That is the message the Fire Service is pushing, after brigades attended 25 chimney fires in Otago-Southland in the last three months.
East Otago Area Fire risk management officer Michael Harrison said each chimney fire had the potential to set a house on fire, which was why it was ''vital'' chimneys were checked and cleaned at least once a year.
''The main cause of chimney fires is people not getting them cleaned. It's really important that you get your chimney cleaned before winter.
"If you haven't had your chimney cleaned yet, it is recommended you get it done as soon as possible. It can do a lot of damage to your home,'' he said.
Warning signs that your chimney is dangerous include smoke filling up the room instead of escaping properly or the fire not burning as well as it usually does.
This could be due to a build up of soot and/or creosote, an object like paper or a bird's nest stuck in the chimney or your chimney could be faulty.
Its mortar might have broken down, bricks might be dislodged, the flue corroded or the ''hat'' might have collapsed.
Mr Harrison said the actual number of chimney fires was probably much higher, as many were not reported.
''The colder months are an extremely dangerous time for fires in the home. If you suspect your chimney is not working as efficiently as it used to, get a professional to check it thoroughly and repair any damage,'' he said.
It was also a good time to make sure smoke alarms were working, he said.
