# How to calculate your rooms heat load

Discussion in 'Grow Room Design/Setup' started by Hydro Druid, Feb 3, 2011.

1. #1
Last edited by a moderator: Feb 3, 2011
Heat is measured in either BTU or Kilowatts. 1KW is equivalent to 3500BTUs.
The heat load depends on a number of factor's

1.The floor area of the room
2.The heat generated by equipment
3 the heat from lighting
4.The number of room occupants
5.The ambient temp ( your room's starting temp ) this will be added asap im still playing with the #'s

1.Floor Area of Room

Room Area BTU = L x W x 40 ( H = 8foot + 5btu per foot after that)

If you have a wall that is facing the sun add in for the extra heat

Sun facing wall BTU = L x H x 40

2.Equipment
This is trickier to calculate than you might think. The wattage on equipment is the maximum power consumption rating, the actual power consumed may be less. However it is safer to overestimate the wattage than underestimate it.

Equipment BTU = Total wattage for equipment x 3.5

Ballast in room BTU = ballast wattage/2 x 3.5

3.Lighting

Lighting BTU = Total wattage for all lighting x 4

Air cooled hood BTU = wattage x 4 / 2
@
400= 200-250 cfm
600= 250-300 cfm
1k = 300-350 cfm
^ is just a guide cfm per hood will be on your ducting/SP....

4.Occupants
even being that im only there for 2 or so of the 12 hrs i like it to be able to handle the extra sweat when i smoke one.

Total Occupant BTU = Number of occupants x 400

Total Cooling Required

Add all the BTUs together.

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

I can't remember what book I got this info from or I would credit it.

~HD