How Does An Air Source Heat Pump Work:Functions,Type,Benefit

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By Debarghya Roy


Air source heat pumps are an energy-efficient and environmentally friendly option for home heating and cooling. They use the ambient air outside to provide indoor comfort, saving energy and money.

ASHPs improve the indoor climate of your home by providing consistent temperatures throughout.

How Does An Air Source Heat Pump Work

Key Takeaways

  • Air source heat pumps are an energy-efficient and environmentally friendly home heating and cooling solution.
  • Different air source heat pump systems, including ductless, ducted, short-run, ducted split, or packaged models, are available.
  • When assessing different air source heat pump systems regarding costs, energy efficiency, and overall performance, it is essential to determine a property’s specific needs and requirements to make a suitable choice.
  • Signing up for government incentives may offset the cost of purchasing and installing an ASHP system.

Understanding Air Source Heat Pumps

Air Source Heat Pumps (ASHPs) are efficient, innovative solutions for residential and commercial cooling and heating needs.

How Does An Air Source Heat Pump Heating System Work?

Air source heat pumps harness energy from the ambient air and transfer it to a building’s interior. This is accomplished through a system of interconnected components, including an outdoor unit called an evaporator, an indoor unit referred to as the condenser, and a compressor that moves refrigerant between the two units.

Incoming warm air absorbs heat from within the evaporator coils contained in the outdoor unit. The refrigerant then boils as its temperature increases, releasing pressure that allows it to travel inside with no added input of energy or fuel required. Once at its destination, the condenser cools off this superheated gas into liquid form, releasing stored heat indoors before starting another cycle back outside.

How Does An Air Source Heat Pump Work In Winter?

An air source heat pump works in the winter by transferring heat energy from the outside air into your home. The process works through a cycle of refrigerants, which starts at the compressor.

It takes ambient air at one location and compresses it to warmer than its actual temperature before rereleasing it on the opposite side. This compressed air then passes through a series of evaporator and condenser coils with aluminum fins that facilitate efficient heat transfer. The fan moves this heated air throughout your house as needed for heating.

Once all the excess heat has been released from these indoor coils, what’s leftover is pumped towards an outdoor coil, which can be reused during future heating events.

Overall, this integration of refrigeration allows an efficient way to use otherwise wasted external energy sources around us, which is especially helpful during winter when temperatures are low.

How Does An Air Source Heat Pump Work With Underfloor Heating?

Air source heat pumps are specifically designed to work with underfloor heating systems. The air outside is drawn in and then passed through a series of coils, which extract the available heat energy from it.

This heated air is then forced through a fan, pushing warm air into your home and providing efficient space heating. When combined with an underfloor heating system, this process provides an even distribution of warmth throughout any given room or area with minimal effort on the user’s part.

Underfloor heating paired with air-source heat pumps produces higher levels of comfort due to achieving lower flow temperatures for more economical running costs than traditional methods of centralized heat generation.

Are Air Source Heat Pumps Effective?

Air source heat pumps are an efficient, energy-saving way to heat and cool buildings. They transfer heat from one area to another more efficiently than traditional heating systems, resulting in up to 70% energy savings.

In addition, technological advances have enabled air source heat pumps to work even more efficiently in cold weather conditions. As far as installation goes, they can be used with both new builds and existing properties since most designs allow for various configurations depending on the property’s size and layout. Heat pumps often defray some of the costs of purchasing and installing them.

How Do Commercial Air Source Heat Pumps Work?

Commercial air source heat pumps are a popular heating and cooling solution for large commercial spaces. Like residential systems, they collect heat from the surrounding air using one or more outside units that contain compressors, coils, and fans.

This collected heat is then transferred to either water, forced-air flow, or both depending on where it’s needed in the space. In contrast to residential systems designed for limited square footage and more minor energy needs, commercial systems require higher capacity levels to keep up with enormous demand.

These multi-zoned systems often use multiple ground-mounted compressors connected with distribution piping to deliver proper circulation throughout an entire warehouse or office building.

Types Of Air-Source Heat Pumps

Air-source heat pumps come in various types, including ductless and split systems, short-run ducted units, and multi-zone and single-zone configurations.

Ductless Vs. Ducted Vs. Short-Run Ducted Air-Source Heat Pumps

Air source heat pumps come in three main configurations: ductless, ducted, and short-run ducted systems. Each type has pros and cons regarding energy efficiency, installation costs, and overall performance.

TypeEnergy EfficiencyInstallation CostsOverall Performance
DuctlessAlthough ducted heat pumps are generally more energy-efficient, ductless systems are not susceptible to the same type of energy losses as ducted systems due to the absence of ductwork.Installation costs for ductless systems, or mini-splits, range from $2,000 to $8,200.Ductless systems are versatile, as they can heat or cool individual areas, making them ideal for smaller spaces or retrofitting existing buildings.
DuctedAir-source heat pumps with ducts can deliver up to three times more energy than they consume, making them more energy-efficient than ductless systems.Ducted heat pump installation costs range between $1,500 and $10,000.Ducted systems offer more even temperature distribution throughout a building but require more extensive installation and may experience energy losses through ductwork.
Short-Run DuctedShort-run ducted systems are a hybrid between ducted and ductless systems, providing energy efficiency benefits while maintaining the even temperature distribution of ducted systems.Installation costs for short-run ducted systems fall within the range of ducted and ductless systems, depending on the specific design and requirements.Short-run ducted systems are suitable for properties with limited space for ductwork or those looking to balance the benefits of ducted and ductless systems.

Each air source heat pump system type has unique benefits and drawbacks regarding energy efficiency, installation costs, and overall performance. It is vital to assess a property’s specific needs and requirements to determine the most suitable air source heat pump system.

Split Vs. Packaged Air-Source Heat Pumps

Two standard systems regarding air source heat pumps are split and packaged. Each method has advantages and disadvantages, making it suitable for different applications and property types. This section will explore the differences between these systems, their functionalities, and their best use cases.

Split SystemPackaged System
It consists of an indoor coil and an outdoor coilRequires a duct system for air distributionBest suited for properties with crawl spaces or basementsOffers more flexibility in terms of installation locationSeparate components can lead to more efficient operationAll components (coils and fan) are housed in a single outdoor unitAir is distributed through a duct system that passes through a roof or wallIdeal for properties without crawl spaces or basementsRequires less indoor space for installationIt may have slightly lower efficiency compared to split systems

In summary, split systems are better suited for properties with crawl spaces or basements comprising indoor and outdoor components. They offer greater flexibility regarding installation location and can operate more efficiently. On the other hand, packaged systems are ideal for properties without crawlspaces, as all components are housed in a single outdoor unit. They require less indoor space for installation but may have slightly lower efficiency than split systems.

Multi-Zone Vs. Single-Zone

Air source heat pumps can be divided into two main categories: multi-zone and single-zone systems, each with distinct differences in their design, functionality, and energy efficiency. Understanding the pros and cons of each system is crucial for professionals looking to make the best choice for their specific heating and cooling needs.

Multi-Zone Air Source Heat PumpsSingle-Zone Air Source Heat Pumps
Utilizes a single outdoor unit connected to multiple indoor units, creating individual comfort zones within a building.Consists of a single outdoor unit connected to a single indoor unit, providing heating and cooling for a specific area.
Compatible with various types of indoor units, such as ducted or ductless systems.Limited to the specific type of indoor unit, either ducted or ductless, it is paired with.
Offers increased energy efficiency by only heating or cooling the areas in use, reducing energy waste.Less energy efficient, as the system will heat or cool the entire area regardless of occupancy.
Cost-effective compared to multiple single-zone systems, as they have a cheaper upfront cost and lower energy consumption.It may require multiple units for larger areas or uneven heating/cooling needs, leading to increased upfront costs and energy usage.
Multi-zone systems can have two or more outdoor units stacked alongside one another for increased capacity and coverage.Single-zone systems are limited in their capacity and coverage without the option to expand.

In conclusion, multi-zone air source heat pumps offer flexibility, energy efficiency, and cost-effectiveness for residential and commercial applications. However, single-zone systems may be more suitable for smaller areas or where individual temperature control is unnecessary. Ultimately, the choice between multi-zone and single-zone air source heat pumps will depend on the specific needs and requirements of the property in question.

How Air Source Heat Pumps Operate

Air source heat pumps use energy from outside, typically the air, and use compressors to concentrate it before delivering it indoors, significantly reducing heating costs.

Technology Behind Air Source Heat Pumps

  1. Air source heat pumps (ASHPs) are a type of heating system that uses electricity to transfer heat from a cool space (outdoors) to a warm room (indoors), making the cool space cooler and the warm space warmer.
  2. ASHPs use a refrigerant system involving a compressor and a condenser to absorb heat at one place and release it at another. The refrigerant options are typically R-22, R-407C, or the more efficient R410A.
  3. There are two primary types of ASHPs: air-to-water and air-to-air. The air-to-water systems provide heated water to radiators or underfloor heating systems and supply hot water directly. Air-to-air systems, meanwhile, transfer heat via a network of fans and ducts in the property.
  4. The technology operates by circulating the refrigerant around copper tubes, connecting inside and outside evaporator radiator coils. The refrigerant absorbs the heat from the outside air and releases it inside the property, warming the indoor spaces.
  5. The efficiency of ASHPs is often measured by the Coefficient of Performance (COP). The COP typically ranges around 3.2 to 4.2, which means for every 1 kilowatt (kW) of electricity it uses, it can produce 3.2 to 4.2 kW of heat.
  6. A notable feature of many ASHPs is their ability to operate in reverse during summer. Instead of extracting heat from the outside air and transferring it indoors, the heat pump can remove heat from inside the property and transfer it outside, effectively acting as an air conditioner.
  7. ASHPs are considered a more sustainable heating solution as they produce fewer CO2 emissions than conventional heating systems, and they can significantly reduce energy costs.
  8. The longevity of ASHPs, combined with their low maintenance requirements, can lead to a lower total cost of ownership over time. Typically, ASHPs can last between 15 and 20 years, reducing the need for frequent replacements.
  9. Despite the high upfront installation cost, government incentives such as tax credits or rebates may be available in some regions to help offset the initial investment in an ASHP.
  10. As per the International Energy Agency (IEA), using heat pump technology, including ASHPs, could reduce global CO2 emissions by up to 8% annually by 2050.
  11. ASHPs can work efficiently even at low temperatures. Some modern units can extract heat from the air at temperatures as low as -15 to -25°C.
  12. These systems are most effective in milder climates but can also be paired with a secondary heat source (like a furnace) to improve their effectiveness in colder climates.

Efficiency Ratings Of Air Source Heat Pumps

Air source heat pumps (ASHPs) are an energy-efficient and low-carbon residential heating and cooling solution. To determine their efficiency, manufacturers use a Coefficient of Performance (COP) rating system to measure the ratio between delivered energy output versus required electrical input.

For example, in the case of an ASHP, the COP gives information on how much heat is generated from each unit of electricity a device uses. A higher COP generally indicates better performance and more significant cost savings on electricity bills.

Additionally, Seasonal Coefficient of Performance(SCOP) ratings provide more detailed insight into optimal operating temperatures and conditions throughout different climates.

SCOP will vary depending on climate circumstances such as temperature, humidity, etc. Still, they should be three or above with no significant decline throughout various season types over multiple years.

Risks And Precautions

Before making a choice on an air source heat pump system, be sure to research potential risks and precautions associated with its usage.

Noise Levels Of Air Source Heat Pumps

The noise levels of air source heat pumps can vary greatly depending on the type and mechanical components installed, along with other factors such as proper installation and maintenance.

Generally speaking, a modern air source heat pump in good working condition should only make a low buzzing sound similar to an air conditioner. On average, an air source heat pump produces 40-60 decibels, much quieter than traditional fossil fuel boilers.

To ensure optimal efficiency and less sound pollution inside the building, homeowners must hire adequately trained technicians when installing or maintaining their systems. Low airflow can affect the efficiency of a system, while leaky ducts may amplify any sounds produced by whirring fans within the system. The incorrect refrigerant charge can also cause noise issues due to compressor strain problems, which require professional attention immediately.

Refrigerant Alternatives With Low Climate Impact

Air source heat pumps offer excellent efficiency compared to traditional heating systems and present a much lower environmental impact on carbon emissions. A critical factor in determining the climate-friendliness of an air source heat pump lies with the type of refrigerant it uses, as this enables its ability to transfer heat from one space to another.

Refrigerants such as hydrofluorocarbons (HFCs) are commonly used but have high global warming potential due to their leakage rate and recovery at the end of life; alternatives like propane, however, possess considerably fewer environmental impacts.

As an added benefit of energy savings, these ‘low GWP’ coolants make for quiet operation, which negates noise pollution concerns when using air-source heat pumps.

Developments out within Europe could be vital in transitioning away from fluids that contribute significantly to climate change. In October 2019, the European Chemicals Agency listed several new HFD alternatives, which included 1-chloro-3,3,3-trifluoro-1 propene or HFO 1234yf alongside natural options such as R290 (also known as propane) or dimethyl ether and CO2 based techniques labeled R744.

Impact On Electric Utilities

Air source heat pumps are quickly becoming popular with homeowners in residential and commercial buildings due to their efficiency, cost savings, and environmental benefits.

  • The increasing popularity of this technology impacts electric utilities as air-source heat pumps require more electricity per household than traditional heating systems.
  • This can be a challenge for utility companies if they need to prepare for the additional strain placed on the electric grid by many people switching to air-source heat pumps.
  • Innovative grid technology can help ensure that electricity generated from renewable resources such as solar panels or wind turbines is used before other energy production.
  • Smart grids also allow utilities to analyze usage patterns to effectively plan ahead for periods when more energy will be needed – like during cold weather when more households are using their air source heat pump systems.
  • Increasing renewable energy generation increases demand for these power sources, which in turn helps create job growth and economic stability in many regions worldwide.
  • Additionally, increased use of low-carbon energy technologies such as air source heat pumps has been identified as a critical strategy in meeting national climate goals set forth by governments around the globe, including reducing global warming emissions through carbon dioxide mitigation strategies.

Sustainability Of Air Source Heat Pumps

The sustainability of an air source heat pump is a significant factor for many individuals looking to reduce their environmental impact and switch to renewable energy.

Learning how this type of system works, as well as its advantages and potential risks, can help you make an informed decision about which heating option is best for your home or business.

How Air Source Heat Pumps Contribute To Renewable Energy

Air-source heat pumps can extract renewable energy from the air, water, or ground to provide a clean, efficient alternative for heating and cooling buildings.

Modern air source heat pump systems consist of an external high-efficiency compressor and internal refrigerant coils that circulate a liquid or gas called a working fluid through pipes.

The refrigerant transfers heat from cold areas (air, water, or ground) into warm regions. It captures low temperatures at its evaporator coil before releasing it as the warmth from its condenser coil indoors. Some systems also feature fan coils that help design complicated configurations while helping distribute heated or cooled air throughout multiple rooms within one building.

The combined efficiency benefits of using air-source heat pumps ensure that our human activities become more sustainable and less wasteful by reducing unnecessary carbon emissions. Ending their journey in unwanted greenhouse gasses production concluded in global warming events further down the line raising implications on imperatives like rising sea levels threats affecting coastal city dwellers alike today all over the world’s coastlines, making this type of technology a vitally important part of our everyday green future endeavors in the future.

Comparing Air Source Heat Pumps To Alternative Heating Solutions

Air Source Heat PumpsTraditional Heating Systems (Gas Boilers)Ground Source Heat Pumps
Operation MechanismTransfers thermal energy from outside to inside the homeBurns fuel (gas) to heat waterUses subterranean heat sources
EfficiencyHigh, uses one-third to one-fifth of total electricity compared to traditional systemsLower compared to heat pumpsSimilar to ASHPs, dependent on ground temperatures
Carbon EmissionsLow, contributes to fighting climate changeHigher, due to the burning of fossil fuelsLow, similar to ASHPs
CostsHigher upfront cost but potential for significant operational savingsLower upfront cost but potentially higher operational costsHighest upfront costs due to complex installation
Ideal Performance RangeWithin 8°C (46°F) annual average temperatureNot applicableDepends on ground temperatures
Government IncentivesAvailable for some modelsVaries by region and technologyVaries by region and technology
RisksPossibility of leakages if not correctly installed/maintainedRisks associated with burning of fossil fuelsComplex installation process can lead to potential issues
Impact on Utility BillsPotential for significant reductionsCan be high depending on gas pricesPotential for significant reductions
Primary Heat SourceAmbient airGasGroundwater or subterranean locations
Long-term PaybackVaries greatly depending on specific geographic climatesTypically lower compared to heat pumpsDepends on ground temperatures and installation costs

Changing From Oil Fired Heating To Air Source

Switching from oil to an air-source heat pump may be the right choice for many building owners. It can help reduce carbon emissions, decrease fuel costs, and provide safer heating in cold climates.

When considering changing to an air-source heat pump, it is essential to understand how subsidies or incentives can assist with cost savings. The Switching Fossil Fuels Grants Scheme (SFGSS) funds renewable options within England while other countries have their plans available.

Incentivized rates are also available from utility companies depending on your location so 

checking the specifics is key when moving forward with this type of transition since overall energy usage must be considered for optimal performance versus immediate energy savings benefit over more traditional methods during colder months when using electric resistance 

space heating like electric baseboard units.

The installation process is similar but different between oil-fired equipment and heat pumps. Contractors will need specific experience in working with refrigerant systems used in all-air split ducted systems or ductless mini splits if direct expansion services are intended, such as exteriorly housed condensers or interior wall/ceiling mounted fan coils are part of the design plan.

Air Source Heat Pumps In New Buildings Vs existing properties 

Air source heat pumps are an energy-efficient way to provide building heating (and cooling). There are two primary scenarios when installing air source heat pumps: use in new buildings or in existing properties.

  • New Build Homes
    • Installation of air source heat pumps (ASHPs) is generally more straightforward during construction.
    • Opportunities to apply for grants depending on regional legislation.
    • Easier to design within regulatory requirements such as Building Regulations Part L that specify minimum efficiency levels but different technologies to achieve them.
    • New builds can achieve higher system efficiencies as everything is installed from scratch without retrofitting.
  • Retrofitting Existing Homes
    • More capital is typically spent before starting, and any incentives tend to bypass retrofits.
    • Adding renewable electricity-based HVAC systems like ASHPs instead of gas or oil-fired boilers can add significant costs to existing investments.
    • Retrofit installations may face challenges in achieving high system efficiencies due to complex tight-spaced hydronic distribution loops and the need for modified ductwork.

Advantages of ASHPs in New Builds

  • They avoid the need for complex pipe configurations often required in retrofit installations.
  • Combining vented loops through radiators/lake fins, correctly sized variable speed compressors and integrated user interfaces can balance comfort and efficiency.
  • ASHPs in new builds can take full advantage of government-supported zero-emission Zone regulations, especially in major cities worldwide.

Comparisons to Traditional Heating Systems

  • Traditional heating systems can lower upfront costs but may offer different long-term efficiency or eco-friendly benefits than ASHPs.
  • ASHPs, while requiring more significant initial investments, especially in retrofit situations, can deliver superior long-term results regarding both efficiency and environmental impact.

Choosing Between Air Source Heat Pumps And Other Renewable Energy Options

When comparing air source heat pumps to other renewable energy solutions, it is essential to consider each option’s cost, efficiency, and environmental impact. Air-source heat pumps require relatively low upfront installation costs compared with ground-source or geothermal systems; however, air-source systems may have higher operational costs due to lower Coefficient of Performance (COP) ratings.

Solar panels can be expensive to install but offer long-term savings in free electricity generated by the sun’s rays. The main downside is that solar generation requires clear skies and direct sunlight; some homeowners report reduced performance on cloudy days or during midwinter months when daylight hours are shorter than during summer.

Wind turbines also generate electricity from one primary energy source, the wind, but require large plots of land and urban permits and approvals for construction, making them impractical in some regions and challenging for all but professional installers to deploy at a residential scale. Each option has advantages and disadvantages depending on location, budget size, and user preferences; therefore, researching existing government incentives and local climate helps determine the best options for individual situations.


Air source heat pumps are an effective and sustainable heating solution that offer a wide range of benefits, including lower energy costs, environmental friendliness, and minimal maintenance requirements.

They can heat water and indoor space efficiently in new builds or existing properties. Air source heat mods provide an eco-friendly alternative to traditional systems such as oil-fired boilers, making them a viable replacement for homeowners looking for long-term renewable solutions.

Governments may also offer incentives to transition from traditional heating methods to air-source pumps which should be considered when deciding to change the current system.

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