---
title: "Differential pressure (baghouse)"
description: "Differential pressure (ΔP) across a baghouse is the pressure drop between the dirty-gas inlet plenum and the clean-gas outlet plenum. ΔP is the headline operational KPI for any fabric filter: too low signals broken bags or open compartments, too high signals fouling, bridging or blinding."
canonical_url: "https://sylio.co/glossary/differential-pressure-baghouse"
last_updated: "2026-06-28T02:29:24.786Z"
---

**Differential pressure (ΔP)** across a [baghouse](/glossary/baghouse) is the pressure drop between the dirty-gas inlet [plenum](/glossary/plenum-clean-side-dirty-side) and the clean-gas outlet plenum. ΔP is the headline operational KPI for any fabric filter: too low signals broken bags or open compartments, too high signals fouling, [bridging](/glossary/cake-bridging-cake-blinding) or [blinding](/glossary/bag-blinding).

## Typical operating bands

<table>
<thead>
  <tr>
    <th>
      Application
    </th>
    
    <th>
      Normal ΔP
    </th>
    
    <th>
      Alarm
    </th>
    
    <th>
      Trip
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      Cement <a href="/glossary/pulse-jet-baghouse">
        pulse-jet
      </a>
    </td>
    
    <td>
      8–15 mbar (3–6 inWG)
    </td>
    
    <td>
      20 mbar
    </td>
    
    <td>
      25 mbar
    </td>
  </tr>
  
  <tr>
    <td>
      Coal utility <a href="/glossary/reverse-air-baghouse">
        reverse-air
      </a>
    </td>
    
    <td>
      10–18 mbar
    </td>
    
    <td>
      22 mbar
    </td>
    
    <td>
      28 mbar
    </td>
  </tr>
  
  <tr>
    <td>
      WtE pulse-jet
    </td>
    
    <td>
      12–20 mbar
    </td>
    
    <td>
      25 mbar
    </td>
    
    <td>
      32 mbar
    </td>
  </tr>
  
  <tr>
    <td>
      Light industrial pulse-jet
    </td>
    
    <td>
      5–12 mbar
    </td>
    
    <td>
      18 mbar
    </td>
    
    <td>
      25 mbar
    </td>
  </tr>
</tbody>
</table>

## Why operators obsess over ΔP

Every additional mbar of ΔP costs ID-fan power and reduces plant throughput. A 5-mbar ΔP rise on a large coal-fired baghouse can mean hundreds of kW of additional fan power and the loss of a few MW of derate-induced generation. Sustained high ΔP also accelerates [bag blinding](/glossary/bag-blinding) and triggers premature bag-change campaigns.

## How sonic horns reduce ΔP

[Sonic horns](/glossary/sonic-horn) keep the bag-surface cake from consolidating into the medium between primary cleaning cycles. Pulse-jet, reverse-air or shaker cleaning then has less work to do and removes a larger fraction of the cake. Plants retrofitting sonic horns commonly see 2–5 mbar ΔP reduction and 25–40% extension of bag life.

## Related terms

- [Fabric filter](/glossary/fabric-filter)
- [Baghouse](/glossary/baghouse)
- [Filter cake](/glossary/filter-cake)
- [Bag blinding](/glossary/bag-blinding)
- [Pulse-jet cleaning cycle](/glossary/pulse-jet-cleaning-cycle)
- [Sonic horn](/glossary/sonic-horn)