streamlining your ventilation system
CO 2 Burners
Some indoor horticulturists utilize CO 2 burners to enrich
the environment with CO 2 . These burners add heat to the
growing space and need to be considered when making
calculations for cooling equipment. The BTU output of a
CO 2 burner will depend on the size of the unit and how
many burners the unit has. A very basic rule of thumb is to
add 10,000 BTUs of cooling for every CO 2 burner with two
burners. However, CO 2 burners sold for indoor horticultural
use normally include a chart listing how many BTUs they
put off. It is important to keep in mind that most CO 2 burners
do not operate continuously but, rather, sporadically. To
put it another way, the BTU rating on a CO 2 burner is only
applicable when the unit is operating. This time of operation
may range from one hour to 12 hours per 24-hour cycle.
Other Electrical Equipment
“ These burners add
heat to the growing space
and need to be considered
when making calculations
for cooling equipment.”
Every piece of electrical equipment used in an indoor
garden—air pumps, atmospheric controllers, fans,
dehumidifiers, etc.—add a small amount of heat to the
environment. In most cases, these pieces of equipment
are negligible and will not have a dramatic effect over the
required cooling loads. However, when making calculations
as to the required BTUs for cooling, it is always a good idea
to go with a slightly higher BTU than a slightly lower one. In
other words, by choosing an air conditioner that has a BTU
rating that is slightly higher than the requirements calculated
from the room size, lighting system, ballasts, and CO 2 burners,
a grower can rest assured that any additional electrical
equipment used in the garden will be covered. It is always
best to error on the side of caution.
The ventilation system of an indoor garden is the heart and
soul of atmospheric control. The temperature, humidity, and
CO 2 levels of an indoor garden directly influence the plants’
ability to photosynthesize. When the atmospheric condi-
tions of an indoor garden are kept consistently in the optimal
range, and if lighting and nutrition are in check, the plants
will have the ability to grow at an accelerated rate. Motorized
fans and air conditioners are the main tools used by indoor
growers to achieve the atmospheric conditions most condu-
cive to heathy growth. Hobby growers can usually get away
with a couple of fans to control heat and humidity, while
commercial growers will most likely need to incorporate air
conditioning systems. One of the most difficult aspects of
sizing an air conditioner for an indoor garden is calculating
all the contributing factors that create additional heat. By
considering the room size, the wattage of the lighting system,
and the heat created by CO 2 burners, an indoor gardener
can more accurately determine the amount of air condition-
ing he or she will need to provide the optimal atmospheric
conditions. Regardless of the size or type of indoor garden,
the basics of a ventilation system will always remain the
same: to control temperature and humidity and to provide the
plants with CO 2 for photosynthesis. When these basic prin-
ciples are met, a horticulturist will be rewarded with more
consistent yields and a higher return on investment.
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