Window A/C circuit requirements

[TomR]

I am adding some new circuits to a 2nd floor apartment and I need to decide how to do the wiring to accommodate window air conditioners.

There are two rooms involved -- a living room and a bedroom. Each room is approximately 12' x 14' and each room has two windows on one end of the room and no other windows. I am already adding outlets in each room for general use purposes. But, I also want to be sure that I provide whatever is needed to enable a tenant to provide a window a/c unit in each room. Any window a/c units will be 110-volt units (not 220-volts), and I assume that each window a/c unit will be roughly 8,000 BTU's or maybe 10,000 BTU's at most.

My question is, should I provide a single dedicated circuit for each window a/c unit -- one for each room? If I did that, I could place each dedicated circuit window a/c outlet on the wall between the two windows in each room.

Or, is it okay to have one circuit with two or more outlets on the wall with the windows in each room and the window a/c units would be sharing that circuit with one or two additional outlets on the same circuit?

[clare]

You DO want dedicated circuits for each A/C unit

[RBM]

Depending upon where you are, and which code version you are using: I would run dedicated 20 amp circuits, AFCI protected, for the airconditioners, and another AFCI circuit for the additional general room outlets

[Ed Pawlowski]

Nice to have, but not really needed. Since you are wiring from scratch it is a good idea. From my long experience using window AC in different houses, it is OK to have other receptacles on the same circuit. Use a bit of common sense though.

You do not want two AC units to be on one. A lamp on a night table, or a clock radio in the bedroom is not taking enough juice to affect anything.

I've been running assorted window ACs for 47 years and never had a problem. Avoid putting one on a circuit with a major appliance potential of course and you will be OK.

[Ralph Mowery]

As a 10,000 btu AC will use about 9 to 10 amps at 120 volts, hooking more than one to a 20 amp breaker will be pushing it. Then if one is running and the other one starts up, the start up current will be more and the breaker will most likely trip. Use a seperate 20 amp circuit for each room unit. As RBM stated, local codes take over,but the AFCI and ground fault breakers are good ideas.

[bob haller]

have you looked into a central AC? if the units each have their own furnace they are affordable, cost less to operate, and the buildings look more modern and up to date plus the windows are always available.

I am just suggesting you price things both ways, you might get more for rent with central ac

[clare]

Or even a mini-split in each unit. Has all the advantages of central without requiring ductwork to be available (works with radiant, baseboard, and other non-forced-air heating systems.

[TomR]

I have also used window a/c units for years with no particular problem. I can remember one or two situations where too much ended up on one circuit and I did have to move some things around to prevent the breaker from tripping. So, I think you are right that, since I am wiring from scratch, it would make sense to do a dedicated circuit for each window a/c and wire the rest of each room separately form the dedicated window a/c circuits.

[TomR]

Thanks. That makes sense. I'll do a dedicated circuit for each window a/c and I'll run the other room wiring on different circuits.

About the 20-amp part, I have this thing that I do where I do all of the new wiring with #12 wire on the entire circuit even if I am only putting in a

15-amp circuit breaker. My thinking is that I would rather have the breaker trip if the tenants put more than 15 amps on one circuit even if all of the wiring on the circuit is 12 gauge and could accommodate 20 amps. For circuits where the code definitely requires 20-amp circuits (such as kitchens, I think), I still use all 12 gauge wire, but I do put 20-amp breakers on those circuits.

About the "AFCI protected" part, I don't think the code in our area requires that yet for what I am doing. But, if I did decide to do that, the only difference would be that I would just use the more expensive AFCI breakers in the service panel for each of those circuits, right?

[TomR]

I appreciate the suggestion, but I am definitely not going to be doing central air at this time. I could always add that later if I wanted. But, for this property, it wouldn't make sense for a lot of reasons.

[RBM]

You are correct. It sounds like a good plan

[Stormin Mormon]

While you have the walls and such apart, I'd think to run 12-2 and put in a

20 amp breaker. Cost a few bucks more for the wire, but it could turn out to be worth it. Cut down on nussiance complaints.

I appreciate the suggestion, but I am definitely not going to be doing central air at this time. I could always add that later if I wanted. But, for this property, it wouldn't make sense for a lot of reasons.

[Stormin Mormon]

Thanks. That makes sense. I'll do a dedicated circuit for each window a/c and I'll run the other room wiring on different circuits.

About the 20-amp part, I have this thing that I do where I do all of the new wiring with #12 wire on the entire circuit even if I am only putting in a

15-amp circuit breaker. My thinking is that I would rather have the breaker trip if the tenants put more than 15 amps on one circuit even if all of the wiring on the circuit is 12 gauge and could accommodate 20 amps. For circuits where the code definitely requires 20-amp circuits (such as kitchens, I think), I still use all 12 gauge wire, but I do put 20-amp breakers on those circuits.

About the "AFCI protected" part, I don't think the code in our area requires that yet for what I am doing. But, if I did decide to do that, the only difference would be that I would just use the more expensive AFCI breakers in the service panel for each of those circuits, right?