The first stage of any installation is a site survey in order to obtain relevant details of the location and also get a general feel as to what the customer's preferences are.

A survey will normally include the following : -

Detailed measurement of the area to be heated / cooled.
Structural information relating to walls, ceiling, building orientation (facing North/South/East/West), window size etc.
Assessment of how many people will use the area.
What heat creating equipment is used within the area, such as PCs, printers, photocopiers etc.
Information on available electrical supply system (confirmation of adequacy)
Positioning of outdoor condensers.
Service height above suspended ceiling/s.
Location of drains (where applicable) for condensate drainage etc.
Special requirements of customer/s, if applicable.

Once all the above information has been collected, a heat calculation can be made, thus offering a duty (usually KW) or size required. Depending upon the size of the room, the duty can be shared or delivered from one single or multiple unit/s.

A detailed quotation can now be given for the customer's particular requirements.

The above mentioned is not exhaustive, but is a good general guide.