Window air conditioner/breaker question

[BigMike40]

Hello all. New here. Love the site. Just had a question about a window air conditioner in my moms mother in law suite. I’ll try and attach the one we had and can get again along with the one I’m thinking about getting to upgrade if the wiring and breaker can be used for the bigger one. Please let me know your thoughts. Thanks in advance. The 12,000 btu is the one she has now. The 18,000 is the one I’m thinking of upgrading to. They both have the same plug. Just wondering if the breaker or wiring that’s used for the current 12,000 setup would hold the 18,000 pull. Thanks

 

[Jadnashua]

You need at least 12g wire and a 20A circuit. The circuit should be sized so the load is no more than 80% of what can be supplied since it could be running constantly worst case, and on a 20A circuit that comes to 16A, or at 240vac 16*240=3840W.

For maximum comfort, on a hot day, the ideal a/c unit would be running nearly continuously. That will provide the best dehumidification. When an a/c doesn't run long enough, while the area might get the desired temperature, it tends to do it in shorter runs, which means it's not dehumidifying anywhere near as much. Humans tend to be more comfortable in drier air. A cold, humid condition is not comfortable for most. While a bigger a/c unit might pull down the temp faster, overall, it won't be as comfortable. It would take a quite large area that was poorly insulated to need an 18,000BTU room a/c unit, and 12,000 may be bigger than ideal. IOW, a smaller unit might actually provide better comfort, but it can't cool the room down as fast if it gets shut off during the day.

 

[Sponsor]

 

[Afjes]

BigMike = What is the present size of the wires going from the breaker panel to the receptacle? What is the present size of the breaker (rating - amps?) feeding that receptacle.

Keep in mind that just because the old AC ran fine does not in any fashion mean the proper size wiring or breaker protection were used to begin with. It is possible that nothing serious just didn't happen yet. This is a more power-hungry until you want to use so we want to be sure the proper wire and breaker are being used for it.

[Reason for edit] To ask BigMike to verify wire feeding the present receptacle and the rating of the breaker feeding the receptacle from the panel.

 

[Fitter30]

Like on any appliance under page 3 electrical plug tells acceptable voltage and what amperage the plug is rated for / size 208- 240/volts 20 amps. If it's hard wired voltage and minimum amps.