All large industrial set ups, residential buildings and offices have systems for heating, ventilation and air conditioning. Most of them are installed based on the standards that are defined for that region. Not only these maintain interior climate, but these systems are also implemented to provide cleaner and more breathable air.
However, these systems are responsible for a major fraction of electricity bills. With more intelligent installations, the power requirement of these systems can be reduced.
Multi staged HVAC systems have variable cooling and heating capacities. This makes it ideal for areas where the weather varies over the seasons. Those which are single stage systems have only one cooling or heating capacity. These systems are more like ones with an on and off switch.
Single stage systems are more useful in places that are generally hot or cold that usually needs one kind of temperature control (either heating or cooling) throughout the year. Multi stage systems are great in scenarios where both heating and cooling in needed with precise control on temperature.
Zoned systems allow the HVAC to be cut off from operating in certain zones when needed. For example, consider an office building which also houses a datacenter. The office will not need cooling or heating throughout the day, but the datacenter or the server rooms will need constant cooling and ventilation. Zoned systems will cut off the office when there are no employees. These are particularly useful in offices and residential buildings.
Use Natural Ventilation
Ventilation can either be forced or natural. Natural ventilation relies on the relative movement of hot and cold air. Hot air rises whereas cold air moves down. By using these convection currents of air, proper natural ventilation systems can be designed that are as effective as forced ventilation.
A good thermostat can control the temperature levels efficiently. They can shut down some parts of the HVAC systems if not needed in an area. Also, they can circulate natural air and make temperature control redundant for a while. This will surely cut down on electricity bills.
Finally, make sure that the insulations in doors and rooms are alright. That also includes plugging in holes in walls or ceilings, in ducts and other places that carry or hold the conditioned air. Cleaning the fans make them operate more efficiently and hence they can provide more by consuming less.