Why Is My Radiator Slow to Heat?

Updated July 19, 2017

Homeowners depend on radiators to take some of the bite out of winter. Unfortunately, some radiators may take a while to heat up even after the thermostat is cranked high.


Homeowners often assume that a radiator or boiler is broken if the heat is slow to warm up. In fact, there are many causes for a slow-warming radiator. Check for simple solutions first before assuming the radiator is malfunctioning.


Air circulation is very important for the dispersal of heat from a radiator. If layers of dust accumulate on the radiator's fins, they will not allow heat to radiate into the room. Wipe down your radiators once a month to keep heat flowing.


The type of radiator can affect the way it gives off heat. Cast iron radiators take longer to heat up but will also give heat off slowly so the radiator continues to warm the room even after the heat is turned down.


A radiator's location also affects heating. If a radiator is against an outside wall, heat will be wasted on the wall. To better heat the room, slide an aluminium-faced foam insulation board between the radiator and the wall to push the heat back into the room.

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About the Author

Adam Richardson began writing professionally in 2002. He has worked as a full-time sports writer and editor with the "Halifax Daily News" and "The New Glasgow News." He graduated with a bachelor's degree in journalism from the University of King's College in Halifax, Nova Scotia.