The Air to Water Heat-Pump: Costs, Efficiency & How They Work

Air to Water Heat-Pumps can save you up to 70% on home heating.

If you are using an air to water heat-pump system, you can reduce your energy bills by between 40% and 60%. Today, air to water heat-pumps are one of the most efficient types of air source heat pumps available on the market. They are an efficient way to reduce the carbon emissions and makes your home more energy efficient. It is an affordable and environmentally friendly heating system.

Air to water heat pumps operate by extracting heat from the air outside and transferring it to a water-based heating system. With a modern air to water heat-pump, you can heat your house as well as have an ample supply of hot water.


How Air To Water Heat-Pumps Work?

Air to water heat-pumps work in a similar way to refrigerators. They extract heat from the air outside and circulate it through a loop filled with refrigerant. After that, heat from outside air moves to a compressor which, as the name suggests, compresses the heat increasing the temperature.

Next, the heat moves to the heat exchanger which is a very significant part of an air to water heat-pump. The heat exchanger moves the heat to the piping which transfers it to radiators or underfloor heating systems. With air to water heat pump system, the heat is also used to produce hot water.

Two Main Types of Air To Water Heat-Pump

There are two main types, split systems and monoblock.

split system air to water heat-pump is comprised of two units. The indoor unit is connected to the heat exchanger, compressor and fan mounted outside via refrigerant. Warmth is extracted from outside and transferred via the refrigerant to the indoor unit that heats the water.

mono block air to water heat-pump does all the work outside the building and the hot water is piped back into the home’s water system.


The Advantages

Air to water heat pumps have several advantages:

  • They are ecologically friendly and can produce 50% of the heat necessary to heat your house using only outside air.
  • They can work as an addition to a fossil fuel heater being the primary heating system.
  • The initial price of air to water heat-pumps is relatively low, and they are a part of the Better Energy Homes programme under which you can qualify for a grant.
  • Air to water heat pumps can be installed efficiently and quickly. Additionally, you can start using the system on the first day of installation.
  • Air to water heat-pumps use renewable energy and don’t produce the greenhouse gases emissions.
  • Air to water heat-pumps can be installed even in the areas where the soil is of poor quality. On the other hand, a ground-source heat pump would be impossible to install at the soil of this kind.
  • Air to water heat pump systems are compact and usually you won’t need any house remodelling.

The Disadvantages

But it’s not all good news as they are not without their disadvantages.

  • Air to water heat-pumps supply a lower amount of heat when compared to oil and gas, this may require larger radiators to make full use of the system.
  • Air to water heat pumps are very energy efficient but they are only carbon neutral when coupled with solar power.
  • You’ll get the best results when installing air to water heat-pumps in homes that are well insulated.
  • Air to water heat pumps can be noisy to run.
  • The initial cost can put some people off.

How Much Does An Air Source Heat Pump Cost?

The initial price of air to water heat-pump installation varies between  £9,000  and £13,000. But you may need to make changes to your current heating system to incorporate the heat pumps, making more specific estimates difficult.

The sum of the operating costs will be determined by various aspects. For example, how big and well insulated your house is, and what the desired temperature you are looking for is.

The Savings

An air to water heat-pump heating system can be a great idea if you are looking to replace an inefficient boiler. But if you are situated near a gas main line or have a modern heating system it might not make sense to invest in heat pumps.

The figures below are based on 2016 data and use averages. They should be taken as estimates.

Air To Water Heat-Pump Sizes

Air to water heat-pump systems are measured in kilowatts (kW). The larger the kW, the more heat is generated and models suitable for homes usually come in sizes of between 5kW and 14kW. But remember that the better your home insulation is, the less energy you’ll spend on heating.

When upgrading your home heating system, you should enlist the help of an energy efficiency expert. They will carefully asses your home and recommend the most suitable size air to water heat-pump so you are not wasting money.

Getting the wrong size air to water heat-pump can result in a cold home if it’s too small. Or a shorter life cycle for the heating system due to short cycling(turning on and off too quickly).

A EPC assessor or energy expert will be able to review you heating bills and evaluate your current insulation to give the best recommendation.

Efficiency & Comparison

The table below shows the seasonal coefficient of performance which indicates year round efficiency. It’s the ratio of heat output over electrical input.

Compared to a standard electric heater, heat pump systems are considerably more efficient.  Both electric heaters and air to water heat-pumps operate using electricity. They convert electricity into heat. However, while an electric heater converts 1 kW of electricity to the equivalent of 1 kW of heat, air to water heat-pumps convert 1 kW of electricity into almost 4 kilowatts of heat.

Therefore, air to water heat-pumps provide you with a higher energy-efficiency and help you reduce your electric bills.

Do You Need Planning Permission?

You do not need planning permission for installing, altering or replacing air to water heat-pumps in homes. This law came into effect in 2014 by the then Minister of Environment Durkan. 

Choosing an Installer

You should be careful to only choose a registered professional that that has experience installing heat pumps in a similar sized project.

Your air to water heat-pump installer should provide an itemised list of all the work to be carried out and confirmation of the work signed by both parties before work commences.

Air To Water Heat-Pump Servicing

An integrated heating system with air to water heat-pumps does need maintenance to make sure it’s operating at peak efficiency.

There are some checks you can do yourself including making sure that the heating system pressure gauge is set and the pump is clear of any blockages. Leaves, dust and other grit can build up in the pump filters so regular checking is a good idea.

Depending on the make and model of the air to water heat pump you choose, you will need to get it regularly serviced by a professional. This is usually once every two to three years and will help to prolong its life. Regular servicing also has the added benefit of saving you money on possible faults caught early and reduces the chance of machine failure.

Last Updated on October 28, 2021


Author: Indra Gupta

Indra is an in-house writer with a love of Newcastle United and all things sustainable.

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