Why does TEP guarantee only the heating and cooling costs and not the entire bill?
The Guarantee is essentially a “structure” program. The program requirements refer to how each component of the structure (insulation, windows, etc.) relates to the others, including the size of the heat pump. Because we know exactly how the home was built and the size and efficiency of the heat pump we can easily estimate the heating and cooling costs. We have no control on the other electrical items a customer will put in the home or how a homeowner will operate these appliances. Each family is different. A family with one child may only do four loads of laundry a week, have a small refrigerator and run the dishwasher every other day. Another family may have three children, a large refrigerator and a freezer, do 15 loads of laundry a week and run the dishwasher twice a day. Their usage for household appliances will be much higher than those of a smaller family. We simply have no control over this type of usage — we only have control over how the building “shell” is constructed — whic
