{"id":3203,"date":"2026-06-04T08:45:36","date_gmt":"2026-06-04T08:45:36","guid":{"rendered":"https:\/\/mywarmhome.co.uk\/stage\/?page_id=3203"},"modified":"2026-10-13T07:56:09","modified_gmt":"2026-10-13T07:56:09","slug":"heat-pump-types-ashp","status":"publish","type":"page","link":"https:\/\/mywarmhome.co.uk\/stage\/heat-pump-types-ashp\/","title":{"rendered":"Heat Pump Types ASHP"},"content":{"rendered":"\n
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HOME HEATING \u00b7 INDEPENDENT ADVICE<\/p>\n\n\n\n

Air Source Heat Pumps<\/h1>\n\n\n\n

How air source heat pumps work, what is inside the outdoor unit, and the practical decisions that matter before installation.<\/p>\n<\/div><\/div>\n\n\n\n

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HOW A HEAT PUMP WORKS<\/p>\n\n\n\n

Four stages. One continuous cycle.<\/h2>\n\n\n\n
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01<\/h3>\n\n\n\n

Collect<\/h3>\n\n\n\n

A fan draws outdoor air across the evaporator.<\/p>\n<\/div>\n\n\n\n

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02<\/h3>\n\n\n\n

Compress<\/h3>\n\n\n\n

The compressor raises the refrigerant pressure and temperature.<\/p>\n<\/div>\n\n\n\n

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03<\/h3>\n\n\n\n

Transfer<\/h3>\n\n\n\n

Heat passes through a condenser into the heating circuit.<\/p>\n<\/div>\n\n\n\n

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04<\/h3>\n\n\n\n

Expand<\/h3>\n\n\n\n

An expansion valve lowers refrigerant pressure for the next cycle.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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THE PRINCIPLE<\/p>\n\n\n\n

Heat from the air, even on cold days.<\/h2>\n\n\n\n

An air source heat pump (ASHP) transfers existing thermal energy from outside air into your home. Electricity runs the compressor, fans and pumps; it does not have to supply every unit of heat delivered. That is why a correctly designed heat pump can deliver several units of heat for each unit of electricity consumed.<\/p>\n\n\n\n

A heat pump can be a significant investment. The outdoor unit is only one part of the system: radiators, pipework, controls, hot-water storage and the property\u2019s heat loss all influence the finished design.<\/p>\n<\/div>\n\n\n\n

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THE MAIN COMPONENTS<\/p>\n\n\n\n

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Fan and evaporator<\/h2>\n\n\n\n

The fan moves outside air across an evaporator coil. Refrigerant circulating inside the coil absorbs heat and boils at a low temperature and pressure.<\/p>\n\n\n\n

Compressor<\/h2>\n\n\n\n

The compressor draws in refrigerant vapour and increases its pressure and temperature. This makes the refrigerant hot enough to pass heat into the home.<\/p>\n\n\n\n

Condenser<\/h2>\n\n\n\n

In the condenser, hot refrigerant releases heat to the heating-water circuit and condenses back towards a liquid. The refrigerant does not normally mix with the water supplied to radiators.<\/p>\n\n\n\n

Expansion valve<\/h2>\n\n\n\n

The expansion device lowers the refrigerant pressure. Its temperature then drops so it can collect more energy at the evaporator.<\/p>\n\n\n\n

Sensors and controls<\/h2>\n\n\n\n

Temperature sensors, pressure controls, fan-speed control, circulation pumps and defrost management work together to balance output, efficiency and safety.<\/p>\n\n\n\n

Common refrigerants include R32 and R290 (propane). Their safety requirements and environmental impacts differ. Equipment selection, siting and handling must follow the relevant manufacturer instructions and applicable regulations.<\/p>\n<\/div>\n\n\n\n

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TWO MAIN ARRANGEMENTS<\/p>\n\n\n\n

Monobloc or split?<\/h2>\n\n\n\n

Both arrangements use the same refrigeration principle. The key difference is where the sealed refrigerant circuit and heating-water interface are located.<\/p>\n\n\n\n

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Monobloc<\/h3>\n\n\n\n

The refrigerant circuit is factory assembled in the outdoor unit. Insulated water pipework connects the heat pump to the indoor heating system. External pipework requires appropriate frost protection.<\/p>\n<\/div>\n\n\n\n

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Split system<\/h3>\n\n\n\n

Refrigerant pipework connects an outdoor unit to an indoor unit, often called a hydrobox. Refrigerant installation and commissioning require appropriately qualified engineers.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

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SYSTEM DESIGN<\/p>\n\n\n\n

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In most monobloc designs the fan, evaporator, compressor, condenser and expansion device are housed outdoors. Warm water travels between the unit and the internal heating system.<\/p>\n\n\n\n

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Advantages<\/h2>\n\n\n\n