I was referred to this awesome site. It has a ton of information on home furnace problems, also tips on how you can possible fix the issues yourself.
This site helped me to solve the problem I was having which was too much heat coming out. It turns out the thermostat was crooked on the wall, and when I made it straight, the issue was solved! I'm not at all handy but even I could handle this one. Great advice and help from this boulder website. Check it out for furnace questions, problems and help!