What Is an Air Source Heat Pump? An Introduction to Efficient Heating and Hot Water Solutions

With the ongoing energy crisis impacting millions of people, and 74% of UK adults worried about climate change, energy efficiency and sustainability are becoming priorities for homeowners across the UK. In particular, air source heat pumps have gained significant attention as a way to achieve both goals.  These innovative low-carbon heating systems offer a greener, more cost-effective alternative to traditional heating methods such as boilers. But what exactly is an air source heat pump (ASHP), and how does it work?  In this blog, the heat pump experts from Adlår will explain the basics of ASHPs, exploring how they harness outdoor air to provide you with reliable heating and hot water year-round.

What is an Air Source Heat Pump?

An air source heat pump (ASHP) is a renewable energy system for your home that works in a similar way to a fridge or air conditioning unit, but in reverse. It is designed to extract heat from the outside air, even when temperatures drop below zero. This heat is then compressed and transferred indoors to warm your home.  There are two main types of air source heat pumps:

1. Air-to-Water Heat Pumps (Wet System) Air-to-water heat pumps transfer heat into a water-based central heating system, making them suitable for both space heating and domestic hot water supply. They’re compatible with underfloor heating systems and larger radiators, both of which distribute heat efficiently at lower temperatures. In the UK, most heat pump data refers exclusively to air-to-water heat pumps.
2. Air-to-Air Heat Pumps (Dry System) These systems transfer heat directly into the indoor air, often using fans or blowers to circulate warm air through the home. Sometimes known as air conditioning units, they can be used for cooling as well as heating, and are common across Europe. Air-to-air systems do not provide hot water, though, making them less versatile for homes in the UK that need a comprehensive heating solution.

However, there are also innovative dual heat pump systems available for homeowners seeking the increased flexibility and control provided by a system with separate pumps for your heating and hot water.

How Does It Work?

At its core, an air source heat pump operates on the principle of heat transfer, rather than generating heat by burning fossil fuels (as traditional heating methods like gas boilers do).  Here’s a step-by-step breakdown of the process:

1. Heat Absorption. The ASHP absorbs heat from the outdoor air through an evaporator coil filled with liquid refrigerant.
2. Compression. Using electricity, the pump compresses this heated liquid, increasing its temperature to a level suitable for domestic heating.
3. Heat Release. In a wet system, the high-temperature refrigerant then warms up water, which is sent to your indoor heating system (radiators or underfloor heating) and/or stored in your hot water tank. In a dry system, the refrigerant’s heat is circulated as warm air through ducts and vents
4. Cycle Repeats. The cooled refrigerant returns to the outdoor evaporator coil to absorb more heat, and the cycle continues.

Capturing ambient energy from the air in this way means that ASHPs draw on renewable energy and use far less electricity than conventional electric heating systems. This continuous process makes them a highly sustainable, environmentally friendly option.

Benefits of Air Source Heat Pumps

Installing an air source heat pump in your home offers numerous financial and environmental benefits, including:

• Energy Efficiency – Air source heat pumps typically produce 3 to 4 kWh of heat for every kWh of electricity they use, making them up to 400% efficient. For comparison, new UK boilers must be 90% efficient, though older ones often have much lower efficiency ratings.
• Lower Carbon Footprint – ASHPs emit far fewer greenhouse gases than fossil-fuel-based systems, making them a more sustainable choice. According to research, they can reduce your carbon footprint by up to 1900 kg of CO₂ per year (compared to a new gas boiler’s annual emissions).
• Reduced Energy Bills – Homeowners can see a significant reduction in heating costs, especially when switching from electric or oil heating systems.
• Year-Round Comfort – Many ASHPs also have a cooling function, allowing them to provide comfort in summer as well as winter.
• Government Incentives – In the UK, the Boiler Upgrade Scheme (BUS) provides £7,500 grants for ASHP installations, making them an affordable option for many households.
• Minimal Maintenance – Air source heat pumps require minimal maintenance compared to traditional boilers. Basic upkeep such as regularly cleaning the air filters, removing any obstructions around the outdoor unit, and scheduling an annual service is all that is required.
• Long-term Investment – Most ASHPs have a lifespan of around 10 – 15 years, meaning that they offer long-term benefits.

To find out more about the benefits of Adlår’s dual heat pump system in particular, download our brochure today.

Key Considerations Before Installing an ASHP

While they offer numerous benefits, it’s important to consider a few factors before deciding to install an air source heat pump. Although ASHPs reduce your operating costs, they require an upfront investment. This can vary depending on several factors, but it is at least several thousand pounds. However, government grants and incentives can offset these costs, making them more accessible to UK homeowners. Installation requires a suitable outdoor space with sufficient airflow to allow the pump access to fresh air. While Adlår’s dual heat pump is whisper quiet, some air source heat pumps may produce a mild hum when operating, in which case they should be positioned away from windows or neighbours to minimise potential noise disturbance. To maximise the efficiency of your ASHP, it’s also important that your home is well-insulated, as they perform best in buildings with minimal heat loss. 

Installation Process for Air Source Heat Pumps

Air source heat pump installation involves several steps, which are carried out by qualified professionals to ensure efficiency and compliance with the highest standards.

1. Initial Consultation – At Adlår, we offer a free 40 minute consultation during which we can answer any of your questions, outline costs, discuss your grant eligibility, and schedule your free survey.
2. Site Survey – An installer will carry out pre-survey checks and assess your property to determine the best location for an ASHP unit.
3. System Design – Based on your home’s needs, they’ll design a system that optimises heat output and efficiency.
4. Installation and Setup – The heat pump unit is mounted outdoors, typically on a wall or on the ground, and connected to the indoor heating system.
5. Testing and Commissioning – After installation, the system is tested to ensure it’s operating correctly.

FAQs

Q: Do air source heat pumps work in very cold weather?

A: Yes, they are designed to work efficiently even in sub-zero temperatures. However, their efficiency may decrease slightly as temperatures drop.

Q: How much space does an ASHP require?

A: An ASHP requires enough outdoor space for the unit, typically installed against an exterior wall. It should have adequate clearance for airflow and maintenance access.

Q: Can I use an ASHP with existing radiators?

A: In some cases, yes. However, ASHPs work best with larger radiators or underfloor heating systems designed for lower-temperature heat distribution.

Q: Is an air source heat pump noisy?

A: Most modern ASHPs operate quietly, emitting only a low hum when in use. Proper placement can further minimise any potential disturbance.

Q: Are there grants available for ASHP installation?

A: Yes, the UK government offers grants through the Boiler Upgrade Scheme (BUS) to help cover the initial cost of installation.

Discover Adlår’s Innovative Dual Heat Pump System

An air source heat pump is more than just an efficient way to heat your home and provide hot water – it’s a step towards a sustainable future. By making this investment, you’re not only reducing your energy bills but also contributing to a cleaner planet. If you’re considering a more sustainable heating solution, Adlår’s dual heat pump system might just be the perfect fit for your home.  Our expert team is here to guide you through the entire process, from initial assessment to installation, ensuring a smooth transition to this greener, more efficient heating technology.  Contact us now to learn more about ASHPs and take your first step towards a more energy-efficient future.