Is my a/c unit too small for my house?
I moved into my newly constructed house in April 2006. I live in Houston, TX (hot and humid summers!) and the builder installed a 5 ton 14 seer Goodman air conditioner. I have a 2 story 2600sf home and the builder only put one unit in. The builder said that they don't start putting in 2 units until the square footage reaches 2700 sf. Despite keeping my thermostat at 78 and sometimes 79 degrees I had $500 electric bills 3 months in a row during the hot summer months. I expected our bills to be around $350 but $500 seemed outrageous to me. Do any of you have an opinion on if my a/c unit is not large enough for my house? Would 2 units make a difference in my electric bills? BTW, I have a roof tech radiant barrier on my roof, and low E windows so I was expecting to save money with that too. Thanks!