Seal up the entire house and get new doors and windows. This includes the
basement and attic. Talk to an insulation contractor about spray foam in the
walls. It won't be cheap, but the savings can be great. Spray foam in walls
is better than blown in insulation because it doesn't settle.
If the boiler has been using about the same amount of oil for many years
now, then the problem probably is not the boiler. If you have steam leaks,
then get them fixed. Before you replace the boiler, look into a new flame
retention burner, and make sure the heater is cleaned every year. Before you
install a new steam boiler, look into changing to hot water. Two pipe steam
is easily changed to hot water, but one pipe steam can be difficult and
costly to change to hot water. If you decide on a new steam boiler, find
someone who has experience on steam. The new steam boilers tend to hold less
water, and certain provisions must be made for this.

wrote in message
oups.com...
i have a 85 year old 4000 sq. foot masonary with no insulation in the
walls and insulation blown into the attic. the windows are old. my
boiler is an oil fired weil mclane from the early 70's rated for 1500
ft of steam. i have been burning about 3500 gallons a year in
northeastern PA. i'm trying to figure out if there is something wrong
with my boiler or vents etc. i know my house could be better insulated
but, given the current insulation situation is 3500 gallons a
reasonable amount of oil to burn? Could heat be escaping somewhere in
pipes, vents? i have asked professionals to look at my boiler and have
received several answers. most have not spent much time really
examining my steam system. some say it should be replaced, some say it
is fine and the issue is insulation related. any ideas?