Two-stage equipment has two output levels: a low stage (typically 60-70% of full capacity) and a high stage (100%). The system runs in low stage most of the time for steadier temperatures and better humidity removal, and only kicks to high stage during peak load.
Two-stage is a middle option between single-stage (cheapest, on/off only) and variable-speed (most expensive, infinitely modulating). For homeowners who want better humidity control than single-stage delivers but can't reach a variable-speed budget, two-stage is usually the right compromise.
Available as two-stage compressors (cooling/heat pump) and two-stage gas furnaces (heating). Both benefit from being paired with an ECM blower for matching airflow modulation.
Last reviewed:
Have a question about this?
Call our Charleston team. We’ll explain how two-stage applies to your home — no charge for the conversation.