My AC blows cold air, so I assume my compressor outside works OK. Please correct if that's an incorrect assumption.

The problem is, there is very little cold airflow that comes out of the floor ducts... To the point that closing all the windows and running AC makes a negligible difference in room temperatures, at least as much as the wife desires it to alter.... I.e. if 85 inside and we set it to 70, the 70°F is never reached.

I have the setup where compressor is outside, and fan/evaporator coils are inside as part of the furnace unit.

Can any components be swapped internally to alleviate this low air condition, or is a new system the only option? My dad said the motor and fan can be upgraded, but he knows refrigeration better than AC hence why I'm here asking.

Lastly, my house was built in the 70s, could this also be a problem with an inefficient HVAC duct design more than the poor and old AC system?

PS, filter is brand new so that isnt the issue

  • Maybe you just need to clean the ducts, over 40 year a lot of dust can accumulate. Jun 30, 2016 at 10:38
  • Full duct cleaning was performed in 2015 when we remodeled before moving in.
    – amalik
    Jun 30, 2016 at 10:40
  • If you remodeled then it's recommended to recalibrate the gates to account for the new room sizes. It's also possible that when they got cleaned the guy changed some gates but didn't reset them. Jun 30, 2016 at 11:43

1 Answer 1


It's possible to change the motor, but doing so may not change anything. In fact, blindly changing the motor could actually cause the system to perform worse.

Without knowing a ton more about the system, it's impossible to diagnose the actual problem. It could very well be poor duct design, an undersized system, or a whole host of other problems. The best bet is to get the system assessed by a local reputable HVAC company.

  • Ok, appreciate the feedback. Is a system assessment part of normal services provided?
    – amalik
    Jun 30, 2016 at 11:32
  • Tell them that the system is not performing well, and you're considering a new unit. Ask them if they can evaluate the old unit, to determine if it can be made to perform better. They should be able to give you a quote on what it would take to fix the old unit, as well as what it would cost to replace it. Depending on the company, the estimates may or may not be free.
    – Tester101
    Jun 30, 2016 at 11:38

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