Splitting Heat/Air Advice

[georgia_boy]

My mother is in the process of renovating her home and adding some new additions. Right now the house is around 1200sq feet and she is adding another 400 or so quare feet on. She is also taking out two walls to make her kitchen/living/den area bigger. She has a 3 ton air conditioner now with natural gas heat. All duct work, furnace, and air return are under the house now. We have a large room that was built in the early 70's that only has one vent in it, and that is because there is no craw space under the room to run more vents.

Our AC installer wants to install the return unit in the celing and run all new duct work in the ceiling so that he can access that room with more vents. My mother is opposed to this because she has heard many horror stories about the drain clogging up or being knocked off by mistake and the return falling throught the celing, which has happened to my sisters in-laws recently. That leads to my question.

Is there a way to send one main trunk off the return under the house up a wall and into the celing, just to feed that room air? I figured you would have to have blowers in the line to push the air up the duct in the wall.

If there is another way that we could do this, I would appreciate the advice. The AC installer has not started as of yet and if she can, she would like to change the way this is being done.

Our installer also wants to bump us up to either a 3.5 ton or a 4 ton unit. We are also going to change the gas furnace out with an electric.

Thanks

[Master Splinter]

3 tonne air conditioner? Whoa, bags I dont get to lift that one into position!