Heat Pump Installation and Repair in West Sussex and Surrey

How an air source heat pump works

An air source heat pump takes heat from the outside air and moves it into your home. It uses the same refrigeration cycle as a fridge, run the other way round, and it keeps collecting heat when the air outside feels cold to you.

1. A fan draws outside air across a coil filled with refrigerant, which absorbs the heat in the air.
2. A compressor squeezes the refrigerant, which raises its temperature.
3. That heat passes into the water in your heating system.
4. The warm water runs through your radiators or underfloor heating and heats your hot water cylinder.

The unit runs on electricity, but most of the heat it delivers comes from the air rather than from the meter. That is where the efficiency comes from.

What a heat pump system includes

• The outdoor unit, which is the heat pump itself
• Indoor controls, and on some systems an indoor unit alongside them
• A hot water cylinder, if you do not already have a suitable one
• Radiators or underfloor heating to deliver the heat
• A buffer tank, on some installations
• A thermostat and controls, usually with an app

Ground source heat pumps

A ground source heat pump works on the same principle but collects its heat from the ground, through pipework laid in trenches or down a borehole. It needs more outside space and more groundwork, which is why air source is the usual choice for homes. We are qualified to install both, and we will tell you which one fits your property.

Is your home suitable for a heat pump?

Most homes can run a heat pump. What changes from house to house is how much work is needed first.

Homes that suit a heat pump now

• Loft and cavity wall insulation already in place
• Double or triple glazing
• Space for the outdoor unit, such as a garden, a side passage or a suitable wall
• Underfloor heating, or radiators that are already generously sized, or room to fit larger ones
• Oil, LPG or electric heating at the moment, which is where a heat pump makes the biggest difference
• Newer homes built to modern insulation standards

Homes that need some work first

• Poor insulation. Improve it first. A heat pump in a house that leaks heat has to work harder and costs more to run.
• Small radiators. Some will need upsizing to give out enough heat at lower flow temperatures.
• Single glazing. Upgrading the windows makes a real difference to how much heat the house needs.
• No hot water cylinder. If you have a combi boiler now, you will need room for a cylinder.
• Limited outside space. Compact units are available for tighter spots.
• An older property. Plenty of older homes run heat pumps well. They usually need more preparation.
• High heat demand. A large house, or one that loses a lot of heat, may need a bigger unit.

Nothing on this list puts a heat pump out of reach on its own. It is the checklist we work through at survey.

What a heat loss survey involves

A heat loss survey is how a heat pump gets sized properly. We visit, measure every room and note how each one is built: the walls, the floor, the ceiling, the windows and the insulation. From that we work out how much heat each room loses on a cold day.

That figure tells us three things. The size of heat pump the house needs. Which radiators can stay and which need to be bigger. And whether anything, such as insulation, should be done before the heat pump goes in.

While we are there, we also look at where the outdoor unit can sit, where a cylinder can go and how the pipework will run. You then get a system design with the equipment specified, an installation plan and a detailed quote.

Heat pump installation, step by step

1. Survey and assessment. We check suitability, carry out the heat loss calculation, recommend the system size and talk through what you need from the system.
2. Design and quote. You get the system design, the equipment specification, the installation plan and a fixed quote.
3. Preparation work. Radiators are upgraded where needed, the hot water cylinder is fitted, the position for the outdoor unit is prepared and new pipework is run.
4. Installation. The outdoor unit goes on a concrete base or wall brackets, the indoor controls are fitted, and the unit is connected to the heating system and wired in.
5. Commissioning. We fill and pressure test the system, commission the heat pump, set the controls and balance the radiators so every room gets its share of the heat.
6. Handover. We show you how the system works and how to get the best from it, leave you the user guide and register the manufacturer warranty.

A typical installation takes two to four days on site, depending on the property and how much radiator work is involved. You get the timeline at survey.

Heat pump running costs in plain terms

Heat pump efficiency is quoted as a COP, or coefficient of performance. A COP of 3 means three units of heat for every unit of electricity used, which is the same as 300 percent efficiency. A modern gas boiler turns a little over 90 percent of its gas into heat.

That sounds like an easy win, but a unit of electricity costs more than a unit of gas. So the comparison depends on what you are replacing:

• Oil, LPG or direct electric heating. A well-designed heat pump is usually much cheaper to run. This is where the case is strongest.
• Mains gas. Running costs tend to be similar. Your tariffs, your insulation and the quality of the design decide which way it falls.

A heat pump only reaches a good COP when it can run at a low flow temperature, which is why the radiator sizing matters as much as the unit itself. Our guide to air source heat pumps goes through the costs in more detail.

Heat pump repairs

When a heat pump stops heating, or starts costing more to run than it should, the cause is usually on a short list. We find the actual fault before replacing anything.

Common heat pump faults we fix

• No heating or hot water output
• Unusual noises from the outdoor unit, such as rattling or grinding
• Ice building up on the outdoor unit, or a unit stuck in its defrost cycle
• Error codes on the controller
• The system losing pressure
• Poor efficiency, with electricity bills higher than they should be
• Thermostats and controls not responding
• The outdoor fan not running

Heat pump brands we work on

Mitsubishi, Daikin, Vaillant, Samsung, LG, Panasonic, Worcester Bosch, Grant, Nibe and Viessmann, along with most other makes.

Heat pump servicing and your warranty

Most heat pump warranties need an annual service to stay valid. A serviced system also runs more efficiently and breaks down less often. A heat pump service with us covers:

• A full inspection and safety check of the system
• The filters and the outdoor unit cleaned
• System water pressure and flow checked
• Electrical connections tested
• The thermostat and controls checked
• The defrost cycle checked
• System efficiency measured
• A written service report with any recommendations

Between services, keep the outdoor unit clear of leaves, snow and anything stacked against it.

Heat pump noise, cold weather and lifespan

Noise. Modern units are quiet, often compared to a quiet fridge. Where the unit sits matters more than the model, so we position it away from bedroom windows and neighbouring properties.

Cold weather. Modern heat pumps keep working well below freezing and are standard across Scandinavia, where winters are far harsher than ours. Efficiency drops in very cold spells, which is why the system is sized for the coldest days rather than the mild ones.

Lifespan. With an annual service, a heat pump should last 20 years or more.