18 Jul THE SABBATH DEBATE: PERMISSIBILITY OF USING AIR CONDITIONING ON SHABBAT. PART 2

After addressing the
question last week
of what to do on
Shabbat when the
house becomes hot
and there is a need to
turn on the AC, this
week we will delve

into other relevant points.
Adjusting the air conditioning vents.
On Shabbat, it is generally permissible to
adjust air conditioning vents as long as
the adjustments are made manually and
not through electronic means. This means
physically manipulating the vents without
utilizing any electronic controls. One may
also open or close the vents based on personal
preference. However, it is important to note
that these actions may impact the efficiency
and power consumption of the air conditioning
system.
Adjustments that increase or decrease
the airflow may result in greater or lesser
electricity usage, which is a subject of dispute
among the poskim. The reason for this dispute
is that when the air conditioner adjusts itself
to the temperature at the new vents’ location,
it may require additional energy consumption.
Although we may not perceive the increase in
electricity usage directly, it does occur, and

more energy is being consumed at the power
plant during that time.
According to Rabbi Elyashiv, it is not
permitted to move the vents due to the
aforementioned reason. However, Rabbi
Aurbach holds the opinion that it is permissible
because the Torah does not forbid actions that
are imperceptible to the human senses, such
as the subtle changes in electricity usage
in this case. Additionally, it can be argued
that this is considered “grama” (indirect
use) of electricity since the increased fuel
burning occurs at the power plant, which is
located far away from the individual’s house.
Furthermore, it is possible that no change
occurs in electricity usage when moving the
vents, and in such cases, there would be no
שמירת שבת כהלכתה) prohibition for grounds
.(פרק יג הלכה מ
The permissibility of moving vents is not
restricted by muktse (prohibition on handling
certain items on Shabbat) because they are
designed for adjustment. Furthermore, it does
not fall under the category of building(בונה
וסותר (, as it is analogous to opening and
. (חוט שני שבת ח״א עמוד רג)window a closing
Of course, it is important to clarify that
adjusting air conditioning vents on Shabbat
is only permissible when the action is purely
mechanical, and there is no activation of

any electrical components involved. This
means that the adjustment should be limited
to manual manipulation of the vents without
triggering any electrical mechanisms. In
such cases, where the action solely relies
on mechanical operation, it is considered
permissible within the framework of Shabbat
observance. Adhering to these guidelines
ensures that the adjustments made to the vents
align with the principles of Shabbat while
maintaining a comfortable environment.
Navigating Rooms Controlled by Smart
Thermostats.
Smart thermostats operate by detecting
the ambient temperature in your home and
transmitting signals to your heating and
cooling system, prompting adjustments
based on your pre-set schedule. According
to poskim, it is permissible to enter a room
with the awareness that opening the door
may introduce warmer air, potentially causing
the AC unit to activate. This is because the
resulting change is considered “grama”
(indirect causation), as there is a delay
between the time the thermostat detects the
change and responds to it.
Collecting water from the Air Conditioning
System.
If the air conditioning unit spills water in
the house on Shabbat, it is generally not

permissible to place a bucket underneath to
collect the water. This is because the spilled
water is considered muktse. Placing the
bucket to collect the water would render the
bucket un-useful, which is not allowed on
.(מבטל כלי מהיכנו) Shabbat
However, in the event that the water creates a
wet and unpleasant environment where people
are staying, it is permissible to place a bucket
to collect the water (רעי של גרף(. Once the
bucket is filled, one may then empty the water
into a sink and return the bucket under the air
conditioning unit to collect any further water
.(שמירת שבת כהלכתה פרק יג הלכה לט)
AC that spills water onto a garden.
In cases where the air conditioning unit
spills water onto a garden or area with plants
and grass, resulting in their growth, it is
generally permissible. This is because the air
conditioning was turned on before Shabbat,
and the person is not actively engaged in
any actions on Shabbat that contribute to the
growth of the plants. Since the growth occurs
as an indirect result of the functioning air
conditioning unit, it is not considered a direct
violation of Shabbat laws.