we have had our entire heating system overhauled for maximum efficiently , any thermostats they were not working properly have been changed out . 

all the windows are closed during winter and are checked on lock up all windows small or big are shut .

we have had our radiators all balanced, meaning they all run at the same temp and have been marked so if they are turned up we can see . 

also we have asked that no one else touch's any of the radiators settings and have painted red lines where they need to be . easy to look at them while locking or unlocking the building