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Air conditioning is not just for summer, it’s for Christmas as well!

Updated: Jul 16

Ice cream by the pool

When we’re having a warm summer, we all think how nice it would be to have air conditioning (and a pool, and endless ice cream…), but not many of us can justify AC when summers in the UK seem to last about 3 days! In fact, it’s a misconception that air conditioning is only for cooling. There are a few other misconceptions about AC, so we thought it would be useful to clear these up!

Heat pump under the Christmas tree

1. Air conditioning is for cooling. Well yes, it is, but did you know most modern AC units for the domestic market heat as well, thanks to the 4-way reversing valve. Fran wants to jump in here and say it’s the heat pump fairies, not a boring valve. Well, however it works, it means you can use your AC in the winter too!

2. Air conditioning is expensive to install. Well that depends. A single room could be installed for as little as £1,500, depending on the capacity of the unit, location of the indoor and outdoor units, power supply, drain, etc.

3. Air conditioning is expensive to run. Here, we need to look at the Seasonal Coefficient of Performance, or SCoP, of the unit and the relative cost of heating sources. The SCoP is the yearly average of how much energy you will get out compared with the energy you put in. A SCoP of 5 means that, for each kW you put in, it averages 5kW out.

Air conditioning units are air-to-air heat pumps and move energy in the form of heat from outside to in or inside to out. They do not create energy, they move it. Another important point is that AC units are more efficient in heating than cooling, so you are likely to better the SCoP figure in heating mode.

With the right AC unit, it’s currently the most cost-effective way of heating a room with the commonly available energy sources. This might surprise you!

Let’s look at an example: the combination of the Mitsubishi MSZ-LN35VG indoor unit and MUZ-LN35VE outdoor unit have a SCoP of 5.1. It’s not the highest possible, but it is right up near the top.

The following graphs are based on information from June 2024 provided by our friends at the Nottingham Energy Partnership. The first graph provides a comparison of the relative cost of heating energy sources, and the second graph shows the CO2 impact of each source. I have added a couple of heat pumps running at different flow temperatures and the air conditioning unit to aid the discussion.



What is surprising is that the air conditioning unit is more cost effective to run than any of the other energy sources mentioned. That’s probably the most important factor for most people, but another important consideration is that it has the 4th lowest carbon footprint. That’s a complete win-win!

A point often raised is: if there are number of rooms requiring air conditioning, does this require multiple outdoor units? The answer is no – most of the main manufacturers produce multi-split units, which have a single outdoor unit and multiple indoor units. Mitsubishi has a unit that will support 6 internal units and Panasonic has a unit that supports 5.

Another consideration is that the indoor unit is not limited to a wall unit. There are a number of options available such as ceiling and wall for Mitsubishi, and ceiling, wall and floor for Panasonic.

Air conditioning can provide a very cost-effective method to heat a room, rooms or a whole property whilst also providing cooling in the summer. With solar panels installed, the cost of cooling will also be partially offset.

For more information on air conditioning and solar, and a tailored quote for your home or business premises, do get in touch.

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