Temperature and air exchange between floors (Mechanical air conditioning)

[baab]

Hello,
In my house there are often several degrees of difference between the ground floor and the upper floors.
During summer, it's too hot in the upper floors, while it's fine on the ground floor.
In winter, it's fine on the upper floors and cold in the ground floor.
There's a chimney-type duct/tube between the floors that could be used to exchange air between floors to cool and warm the rooms, depending on the season.

What simple system could I use to exchange some air between the floors ?

I don't want an expensive installation (such as air conditionning), and I already have a central heating system.
I'm thinking of a fan/extractor-type system on both sides of the duct/tube, but I can't see anything about it on the Internet, and I'm not sure it's feasible (especially for bringing warm air from the upper floors to the ground floor in winter).

could you help me here?

 

[argile_tile]

you close vents in basement open them in all upper floors in summer. all vents open all bedroom doors open (or vents installed over doors).

if you insist your vents don't work. it's all about dress quality. you could use cardboard cyclinder with a $10 walmart fan and a hole in the ceiling: but it won't look good - and you'd have to operate it manually.

what not to do is close vents on ground floor: your ac needs all vents (mostly) open to work right

 

[argile_tile]

also - these units (say, installing a mini unit, or a window unit) are super efficient. i wouldn't say a fan that blows cool air from main floor up to first floor would "save you money". it might actually be a higher electrical cost per BTU transferred between floors. also how would you distribute the air evenly so the cooler air reached all rooms?

i have to emphasize using the system you have (ie installing extra vent controls and vents over doors), or a separate system, and not attempting a DiY exchange of air between floors: as a rule it won't work.

and if that in the end doesn't transfer airflow to all rooms or can't cool - then you need a 4 ton instead of a 3 ton or a separate unit for the upstairs.