Guide to Heating Loads for Industrial and Commercial Premises

The heat loss from a space H metres high, W metres wide and L metres long, with windows Lw long and Hw high, to a temperature of T⁰C above the outside temperature (e.g. -1⁰C outside 21⁰C required inside T = 22⁰C) is made up of heat losses from:

    Air Changes = H x W x L x No. of air changes /hr x 0.33 = A

    Roof  = W x L x U value of roof material (w/m^{2 0}C) = R

    Floor = W x L x U value of floor material (w/m^{2 0}C) = F

    Walls = Length of walls (i.e. 2W + 2L) x H x U value of wall material (w/m^{2 0}C) = W

    Windows = Hw x Lw x (U value of windows less U value of wall) = Win

SO THE TOTAL HEAT LOSS = (A + R + F + W + Win) x T     kWs
                                                               1000

Additionally for internal walls, "T" is again the temperature difference between two spaces but if the "outside" or the adjacent room is at a higher temperature then this equals a heat gain (i.e -T). 

If quick heat up is required the heating load should be the heat loss + 50% with overall control by a thermostat.

Having calculated heat losses select the appropriate number of heaters for your applications.

Note: for high roofed buildings, loading bays with high air changes or intermittently heated areas contact Mearsecroft
Created and updated by Spiders Webs