Electricity Billing of DC Inverter Air Conditioner

The bottom line for efficiency is the EER or energy efficiency rating....how many btu's you get per watt of electricity....so an 18k btu unit drawing 9 amps@ 230v is using 2070 watts of power 18,000/2070 = 8.7 EER....You should be looking for something in the 14 or higher EER range...

never saw an EER of 14. Are you sure about about your calculation.? below is the technical specs of the A.C i want to purchase. i just want to know the current range of

2.5 to 9.7A.

Here is a comparison of refrigerants EER, heating, and cooling capacity. R-410A is the best choice. High EER, heating, and cooling capacity is not much a difference.

Obviously this is a variable load unit....2200 watts to 5700 watts...

"A net refrigeration effect of nominal 18,000 Btu will be 5270 watts.

This EER is 5270/ 1950 = 2.7 It is also called (COP) coefficient of performance. One estimating rule of thumb is that an air -cooled unit compressor and fan will draw about 1.2 KW per ton of refrigeration. That is a COP of 2.8 "

They take a median estimate at rated capacity 5200 watts 1640 rated power consumption 7.1 amps power draw with a 3.6 COP....

There are different ways to measure the efficiency...Now if you look at the 18,000 btu's at 7.1 amps * 230 volts is about 1640 watts divided into 18,000 btu's is about an 11 EER....

If you are going with a variable load A/C system, you might want a larger say 2 ton unit that would allow a shorter run time under max load and spend most time at reduced load during operation, which would tend to lower electrical usage....

ps: you clearly need more insulation in your walls and ceiling...

2 ton unit...

ps: You might just need to have the evap coil cleaned or may be leaking refrigerant....when's the last time you had the unit serviced?

Unless the unit is free, don't waste your money. Both units are rated at 1.5 ton so the will cool about equally.

You should be able to do the math to compare the cost to operate the different units with their different AMP draw levels.

Figure worst case and compare the numbers for operating 14 hours a day.

Get some consultant or an HVAC expert provider in the field, ask if they have or can recommend a system that is a saving and already tested. They will actually assess first your AC setup and see the points to improve.
Why not invest in Green tech like solar, I think there's $/kW incentive.

The answer is, a definite maybe, since as usual you have not given enough data to make an informed decision. Things like indoor and outdoor ambient conditions play a large part in how much comfort an a/c can provide, and when they're coupled with the highly variable response to what/how different people feel under identical conditions, it's even more difficult.

On the other hand, if you're current unit's compressor is running all the time and it's still too hot/humid for you, an identically sized inverter unit may actually cost you more to run under the same circumstances. Here's what those numbers mean; 7.2A is the average draw under rated test conditions, so you save 20% over the 9A your current draws at the same conditions. The "gotcha" comes from the other numbers; the 2.5A is the unit running under lower temperature/humidity conditions when just the fan is running, the 9.7A is the draw when both the fan and the compressor are running constantly and you're tapping into the unit's reserve capacity.

Only you know what your operating conditions are, but if I were you my choices would be to raise the thermostat, reduce the heat gain, move the unit to a place out of direct sunlight, and lastly replace the unit when it finally quits from overwork.

If you can't afford the present electric bill, how are you going to afford a whole new unit?

You might save a little in running costs, but it will take quite a while to recoup any additional investment.

i am going to buy on installment

I think that the interest you would be paying on an installment purchase would far outweigh the small energy savings you may get from the proposed new unit. A far better investment would be improving the insulation in your dwelling.

The first thing is to determine what it is you are paying for.

You are not paying for "amperes" so forget about them. You are paying for KWH, . . . that is KW and running time.

So what are the KW ratings of your present unit as compared to the proposed replacement and what output "BTU" are you getting out of them.

Calculate and compare your "BTU" per KW coefficient for the two alternatives. The choice will become clear.

KW= V X I X P.F , since V and P.F are constant so KW is dependent on current draw. simple rule

The answer is No, you will not save your electrical bill. It will still be there.

Instead of a new AC unit maybe get a solar system to offset the electrical bill.

Have you considered changing the supply?

I installed 4kw of solar panels (5 years ago) and the savings are worthwhile. (unless it's overcast or snow.)

Admittedly they are not everything, e.g. at night. (they are saying they have developed
panels that work at night! I think that's a bit sus.) Give it a thought, it may help?
p.s. I have no shares or interest in the sale of panels.

jt.

Decided to read up on Russian Flu - with a book written by Ivan Heckovakof.

How well is the space insulated and shaded?

The inverter does not make (possibly) a perfect single phase sine wave, as is house current. This "spiky" Alternating Current is almost like square waves in some instances, and almost like triangle waves in others. This might provide a sharper inrush current to certain compressor types (as a solenoid oscillator), and perhaps make better use of magnetism to get the mechanical work out of the "same" device. Or, it could be your air conditioner that pulls 9 amps full time will blow this inverter, and you will be out the money you spent buying it.

"the bill is too much for me and my pockets are drying up." Ok. You are looking to save money.

" now i want to replace this A.C with a 1.5Ton DC inverter A.C ." So now, you are looking to spend money that's burning a hole in your pocket.....

" the specs of the DC inverter A.C are " Cooling Ampere= 7.2 A (2.5-9.7A) " . I cannot understand it. what is 7.2A and what is the range of 2.5A-9.7A. ? " The entire purpose of the inverter in the A.C. package is for variable speed control of the compressor/fan. If the speed is variable, the amperage draw will also change, hence the range given of amp draw, and an average number also given.

"Will i be able to save my electricity billing by installing this DC inverter AC?" I would say probably not. Not enough to make it pay for the new A.C. package, especially if you have done nothing to slow down or reduce the heat load of your house.