Pollution control unit cost is quoted against a configuration, not read off a list. The three quotations a buyer collects for one duct often arrive under three names: an ESP quote from one supplier, an ecology unit quote from another, a PCU quote from a third. The equipment role is the same; the scope rarely is. A North American PCU quotation tends to carry factory fire suppression, wash-down drains and a differential-pressure alarm, because Section 506.5.2 of the 2021 IMC puts them on the unit. A UK ESP quotation typically carries one electrostatic stage and leaves the fan to whoever designs the extract system. Read this and you can rebase three such quotations onto five lines, see whether the price gap is scope or equipment, and send the blanks back to the suppliers before anyone is chosen.
This guide helps you decide whether a price difference between quotations headed ESP, ecology unit and PCU comes from their scope and basis or from the equipment itself.
It does not quote a price, rank suppliers, select equipment or size a fan.
For product-specific review, see the in-duct electrostatic precipitator page and the kitchen ecology unit page; the six factors behind a single quote are in electrostatic precipitator price.
| What the quote covers | What you provide | What you get back | Lead time and MOQ (Polygee) | Biggest cost lever |
|---|---|---|---|---|
| The treatment section and its controls, plus whatever accessories the market or the code adds; the fan and the duct only where the quotation says so | Design airflow, the stage requirement or the discharge complaint, the unit location, the target market and the Incoterm | A stage list, pressure drop per stage with its basis stated, the models the certificates name, and the commercial terms | 7 to 15 days for standard models; minimum order one unit | Whether the fan and the code accessories are inside the number; after that the stage count, then the airflow |
Why the name on the quotation shapes its scope
The name on a quotation usually tells you which market’s habits shaped its scope, and that is where most of the price gap hides. A pollution control unit, an ecology unit and an in-duct ESP are one duct-mounted role under three regional names. UL itself listed ecology units and exhaust filtration units among the names in use when it set up its certification category, and the naming is explained in what a pollution control unit is. What the names carry with them is a set of expectations about what the supplier includes. Those expectations come from the code and from the specification habits of each market, not from the equipment.
If the heading is PCU and the site is in North America, expect the alarm, the suppression and the wash-down drain inside the number, because Section 506.5.2 puts them on the unit. If it is ecology unit, expect three stages and a service side for each, because the term describes an arrangement. If it is ESP, expect one stage and no fan, because the fan selection usually sits with whoever designs the extract system.
| Heading on the quotation | Market habit behind it | Tends to be inside | Tends to be outside | Why |
|---|---|---|---|---|
| PCU | North America; the IMC, UMC and NFPA 96 | Filter stages in a listed cabinet; factory-installed fire suppression; wash-down drains and the connection for them; an airflow differential-pressure control with a visual alarm; controls | The exhaust fan, which the code lists separately; the enclosure or roof curb; the grease interceptor the drain discharges to | Items 8, 9 and 11 of IMC 2021 Section 506.5.2 require the alarm, the suppression and the wash-down drain; item 2 lists the fan on its own (the 2024 edition renumbers them) |
| Ecology unit | The Gulf, South Asia, parts of Southeast Asia | Commonly three stages in series: electrostatic, then UV, then activated carbon; whether the first carbon fill and the first lamps are inside the number varies by offer and has to be asked | The fan in many offers; the plant-room straight run and the access clearance the stages need | The term describes an arrangement of stages, so the stage count sets most of the number; the building has to give each stage its service side |
| ESP | The UK, Europe, most engineering specifications | One electrostatic stage, its power supply and controls | Odor stages, specified separately if at all; the fan, which the ventilation contractor or the mechanical engineer usually selects | DW/172 (clauses 24.1 and 24.11) asks that the added resistance of any pollution control be included when the fan is selected; that selection sits with whoever designs the extract system, so the fan is usually outside the ESP supplier’s scope |
This table answers what a heading tends to imply. What it does not answer is what a particular quotation contains; only its stage list and its scope table do, which is what the next section extracts.
Point to remember. A PCU quotation that reads dearer than an ESP quotation for the same airflow may be carrying the three items the code requires on the unit anyway. An ecology unit quotation may be carrying two stages the ESP quotation never offered. Until the scope is aligned, the comparison is between habits, not between cabinets.
The five lines that make two quotations comparable
Five lines decide whether two quotations describe the same thing. They are the stages and their order, the airflow the price was built on, the pressure-drop basis and unit, the fan and the static pressure it was selected against, and the listings, reports and accessories included. The sheet below, the Three-Quote Rebasing Sheet, is the buyer asset of this page: one quotation per column, five lines down, and a last column telling you what to ask when a cell is blank. It can be pasted into an email as it stands.
| Line | Quote A (headed ESP) | Quote B (headed ecology unit) | Quote C (headed PCU) | What to ask if the cell is blank |
|---|---|---|---|---|
| 1. Stages and order | List every stage in flow order, including any pre-filter, and state which are optional | |||
| 2. Airflow the price was built on | The design airflow in m³/h and CFM, and whether the figure is a rated maximum or your design point | |||
| 3. Pressure drop, basis and unit | Cell only, complete module with its distribution plate, or the whole unit with every stage; in Pa or in. w.g.; at what airflow; clean or loaded | |||
| 4. Fan and static pressure | Is a fan included, and against which total static pressure was it selected? If not, which figure is the contractor expected to use? | |||
| 5. Listings, reports and included accessories | The models each certificate names; the report number and its test airflow; suppression, wash-down, alarm, controls, spares, consumables, warranty boundary, Incoterm |
This sheet answers whether three quotations describe the same scope. What it does not answer is which supplier to choose; that depends on the equipment, the evidence behind it and the site.
Line 1: stages and order
A single-stage electrostatic quotation and a three-stage electrostatic, UV and carbon quotation are not competing offers for the same thing, and neither is a two-stage offer against a three-stage one. The stage list is the first thing to extract, because it decides what the discharge will contain and what the building has to provide in straight run and access. Stage by stage, what each one controls and what it cannot is set out in what an ecology unit is.
Line 2: the airflow the price was built on
Module size follows airflow, so a quotation built on a rated maximum and a quotation built on your design airflow are priced for different equipment. Ask for the airflow behind each price and check it against your own design figure in both units, because a North American quotation will state CFM and a Gulf or European one will state m³/h.
Line 3: pressure drop, basis and unit
The figure buyers compare wrongly most often is the pressure drop, because the unit and the basis both vary between quotations. Convert the unit first: one inch of water gauge is about 249 pascals, so 0.5 in. w.g. is roughly 125 Pa and 0.75 in. w.g. is roughly 187 Pa. Then establish the basis, which is the larger problem. A resistance figure may describe the collection cell on its own, the complete module including its airflow distribution plate, or the whole train including a pre-filter and a carbon bank. Those are three legitimately different numbers for the same equipment. The smallest is the most flattering, so it is the one most likely to appear in a headline. Subtracting a cell-only figure in pascals from a whole-train figure in inches produces a comparison that favors whoever quoted the cell and means nothing. In a UK project this line is also the compliance line, since DW/172 asks for the added resistance to be included in the fan selection.
Line 4: fan and static pressure
Whether a fan is inside the quotation changes the number more than any stage does. Whether the fan was selected against the total static pressure including the treatment stages decides whether the installation works at all. A quotation without a fan is not incomplete; it is a different scope, and the sheet has to say so. A retrofit adds one more question, which is whether the existing position and its fan can take the stage at all. The four site measurements that settle it, of which the static pressure still available is the one that concerns the fan, are in replacing an existing ESP.
Line 5: listings, reports and included accessories
The last line is where a North American quotation and a European one differ most. Ask for the listing the code path asks for, UL 8782 on a 2021 or 2024 IMC site, the models the certificate actually names, the test report and its airflow, and then the accessories: suppression, wash-down, alarm, controls, spares, consumables and the warranty boundary. The six documents that can be checked rather than believed are listed in the commercial kitchen ESP buying guide.
A worked example: three quotations, one duct
Rebased onto the five lines, three totals that looked rankable turn out to describe three different scopes. A kitchen with a design exhaust airflow of 12,000 m³/h, which is about 7,063 CFM, receives three quotations. Before rebasing, the buyer has three totals and a strong instinct to rank them. After rebasing, the sheet reads like this.
| Line | Quote A (ESP) | Quote B (ecology unit) | Quote C (PCU) | What the line shows |
|---|---|---|---|---|
| 1. Stages | One electrostatic stage | Electrostatic, UV, carbon | Pre-filter and one electrostatic stage | B is two stages more than A; C adds a pre-filter A does not have |
| 2. Airflow | 12,000 m³/h | 12,000 m³/h | 7,000 CFM, about 11,893 m³/h | All three are close to the design point; C is slightly below it and should confirm |
| 3. Pressure drop | 40 Pa, cell only | 0.6 in. w.g., about 149 Pa, whole unit | 0.75 in. w.g., about 187 Pa, whole unit, loaded | Three bases and two units of measure; none can be subtracted from another until all three restate the complete unit, clean and loaded, at 12,000 m³/h |
| 4. Fan | Not included | Not included | Listed fan on a separate line | Only C has priced the fan; A and B leave the static margin to the contractor |
| 5. Included | CE stated for the model; no accessories | First carbon fill and first lamps; models named on the certificate | Factory suppression, wash-down, differential-pressure alarm, controls | C carries the three items Section 506.5.2 requires; A and B would need them added for a North American site |
The reading is not that one quotation is right. It is that A and B are not offers for the same thing. C’s higher total contains three code items and a fan line the others omit. And the pressure-drop line has to be re-asked of all three before any fan selection is trusted. The blanks and the mismatches go back to the suppliers as questions; the totals are compared only after the answers come in.
Where the money goes once the lines are aligned
Once the five lines match, what remains is the equipment. What moves that is already written up: the six factors behind a single ESP quotation are in electrostatic precipitator price, and the drivers of a multi-stage offer, stage count first, are in ecology unit price. The two levers those pages do not treat as scope, the code accessories a North American site requires and the fan line, are what this page adds.
Our own basis, so we can be put on the same sheet
Here is our own basis, so you can put us on the same sheet as the other two and apply the same questions. We build in-duct electrostatic precipitators that are supplied as a single stage or as the first stage of a multi-stage unit, and we quote against the five lines rather than a headline.
| Line | Polygee’s answer | Basis |
|---|---|---|
| 1. Stages | Electrostatic stage alone, or electrostatic followed by UV and activated carbon modules, each listed on the quotation | Stage list stated per offer |
| 2. Airflow | Priced at your design airflow, in m³/h and CFM | Your stated design figure; a rated maximum is not substituted for it |
| 3. Pressure drop | A complete in-duct module including its airflow distribution plate is rated at no more than 150 Pa; the electrostatic cell itself contributes roughly 20 to 30 Pa; brochure equipment resistance is 31 Pa on the LK-E0, 23 Pa on the LK-E1 and 34 Pa on the LK-E2. For UV, one measured value exists, 65 Pa on a UV80 under report 2018I20-35-1594159016; other UV and carbon figures are issued per model with the configuration proposal | Each figure carries its basis; we do not subtract our cell figure from anyone’s whole-unit figure, and we ask you not to either |
| 4. Fan | Not part of the standard supply; can be supplied with the unit and is then selected against the total static pressure of the configuration, stated on the quotation | Fan parameters issued per project |
| 5a. Listings and reports | UL 867, File E522667, on the LK and SE 6K, 12K and 18K models; CE certificate FQC2602501 on the LK30 to LK480, the LK-E models it names and the UV series; RoHS does not cover the UV, CB or SPP lines; grease removal on the LK series up to 97.6% in CMA-accredited third-party tests under report ZY05W230298 | Per model, in writing |
| 5b. Commercial terms | Minimum order one unit; standard lead time 7 to 15 days; deposit of 30 percent, or 50 percent on some orders, with the balance before shipment, by T/T or L/C; Incoterms EXW, FOB or CIF to suit the buyer; warranty one year on the complete unit, with the electrostatic cells and the SPP power supply covered, UV lamps and carbon media treated as consumables, and labor excluded; spare parts held in stock and supplied for one year after a model is discontinued; OEM logo and cabinet color available | Per order, in writing |
One figure we do not put on the sheet is a cleaning interval for the electrostatic cells. It depends on the cooking process, the run hours and the oil in use, so we give it in writing against your stated conditions at quotation rather than as a catalogue number.
Where this guide stops
This page rebases quotations you already hold. It does not build the request that makes offers arrive comparable in the first place; that is the job of the ecology unit price page and its worksheet. It does not explain what moves a single ESP quotation either; that is the job of electrostatic precipitator price. Which documents to demand from each supplier is the job of the commercial kitchen ESP buying guide; what the names and the listings mean is the job of what a pollution control unit is. This page gives no price band, ranks no supplier and sizes no fan.
Three layers apply to what the sheet tells you, and clearing one does not clear the next.
- Aligned scope. The filled sheet shows what each supplier has offered. Passing one layer does not clear the next.
- Evidence behind each line. The listing file and the test report show what the offer is supported by; the models named and the test airflow decide whether they apply to the unit quoted.
- The installed system. Only the fan selected against the real total static, and the stages maintained, show what the kitchen gets. A quotation that wins on the sheet still has to win on the file numbers and then on site.
Buyer record
- Before comparing totals: fill the five lines for every quotation, in the same units, and send the blanks back as questions.
- Request from every supplier: the stage list in flow order · the airflow the price was built on · pressure drop per stage with basis, unit and condition · whether a fan is included and against which static · the models each certificate names, the report number with its airflow, and the accessory list.
- Record for your own file: which quotation includes the items your code path requires, so that an apparently cheaper offer is costed with them added.
- Triggers a re-check: a change of design airflow · moving the unit into an enclosed run · a change of target market or Incoterm · a change of menu that changes the stage list.
Key takeaways
- Names: judge PCU, ecology unit and ESP quotations as one role scoped by three markets, not as three products.
- Scope: judge a North American quotation knowing it carries the alarm, the suppression and the wash-down drain the code asks for, not as padding.
- Pressure drop: judge figures only after the unit and the basis match, not by the smallest number on the page.
- Fan: judge whether the fan is inside the scope and what static it was selected against, not whether the total is higher.
- Evidence: judge the aligned sheet against file numbers and reports, not against the headline.
Frequently Asked Questions
- How much does a pollution control unit cost?
- There is no list price. A pollution control unit is quoted against a configuration: the airflow it treats, the number of stages, the accessories the code or the specification adds, whether a fan is included, and the commercial terms. Two quotations for the same duct can differ by a fan line and three code items without either being wrong, which is why the five lines on this page are aligned before totals are compared.
- Why is a PCU quotation higher than an ESP quotation for the same airflow?
- Usually because of scope rather than equipment. Section 506.5.2 of the 2021 IMC requires a differential-pressure alarm, a factory-installed fire suppression system and wash-down drains on a pollution control unit, and a North American quotation tends to include them. An ESP quotation written to a UK or European specification usually carries one electrostatic stage and leaves the fan and any odor stages to others. Add the missing items to the lower quotation before comparing.
- Can an ecology unit quotation be compared with a PCU quotation?
- Yes, once the stage list, the airflow, the pressure-drop basis, the fan and the included accessories are aligned. An ecology unit offer commonly carries three stages, electrostatic, UV and carbon, while a PCU offer may carry one filtered stage with the code accessories. Compare the stages first; a three-stage and a single-stage offer are not competing offers for the same thing.
- Which pressure-drop figure should I ask for?
- Ask every supplier for the same basis at the same airflow: the complete module including its distribution plate, at your design airflow, stated clean and loaded, in a single unit of measure. One inch of water gauge is about 249 pascals. A cell-only figure in pascals cannot be compared with a whole-train figure in inches, and subtracting one from the other means nothing.
Send us the three quotations
Holding three quotations you cannot line up? Send us the three, or the sheet as far as you have filled it, together with your design airflow, where the unit will sit and the market it is going to. We will come back with the Rebasing Sheet filled for each of them as far as their text allows, the questions to put back to each supplier for the blanks, and our own column completed on the same basis. Where our standard unit does not carry an item your code path requires, the column says so rather than leaving the cell blank. You get back a comparison you can defend in a procurement review, with our offer quoted EXW, FOB or CIF as you prefer.
Send the quotations →Why we write this
We build in-duct electrostatic precipitators and quote them into markets that call the same equipment by different names. The questions we hear most from buyers holding several offers are why the totals differ so much, whether the pressure drops can be compared, and whether the fan is supposed to be inside the number. This page answers those with a sheet that works on anyone’s quotation, including ours. It does not size or configure equipment; sizing and quotation live on the product pages.
Scarlett leads commercial work at Polygee, which designs and builds commercial kitchen exhaust filtration equipment and has done so since 2004. The commercial terms and pressure-drop figures on this page are Polygee’s stated basis and are available in writing for any model quoted. This article explains how to compare quotations for planning purposes; the figure for any project comes from a written quotation.
References & further reading
- International Code Council — 2021 International Mechanical Code, Section 506.5.2 Pollution-control units, items 2, 8, 9 and 11. codes.iccsafe.org
- BESA — DW/172 Specification for Kitchen Ventilation Systems, 2018, clauses 24.1 and 24.11 on low-level discharge with pollution control and on the resistance of pollution control equipment in fan selection.
- UL Solutions — Updates to UL 8782, Pollution Control Units for Commercial Cooking (December 3, 2019), on the naming of the category. ul.com
Related reading
- What a pollution control unit is — the code definition, the three names, and which IMC edition asks for UL 8782.
- Electrostatic precipitator price — the six factors that set a single ESP quotation, in the order a buyer meets them.
- Ecology unit price — how to write the request so that multi-stage offers come back comparable.
- Commercial kitchen ESP buying guide — the six documents to ask for and check.