To clarify. I just replaced several windows, with Pella ones. I tried to replace at least 1 window in each room, and will eventually replace all of the windows. The new windows and old windows do not seem to have much of a draft, however, I have a chimney that often gets a backdraft,so I am having some cap type things??? put on the clay chimney exhausts on the roof. The home is 3 stories. The 3rd floor used to be an attic, and I had it remodeled into a loft type apartment.The 3rd floor is insulated, as for the bottom floors, I really don't know what type of insulation is in place(whatever they use for stucco and plaster walls). I wouldn't mind paying the heating bill if it was actually warm, but even with the heat turned to 72-75, I'm freezing from Dec.-March. The fireplace is the only thing that warms the place up. It has a blower that kicks out hot air when the fireplace gets to a certain temp..I really don't like the smell of wood, and its messy, so I try not to use the fire place unless it's cold and I have company. Thanks "brickeyee" for the advice on the Space Pak, I'm going to look into it. Anymore suggestions are helpful, keep it comin'!! Thanks to all. :)

After reading this entire posts and seeing no definitive answers, I'd figured I would chime in. As an architect I see a lot of projects where we replace an existing boiler with a Direct Vent (DV) boiler. 90% of the replacements use a horizontal, thru-wall vent. This is done typically because it is easier and less costly than going through a roof. Note on the attached link that there are maximum distances for vents and you are limited to where the outlets are in relation to windows, doors, A/C condensers, air intakes, overhangs, etc. You say you could use the 'unused, walled-in chimney' as a vertical vent. I assume this means a wood framed chimney enclosure. You could run PVC vent pipes vertically through this chimney but you would have a difficult time accessing the pipe joints and brackets during installation. DO NOT THINK ABOUT connecting to an old masonry chimney, even if it is terracotta lined. The direct vent gases are cool and will condense inside the chimney fast leaving a pool of highly corrosive water at the bottom of the chimney. This will eventually degrade the chimney and create possible CO leaks. For new construction I typically specify running the pipes vertically with a roof termination. This eliminates the steam plume shooting through the house wall while the boiler is on. Note that Weil McLain requires the pipes to slope back toward the boiler. I believe they collect the condensate and reheat it. Not certain how this works. I know that in a vertical installation there will be less vapor exhausted and more condensate generated as it rises through the pipe. This is typically collected at the bottom of the vertical stack into a condensate pump. This water is corrosive so be careful where it is pumped to (i.e. keep it away from landscaping). As long as you can find an inconspicuous location to vent the gases, the sidewall is the way to go for a retrofit. Here is a link that might be useful: Venting

If the deterioration of the brick is really due to excessive moisture in the chimney flue, adding a coating to the exterior will do nothing to solve the problem. It may, in fact, make it worse. The only cure would be lining the chimney. Here you have two choices: a stainless steel liner or a poured in place liner. The latter will actually strengthen an old unlined chimney because the material bonds to the chimney interior and becomes an integral part of it. There are at least three companies. Supaflu (www.supaflu.com) is the only one I've had direct, positive experience with. If you're having difficulty with rain or assorted creatures entering the chimney, a cap may be worthwhile. If you haven't had any of these problems, I'd say it's unnecessary. If the flashing around the chimney needs replacement, by all means have it done, but I'd certainly pass on any interior coating unless a liner is installed first.

No the property was not condemned. In my town, when a property is sold but not correctly maintained it can be sold "as is" for a low price so and if things are not up to Code, the new Owner is obligated to correct those violations. I purchased the house "as is" for a very good price and have been making those corrections. I did pay the other "inspector" $700 to "inspect", clean and make small repairs to the boiler and fireplace in September I believe it was. Thankfully, CO detectors were installed by the previous Owner prior to us taking possession. Our DOB mandated that HE do this before I moved in. As of yet, none of gone off - thank God.