5) Adjust your thermostat. If you are away for long periods every day, adjust your thermostat to a higher temperature for the time you are away. This will lessen the amount of time your unit has to work each day and will lengthen its life cycle. An additional benefit will be a lower utility bill each month. Some newer thermostats allow you to pre-program your thermostat to match your schedule so that your home will still be cool when you arrive. Optimizing your system’s usage will maximize its life in the long term.

The concrete pads under home air conditioner and heat exchanger units tend to settle over the years. As long as there’s no strain on the copper coolant tubes and electrical lines, and the unit stays dry and level, it’s OK that the pad has sunk. But if it continues to sink and pulls the lines tight, or if water puddles around the unit, you’ll need to take action. Here’s how to fix it.
Demand controlled kitchen ventilation (DCKV) is a building controls approach of slowing down kitchen exhaust fans and subsequent supply air in response to the actual cooking loads in a commercial kitchen. Traditional commercial kitchen ventilation systems operate at 100% fan speed independent of the volume of cooking activity and DCKV technology changes that to provide significant fan energy and conditioned air savings. By deploying smart sensing technology, both the exhaust and supply fans can be controlled to capitalize on the Law of Affinity for motor energy savings, reduce makeup air heating and cooling energy, increasing safety and reducing ambient kitchen noise levels.[30]

Although HVAC is executed in individual buildings or other enclosed spaces (like NORAD's underground headquarters), the equipment involved is in some cases an extension of a larger district heating (DH) or district cooling (DC) network, or a combined DHC network. In such cases, the operating and maintenance aspects are simplified and metering becomes necessary to bill for the energy that is consumed, and in some cases energy that is returned to the larger system. For example, at a given time one building may be utilizing chilled water for air conditioning and the warm water it returns may be used in another building for heating, or for the overall heating-portion of the DHC network (likely with energy added to boost the temperature).[4][5][6]

The heat-exchanger cools the air that is being forced through it by the furnace blower. As the warm air comes in contact with this cool surface the water in the air condenses. By pulling the water molecules from the air. According to the psychometric chart[42] as relative humidity decreases in order to feel cool you will have to lower the temperature even more. A common way to counteract this effect is by installing a whole-home humidifier.[43] Similarly, installing a high efficient system this need to turn the temperature down wont have such and influence on your energy costs.

Air conditioner equipment power in the U.S. is often described in terms of "tons of refrigeration", with each approximately equal to the cooling power of one short ton (2000 pounds or 907 kilograms) of ice melting in a 24-hour period. The value is defined as 12,000 BTU per hour, or 3517 watts.[32] Residential central air systems are usually from 1 to 5 tons (3.5 to 18 kW) in capacity.