Where can i find the heating plans for my house? Are the original plans kept anyplace?
I am looking to understand my heating ductwork better, so I can try and improve the force of air on my second floor. I have forced hot air heat in the house, and the 2 bedrooms upstairs heat up, but the force of air is negligable compared to the 1st floor and the cellar heating vents.

As a heating and ac technician, this is one of the most common complaints that I hear. In most cases this problem is due to under sized duct work. Unless you can find the blueprints from when your house was built you won’t be able to see the layout. A few things you can do: Most duct systems have dampers near the furnace. Try closing a few that supply the lower level to try to move more air upstairs. Also, furnace blowers usually have three or more blower speeds. High speed is almost always used for cooling and low is for heating, leaving medium and medium high speeds unused. It isn’t a bad idea to have a annual inspection on your heating system to make sure everything is working properly. While the technician is there you can ask him if it is possible to increase the fan speed in heating mode. Hope this helps.
The city should have the plans for your home. You would have to go to city hall and request a copy. Chances are you will have to pay for the plans and wait a few days for them to retrieve them. Low air flow to the second floor is pretty common though. You can have boosters installed to help push the air to the second floor. For the time being, you could close the vents off on the lower floors. You’ll have to play with what vents to close to get an even heat.
You need a qualified A/C Tec. to come in and balance your heat and a/c load.He can tell if you need to install a booster in the system.I don’t think you will fine any heat,A/C plans for your house.If you do the A/C contractor would be the man to see.Go back to your builder,and find out who he used.