Thank you so much for the responses so far. It is definitely not the thermostat. Just when the weather turned cold this year we lost power to our old thermostat and called our friend who works in HVAC to come take a look. He tripped the breaker which fixed the issue and that is how we knew to do that this time around. When researching causes my husband decided he wanted to Nest and we got it mostly for aesthetic purposes. So, definitely not the Nest or its set up causing the issue. Bare with me as I am new to all of this but will try my best to describe our system. I thought it was Carrier but was wrong. It is a 1988 Amana all-electric heat and cooling system. It was a tested factory model that the previous owner got from her father who worked at the plant and it was installed in September 2001. The breaker is in the crawl space and we have a 1700 square foot two story home. Are there any other details that might be helpful? My husband has a good friend who has worked in HVAC repair for several years. He is a friend but still not cheap! I think we may just call him back over to test what is pulling so much power that it is tripping the breaker, but thought I would check here first for some tips. Thank you everyone!

I'd be more than happy to help you but your model number is incorrect. I think you mean a B1HH048 and your missing a number from the serial number. I think the unit was made in middle of January 1998... from what i can tell.

Here are the load calculations that I did on loadcalc.net (thanks for the tip, garden webber) for a Below Average construction regarding tightness (R30 in attic, brick exterior walls w/o insulation, single pane windows with storms) Total BTU's Cooling: 37006 Total BTU's Heating: 43690 Sensible Load: 33364 Laten Load: 3642 See original posting on 9/6/12 for estimates received, I am also waiting for an American Standard certified installer for a quote, any recommendations are appreciate. My house always smells stale and I noticed there are air filtrations system, however, I am on a budget and don't plan to stay in the house more than three years. Thanks in advance for any suggestions.

I would start by Check for voltage on the control board. If that checks out start tracing the low voltage wiring at the contactor. Sounds like there may be break in the line somewhere.