Air Cleaner CADR, Quantity & Purchase Calculator

Compare air cleaner capacity, quantity and purchase cost

A purchase comparison based on price and advertised floor area can overlook ceiling height and operating settings.
This calculator derives room volume from measured area and height, then calculates the CADR needed for a target ACH that you choose.
Enter candidate CADRs, power consumption, quotes and unit limits to compare integer purchase combinations meeting that target.

Use it to compare one large unit with several smaller units, or to explore adding equipment alongside a unit you already own.
The result describes capacity and purchase tradeoffs among the candidates you enter.
A cheaper combination that falls short of the target is excluded from the feasible purchase ranking.
The tool does not select brands or retrieve product prices.

Room area, ceiling height and your target ACH

Normalize CADR units and check test conditions

Use a value explicitly identified as clean air delivery rate, rather than an ordinary fan airflow figure.
A number expressed per minute cannot be compared directly with a number expressed per hour.
Select the unit for each model; the calculator converts all candidate values to m³/h before combining them.

Match the test particle and verify that the test standards are comparable.
Fan-setting names do not have to match across brands, but each model needs verified CADR and power at the setting you intend to use.
Combining maximum-speed CADR with sleep-mode power can overstate efficiency.
For the “other” particle option, record the actual particle and test standard in the note and verify comparability with the supplier.

Required CADR and purchase-combination formulas

Each candidate receives an integer count within its model limit.
The combination must also fit the total unit limit and any positive budget limit.
Only combinations meeting the target CADR enter the purchase ranking.
With up to four models and zero to eight units per model, the full count space contains at most 6,561 combinations.
The calculator searches this bounded space completely and does not round displayed capacity before deciding whether a combination meets the target.

How to use the calculator

1. Measure one room and enter area, height and your chosen target ACH.
   Check whether the proposed scope includes separately enclosed rooms.
   
2. Add up to four models, with their names, CADRs, units, test particles, setting notes, power and purchase quotes.
   
3. Set each model’s maximum count.
   Use zero to exclude a candidate, or remove its row.
   
4. Set the total unit limit and budget.
   A budget of zero means no spending limit; it does not mean a zero-cost budget.
   
5. Enter operating hours and comparison days, confirm the room and data assumptions, then calculate.
   
6. Editing clears previous results.
   Recalculate and save the TXT comparison before checking the specifications with your supplier.
   

Inputs accept grouping commas.
Area, height, CADR, power and hours accept decimals; counts, days and KRW prices require whole numbers.
Area is capped at 1,000 m², height at 20 m and target ACH at 30.
These are software input bounds, not recommended values for particular rooms.
Quotes use Korean won in both language versions, without currency conversion.

Worked example: 500 m³/h for a 40 m² room

A room with 40 m² floor area and a 2.5 m ceiling has a volume of 100 m³.
A user-selected target ACH of 5 requires 500 m³/h.
The following inputs are fictional test values, not manufacturer specifications or market prices.

Three B units also meet the target with 600 m³/h and 45 W, but cost KRW 360,000.
They tie with A+B on power, so the lower purchase price makes A+B the displayed lowest-power choice.
Reducing unit count and reducing initial purchase cost can therefore lead to different choices.

Read the three comparison objectives

The table shows at most ten feasible combinations by purchase price and reports the total feasible count.
All three objective winners are selected from the entire bounded search, not just those ten rows.
The fewest-unit winner may therefore appear in its summary card even when it is outside the displayed table.

When budget or quantity limits prevent a solution

Review the maximum count of each model, the total unit limit, the budget and other verified candidates.
Lowering the target may create a feasible combination, but it changes the requested performance.
A data-comparison hold is different from a capacity shortfall: mismatched test particles or unconfirmed assumptions prevent combination ranking.

High ceilings, existing devices and operating schedules

• Higher ceilings: increasing the 40 m² room’s height to 5 m doubles volume to 200 m³ and the required delivery at ACH 5 to 1,000 m³/h.
  Equal floor areas do not necessarily require equal capacity.
  
• Existing equipment: a confirmed zero additional purchase price can represent a unit you already own.
  Set the model limit to the actual available count and verify its current operating data.
  There is no mandatory-use constraint, so check whether the selected combination actually includes the existing unit.
  
• Longer operation: hours and days affect energy, not required CADR or the capacity verdict.
  A longer runtime does not convert a combination below the instantaneous target into one that meets it.
  
• Supplier comparison: the TXT report preserves dimensions, target, units, model notes, constraints and results.
  Check tax, delivery and quantity discounts with the seller, then update the applicable per-unit quotes.
  

Model limitations and costs outside the comparison

Adding independent CADRs is a modeling assumption for simultaneous operation in one well-mixed room.
This tool does not simulate furniture, partitions, connected levels, doors, filter loading or airflow interaction.
It does not establish whole-home coverage or the time required to reach a particular pollutant concentration.

Particle CADR is not converted into odor or gas removal performance.
Equivalent clean-air delivery does not establish outdoor ventilation or carbon-dioxide control.
Noise tolerance, physical dimensions, placement and replacement-filter availability remain separate purchase considerations.

Only entered initial purchase quotes are added to the ranking.
Energy is expressed in kWh without inferring household tariffs, taxes, discounts or the consumption of other appliances.
Filter, maintenance, replacement and rental costs are excluded.
Collect those figures separately when comparing ownership costs or rental contracts.

Frequently asked questions