Aggregating Unit Counts for a Company-Wide Air Purifier Budget

Key takeaways

• Headquarters typically wants one consolidated figure, not a scattered set of branch estimates
• Each branch's requirement should still be calculated individually from its own floor plan
• The CADR formula applies the same way regardless of branch size or layout
• Rolling up branch totals into unit tiers gives a clean company-wide summary
• A coordinated survey across branches keeps the aggregation accurate and consistent

Why Headquarters Usually Wants One Total Number, Not Per-Branch Estimates

When a company operates several branches, headquarters generally wants a single, clean answer to "how many air purifiers do we need," not a scattered list of separately calculated branch estimates that someone at headquarters has to add up manually. A facilities lead asked to produce this figure needs a consistent method applied across every branch, then a clear way to roll the results into one total.

Getting this right the first time avoids a round of follow-up questions asking why one branch's figure looks different from another's, or whether every branch was actually assessed the same way.

Calculating Each Branch's Requirement With the CADR Formula First

Every branch still needs its own calculation, since floor area, ceiling height and room layout differ from site to site. The formula stays constant: required CADR in cubic metres per hour equals floor area in square metres, multiplied by ceiling height in metres, multiplied by a target air changes per hour, typically 4 to 5 for office-type spaces.

Apply this room by room within each branch first, since a branch with several enclosed rooms will need more units than one open-plan branch of the same total floor area. Skipping this step and estimating at the whole-branch level tends to under- or over-count compared to a room-by-room calculation.

Rolling Up Branch-Level Numbers Into a Company-Wide Total

Once each branch has its own room-by-room unit count and tier, rolling these up is a matter of totalling unit counts by tier across every branch, for example, a combined count of compact units, mid-range units and larger units needed company-wide. This gives headquarters a single summary table rather than a stack of separate branch reports to interpret individually.

Presenting the total alongside the branch-level detail, rather than instead of it, also lets headquarters spot-check any branch that looks unusually high or low relative to its floor area, and gives whoever reviews the figure a way to trace it back to its source if a question comes up later.

Accounting for Branches of Different Sizes and Layouts

A common mistake in this kind of exercise is assuming every branch scales the same way from a flagship location's numbers. A smaller branch with several partitioned rooms can need more units relative to its floor area than a larger, mostly open-plan branch, simply because each enclosed room needs its own unit regardless of overall size.

Keeping the room-by-room calculation for each branch, rather than extrapolating from one branch's total, is what keeps the company-wide aggregation accurate. It also flags outliers early, such as a branch with an unusually high ceiling or an oddly shaped floor plate, before those get smoothed over by an average that does not actually apply to every site.

Getting a Coordinated Survey Across All Branches

For a business with several branches, coordinating a single round of room-by-room surveys across every site keeps the aggregation both accurate and consistent, since the same method and the same surveyor's judgement apply everywhere rather than varying branch by branch.

Scheduling the surveys in one coordinated batch, rather than letting each branch arrange its own separately over several months, also gets the full company-wide total ready for headquarters faster.

Use the free Air Purifier Size Calculator to work through the formula for each branch, then request a coordinated room-by-room Air Report to confirm the totals before presenting them to headquarters.

Presenting the Aggregated Figure Alongside a Rollout Timeline

Headquarters usually wants the unit count paired with a sense of how the rollout will actually happen, not just a total number sitting on its own. Grouping branches by region or by how soon each one needs coverage, then presenting the aggregated total against that phased timeline, makes the figure easier for headquarters to act on rather than treating it as one large, undifferentiated commitment.

This phased view also gives finance flexibility to release budget in stages rather than committing to the full company-wide total in one go, which tends to make approval smoother for a rollout spanning many branches.

Keeping the Aggregated Figure Current as Branches Change

A company-wide total is a snapshot, not a permanent figure. As branches open, close, or expand their floor space, the aggregated count should be updated rather than treated as a one-time exercise filed away after the initial rollout is approved.

Assigning ownership of this figure to one team, typically facilities, keeps it from going stale as the branch network changes shape over time, and gives headquarters a reliable number to reference whenever a new budgeting or procurement question comes up, rather than starting the whole aggregation exercise over from scratch each time.

Next step

Work through each branch with the Air Purifier Size Calculator, then confirm the totals with a coordinated room-by-room survey before presenting to headquarters.

Frequently asked

Why does headquarters usually want one aggregated unit count?

A single consolidated total is easier for headquarters to review, approve and budget against than a scattered list of separately calculated branch estimates that would otherwise need to be added up manually.

How is each branch's requirement calculated before rolling it up?

Each branch is assessed room by room using the standard CADR formula: floor area multiplied by ceiling height multiplied by a target air changes per hour, since floor area, ceiling height and room layout differ from branch to branch.

Can branches of different sizes be surveyed together efficiently?

Yes, by coordinating a single round of room-by-room surveys across all branches rather than scheduling each separately, which keeps the method and judgement consistent and makes the final aggregation more accurate.

Related reading

• How Many Air Purifiers Does Your Office Need?
• Commercial Air Purifier Rental in Singapore