How Air Source Heat Pumps Work: A Simple Explanation June 26, 2025 Air source heat pumps are becoming an increasingly popular choice for UK homeowners looking to reduce their energy bills and environmental impact. But how do they actually work? This guide breaks it down in simple terms, covering the components, operation, types, and key benefits, so you can make an informed decision about switching to this efficient heating and cooling solution. Understanding the Process Behind Air Source Heat Pumps An air source heat pump is a renewable heating system that extracts heat from the outside air and transfers it into your home. Unlike traditional systems that generate heat by burning fuel, heat pumps move heat using a refrigerant cycle, making them far more efficient and environmentally friendly. Key Components Refrigerant: A fluid that changes from liquid to gas to absorb and release heat. Compressor: Increases the temperature of the refrigerant. Evaporator & Condenser Coils: Absorb heat from outside air and release it indoors (or vice versa). Reversing Valve: Allows the system to switch between heating and cooling. Fans & Blowers: Help circulate air and transfer heat efficiently. How They Work In Heating Mode: The outdoor unit extracts heat from the air, even in sub-zero temperatures. The refrigerant absorbs this heat and evaporates. The compressor raises the temperature of the gas. The heated refrigerant passes through the indoor coil, warming the air. The refrigerant condenses and the cycle continues. In Cooling Mode: The system reverses direction. Heat is extracted from indoor air and expelled outside. Cool air is circulated back into the home. This repeats until the set indoor temperature is reached. Types of Air Source Heat Pumps Air-to-Air: Transfers heat to indoor air, ideal for homes with ductwork or fan units. Air-to-Water: Transfers heat to a water-based system, suitable for radiators or underfloor heating, and can also supply domestic hot water. Benefits of Air Source Heat Pumps Energy Efficiency: Delivers 3–4 units of heat per unit of electricity, up to 400% efficient. Environmental Impact: Lower carbon emissions than gas, oil, or electric resistance heating. Cost Savings: Lower running costs compared to oil, LPG, or older electric systems. Dual Functionality: Provides both heating in winter and cooling in summer. Installation and Maintenance Overview Installation: A heating expert assesses your home’s size, insulation, and heating needs. The outdoor unit is installed in a well-ventilated area. Indoor connections are made to radiators, underfloor heating, or air handlers. The control system is configured for optimal operation. Maintenance: Clean or replace filters monthly. Keep the outdoor unit free from leaves and obstructions. Book annual professional servicing. Check refrigerant levels and system pressure regularly. Debunking Common Myths “They don’t work in cold weather.” Modern units operate effectively in temperatures as low as -25°C. “They’re noisy.” Today’s models are no louder than a fridge or standard air conditioning unit. “Only suitable for new homes.” Retrofitting is often possible, especially with good insulation. “Not enough heat for older homes.” When properly sized, they can comfortably heat most properties. Looking to make the switch to an air source heat pump in Portsmouth, Hampshire, Southampton, or West Sussex? Clean Heat Solutions provides expert advice, installation, and maintenance for modern heat pump systems. Call us on 07391473964 or fill out our contact form to learn how this efficient solution can benefit your home.