; in Europe, SCOP is preferred.
Testing and certification involve strict lab measurements. These tests are done under typical seasonal profiles, following EN 14825.
Noise comfort is a crucial consideration, particularly in residential neighborhoods and multi-family buildings. A low-noise heat pump creates a nicer environment inside and outside. Recommended maximum noise levels for common installation sites follow European and manufacturer guidelines:
| Measurement Distance | Recommended Noise Level (dB(A)) | Notes |
| 1 meter | ≤ 40 | Ideal for sound pressure level close to the outdoor unit, especially near bedroom windows |
| 4 meters | ≤ 35 | Typical distance to neighboring properties or general outdoor ambient measurements |
The actual heating capacity at low temperatures varies among models. Make sure the model you pick can handle your home's highest heating needs, even in the coldest weather.
| Outdoor Temperature | Heating Capacity Efficiency |
| 47°F (7°C) | 100% |
| 17°F (-7°C) | 80–90% |
| 5°F (-17°C) | 70–85% |
| -4°F (-20°C) | 50–75% |
Explanation:
“Heating Capacity Efficiency” expresses the percentage of nominal/rated output the heat pump can deliver as temperatures decrease.
Values shown reflect high-quality, cold-climate-certified models commonly available in Europe and North America.
Performance at extreme cold may vary—always consult manufacturer datasheets and national certification lists (such as NEEP Cold Climate Heat Pump Product List or Eurovent Heat Pump Certification).
Selecting a heat pump from a reputable brand ensures reliable performance, superior build quality, and strong after-sales support. Consider brands known for:
| Brand | Origin | Notable Strengths |
| Daikin | Japan | Reliability, wide product range |
| Mitsubishi Electric | Japan | Superior cold-climate performance, innovation |
| Bosch | Germany | Efficiency, long-standing presence in Europe |
| Viessmann | Germany | High-end build quality, advanced integrated controls |
| Carrier | USA | Innovative technologies, strong international support |
| Panasonic | Japan | Quiet operation, durable compressor engineering |
| NIBE | Sweden | Advanced efficiency, outstanding performance in cold |
| SolarEast | China | Cost-effectiveness, strong OEM/ODM manufacturing |
Switching to R290 refrigerant is becoming the norm in Europe due to tight environmental rules. Starting in 2025, the EU will phase out high-GWP refrigerants. They will promote natural alternatives, such as R290. This aims to reduce greenhouse gases and maintain high efficiency. Many European markets now favor R290 as a sustainable, future-proof heating option.
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Combining your heat pump with a PV solar system and battery storage saves you money. This setup uses renewable solar energy to its fullest.
*Operating Principle: Solar panels create electricity when the sun is out. This power can be used right away by the heat pump or saved in batteries for later. This helps lessen the need for grid electricity.
| Scenario | Annual Electricity Cost ($/€) | Typical Annual Savings |
| Heat Pump Only | $1,200 / €1,100 | - |
| Heat Pump + PV | $600 / €550 | 50% |
| Heat Pump + PV + Battery Storage | $350 / €320 | 71% |
*Actual results vary by local utility rates, insulation standards, solar system size, and climate.
Hybrid heating systems combine heat pumps with traditional methods, such as gas or oil boilers. This combination boosts efficiency and reliability.
*Operating Principle: The system smartly switches between the heat pump and traditional boiler. It does this by considering outdoor temperature, cost, and efficiency.
| System Type | Annual Operating Cost ($/€) | Annual Savings Compared to Boiler Only |
| Boiler Only | $2,500 / €2,300 | - |
| Hybrid System | $1,300 / €1,200 | 48% |
*Actual savings will depend on local fuel costs, efficiency of components, building insulation, and weather conditions.
Air-to-water heat pumps can be installed in many places. The choice depends on the building type and the space available. Common installation scenarios include:
Balcony: Ideal for apartments or homes lacking ample outdoor ground space. Balconies offer easy access. However, you may need to think about vibration and noise control to meet local rules.
Rooftop: Makes use of empty roof space. This cuts noise at ground level and keeps the look nice. It is often preferred in urban settings and multi-story buildings.
Garage: Raised platforms designed to improve airflow. They also make it easier to service heat pump units in garages or enclosed spaces.
Garden: Suitable for detached or standalone homes with enough outdoor space. Allows for straightforward installation and optimal airflow, often resulting in improved system efficiency.
Pre-installation Checklist for Air-to-Water Heat Pumps
Check that the installation site is sturdy and has enough space for the heat pump. Also, ensure there's easy access for servicing.
Review local building codes and get all necessary permits before installation.
Assess noise levels and consider the location relative to bedrooms or noise-sensitive areas.
Plan for adequate drainage to safely remove condensation generated during operation.
Verify that the heat pump is accessible for routine maintenance and servicing.
Look at the site for shading, obstructions, or anything that might block airflow and reduce system efficiency.
Talk to heat pump installers or HVAC experts. They can help you size your system correctly and find the best spot for the equipment.
Picking the right contractor for your heat pump installation is key. It helps your system work well, last longer, and perform at its best. Here are key factors to consider:
Experienced contractors who work with well-known heat pump brands understand the systems better. They know how these systems perform in different climates.
*Tip: Contractors who have long-term ties with trusted manufacturers usually offer better skills and steady product quality.
Contractors who keep learning and stay updated with new tech can offer better solutions. This leads to improved performance and energy efficiency.
*Tip: Ask for information about recent certifications or technology training they have completed.
Check for key certifications like Keymark, BAFA-Liste, ErP energy ratings, and CE marking. These ensure that products meet strict European safety and efficiency standards.
*Tip: Always validate contractor and product certifications directly with recognized certification bodies.
Pre-Sale: Expert consultation on system sizing, installation planning, and incentives.
Installation: Skilled, brand-trained technicians ensure safe, efficient, and code-compliant setup.
After-Sale: Reliable maintenance, quick troubleshooting, and warranty management.
Global & Local: Get genuine parts and technical updates from worldwide manufacturers. Our local teams know regional rules and climate well.
*Tip: Always ask for details about pre-install and post-install services. This helps ensure good performance and peace of mind.
Check warranty coverage for key parts like compressors, water tanks, and control electronics. Extended warranties show that manufacturers are confident. They also give you extra peace of mind.
*Tip: Consider contractors who work with manufacturers offering generous and transparent warranty terms.
Check real user reviews on platforms like Google, Trustpilot, and specialized HVAC forums. Also, get feedback from professional installers and industry peers. This helps you understand brand reliability and how well contractors perform.
*Tip: Before making a final choice, talk to several HVAC specialists. This way, you’ll get useful and varied insights.
Application: Swapped out an old boiler system for a 300-unit domestic hot water heat pump system in a busy hotel.
Result: Achieved about 55% savings on annual electricity costs. This cut operational expenses while still providing reliable hot water for guests.
Application: A commercial space heating system was set up to warm a big office complex in Romania.
Result: The system maintained a steady indoor temperature, even at -12°C. This cut heating costs by over 45% and boosted the building’s energy efficiency rating.
Application: Deployed a commercial swimming pool heat pump system for a large water park.
Result: Year-round pool operation is now possible. The water temperature stays stable, leading to a 60% cut in energy use compared to old electric heating systems.
1. I heard that heat pumps don't feel as warm as traditional boilers. Will it be cold in winter?
This is a common misconception. Traditional boilers provide intense, short bursts of high-temperature heat. In contrast, heat pumps deliver consistent and evenly distributed warmth.
Heat pumps run longer on less power. This helps keep a steady indoor temperature without big changes.
If the system is sized and installed correctly, it will keep your home warm, even in the coldest winter.
2. What if my household uses a lot of hot water during morning and evening peak times?
It depends on the size of your hot water tank.
A qualified installer will suggest the right capacity for you. They consider your family size and habits, like taking showers at the same time or using a large bathtub.
A good system gives enough hot water for the whole family. You won’t run out in the middle of a shower.
3. Will the heat pump stop heating during defrosting? Is it noisy?
Defrosting: In humid, cold weather, outdoor units may frost up. Modern heat pumps have intelligent automatic defrosting. Most cycles run for only a few minutes. Premium models can keep indoor heating going with internal loops or extra heating.
Noise: Defrosting can be a bit louder than usual, but it's still acceptable. Pick a quiet brand, such as Panasonic or Daikin. Also, place the outdoor unit away from bedroom windows. This helps reduce noise.
4. Does the $8,000–$15,000 price include everything? Are there hidden costs?
Always request a detailed itemized quote. A full installation cost should include:
Heat pump unit and water tank
Pipes, valves, brackets, and other materials
Installation labor
Electrical upgrades (if needed)
Removal of old equipment
Radiator upgrades (if incompatible with heat pump system)
5. How long does it take to recover the investment? Your payback period depends on:
Local electricity and gas/fuel prices
Government subsidies or incentives
Efficiency of your old system (the less efficient, the more you'll save)
Check the efficiency of your new heat pump (COP). Then, ask your installer for a personalized ROI analysis based on your past energy bills. In high-energy-cost areas, payback typically falls between 5–10 years.
6. My house is old with poor insulation. Can I still install a heat pump?
Yes, but consider the following:
Energy audit: Identify heat loss points like the attic or window seals. Basic insulation upgrades can dramatically improve heat pump efficiency.
Choose a high-temperature model: If you have old cast iron radiators, select a unit capable of higher output temperatures (65–75°C).
Set realistic expectations: Poorly insulated homes will always cost more to heat. A heat pump can still save money compared to a boiler. However, the savings may be smaller in a modern, well-insulated house.
7. What's the lifespan of a heat pump? Is it hard to maintain? What if it breaks?
Lifespan: A well-maintained heat pump can last 15–20 years, similar to a boiler.
Maintenance: Basic upkeep is simple—just clean the filters regularly. It’s recommended to have a professional inspection every 1–2 years.
Repairs: This is why choosing a reliable brand and certified installer is key. They can provide fast service and genuine parts. Check the warranty terms and emergency repair steps before signing the contract.
Ready to ditch high energy bills and your outdated boiler? An air-to-water heat pump isn’t just a replacement. It’s a wise choice for a comfy, eco-friendly, and budget-friendly future at home. It uses free energy from the air to give you dependable heating and hot water. It's also very efficient.
Choosing the right system and a trusted installer is key to unlocking these benefits. A professional installation ensures your system runs at its best. This guarantees your comfort and peace of mind for the next 15 to 20 years.
Stop guessing about your potential savings. Contact our experts today for a free, no-obligation home assessment.
We'll give you an accurate heat-load calculation. Then, we'll suggest the best system for you. Finally, we'll provide a clear breakdown of your costs and long-term savings. We can help you find government incentives for a warmer, greener, and more affordable home.
