Im assuming you are referring to the "heater" as the furnace, right? I have 2-different suggestions for you. The easier of the two would be change your furnace filter. I would recommend buying one with an allergen filter. You will have to spend a little more money but it will be worth it because of your allergy situation. My next suggestion would be having the duct work cleaned in your apartment. It seems to me that you are having really bad allergies when the furnace is running. That leaves me to believe you may have some allergens in the duct work. Hopefully after either of the suggestions you will find relief. Good Luck! Keep us posted and how it goes.