Is the sun shining today? Open your blinds and curtains in the morning. The sun’s rays will help heat the room (our pets already know this). When the sun goes down, close your blinds and curtains, kind of like you’re tucking your house or apartment in for the night. Repeat the next day.
Some friends tell me opening blinds is a pain because it takes time…and then there’s the nakedness factor. Just a suggestion, but wait until you’re dressed! If you’re really pressed for time, only open the curtains in the rooms that get direct sunlight. Take a break on cloudy days. If you live with others, get them involved too. No excuses!