BTU and EER
Most zephyr conditioner have their capacity shit in British thermal units ( Btu ) . A Btu is the amount of heat necessary to raise the temperature of 1 pound ( 0.45 kilograms ) of water one arcdegree Fahrenheit ( 0.56 point Celsius ) . One Btu equals 1,055 joules . In heating and cool down terms , one short ton equal 12,000 Btu .
A distinctive windowpane air conditioner might be value at 10,000 Btu . For comparability , a typical 2,000 - square - foot ( 185.8 straight meters ) house might have a 5 - ton ( 60,000 - Btu ) air conditioning organisation , inculpate that you might call for perhaps 30 Btu per substantial foot . These are grating estimates . To size an air conditioner accurately for your specific app , you should contact an HVACcontractor .
The free energy efficiency valuation ( EER ) of an line conditioner is its Btu valuation over its wattage . As an model , if a 10,000 - Btu air conditioner consume 1,200 watts , its EER is 8.3 ( 10,000 Btu/1,200 watts ) . Obviously , you would care the EER to be as high as possible , but commonly a higher EER is accompanied by a high price .
rent ’s say you have a selection between two 10,000 - B.Th.U. social unit . One has an EER of 8.3 and consumes 1,200 watt , and the other has an EER of 10 and consumes 1,000 watts . permit ’s also say that the price difference is $ 100 . To determine the vengeance period on the more expensive unit , you require to make love around how many hour per twelvemonth you will be execute the melodic phrase conditioner and how much a kilowatt - hour ( kWh ) be in your arena .
assume you be after to use the air conditioner six hour a day for four month of the year , at a cost of $ 0.10 / kWh . The difference in energy consumption between the two units is 200 watts . This means that every five hour the less expensive unit will consume one additional kWh ( or $ 0.10 ) more than the more expensive social unit .
Let ’s do the math : With roughly 30 days in a month , you ’re operating the tune conditioner :
4 months x 30 day per month x 6 hours per mean solar day = 720 hours
[ ( 720 hours x 200 watts ) / ( 1000 watt / kilowatt ) ] x $ 0.10 / kW hour = $ 14.40
The more expensive atmosphere conditioning unit costs $ 100 more to purchase but less money to operate on . In our good example , it ’ll take seven yr for the high price building block to break even .
