The North Carolina Attorney General's Office warns that scam artists sometimes pose as government officials and go door-to-door, touting energy savings for people. They say the need to come inside and take some measurements. The Attorney General says they use the opportunity inside to pocket valuables or see if there's anything worth coming back for and breaking in. You shouldn't let people like this into your house unless you call them.
If you can check with your utility company to set up an appointment for an energy-saving expert to come to your house.