Good to know

The amount of heat generated is known as the heat gain or heat load. Heat is measured in either British Thermal Units (BTU) or Kilowatts (KW).  1KW is equivalent to 3412BTUs.

The heat load depends on a number of factors, by taking into account those that apply in your circumstances and adding them together a reasonably accurate measure of the total heat can be calculated.

Factors include:

The floor area of the room

The size and position of windows, and whether they have blinds or shades

The number of room occupants (if any)

The heat generated by equipment

 The heat generated by lighting

Floor Area of Room

The amount of cooling required depends on the area of the room. To calculate the area in square metres:

Room Area BTU = Length (m) x Width (m) x 337

Window Size and Position

If, your room has no windows, you can ignore this part of the calculation. If, however there are windows you need to take the size and orientation into account.

South Window BTU = South Facing window Length (m) x Width (m) x 870

North Window BTU = North Facing windows Length (m) x Width (m) x 165

If there are no blinds on the windows multiply the result(s) by 1.5.

Add together all the BTUs for the windows.

Windows BTU = South Window(s) BTU + North Window(s) BTU

Occupants

You will have to take that into account people who normally working in the space. The heat output is around 400 BTU per person.

Total Occupant BTU = Number of occupants x 400

Equipment

Clearly most heat in a room is generated by the equipment. This is trickier to calculate that you might think. The wattage on equipment is the maximum power consumption rating, the actual power consumed may be less. However it is probably safer to overestimate the wattage than underestimate it.

Equipment BTU = Total wattage for all equipment x 3.5

Lighting

Take the total wattage of the lighting and multiply by 4.25.

Lighting BTU = Total wattage for all lighting x 4.25

Total Cooling Required

Add all the BTUs together.

Total Heat Load = Room Area BTU + Windows BTU + Total Occupant BTU + Equipment BTU + Lighting BTU

This is the amount of cooling required so you need one or more air conditioning units to handle that amount of heat.

Disclaimer: These calculations are intended as rough guide only. Complete accuracy cannot be guaranteed.

The energy class of an air conditioning unit is the category that has been classified by certified international organizations (from A, which is the best efficiency, to G) and shows how much energy a unit may save in certain circumstances, in order to give us the desirable cooling or heating capacity.

Concerning the air conditioning units it depends on the rate of EER (Energy Efficiency Rate) for summer and of COP (Coefficient Of Performance) for winter. The higher these factors are the better energy classifications the units have and also more economical operation. Below you may see the energy classification table:

When someone is purchasing an air conditioning unit, apart from all the rest technical features, he should choose a unit that operates at low noise at the high fan speed. At this state the noise level of the indoor unit (8.000-9.000Btu/h) should not be over 40db and of the outdoor unit over 55db

Heat pump is a unit that operates cooling and heating. During summer it takes out heat from the room (cooling mode) and during winter takes heat from the environment and sends it to the room (heating mode). It does not convert electric energy to heating energy; it transfers heat from the environment and adds it to the room. That is the reason why the cost of heating might be lower by using a heat pump than by using petroleum, even 30% or higher, depending on the cost of the petroleum and the quality of air conditioning.

The constant speed air conditioning units are the units that have constant speed compressor. These compressors rotate with the same speed of the electromotor that rotates them and it is steady (so it is their power) independently of the cooling/heating loads that the air conditioned rooms need. When using units with constant speed compressor, the control of the temperature in the rooms is done by using ON/OFF thermostats.

The Inverter technology (DC) is the latest evolution of technology concerning the electro motors of the compressors. The DC Inverter unit operates more efficiently (so with lower cost), due to the fact that the rotations of the compressor are fluctuating in accordance to the needs of cooling or heating. It may control accurately the selected temperature (there are very small fluctuations) and operates at low noise.

As it has already been mentioned, the DC Inverter units operate with higher efficiency compared to the constant speed ones and that is why they operate with lower cost. The lower cost in the energy consumption can reach even the 44% comparing to a constant speed of the same cooling and heating capacity. In combination with the rest advantages (accurate control of temperature and low noise), they have become unequalled.

Any air conditioning unit has filters that clean the air from dust, odors, microorganisms etc. However, the current needs of comfort and hygiene are leading some manufactures to supply the units with ionizer also. The ionizer is an additional filters currently the one of the most advanced air-cleaning technologies in the world (COLD PLASMA). The Cold Plasma ionizer releases positive and negative ions, thus it disinfects and diminishes bad smells in the room. Furthermore it gathers house dust, pollen and other small particles that are responsible for allergies. At the same time it generates negative ions, in order to create a safe, healthy and relaxing environment.

The small air conditioning units designed for a room do not have the ability of refreshing the air. That is why when the unit is not operating; the room should be ventilated properly. In central air conditioning systems, the ventilation and the use of fresh air are applicable.

Normally one indoor unit should be used for one room only, since each room has different needs. Also, people who live in two different rooms might have different comfort needs. This way the operating setting of the unit might satisfy the needs of the one room, but not of the second.

During the heating mode, the out coming air from the indoor unit has a temperature of 40°C approximately. At this temperature the relative humidity becomes very low (35% to 40%). That is why the heated air should be directed long from the place that a human is sleeping or resting, so as to be given enough time to the heated air to be mixed with the room air and to reach the normal temperature and humidity. The small room air conditioning units do not have the capability of humidifying the air, as it happens with the central units.

We do recommend at least annual air conditioning system checkups and these should be done in the Spring.  By undertaking this programme of maintenance, you would minimise the risk of expensive repairs later on.  Also, the main advantage is that your system should function efficiently during the Summer months.

Maintenance it is a whole range of activities for preventing equipment failures by timely diagnosis and prevention.

The standard list of service works for split systems includes:

• Cleaning the air filters.
• Cleaning and desinfection of the evaporator.
• Cleaning the condenser.
• Cleaning and desinfection of the drainage system.
• Checking the operation.
• Checking the working pressure.
• Checking the joints for gas leakage.
• Measurement of operating currents.
• Measurement of operating temperatures.