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Old house - will I be able to have window units in my rooms?

Old house - will I be able to have window units in my rooms?


  #1  
Old 06-16-14, 09:49 PM
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Old house - will I be able to have window units in my rooms?

I live in an old 3 bedroom/1 bathroom house. I just bought it in fall of last year. This is my first summer and I'd like to put window units in each bedroom.
Potential Problem: All bedroom lights and outlets are on the same circuit.

This means I have:
14 CFL bulbs
1 desktop computer and printer
1 20" lcd tv
Various electronics being charged (laptops, cell phones, etc)
Bedside electronics (clock radio, etc)

Will I safely be able to add 3 ac units to that 1 15amp circuit?
Each unit is ~5000 btu (500 watts or so I think) so that by itself seems to be a full load.

What is recommended in this case? Adding a new outlet?
 
  #2  
Old 06-16-14, 10:04 PM
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Each air conditioner needs a dedicated 20A AFCI protected circuit.
 
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Old 06-16-14, 10:05 PM
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Adding a new dedicated circuit for each is best but given the small size you may get by with one 20 amp circuit for all three.
 
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Old 06-17-14, 03:54 AM
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I have a 6,000 BTU window shaker in our bedroom . IIRC , it has a name plate amperage of around 6 amps / 120 VAC ?

You are not going to get 3 window shakers to run on the existing 15 amp circuit + all the other stuff already on the circuit .

I agree , if you are going to re-wire it , run 3 circuits & be done with it .

God bless
Wyr
 
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Old 06-17-14, 05:35 AM
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Thanks for the help!
What is the reason for using a separate dedicated 20a for each? That's going to get very expensive. Is that code? Even for a ~5amp window unit?
I've lived in many houses up in New England and never had dedicated circuits. They use less wattage than space heaters and I've never heard of that recommendation for those. Just curious
It sounds like I should add a few new outlets. Two rooms share a wall with the box so that's where I'll start I guess
 
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Old 06-17-14, 06:14 AM
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The startup of a compressor draws several times the run current.
 
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Old 06-17-14, 06:17 AM
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You would be grossly overloading your circuit. Adding outlets to it will not correct your problem. Time to hire an electrician to run a few new circuits to that area.
 
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Old 06-17-14, 08:16 AM
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bigboypete, that's what I meant by adding new outlets. New outlets on a new circuit. I think what I will do is add 1 new 20amp circuit that supplies 2 of the 3 bedrooms. They will both be on the same wall of the house that the panel is on so it shouldn't be too pricey/difficult. Then I'll run 2 of the window units on that circuit and leave the 3rd one on the original circuit
 
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Old 06-17-14, 08:29 AM
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leave the 3rd one on the original circuit
You can try that, but I think with the other loads you already have on the 15 amp existing circuit that you'll have problems.
 
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Old 06-17-14, 08:47 AM
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I know the people who owned the house before us had 2 units running upstairs during the summer without problem, and they used incandescent bulbs in all the lights, too!
 
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Old 06-17-14, 09:08 AM
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They got lucky. Our answers are not based on luck.
 
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Old 06-18-14, 02:19 AM
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The reason I would be running 3 new 20 amp circuits is I would be running them my self . No labor cost for these kinds of weekend projects . And I normally do not run 15 amp circuits on new circuits .

Some localities , 15 amp circuits are used for your general lighting and appliance circuits and 20 amp circuits are only run for the " dedicated " circuits . Around here all are installed as 20 amp circuits .

God bless
Wyr
 
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Old 06-18-14, 05:09 AM
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I know the people who owned the house before us had 2 units running upstairs during the summer without problem, and they used incandescent bulbs in all the lights, too!
Lights are a very minor load when compared to A/C units. The others have given you the best advice based on the info given. You could "roll the dice" and try running them on existing circuits but their is a danger of overloading the circuit, which should trip the breaker if properly protected/sized. If it is not properly sized, you risk overheating the wires and starting a fire.
 
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Old 06-18-14, 10:01 AM
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It says right on the side of the units you need a dedicated circuit.
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