In 1980 we built a cement block home in north central Florida. Winter nights typically range in the 30's and 40's and occasionally well below freezing. Originally, it was 1,000 square feet and had a "passive solar" design with most windows facing due south. The trees lose their leaves in winter, which helps sunlight to enter and warm the house in the daytime. The rectangle ranch design allows cross ventilation easily through the main living quarters. Eventually, over the past 28 years, we did add on an extra 800 square feet, totaling 1,800 sq. feet. A large screen porch is also attached for use mostly in mornings and evenings on hot summer days. We use natural gas for cooking on top burners only. The oven and water heater are electric.
Our average energy bill each month ranges from $40 in winter to $60 in summer months.
We do not own a clothes dryer. All of our laundry is hung outside on a clothes line. Most people think this is a lot of work, but really it is quite simple and quickly done. If rain is expected, I can hang laundry in our workshop beside a carport or in the carport.
We do have central heat and air conditioning. I rarely use the heater. While days are hot and humid in summer, we generally use the air conditioner from 2 PM until 7 PM on very hot days only. At other times, we rely on paddle fans in every room and/or portable oscillating fans. I turn off fans if I leave the room for extended periods of time.
I clean my air conditioner filter once every month during the months the air conditioner is used.
We always turn off light switches when leaving a room. The only lights that are on are the ones we need on.
We often use a toaster oven for baking, unless a larger oven is required.