Central AC units are normally hardwired into the electrical system. Home air conditioners are offered in two styles: a whole home central AC unit that is often combined with a central heating system, and window units designed to cool off individual rooms. The two types of appliances require different electrical voltages to work properly. Even a small air conditioner can put a strain on a home electrical system. Central Air Conditioners Central air conditioners require a 220-volt or 240-volt, dedicated circuit for operation. When a central air conditioner starts up, it may require up to 5,000 watts of electricity, making it one of the largest consumers of electric power in the home. An air conditioner's cooling capacity is measured either in British thermal units (BTUs) or in "tons." The greater the number of BTUs or tons, the greater the cooling power of the unit. A larger unit also requires more electrical power. Buying a unit too large for your home wastes electricity, and causes the unit to wear out faster.

Window Air Conditioners Window air conditioners are offered in either 110/120-volt or 220/240-volt models, depending upon their cooling capacity. when were window ac units inventedA unit designed for cooling one small room such as a bedroom normally provides 15,000 BTUs and often works on a smaller, standard 110/120-volt wall outlet. mobile home ac package unitsBecause of its large power consumption, you should not have any other appliance on the circuit to avoid an overload. water coming from ac unitA window unit larger than 15,000 BTUs may require a 220/240 dedicated circuit. Adding Circuits Many homes do not have 220/240-volt circuits as standard equipment in living spaces, and they must be added by a qualified electrician. This can cost between $500 to $1,500 as of the date of publication, depending on the type of home and its location and the work that must be done, according to Bill Ferrera of Ferrera Electric in San Francisco.

All window air conditioners provide the necessary information about the electrical requirements on the unit packaging. As with a central unit, buying a window unit that is too large wastes energy and money. Sizing a Unit The specifications listed for individual air conditioner units state the size of the area they cool. For example, an AC unit that cools a 120-square-foot area would work best in rooms that are 10 feet wide and 12 feet across. By matching your room or home size with the unit's specifications you can select the appropriate size air conditioner. Other factors you might consider are the number of windows and amount of insulation. If more heat comes through the windows, you will need a larger unit. A poorly insulated home will allow cool air to escape faster and might require a larger window unit. A trained technician can help you determine the proper central AC unit for your needs. References Sylvane: 5 Things To Consider When Buying A Window Air ConditionerDon Rowe: How Many Watts Do You Need?

Popular Mechanics: Buying A Central Air Conditioning System Photo Credits Jupiterimages/Comstock/Getty Images Suggest a CorrectionTo allow for future growth so that you can operate the router in any hardware configuration without upgrading the power infrastructure, we recommend that you provision 9600 W for each three-phase delta AC power supply or 6000 W per each three-phase wye AC powerTable 1 lists the power requirements for various hardware components. For PIC power requirements, see the PTX Series Interface Module Reference.Table 1: AC Power Requirements for Components ComponentMaximum Power Requirement (Watts)Base system (includes fan trays at typical speed, one host subsystem, one CCG, nine SIBs, and the craft interface) and two PDUs and six PSMs1819 WCCG10 WCooling system557 W (typical speed)3062 W (higher speed)Craft interface10 WHost subsystem (Control Board and Routing Engine)144 WFPC562 WPSM96 WSIB58 W PIC—Generalized typical value58 WPIC—Generalized maximum value77 W If you do not plan to provision 9600 W for each three-phase

delta AC power supply or 6000 W per each three-phase wye AC power supply, you can use the information in Table 1 and in the PTX Series Interface Module Reference to calculate power consumption for your hardware configuration, input current from a different source voltage, and thermal output, as shown in the following examples for an AC-poweredRelated DocumentationPTX SeriesUnderstanding Normal-Capacity Power System Power ZonesPTX5000 AC Power System DescriptionConnecting Power to the PTX5000 Three-Phase Delta AC PDUsConnecting Power to the PTX5000 Three-Phase Wye AC PDUsPTX5000 AC Power Electrical Safety GuidelinesPTX5000 AC Power Cord Specifications Because air conditioners operate at comparatively high power levels, a PFC (Power Factor Correction) circuit is generally incorporated into the power supply. In low-cost systems for countries with no restrictions on power line harmonics, the PWM (Pulse Width Modulation) function of the MCU is typically used to implement a partial-switching configuration.

This enables some improvement of the power factor while requiring few components. Japan has relatively loose restrictions on power line harmonics, so Renesas offers a variety of MCU products for different price ranges. They can be combined with IGBTs to match the requirements of customers. In high-end air conditioner models and models for countries with strict restrictions on power line harmonics, a full-switching configuration employing a PFC IC is used. Typically, a continuous conduction mode PFC circuit is employed to ensure efficiency. The use of full-switching PFC circuits has generally been limited to high-end models due to the larger number of components and the increase in noise. Now, however, the R2A20114A continuous conduction mode PFC IC from Renesas provides interleaved operation at high power levels along with inexpensive anti-noise measures, enabling manufacturers to design low-cost air conditioner models that combine a high power factor and high efficiency.Have you ever wondered why some power ratings are expressed in WATTS, some in AMPERES or AMPS, some in VOLTS, and some in KVA?

This page will explain in simple terms the difference between the power ratings and describe when each should be used in your data center and network architecture planning. A KVA is simply 1,000 volt amps. A volt is electrical pressure. An amp is electrical current. A term called apparent power (the absolute value of complex power, S) is equal to the product of the volts and amps. On the other hand, a watt (W) is a measurement of real power. Real power is the amount of actual power that can be drawn from a circuit. When the voltage and current of a circuit coincide, the real power is equal to the apparent power. However, as waves of current and voltage coincide less, less real power is transferred, even though the circuit is still carrying current. Differences between real and apparent power, and thus watts and volt amps, arise because of inefficiencies in electrical transmission. The resulting inefficiency of electrical transmission can be measured and expressed as a ratio called the power factor.