Close doors automatically

Sometimes there are doors that users tend to leave open between spaces at different temperatures. Sometimes closing them automatically will help, either using a cheap hydraulic door closer. Before you do this, consider why they leave it open. If it’s just forgetfulness, a door closer is a good idea. If there’s some underlying reason, you could just spend money only for them to then block the door open with the nearest fire extinguisher.

Sometimes groups feel a door must be left open to welcome and help people coming in. In this case, you could consider stationing someone at the door to welcome newcomers and assist those who need help, installing a glass panel in a door so newcomers can see what is happening inside, or installing an automatic door.