Flames broke out at separate properties in Loxwood, at around 7.45pm and just after 9pm, with a third fire in Woolbeding Common.
Crews attended houses in Station Road and The Ride in Loxwood and were able to extinguish each blaze quickly, West Sussex Fire and Rescue Service said.
Jackie Boyle, community fire safety officer for the fire service, said: “We know that many people are turning to open fires to keep out the cold, but if basic safety precautions aren’t followed they can become a serious fire hazard.
“The best piece of advice we can give to anyone planning to light a fire this winter is to make sure they get their chimney checked and swept by a qualified professional.
“Chimney fires are one of the most common incidents that our crews attend, but most are completely preventable.
“The consequence of a chimney fire isn’t just the damage caused by the blaze itself; there is also the damage from the soot and smoke, which can affect all of your personal property.”