How efficient is air conditioning in your home?

Air conditioning in a domestic room

It’s a question we get asked all the time by our customers, so we’ve provided some insight in this blog to give you more of an idea as to the benefits and efficiency of air conditioning in your home.

How does air conditioning work?

First, it’s important to explain how an air conditioning system works. Air conditioning systems today can be used to not only control the temperature, in both cooling and heating, but to move the air around a space and alter the humidity slightly in cooling mode, compared to external atmospheric conditions.   

Air conditioning has two modes – cooling and heating:

In cooling mode

The external part of the air conditioning system houses a compressor, a heat exchanger (aluminium fins wrapped around copper tubes), a fan and an expansion valve. The internal part of the system houses a heat exchanger (like the external one, but a different shape) and a fan. The two units are then mechanically piped together using copper tubing. This allows refrigerant fluid to travel between the two.

The refrigerant in the system starts as a gas, the compressor pressurises this into a superheated gas. It then travels to the heat exchanger in the external unit. Air then passes over this heat exchanger by the fan. This expels the heat from the refrigerant to the air and changes it from a gas to a liquid at ambient air temperature. Still in the external unit, it travels to the expansion valve where a pressure drop occurs.

This is what starts the refrigeration process – as the refrigerant leaves the external unit it travels to the internal unit, where it starts to boil off at a low temperature inside the internal heat exchanger. The fan then blows this air into the room over the heat exchanger, which starts to reduce the temperature in the room. As the refrigerant boils off, it turns the liquid to a gas having gathered the heat from your room and takes this back to the compressor, where the cycle starts again.

In heating mode

In heating mode, the external unit has a reversing valve which changes the direction of refrigerant flow to send the hot refrigerant gas to the internal unit and then into the room.

How efficient is air conditioning in heating mode?

In short, very. Air conditioning can be up to 350%  efficient, whereas gas, oil or central heating products are between 85 – 100% efficient. That’s because for every 1 kilowatt of electricity, an air conditioning system can produce up to 4 kilowatts of energy (heat) into your home and extract up to 3 kilowatts of energy (heat) out of your home. Compare this with electric storage heating that when it uses one kilowatt of electricity it only produces one kilowatt of energy (heat) back. It makes sense how air conditioning is the more efficient.

Below we’ve used an example to show what impact this can have on your heating bills:

Storage heaters

Linda lives in a small bungalow that has 4 electrical storage heaters, one in each room and is not happy with the price of the bills (all energy figures include VAT @ 20%). Currently Linda has 4 x storage heaters in her bungalow that are 2kw each, so a total of 8kw in total. She pays the following:

  • 8 kw x £0.18 pence per kilowatt hour = £1.44 per hour to heat Linda’s home
  • £1.44 x 10 hours a day = £14.40 a day to heat Linda’s home
  • £14.40 x 172 days of the year it will be turned on = £2,476.80 per annum to run Linda’s home heating

Air conditioning

Linda decides to install air conditioning in her bungalow, replacing her electric storage heaters. Each air conditioning unit has an output of 2 kw in heating mode. At a ratio of 4:1 this means Linda only puts in 500 watt of electricity into each air conditioning unit.   

The heating costs instantly reduce to the following:

  • 2 kw x £0.18 pence per kilowatt hour = £0.36 per hour to heat Linda’s home
  • £0.36 x 10 hours a day = £3.60 a day to heat Linda’s home
  • £3.60 x 172 days of the year it will be turned on = £619.20 per annum to now run Linda’s home heating.

In this particular example, Linda has made a saving of 75%!

In addition to this saving, Linda also has the option to use the air conditioning to cool her bungalow during the summer months, She is also able to de-humidify her house allowing her to protect her home and furnishings from mould and mildew.

Linda also has the added bonus that she’s cutting her carbon footprint by using air conditioning to heat her home.

You may even qualify for 5% VAT

The HMRC have highlighted that certain social groups can qualify to pay only 5% VAT on their air conditioning – if used in heating mode. To summarise:

  1. If you are 60 years of age or above, or are in receipt of outlined benefits (see pdf below);
  2. That the supply of the installation is to a ‘relevant housing association’;
  3. Where residential accommodation is a building or part of a building used solely for a ‘relevant residential purpose’, including children’s homes, care homes and accommodation for the armed forces.

If none of the above conditions are met you may still be able to qualify for the ‘60% test’ – this outlines the portion of materials vs labour/service:

  • If the total price of your materials for air conditioning do not exceed 60%, then you are able to only pay 5% VAT on the total cost of your air conditioning;
  • If the total price of your materials exceeds 60%, then you will pay full VAT on the materials portion and only 5% on the labour/service portion.   

Find out more in the BESA guidance pdf.


How Lynx AC can help you be more efficient

Lynx AC are a first class provider of air conditioning system installations. We are a Mitsubishi Electric Diamond Quality Partner and a Daikin D1+ Premium Partner, which means you’ll get the best products with the best service for your home.

It’s critical to also consider the warranty period you will receive for your air conditioning installation. Warranties for air conditioning systems are generally 1 to 3 years, however, Lynx AC provides warranties for up to a marketing leading 7 years.

Simply call us on 01522 788799 and we’ll arrange for one of our qualified team members to come out to you.