Effects of too much static pressure

Old 11-23-19, 06:41 AM
Thread Starter
Join Date: Sep 2017
Posts: 144
Received 15 Upvotes on 14 Posts
Effects of too much static pressure

lawrosa stated “Most HVAC units are installed incorrectly from the start with duct work being too small. Starting out with high static pressure. then install a garbage pleated filter and static goes up even more. This reduces the life and performance of your equipment.”

Accepting this as valid, I have a question. I have a forced air system with two long legs. One leg receives more air so I added a guillotine style baffle where that leg split from the main trunk. Then smaller similar baffles to the individual runs where they branched from that larger main supply legs until I got the system regulated to where the heating/cooling was balanced as we want it. I am happy with the performance but I do hear the air rushing out out of the most distant vents I did not hear it before making these mods. It is the furthest from the blower and was the room that needed additional air. The house is now much better balanced.

Other than making the fan possibly work harder and possibly shortening its life what am I in for because of my mods? It is a 20 year old system which I am not ready to tear out and replace just yet.

Not challenging your facts. Just wanting to know if I have done something dangerous. If all I have done is reduce its life and efficiency then that is acceptable.

Last edited by clancy; 11-23-19 at 09:34 AM.
Old 11-24-19, 04:32 AM
GregH's Avatar
Super Moderator
Join Date: Jan 2001
Location: Manitoba
Posts: 9,500
Received 68 Upvotes on 62 Posts
When you install a damper or close an existing one it blocks air from one duct to force air into another.
When ever you do this it increases the system's static pressure which increases the workload on the fan.
Your fan and it's motor in turn needs to have the capacity to work at this higher static pressure.

The way you can check this is to use a clamp on ammeter on the fan motor to make sure it is operating at or below it's rated running amperage.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: