The dispatcher calls Bob and reports that a good customer wants their home heat pump checked out. The power bill has taken a dramatic rise in the last two months.
It is 28 degrees outside. Thank goodness it isn't snowing, Bob thinks. He then arrives at the house and talks to the housewife. She shows him her power bill and it is at least 40 percent higher than the month before. She says that the house has been comfortable, but that the light on the thermostat seems to stay on a lot more. In fact, it is on now. Bob walks down the hall for a look at the thermostat and it is on. He goes outside to the outdoor unit and looks around. The large copper line going to the house seems normal. There was a little ice on the outdoor coil. He goes to the basement and looks at the indoor unit. All seems normal there. He removes the electric heat access panel and uses his ammeter to check the electric heat. Two out of three heating elements are drawing current.