Our Guide To Air Conditioning

 

 

 

What does air conditioning do?

 

 

  • Cool - effectively and quickly
     
  • Heat - more efficiently so than conventional central heating systems
     
  • Regulate humidity – by controlling the amount of moisture in the air
     
  • Ventilate - providing a source of clean air in rooms with no windows
     
  • Filter - reducing the amount of dust particles, pollen and other contaminates circulating in a room for allergy sufferers

 

 

 

How does it work?

 

 

Air conditioning compromises of;

 

  • An indoor unit also known as an ‘evaporator’
     
  • An outdoor unit also known as a ‘condenser’
     
  • A compressor (which is found in the condenser unit)
     
  • An ‘expansion valve’


 

  • It starts when the refrigerant enters the compressor (at the bottom of the outdoor unit) as an ambient gas.
     
  • As the gas goes into the compressor chamber it becomes pressurized and very hot.
     
  • This gas then gets passed up into the condenser through a series of copper coils and as the heat dissipates into the air outside the refrigerant gas then becomes a warm liquid.
     
  • The liquid refrigerant then travels through the expansion valve a very small amount at a time and into the evaporator as a cool liquid.
     
  • This refrigerant liquid evaporates at a much lower temperature than water and turns to gas as it passes through the coils in the evaporator.
     
  • As it evaporates it draws the heat out of the room with it and as the fan in the indoor unit blows across metal fins that cover the coils it gives the sensation of cooling.
     
  • The cool gas finally passes from the evaporator into the compressor and the process starts again.
     
  • This cycle will repeat until a point where the thermostat recognises that the actual temperature of the room is now matching the desired temperature set by the user on the system and the compressor shuts down.
     
  • When the thermostat recognises that the actual temperature in the room is not matching the temperature specified by the user the compressor will start up again.

 

 

 

What types of system are there?

 

 

 TYPE OF SYSTEM

 DESCRIPTION

 High Wall Mounted

 Fixed just below the ceiling

 Low Wall Mounted

 Fixed just above ground level similar to a radiator

 Floor Mounted

 An upright rectangular box fixed to the floor

 Under Ceiling/Ceiling Suspended

 Fixed to a solid ceiling where there is no recess above it

 Floor and Ceiling

 These can be fitted like a low wall mounted or an under ceiling

 Ceiling Cassette

 Fixed into a recess in suspended hollow ceilings, flush with the roof

 Ducted

 A concealed unit feeding air flow into ceiling/wall ducts

 

The most common systems are 'single split' systems where one indoor unit runs to one outdoor unit. However, if climate control is required in more than one room then a 'multi split' system may be more effective which involves multiple indoor units all running to a single outdoor unit.

 

What size system do I need?

 

 

Systems are measured in Kilowatts (KW) and/or British Thermal Units (btu);

 

 

Table A

 

 KW

 BTU

 2

 7000

 2.5

 9000

 3.5

 12000

 4

 15000

 5

 18000

 6

 21000

 7

 24000

 8

 30000

 10

 36000

 13

 43000

 14

 48000

 

 

There are many factors which will contribute to deciding on the size of unit a specific room will need. Below is a very basic formula to give you an idea;

 

Size of system = Room size x Wattage of cooling power required per square metre
(KW = m2 x w/m2)

 

 

Table B

 

 TYPE OF AREA

 W/M2

 Residental

 100

 Office

 120

 Office - busy/with window

 140

 Call centre

 150

 Retail

 125

 Comms/Server room

 200

 Conservatory

 300

 Doctor/Dentist

 120

 Restaurant

 150

 Gym

 150-180

 Public area

 120

 

 

NOTE: The height of a room isn’t a factor as some would imagine. This is due to the nature of hot air which rises, leaving the heavier refreshing cool air to sink into the room.

 

 

Examples;

 

 

A conservatory measuring 4 metres by 3 metres will, according to the formula, require a 3.6KW (3,600W) system.

 

4 metres x 3 metres = 12 square metre room size.
 

12 square metres x 300 watts of cooling power required per square metre = 3600 watts
 

Given that a Kilowatt is 1000 Watts we can divide 3600 by 1000 to give us 3.6KW
 

This is where the guide ends and we need to consider external factors. Imagine that the conservatory in question is in a family home and is used as a second living room by the children. There is a PC, a big screen TV (to which a games console is connected) and even though only two children live there they often have friends round. When you consider all these heat-generating elements we can assume that our cooling requirements will be higher than 3.6KW.
 

We can see from Table A that systems come in 3.5KW or 4KW sizes. In this circumstance it would be wise to opt for the larger system rather than ignore what the room is being used for and hope one just under requirement will be enough.
 


A bedroom measuring 3 metres by 2.5 metres will, according to the formula, require a 0.75KW (750W) system.

 

3 metres x 2.5 metres = 7.5 square metre room size.
 

7.5 square metres x 100 watts of cooling power required per square metre = 750 watts
 

Given that a Kilowatt is 1000 Watts we can divide 750 by 1000 to give us 0.75KW
 

Again, our guide has served us well up to this point but here is where we must think about the specifics of the room. What if the room in question had a large south facing window with only a thin curtain? This would absorb the sun’s rays all day throughout the summer months with nothing to block the heat.
 

When we consider that the smallest unit available is a 2KW our initial thoughts may be that it is too big for a room requiring a mere 0.75KW of required cooling but again, taking into consideration the large heat generating window, we can accept that a 2KW system will be exactly what is required.

 

 

 

What is inverter technology?

 

 

An inverter is used to control the speed of the compressor motor to allow continuously regulated temperature. In contrast older fixed speed compressor air conditioning systems regulate temperature by either working at maximum capacity or by being completely switched off.

Inverter powered air conditioning systems can set the speed of the compressor anywhere from full capacity to fully off depending on how much cooling power is required for the room. Because of this the air conditioning system can run consistently providing adequate cooling or heating whilst drawing just enough power to do so.

Eliminating stop-start cycles increases efficiency, extends the life of components, and helps eliminate sharp fluctuations in the load the air conditioner places on the power supply. Ultimately this makes inverter air conditioners less prone to breakdowns, cheaper to run, and the outdoor compressor is generally quieter than a standard air conditioning unit's compressor.

 

 

 

Do I need an inverter system and if so which one?

 

 

In times of environmental responsibility and costly utilities, it has been necessary for the industry to evolve and embrace inverter technology which is why almost every single new system uses it. That said there are varying levels within this and each is designed for a specific purpose and budget.
 

  • Many manufacturers offer a standard inverter as a base model with regard to energy efficiency which is often the most inexpensive to buy. These are ideal for those who don’t want a system that is going to be used regularly where regular running costs aren’t going to be a concern.
     
  • Next there is a mid range system which is often the most popular. Whilst slightly more expensive than the standard inverter it is also more efficient which is reflected in the running costs.
     
  • Finally there is the top end inverter. This will inevitably be more expensive than the others but with regular use (i.e. cooling through summer and heating through winter) it will prove it’s worth when it yields the least energy consumption of the three.
     

Essentially it is how much use your air conditioning system will get that will dictate how much you should spend initially and in turn how much you will spend on energy bills. In short there isn’t a ‘best inverter’ but there will be a best inverter for you.

Every single system we sell on our website is listed with the whole specification straight from the manufacturer so you can compare all of them against one another to work out which one is best for you and your budget. Some things to look out for are;


COP – The ratio that measures the energy efficiency of the HEATING performance (the higher the better)

EER –The ratio that measure the energy efficiency of the COOLING performance (the higher the better)

Energy Label – Rated from A+++ down to G

Annual Energy Consumption – The lower the better.

 

 Energy Efficiency Class  SEER  SCOP
 A+++  8.50 >  5.10 >
 A++  6.10 < 8.50  4.60 < 5.10
 A+  5.60 < 6.10  4.00 < 4.60
 A  5.10 < 5.60  3.40 < 4.00
 B  4.60 < 5.10  3.10 < 3.40
 C  4.10 < 4.60  2.80 < 3.10
 D  3.60 < 4.10  2.50 < 2.80
 E  3.10 < 3.60  2.20 < 2.50
 F  2.60 < 3.10  1.90 < 2.20
 G  < 2.60  < 1.90

 

 

 

Which manufacturer is the best?

 

 

There is no answer to this question. We supply and install air conditioning systems from names you may have heard of from other product ranges such as LG, Panasonic, Toshiba, Mitsubishi and also from the likes of Daikin who specialize exclusively in air conditioning and are known and respected throughout the industry.

Again, it all comes down to your personal requirements.  A 5KW wall mounted Daikin system may be similarly priced to a 5KW wall mounted LG system but the Daikin may have a higher Energy Label, higher COP & EER ratings and a lower Annual Energy Consumption so this would be the obvious choice. At the same time it may be the opposite for a low wall mounted 3.5KW system when comparing the same specification from again Daikin and LG with the LG coming out on top (see our range of wall mounted air conditioners).

We will always do our best to advise you as to which system could work best for you but with our handy technical specifications available for each product we have made this as easy as possible for you to do.

 

 

 

What does installation involve?

 

 

Essentially there will be an indoor unit (evaporator) and an outdoor unit (condenser). Between these will run two lagged copper pipes, a 3 core and earth power cable and a drain.

On a simple ‘back-to-back’ installation where the indoor unit and outdoor unit are adjacent to one another on the same wall this ‘pipe run’ will be minimal going straight through one hole.

In some circumstances it isn’t practical for a back-to-back installation so pipes may need to be run above suspended ceilings, though attics or across walls in specialist ‘trunking’.

If a ‘multi-split’ system where several indoor units all converge to run into one outdoor unit has been installed, then a more complex network of pipe runs will be required.

Where the pipes from the indoor unit must run upwards the gravity drain will be rendered ineffective, therefore a condensate pump will be required to expel the condensate water.

In any case you can be sure of a professional and high quality finish to every project with each one given the same care and attention to detail.

 

 

 

Am I covered by warranty?

 

 

Of course. All of our installation work is covered by a minimum 12 months guarantee and all systems are covered by a minimum 12 months manufacturer’s warranty with some offering up to 7 years.
 

We also carry out annual servicing to ensure that your air conditioning systems operate more efficiently. Poor maintenance and dirty components can increase energy consumption by as much as 60%*.


At the same time our engineers can also check for potential defects and rectify them before they escalate into further problems. This is in keeping with manufacturer’s warranty terms who specify that systems must be regularly maintained by certified and trained professionals.

 

 

 

*Source - Fujitsu Air Conditioning - May 2013