Air duck life span / Air flow

ACE II

I recently purchused a forclosed home and have come to find that some of the duct work in the crawl space is in disrepair. The house was built in 1974 (not sure if it is original duct or not) What is the life span of crawl space duct work. Also, a previous owned bricked up the garage and built a subfloor and did run duck work into the room under the subfloor but the air flow is low in that room. Is that because they didnt replace the HVAC unit or because the duct is to small? I have a funny feeling that im going to have to replace th unit and all the duct work, does this happen alot?

Marty S.

What kind of duct? Flex can tear but is easy to fix or replace. Tin duct will last forever if it's not wet. No idea on duct board,nobody in the area uses it.

Not enough air in the addition could be too small of duct or the placement of the branch. Good air flow in the rest of the house?

beenthere

For the renovated garage. Cap off the supplies it has now. And install a mini split. Much cheaper then a whole new system and duct work.

ACE II

addition has flex but it sags and seems bad inside.. not sure why. the rest is metal. Has anyone ever had there ducts cleaned out?