The passage must not be smaller than 30 high x 22 wide and no longer than 20 unless it s at least 6 tall and then no more than 50 passageways must have a solid floor no less than 24 wide.
Attic furnace requirements.
Attic hvac systems save space.
That means you have higher energy costs and less efficiency since you re blowing the air down instead of allowing it to rise naturally.
So why put an hvac system up in the attic at all.
Upright furnaces shall be permitted to be installed in an attic furred or under floor space exceeding 5 feet 1524 mm in height provided the required listings and furnace and duct.
If you place the furnace in the attic then you must install the infrastructure in the building to force the warm air to the bottom floor.
It will not require long lengths of pipe to deliver heat to the rooms as a basement furnace does.
Air ducts lose a fair amount of heat through leakage so shorter lengths are more efficient.
Attic furnace passageway minimum dimensions requirements.
Well mainly it s a way to save space.
The opening passageway must allow for unobstructed access.
904 10 furnace upright and horizontal.
30 inches high 762 mm 22 inches wide 559 mm 20 feet max length 6096 mm.
Most updated central air conditioned homes have a new air conditioner split system meaning the ac is broken up into parts.