What size air conditioner for 1800 square foot house?

Answer 1

It depends on how well the house is insulated, how many windows it has and on which side of the house they are on, pluse whether they are single pane, double pane, etc., and where the house is located (Northeast, Southeast, Southwest, Northwest, it all makes a big difference). A load calculation should be done on the house to determine the heating and cooling loads. The better the house is insulated, the less heat gets into the house so there is less to remove. An oversized unit will not run long enough to reduce the relative humidity. Humans like a comfort zone with a balance of temperature and humditiy, of say about 75 degrees with 50 percent relative humidity. The lower the relative humidity, then the higher the temperature can be and we will still be comfortable. Contact your local electric power supplier and see if they provide energy audits or do load calculations for free.