Hello Paul, I lived for 6 months in a house with chimeney, terrible thing to have to live with but since it was not my house I had no saying specially since I was not working at the time and they get free wood from all the trees they have, that's when my sinus got worst and had to to use asthma inhalers everyday. Then 18 months in a house with central heating, old house too, that's when my sinus really got so bad I ended up in the emergency room the pain was so terrible I could not eat and was so nauseous I was trowing up , or was it because of the pain? then I had to add all kinds of medicines just to be able to function, in that house they use the heater year round pretty much since there is no real summer you see? and the owners like to walk around with no shoes and a t-shirt.
After that I have been on my own apartment now for 8 months now things got better but never really great, the sinus rinse with chamomile tea really helped a lot but I still had to take claritin and my asthma inhalers (2 types) plus a few other things like teas and no milk, or wheat, I did noticed those things made both asthma and sinus worse.
The heater in this apartment is wall mounted, was inspected by maintenance before I moved in and the main parts where replaced with new ones, I usually do like to wear warmers or layers instead of having the room at 70 degrees, not so much because of the gas bill it's just like I said I did not grew up like that.
I did think for sometime that mold might have something to do since it is a big problem in the previous city I lived in, the house smells like humidity always, but where I live now is not a problem this apartment complex has no problems with molds ,bathroom has a window and even though it is very close to the beach like the previous house. Rugs and carpets? previous house has wood floors all over the house, this apartment is wall to wall carpet.
This morning I checked the water heater it does have ducts to the outside but I still turned it to pilot will turn it on when needed only.
I gotta tell you I feel great! I still have a little coughing here and there and do use an inhaler at night just so the little cough I do get does not wake up during the night but no claritin for days now or sinus rinse. AND...I ate ice cream today ! and a lot of it ! it's kind of like a test since before I could not eat not even a full spoon and I would start coughing and sneezing and congested right away.
I still get a little congested in the morning but goes away after blowing my nose a couple of times.
I hope all this helps others and you too Paul , I live in central California BTW planning on the future to move to South CA where the sun does shine and there is less need of heating your home......I like hot weather anyways much better than anything else I am happy at 70-80-90 and even 100's degrees
here's some info I found regarding this issue