Here is a picture.

Essentially every corner has a hole cut in it and I'm wondering if those should be sealed? I can get close ups if needed.

Question from user Reality_Is_Left at hvacadvice at reddit.

Answer:

If there are holes cut in every corner of your furnace, it's likely that they serve a specific purpose and should not be sealed without proper understanding. Furnaces are designed with specific ventilation requirements to ensure proper airflow and heat distribution. Sealing these holes without understanding their purpose could potentially disrupt the functioning of the furnace and pose safety risks.

It's important to consult with a professional HVAC technician or the manufacturer of your furnace to determine the purpose of these holes and whether or not they should be sealed. They will be able to provide you with the most accurate guidance based on the specific design and requirements of your furnace.

holes in corners of ductwork near furnace