Radiator valves will turn your radiators on and off. Simple right? But did you know you cannot actually control the amount of heat your radiator is putting out? The big misconception is that if your valve is halfway closed or slightly opened, your radiators will heat up less. WRONG. 

A radiator valve opened in the slightest is the same as having it opened fully. This is due to the way cast iron metal retains heat. Most cast iron radiators will retain heat for at least one hour, after you shut off your valves - so if your apartment is too warm, shut your valve off for a period of two hours. Periodically turn your valves on and off to maintain a comfortable temperature. 

Note also that leaving the radiator shut off or valve cracked, will ruin the seat of the valve and it will no longer close tightly. Correctly installed self-contained mechanical thermostatic radiator valves by manufacturers like Honeywell Braukman or Danfoss can regulate to a set temperature. These can replace or supplement the radiator shutoff valve.

Additionally, copper or finned baseboard style radiators will not retain heat as efficiently as cast iron - something to consider when you are renovating your apartment and looking for style instead of comfort.

Kole Palushaj is an NYC building resident manager/superintendent and founder of the Illyrian Building Managers Association.