Manually operated systems usually simply involve a switch in a prominent/logical location to allow the fans to be run when
user thinks the most benefit is to be had. This sort of system is considered a Night Cooling system as it allows the user
to switch on the fan at night when going to bed so they can draw in the cooler night air. It can then be shut off in the
morning from the same switch.

This system is still switched on manually using a switch in a prominent/logical location however it also incorporates a
temperature sensor indoors. The temperature sensor allows the system to switch off automatically when the desired temperature
is reached so the building is not overly cooled.

Time Clock operated systems may be operated exclusively by a time clock or in unison with a manual switch.
Systems operated exclusively by a timeclock are usually considered a Night Cooling system, setup to run automatically during
the cool evening hours and shut off in the early morning before the temperature rises during summer months. A timeclock only
system may also be setup with additional runtimes, however they are always switched automatically based on time of day/month/
year.

Systems that incorporate a timeclock and a manual switch are usually setup to run only after the manual switch is pressed.
The timeclock in this case is usually setup to automatically switch off the Night Cooling at an optimum time in the morning
before the temperature rises.

Using a timeclock alone or in unison with a manual switch the system may be setup to operate in various ways, including the
possibility of having the system provide heating in winter by drawing in warmer outside air(Mixed Mode Ventilation). These
sort of systems will however always operate regardless if the temperature conditions are not perfect as they are not setup
with detection systems.

Fully automatic systems are operated based on interaction between multiple elements and are able to adapt to the current
temperature conditions. These systems may incorporate time clocks, various sensors(temperature, occupancy, etc.), switches
and digital controllers to bring it all together. Due to the complexity of these systems they are able to make decisions based
on the current conditions to provide the most efficient cooling/heating while keeping a building environment comfortable.
As such these sort of systems have been dubbed "Smart Ventilation" by Healey Engineering.

To take full advantage of the system it is usually interconnected with the air conditioning, allowing the system to shut off
the AC is there is more efficient "free" cooling or heating to be had without the need for user input. This sort of system
can be fully autonomous or incorporate manual switches to activate certain functions, such as setting the AC up so it won't
ever run unless manually switched on. As this is the most complex of the systems it is the one capable of being setup in the
most ways, whether by time or calendar based scheduling or sensor interaction, and as such it must be designed carefully.

The system uses a main fan to extract air from the space to force air movement when active. The location will depend on the
design however these are usually located with an intake grille somewhere central in a building and usually on the highest level,
above a major staircase is often a good location for example.

Similar to the extraction fan a supply fan blows into the building, pressurizing the space. This may be ducted in in a single
location or be supplied directly to various room by a network of ducts. In this configuration you must be wary of your supply
grille design as you don't want to create a heavy draught in a specific location, rather you wish to provide an airflow path
throughout the building.

As an alternative to placing an extra grille on the ceiling of the building the extract or supply fan ducting can be linked
into existing/new ducts for the air conditioning system. If this route is taken one must pay attention to not "overloading"
the ducting with more air than it can take (as it can cause damage/wear to the ducts, fan and AC units) and ensure this system
cannot run simultaneously with the AC.

With the volumes of fresh air that will be passing through the building one must consider where it's coming from or where it's
going. A small scale manual system may simply require the user to open their windows when the fan is on, while a large scale
automated system may involve automated louvers that open when the fan is active and change their position based on fan speed
and changing conditions.

Regardless of the system type and scale the design must take into account where the air is coming from and where it is going
to. The flow path of the air must be taken into consideration to ensure an effective result.

Also ventilation openings of all sorts may be used to provide cross ventilation if the conditions allow it. The most basic
implementation of this would be someone opening windows or doors at both ends of a house when a seabreeze is coming in. A
much more complex system may however be able to detect wind speed and open louvers or windows automatically when it detects
a sufficient breeze, providing cooling without even the power draw of a fan.