How Often Should a Chimney Be Swept? Sweep Planner
"Once a year" is the answer most people have heard, but it only holds for smokeless fuel. The guidance published by HETAS and the National Association of Chimney Sweeps says a flue serving a wood burner should be swept quarterly while it is in use, and the same goes for bituminous house coal. This planner turns your fuel and the months you actually light the stove into a sweep count and a month-by-month schedule, so the first sweep lands before the first fire and not halfway through January.
Your stove and burning season
Why wood needs sweeping more often than smokeless fuel
Wood smoke carries water vapour and unburnt tars. When it meets a cooler flue wall those condense into soot and, at worst, the hard, glossy deposit called creosote. That layer narrows the flue, weakens the draught and is the fuel for a chimney fire. Smokeless manufactured fuels leave far less of it, which is why the published guidance relaxes to once a year for them, while wood and house coal stay at quarterly during the months the stove is in use.
How the planner sets the months
- First sweep before the first fire. It is placed in the month before your season starts, so the flue is clean and checked after a summer of birds' nests and debris.
- Then one every three months of burning for wood, multi-fuel and house coal. A six-month season gets two sweeps, a year-round stove gets four.
- Smokeless only gets one sweep a year, before the season.
Treat these as minimums. Damp logs, a stove run slow and cool for long spells, or a sweep who tells you the deposit is heavy all mean sweeping sooner. Ask for a sweeping certificate each time: some home insurance policies ask for proof that the chimney has been swept, so check yours, and keep the certificates with your stove's installation paperwork.
Want the seasoning calendar and our log-price watch in your inbox?
Join the Kindling List
