RTU vs Concentrate Chemistry: Cost-per-Clean Maths for Contractors
Price chemicals per litre of working solution, then add labour and dosing errors.
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One 5-litre drum, 50 to 200 spray bottles. That is the range Freshway's listing for Agar Citra-Mist implies: the page directs 25 to 100 mL of concentrate per 500 mL spray bottle, and 5,000 mL divided by 100 mL is 50 fills, while 5,000 mL divided by 25 mL is 200. The fourfold spread is decided by whoever fills the bottle.
RTU vs concentrate: which costs less per clean?
For RTU vs concentrate cleaning chemical cost, concentrate usually wins on chemical cost per clean once dosing is controlled, while ready-to-use wins where mixing errors, training gaps or small volumes would waste that advantage. Compare cost per litre of working solution, add labour and error costs, then decide by task, not by brand.
This guide is for contract managers and buyers setting up chemical cupboards across several sites. The Freshway commercial chemical dilution guide already explains how to read ratios and run dispensing systems. Here the focus is the cost structure behind the RTU or concentrate decision, worked through without inventing prices.
RTU convenience vs concentrate yield
Ready-to-use (RTU) products arrive at working strength. Freshway lists Freshway Spray and Wipe 320 as a ready-to-use solvent surface cleaner that needs no dilution, in 5 L and 20 L packs. Every litre bought is a litre used, and the only preparation is decanting into a labelled trigger bottle.
Concentrates multiply. Freshway lists Agar Super Force with a dilution range of 1:160 for light soil to 1:50 for heavy soil. A 1:160 mix is 1 part concentrate plus 160 parts water, so 5 L of concentrate makes 5 × 161 = 805 L of solution. At 1:50, the same 5 L makes 5 × 51 = 255 L. Yield depends on the soil level the site actually has.
Simple maths without inventing prices
Use symbols, then put your own trade prices in. Let P be the pack price, V the pack volume in litres and N the water parts in a 1:N ratio.
- Concentrate: cost per litre of working solution = P ÷ (V × (1 + N)).
- RTU: cost per litre of working solution = P ÷ V.
- Cost per clean: cost per litre of solution × litres used per clean, plus the labour minutes spent preparing and the cost of errors.
The first line shows why concentrate tends to win on chemical cost: the divisor is multiplied by (1 + N). At 1:50 the divisor is 51 times larger than for the same volume of RTU. That only holds if the dose stays at the label rate. If staff double the dose "to be safe", N effectively halves and much of the saving goes with it.
Where the cost actually sits
Chemical is often the smallest line. The table separates the components a buyer should price.
| Cost component | Ready-to-use | Concentrate |
|---|---|---|
| Chemical per litre of working solution | Pack price ÷ pack litres | Pack price ÷ (pack litres × (1 + N)) |
| Preparation labour | Decant only | Measure, mix and label each time, unless dispensed |
| Error cost | Low: strength is fixed | Overdosing wastes product; underdosing means re-cleaning |
| Freight and handling | Carries the water weight | Less weight and storage per litre of solution |
| Packaging waste | More containers per litre used | Fewer containers if bottles are refilled |
| Training | Minimal | Ratios, measuring and labelling |
Error costs
Dosing errors cost money twice. Too strong wastes concentrate and can leave residue that re-soils or needs rinsing. Too weak fails to clean, so the task is repeated. On RTU, those errors cannot happen at the mixing stage, which is why RTU often makes sense for casual staff, small sites and tasks done a few times a week. WorkSafe Victoria lists decanting and mixing among chemical tasks in its hazardous substances guidance, so every mixing step also carries an exposure and training obligation.
Dosing hardware
Measured dosing turns concentrate's paper saving into a real one. The simplest tool is a printed bottle. Freshway lists the Agar Spray and Wipe 500 mL bottle with a screen-printed dilution guide on the outside, so staff fill to a line rather than guessing. Compare bottles and triggers in the spray bottles and triggers range. Wall-mounted proportioners are the next step up and need their own checks, as the existing dilution guide describes. The payback logic is the same either way: hardware pays for itself when it stops overdosing, so record usage before and after you install it.
Transport weight and handling
RTU is mostly water. Every litre delivered, carried up stairs and stored in a cleaner's cupboard is a litre that could have come out of the tap on site. For mobile teams, concentrate means fewer drums in the van. WorkSafe Victoria's hazardous manual handling guidance recommends reducing the size and weight of objects to be lifted, which favours smaller packs and concentrate where carrying is frequent. Packaging matters too; fewer containers per litre of solution means fewer to recycle under NSW EPA recycling and reuse programs.
Spec a hybrid cupboard
Most sites end up with both. A practical split:
- Concentrate for high-volume, repetitive tasks with stable soil: floor mopping, scrubber tanks and daily surface wiping from refilled printed bottles.
- RTU for low-volume or high-risk tasks: occasional spot work, sites without a mixing point, and teams with high staff turnover.
Agar's own Citra-Mist page describes the product as able to dilute to 1 in 20, which is a good example of a concentrate that suits refilled spray bottles. Browse further options in the Agar multipurpose cleaners collection.
Training implications
Concentrate needs a short, repeated lesson: which product, which ratio, which line on the bottle, and how to label a decanted container. RTU needs only the labelling step. Keep the current SDS for every product in the cupboard; WorkSafe Victoria's safety data sheets page sets out what a compliant SDS must contain. If a site cannot guarantee that training, price it as an RTU site.
Decision checklist
- Calculate cost per litre of working solution for each candidate using the formulas above.
- Estimate litres used per clean and the minutes spent preparing.
- Ask who mixes, how often staff change and whether a measured dosing method exists.
- Choose concentrate for high-volume tasks with controlled dosing, RTU for the rest.
- Review usage after one month and compare it with the expected yield.
Frequently asked questions
Is concentrate always cheaper than RTU?
Per litre of working solution, usually yes, provided staff dose at the label rate. Overdosing and repeat cleans can close the gap quickly.
How do we compare products with different dilution ratios?
Convert each to cost per litre of working solution: pack price divided by pack litres times one plus the water parts. Then compare at the ratio your soil level needs.
When is RTU the better buy?
For small volumes, sites without a mixing point, high staff turnover, or tasks where a mixing error would damage a surface or fail an audit.
Do concentrates need different labelling?
Any decanted container needs labelling, whether the contents are diluted concentrate or RTU. Keep the current SDS available for each product.
Next steps with Freshway
Put your trade prices into the formulas, check dilution rates and pack sizes on each product page in the cleaning chemicals range, and decide task by task. Contact Freshway if you want help setting up a hybrid cupboard for several sites.
