Close the draperies over large windows and glass doors to form a barrier against heat loss during the winter and heat gain during the summer.
If you have room air conditioners, close all heating system vents so the cool air isn’t wasted.
If your home has rooms that are seldom or never used, close the vents in these rooms and shut the doors most of the time. Make sure the rooms get enough heat to prevent mildew from growing or contents being damaged.
Aim the vents of room air conditioners upward for better air circulation; cold air naturally settles downward. On central air conditioning systems, adjust the registers so the air is blowing up.
Make sure the outside portion of an air conditioning system is not in direct sunlight or blocked from free airflow.
Keep the fireplace damper closed except when you have a fire going. Otherwise, updrafts will suck heated air out through the chimney.
Maintain proper humidity. A house that’s too dry can feel uncomfortably cold even when the temperature setting is correct.