3 questions “Funnel the Spec” to one product type.
Start at the top, follow the path down, end on the recommendation. Designed for distributors to send a customer ahead of a quote call.
Question 1
What dew point does the end-use actually need?
+38°F or warmer
Question 2a
Indoor install with reliable electrical?
If Yes
Recommend
Refrigerated Dryer
The default. Cheapest dew-point dollars in the catalog when conditions allow.
If No · portable / no power
Recommend
Deliquescent Dryer
No electrical, no regen cycle — follows the compressor anywhere.
0°F to ‑40°F
Question 2b
Is the dryer flow under ~100 CFM at one point of use?
If Yes · small POU
Recommend
Membrane Dryer
Bolt-in cartridge. No electrical, no moving parts, low maintenance.
If No · plant-wide flow
Recommend
Desiccant Regenerative
Twin-tower the only option to hit ‑40°F at material plant CFM.
‑40°F or drier
Question 2c
Is the dryer footprint in a hazardous-classified area (Class I Div 2, ATEX zone)?
If No
Recommend
Desiccant Regenerative
Heated or heated-blower variant for the deepest dew points and best purge economics.
If Yes
Recommend
Explosion-Proof Desiccant
Certified motors, heaters, and controls. Van Air is SPC's lead here.
If the customer doesn't know the answer to Question 1, work the use case backward: "What does your customer or process do with the air at the end of the line?" Sandblasting → +50°F is fine. Bottle-cap actuators → +38°F. Outdoor instrumentation in Minnesota in January → ‑40°F. Petrochemical analyzer in a hazardous zone → ‑40°F plus EP certification.
The decision is dew point first, install environment second. Everything after that is brand and budget.
SPC distributor playbook Air Dryers · how to quote in one call