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This is why households across the UK are being urged to inspect their radiators before turning the heating on.
With autumn underway and temperatures beginning to drop, simple checks can stop efficiency problems and reduce energy bills before winter arrives.
Chris Jessop, group customer relationships director at boiler manufacturer Ideal Heating, warned that tackling maintenance early prevents costly emergency callouts.
Give radiators a thorough clean
He advised homeowners to give every radiator a thorough clean before firing up their central heating for the season.
Dust and pet hair settle between panels and behind units throughout the summer months when systems remain turned off.
Clearing away this layer of grime improves airflow around the room and avoids the unpleasant burnt smell that often accompanies switching heating on.
Check for cold spots and bleed trapped air
Checking for uneven heat distribution across panels is another crucial step before colder weather sets in.
If a radiator feels hot at the base but cold towards the top, trapped air inside the unit is stopping water from circulating properly.
Bleeding the unit using a radiator key releases the pocket of air and allows hot water to fill the panel completely.
Cold patches at the bottom of a radiator suggest a much more serious buildup of rust and dirty sludge.
This internal debris blocks the flow of water and forces the boiler to work much harder to warm the property.
Removing system sludge requires specialised flushing equipment and should always be handled by a qualified heating engineer rather than attempted alone.
Clear furniture and obstructions
Homeowners should also inspect the layout of each room to ensure warm air can move freely.
Large pieces of furniture such as sofas, armchairs, cabinets and heavy floor-length curtains placed against radiators absorb valuable heat instead of warming the room.
Pulling items just a few inches forward allows natural convection currents to spread warmth across living spaces efficiently.
Stop drying clothes directly on panels
The heating specialist also warned against using radiators as clothes airers to dry wet laundry and bath towels.
Draping damp fabrics directly across panels traps warmth and traps moisture inside the home, increasing indoor humidity and encouraging condensation and mould growth.
Households are encouraged instead to dry clothes on a freestanding airer placed in an airy, well-ventilated room.
Test systems before winter sets in
Testing central heating systems early gives families ample time to spot underlying boiler faults before freezing conditions arrive.
Relying on a boiler during sub-zero temperatures without verifying its health risks sudden breakdowns when tradespeople face peak winter demand.
Anyone whose radiators fail to warm up after bleeding and cleaning should contact a registered heating engineer for professional servicing.