If you are thinking about cutting your energy bills, concentrate on appliances that heat or cool the house, or heat water. Including washing machines, tumble driers and dishwashers, hot tubs, patio heaters, showers, water heaters. Nothing else comes close. Lighting is quite a low usage per individual lamp, but you can (should be able to) buy Energy Saving lamps that use about 80% less electricity. You will notice the difference if you like to have a lot of lamps burning for a long time.
Obviously thick insulation will prevent heat wastage from the house, but if you have enormous windows then you will lose a lot through there. Unfortunately for you, the US has for many years had a cheap energy policy, and this has encouraged wasteful use. This is one of the reasons why American cars, fridges, washing machines etc are not bought in Europe (not an attack, just an observation)
In the UK, most of our energy is used in winter to heat the house. Air conditioning is very rare in ordinary houses. Energy has always been quite expensive so we are mostly quite frugal. For example my gas usage (hot water only) is about 5kWh/day in summer, and between 70 kWh and 100kWh/day (almost all heating) in the coldest three months of the year. This is a reasonable sized house. My electricity is 18 to 20kWh/day all year round, which includes two fridges and one freezer, plus the usual appliances and quite a lot of energy-saving lighting.
I am guessing Pennsylvania is quite a lot colder. Out of interest, the current UK standard is for 250mm of insulation (ten inches) in the loft, although our climate is quite mild. How much do you have?