8. DIAGNOSTICS AND CALCULATIONS<br>

# 8. Diagnostics and calculations

## 8.1. Calculation method

### 8.1.1. Distribution of heat loss

The basis for sizing all terminal units in a room is the heat loss of that room (or ‘reduced’ heat loss, when radiant heating is also used in the room) plus part of heat loss of other rooms assigned to that room, and possibly minus part of heat loss assigned to other rooms. This value is called here the required output of terminal units – Qreq/Freq.

The required output of terminal units is spread over radiant heating units, convectors and other heaters, if any (e.g. electric heaters). The Qreq/Freq distribution table is available both in Instal-heat&energy as well as in Instal-therm. If contributions of radiant and convection heating units are set to “auto”, then radiant heating prevails and it is designed in the first place. The remaining part of heat loss must be covered by the output of convectors. The calculated value is reduced by subtracting the estimated heat output of radiator circuit pipes and of other piping crossing the room (except for pipe feeds of radiant heating units, the output of which is already accounted for) and the result is the required output of convectors.