Decree No. 34/2016 Coll. Sets the deadlines for cleaning flue gas passages in appliances up to 50 kW according to fuel type and heating season length. For solid fuels (wood, coal, briquettes), this is 3 times a year for year-round operation and 2 times a year for seasonal operation of up to six months per year. For liquid fuels (oil boilers, diesel generators), the deadline is 2 times a year for year-round operation and 1 time a year for seasonal operation. For gaseous fuels, cleaning once a year suffices regardless of operating duration. The distinction between year-round and seasonal operation does not depend on the building type but on how long the appliance is actually used in a given year.
The most common mistake is calculating deadlines identically regardless of the fuel source. For instance, with wood-burning stoves used only at weekends during winter, owners underestimate that this still constitutes seasonal operation requiring two cleanings per year, not one. Conversely, for a chalet heated year-round by a solid fuel boiler, the deadline is calculated as for permanent residence.
How much does chimney cleaning cost
The cleaning price depends on the appliance type, chimney height and amount of deposits. As a guide, it ranges from 500 to 900 Kč per chimney in a detached house. Combining cleaning with an annual inspection in one visit is usually cheaper than two separate visits by the chimney sweep. In apartment buildings, the building's owners' association arranges cleaning collectively: the chimney sweep inspects all chimneys in the building during one visit, so the cost per flat is usually lower than when ordered individually.
Self-cleaning for solid fuels
For solid fuel appliances up to 50 kW, the user may carry out cleaning themselves if they have the necessary equipment and experience. However, a chimney sweep must still inspect the flue once a year. Without this annual inspection, the owner does not hold a valid certificate, even if they clean the chimney with the utmost care. For liquid and gaseous fuels, self-cleaning is not permitted by regulation, cleaning and inspection must always be carried out by a person holding a chimney sweep trade licence.
DIY cleaning does not absolve the owner of responsibility for the result, if the chimney sweep finds during the annual inspection that the flue has not been cleaned sufficiently, this will be recorded in the inspection certificate. In practice, therefore, many homeowners have solid fuels cleaned by the chimney sweep as well, so that both obligations, cleaning and inspection, are settled in a single appointment.
Why deadlines must be met
Neglected cleaning increases the risk of soot deposits, which are the main cause of chimney fires: the article deals with this topic in detail. Chimney fire: what to do and mandatory inspectionExcessive deposits further impair chimney draught and can cause flue gases to backflow into living areas. In solid fuel appliances, soot and tar accumulate more rapidly than with gas, which is why the regulation requires much more frequent cleaning for solid fuels.
Cleaning, inspection and statutory review: do not combine them.
Cleaning alone does not replace an inspection or a statutory check. The differences between these three procedures and who is authorised to carry them out are summarised in the article. Chimney inspection, cleaning and certification: the differencesFor owners of a gas boiler, several specific requirements described in the article also apply. Chimney sweep inspections for gas boilers: what to know.
Managing deadlines in practice
The simplest approach is to agree with the chimney sweep on a regular schedule for the entire heating season in advance, for solid fuels, perhaps in autumn and mid-winter; for gas, once in spring or autumn. Chimney sweep companies routinely remind customers they have worked with before of approaching deadlines, which reduces the risk of missing the deadline. In apartment buildings, it is also worthwhile to keep a simple record, when the last cleaning and inspection took place and for which chimney, so that the building's owners' association committee does not have to rely on the memory of individual flat owners.
When cleaning is not enough
If the chimney cross-section has been neglected for a long time and blocked by a hard layer of soot and tar, ordinary brushing will no longer clean it. In such cases, milling the flue gas path is required, when it is needed and what it costs approximately, the article explains. Chimney reaming: when is it necessary and the priceThe longer cleaning is delayed, the more likely it is that simple brushing will no longer suffice and a more forceful intervention will be required.