Air Source Heat Pump Drawbacks You Can’t Afford To Ignore

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By Debarghya Roy


Air source heat pumps are popular eco-friendly heating systems, designed to provide a home with affordable warm air. They work by taking in outside air and compressing it until it reaches a set temperature. While the upfront costs for an Air Source Heat Pump (ASHP) can be expensive compared to traditional heating systems, their running costs could end up being lower over time. However, there are many disadvantages associated with air source heat pumps that need to be considered before investing in one.

air source heat pump disadvantages

An image depicting the air source heat pump

Key Takeaways

  • Air source heat pumps come with higher upfront costs and require extra installation space compared to traditional heating systems.
  • Their performance decreases in colder temperatures below 0°C, leading to increased electricity bills due to lower overall energy output.
  • Lifestyle changes or renovation projects may be necessary for optimal soundproofing and insulation requirements from the outside of a property.
  • Alternatives like ground source heat pumps, biomass boilers, gas boilers, electric heating and solar thermal panels can provide a renewable eco-friendly option that do not depend on electricity but still cost less than air source pumps in terms of long term running costs.

The Disadvantages Of Air Source Heat Pumps

Air source heat pumps have several disadvantages when choosing a heating system, such as 

Higher Upfront Costs

One disadvantage to purchasing an air source heat pump is the initial cost. The equipment, installation, and additional insulation requirements for an ASHP all add up to a substantial investment of time and money that must be factored in when deciding whether to use this heating solution.

Air source heat pumps typically require an extensive retrofitting process and increased surface area from larger radiators or sometimes even extra wall space for placement in order to operate efficiently.

Additionally, some homes may need extra insulation in attics or other areas where ducts carry cold air that could reduce their performance during freezing temperatures.

Reduced Efficiency In Colder Temperatures

Air source heat pumps tend to have reduced efficiency when the temperature drops below 0°C, especially compared to other conventional heating sources. 

This is due in part to their Coefficient of Performance (CoP) rate, i.e., the ratio of energy output relative to the amount consumed.

The lower the outdoor temperature, the lower this measure becomes, and as a result less energy can be lost from a property or environment. 

Essentially this means that air source heat pump users could find themselves paying more for electricity than if they were using traditional methods such as gas boilers for their primary heating needs.

The higher cost also equates to a decreased ability to produce adequate heat in cold periods where temperatures dip temporarily over 0°C often during winter months with owners relying on secondary heating solutions as well.

Dependence On Electricity

Air source heat pumps are dependent on electricity in order to function properly. This means, as a homeowner, you will need access to reliable and affordable electricity in order for your heat pump to work effectively.

In comparison with traditional heating systems such as fossil fuel boilers or electric radiators, air source heat pumps typically require more energy input overall which may result in an increased cost compared to other forms of heating when running continuously.

This could mean higher bills over the course of the year if the temperature drops drastically and large amounts of energy are required to maintain comfort levels inside the home.

Extra Installation Space Required

Air source heat pumps require more space than traditional boilers in order to be installed, and carefully consider the location. This is because it needs an outdoor unit which should be away from direct sunlight or any other risk of overheating, usually placed on a wall outside the house.

Another factor regarding installation spaces is aesthetics. Many people are concerned about how these units affect their home’s external look, as well as keeping noise levels low.

Furthermore, maximizing the heating efficiency of an air source heat pump requires adequate insulation throughout your property, otherwise there could be serious losses during peak operation times due to inadequate retainment of hot air indoors during winter time.

Specific Air Source Heat Pump Disadvantages

Little issues such as noise pollution and placement concerns, lesser efficiency in cold temperatures, and additional insulation costs can compound into a bigger issue.

Noise Pollution And Placement Concerns

Air source heat pumps are becoming increasingly popular due to their cost-efficiency and environmental friendliness. However, they do come with some disadvantages in terms of noise pollution and placement concerns.

Air source heat pump systems generate noise from the fans operating 24/7, which can cause buzzing, vibrating or humming sounds in the garden area. As a result of this operational noise, there could be disturbance to neighbors or wildlife depending on how close they live relative to the system located outside.

Therefore, proper placement of air source heat pump units is important for reducing its noise impact on the environment and people living nearby. 

Generally speaking an ideal location should be away from windows at least three meters apart for low levels of health risks associated with infrasound levels such as vibration feeling and hearing loss respectively.

Also an appropriate envelope needs to be chosen so that it mitigates any possible acoustic emission losses indoors by blocking out sound internally yet allowing airflow around the unit outside.

Efficiency Decreases In Very Cold Weather

In colder climates, the outdoor ambient temperature affects air source heat pumps directly, since these units rely on outside air for their operation. 

Therefore, when temperatures drop below freezing point and get lower than 0°C (32°F) an air source heat pump struggles to cope with increased demand as it has to transfer energy from colder outside temperatures into warmer inside space.

Moreover, if extreme cold weather continues and stays below -10°C (14°F), some models may not perform at all or have extremely low efficiency levels due to insufficient capacity of filters and other components that are affected by severe conditions.

However, Mitsubishi’s cold climate heat pumps can operate up to 400% efficiency in moderate weather meaning they can produce four times as much energy than is consumed making them an ideal choice for places with harsher winters.

Extra Insulation Costs

For air source heat pump owners, properly insulating their home can greatly reduce their energy bills and improve the efficiency of air source heating systems. 

High levels of insulation help to keep warmth in the house, reducing the amount of energy required to heat it. Having insufficient insulation around window frames, doors, attics, walls and flooring could mean that a homeowner may be losing up to 30% or more of warm air generated by an air source heater within 24 hours.

To get optimal performance out of your unit you must invest in appropriate materials such as modified Polystyrene sheets for ceilings and walls as well as double glazed windows that use Low E-coatings which helps reflect heat back indoors while minimizing solar gain from outside sources.

Alternatives To Air Source Heat Pumps

For those seeking a more cost-effective and eco-friendly way to heat their home, there are various alternatives.

Ground Source Heat Pumps

Ground source heat pumps, also known as geothermal or geoexchange systems, are an energy-efficient and eco-friendly heating and cooling solution for properties.

These systems consist of a ground loop buried below ground level which absorbs naturally occurring warmth from the Earth’s surface to warm a building during winter and cool it in summer.

Ground source heat pumps use much less energy than air source heat pumps, due to their greater efficiency at transferring thermal energy stored in the earth. This higher efficiency translates into lower electricity bills over time despite its greater upfront cost due to the need for a dedicated underground ‘ground loop’ system.

In addition to lower running costs, these systems reduce pollution often associated with combustion-based sources of heating like gas boilers because they do not involve burning fuel onsite for operation.

Image of ground source heat pump

Biomass Boilers

Traditional heating systems that use fossil fuels, like gas and oil boilers, emit carbon emissions. As part of a renewable energy system in homes, biomass boilers are an alternative to air source heat pumps.

These boilers burn organic matter such as wood chips or pellets to generate heat. Biomass can be sourced from sustainable sources with the corresponding environmental benefits.

The installation requires significant space to house the large components of individual renewables systems. 

For example larger radiators may need to be installed so the biomass boiler doesn’t have to work as hard and will remain effective throughout its life-span up to 20 years.

Gas Boilers

Gas boilers provide a reliable and efficient heating system for homes in colder climates. Natural gas is typically cheaper than electricity and oil, making it an affordable option for many households.

Gas boilers are able to generate an output of heat quickly, allowing them to be more effective at meeting specific heating needs when compared to air source heat pumps which may have slower reaction times due to their reliance on electricity.

However, even with fan assistance, gas boilers often struggle to meet higher house temperatures during cold spells or extreme weather conditions whereas air source heat pumps seem less affected by these environmental factors.

Furthermore, it is important to note that while natural gas has historically been the cheaper option long-term when compared with other fuels such as electricity and oil

Electric Heating

Electric heating is an increasingly popular alternative to air source heat pumps, particularly in climates where the temperature falls below freezing for extended periods.

Electric heating offers several advantages over traditional air source heat pump systems such as its simplicity and smaller size. Instead of relying on a complex system involving condensing, evaporating, and units using refrigerant gas to draw heat from the outside air, electric heating relies solely on electricity for energy conversion.

This means that electric heating systems require neither additional installation space nor extra insulation costs like those needed with some other forms of renewable energy infrastructure.

Solar Thermal Panels

Solar thermal panels are an increasingly popular choice for people who want to reduce their reliance on non-renewable energy sources. These panels can be used to power air source heat pumps and offer several benefits, including reduced electricity bills and lower carbon emissions.

By harnessing the sun’s heat, solar thermal systems provide a clean energy alternative that is more cost-effective in the long run than other traditional heating methods like gas or oil boilers.

Combining solar thermal panel systems with air source heat pumps provides additional flexibility. When electricity production from solar cells cannot meet demand due to prevailing weather conditions or prolonged winter darkness periods, then back up services provided by air source pumps become available.

How To Mitigate Air Source Heat Pump Disadvantages

By selecting an efficient model, installing extra insulation and optimizing the placement of your heat pump for minimal noise pollution, you can maximize the performance of your air source heat pump system.

Choose A High-efficiency Model

When shopping for an air source heat pump, it is important to consider the Seasonal Coefficient of Performance (SCOP). This rating indicates how much energy is used by the unit compared to what is generated over a three-month period.

A higher SCOP means that more energy will be saved and efficiency will increase. Installing a high-efficiency model can help minimize some of the common disadvantages associated with air source heat pumps, such as reduced performance in colder temperatures and dependence on electricity.

Additional advantages include improved comfort levels, lower running costs, and reduced environmental impact due to fewer GHG emissions from burning fossil fuels for heat generation.

Install Extra Insulation

Extra insulation is essential when installing an air source heat pump in order to ensure that the maximum amount of generated heat is utilized, and not wasted.

Insulating the walls and floors of a property before installing an air source heater will reduce running costs as less energy usage resources are needed for heating homes or businesses.

There are various types of insulation materials available including spray foam, mineral wool, batt/blanket fiberglass, cellulose loose fill, reflective installed system (RIM) and rigid foam board.

Each material has its own advantages and disadvantages so it’s important to consult with a professional to find out which type best suits you needs. Installing extra insulation can also contribute toward reducing carbon emissions from large buildings by increasing energy efficiency as more hot air is retained within the spaces located within a property.

Optimize Placement For Minimal Noise Pollution

Air source heat pumps produce significant operational noise, which can cause problems with neighbors and reduce the user’s quality of life. In order to limit this issue, it is important to properly plan for installation placement.

It is best practice to install air source heat pumps away from bedrooms and living areas in order to prevent noise complaints from neighbours or other occupants.

Sound barriers are also available and should be strategically placed and angled, usually upwards in order to limit exposure within a certain area.

Is An Air Source Heat Pump Right For You?

Air source heat pumps come with pros and cons that must be considered when determining whether it is the right choice for you.

Climate And Temperature

Climate and temperature are important factors to consider when selecting the right type of air source heat pump. 

In warmer climates, SEER stands for Seasonal Energy Efficiency Ratio, and is a measure of how efficiently an air-source heat pump cools in BTUs per hour (BTU/h) divided by the amount of energy it takes to operate over the course of a cooling season.

On the other hand, in cooler climates where homeowners rely on their air source heat pumps for heating as well as cooling, HSPF stands for Heating Season Performance Factor, i.e., a measure of how effectively an air-source heat pump heats in BTUs per hour over the winter months.

Choosing an appropriate model based on your climate’s temperature is key to enjoying maximum efficiency with minimal long term costs associated with maintenance or replacement needs; moreover both ratings should be taken into account before making a purchase decision.

Property Size And Layout

Air source heat pumps can be complex and expensive to install, so it is important for homeowners to consider the size and layout of their property in order to optimize the performance.

Larger properties may require multiple units, as a single unit will not provide adequate heating or cooling for larger spaces. Placement of the unit determines how evenly warm or cool air reaches each room – if there are obstacles such as furniture blocking airflow that could reduce its effectiveness.

If a home has high ceilings it may need more surface area in order to effectively disperse heated or cooled air through the residence.

Budget And Energy Efficiency Needs

When selecting an air source heat pump for your home, it is critical to consider how efficiently the unit will operate. The higher efficiency a unit has, the less energy will be required to run it and you could save money on your monthly utility bills.

Investing in a more efficient model can also help reduce its environmental impact leading to lower carbon emissions that contribute to global warming. Some models are certified by ENERGY STAR as rewards for their high level of efficiency and cost-savings potential compared with other models. these units may qualify for tax credits or rebates under certain conditions as well.

Additionally, when purchasing a highly efficient air source heat pump, investing in extra insulation may help maximize its performance while reducing wasting energy through unintentional leakages from joint areas during operation.

Available Space For Installation

Air source heat pumps require specific amounts of space for installation and placement in order to function optimally. The minimum distance required between the outdoor unit, walls, or objects should be at least two feet and it is preferable if this distance can reach three or four feet in order for circulation.

This allows plenty of room for the refrigerant and air flow through the compressor, evaporator coils, and condenser fan blades. The recommended outdoor unit placement includes avoid areas with excessive dust/debris concentration as well as exposure to direct rainfall or snow accumulations. It should also be placed out of sight from neighbours since these kinds of units can generate operational noise that may annoy them.

It is important to note that if there isn’t enough available space to account for all these requirements every single element listed will have a negative impact on performance. 

Installing an air-source heat pump too close will obstruct airflow around the system leading to poor efficiency while exposed locations could cause parts inside getting damaged due to weather factors such as icy winds or water mixed with dirt/grit etc. 

As a result maintaining ideal conditions on all fronts is essential otherwise you risk significative shortfalls compared what was promised when purchasing which might lead then having uncompelling experiences in terms reduced output during certain climates.

According a study, evidence suggests that good insulation and proper ventilation can compensate minor losses. 

However questionable installations are likely induce additional costs managing heating capacities over lifetime period .


Air source heat pumps are a cost-effective and energy-efficient alternative to more traditional heating systems. However, it’s important for homeowners to be aware of its shortcomings before investing in one. While they are cheaper than other eco-friendly heating systems upfront, their operational costs may be higher, and the heat output is lower compared to conventional oil and gas systems. In addition, air source heat pump installations typically require extra insulation and additional space that many homes have difficulty accommodating. Lastly, they can become less efficient when temperatures drop below freezing levels which reduces their overall energy efficiencies versus traditional boilers over time if used frequently in cold climates where harsher winters occur regularly.


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