How Air Conditioning Works

A refrigarent absorbs excess room heatCooling Mode
A special liquid called a refrigarent, which is sealed within the system, absorbs excess room heat. As the refrigarent absorbs heat it changes into a gas and passes through small copper tubes to an outdoor unit where the heat is released into the atmosphere. The gas then changes back into a cold liquid, returning to the indoor unit where the air is fanned over it and out into the room. This cycle is automatically repeated to maintain the required room temperature.

Heating mode
Heat pump systems also allow the above cycles to be reversed. A heat pump extracts "free" heat from the outdoor air, even on the coldest days when the temperature may fall as low as -10 degrees Celsius and transfers the heat indoors. Heat pumps units therefore avoid the need for a boiler and allow you to cool and heat the same unit, with savings in costs and energy throughout the year.

Is it expensive to run ?
The indoor section of the system contains a small fan and some electronic controls and has a power consumption of that of a light bulb. The compressor which is housed in the condensing unit consumes a greater amount of power but only runs when the room requires heating or cooling. When a unit is sized correctly we would expect equal on and off periods. With this in mind we have built in a 50% diversity factor. The example is based on a 3.5kw split system with a power consumption of 1.2kw.

Enhanced Capital Allowances
In 2001 the UK Government introduced Enhanced Capital Allowance (ECA) to reward business that invest in energy saving equipment.

ECAs are given on 100% of your expenditure in the first year. This means you can reduce the profits for the period of the investment on which you pay tax by 100% of the expenditure incurred when buying qualifying capital equipment.

Therefore on equipment costs of £10,000, your business will reduce its taxable profi by the full £10,000. That makes the first year saving from the ECA £3,000, much greater than the standard capital allowance first year saving of only £750*, a figure which goes on decreasing on the remaining balance for later years.

To fin out more information and the full list of equipment that qualifies under ECA visit: www.eca.gov.uk

*Figures correct at time of publishing please visit the main ECA site for current information,