HVAC Basics

Compare duct leakage testing with air balancing, including what each measurement proves, why one cannot replace the other and when a project needs both.

Learn how one mini-split condenser shares capacity among multiple heads, handles mode calls and changes performance as zone demand and combinations vary.

Read a duct leakage report by checking CFM25, pressure, normalization, test boundary, acceptance authority and compatible before-and-after results.

Learn how to compare duct leakage before and after sealing, including matching test boundaries, conditions and the extra checks needed to verify comfort.

See when duct leakage testing is useful after construction, comfort complaints, sealing or replacement—and when airflow or load testing is the better choice.

Evaluate mini-split cooling in cold outdoor weather by checking model operating limits, low room load, controls, drainage and required manufacturer accessories.

Learn how supply and return leakage can reduce cooling delivered to rooms, why temperature alone is incomplete and which measurements quantify the loss.

See how crawlspace duct leakage tests separate supply loss from return air entry, and why moisture, soil gases and crawlspace boundaries affect diagnosis.

Check mini-split line-length limits, factory-charge coverage, added refrigerant and elevation rules using exact model installation data and weighed records.

Learn how attic duct leakage differs from insulation heat gain, which tests identify each problem and why cold register air does not prove intact delivery.