Capital decision · figures, not promises
Paint booth ROI calculator and full workshop fit-out model
Four scenarios on one engine: a single machine, an equipment package, a facility built from scratch, or an upgrade to plant you already run. Enter your figures and get total cost of ownership, payback and net present value — as a range, not a single number.
What this model measures
Four analysis layers instead of profit-versus-price
A capital equipment decision is not settled by purchase price. This calculator builds the case on four layers, each with its equation printed in the method section below.
Total cost of ownership
Purchase price is one layer of four. Energy, servicing, filters and training accumulate across the horizon, and residual value is deducted at the end of it.
Cost of poor quality
Rework never arrives as an invoice. It is stated explicitly here: reworked jobs per year multiplied by the cost of redoing one, before the change and after it.
Overall equipment effectiveness
Availability × performance × quality. An optional layer that stays switched off unless you hold measured downtime figures — the model assumes no failure rate on your behalf.
Decision metrics
Payback period, net present value, internal rate of return and ROI — each presented as a conservative, expected and optimistic case.
The calculator
Pick your scenario, then enter your figures
Four fields produce a first result. The deeper inputs — tariff, discount rate, horizon, rework rates — sit under Advanced assumptions and are not needed for that first pass.
Result — Single product
| Case | Net annual (SAR) | Payback | NPV (SAR) | IRR |
|---|---|---|---|---|
| Conservative | — | — | — | — |
| Expected | — | — | — | — |
| Optimistic | — | — | — | — |
| Period | Cash flow (SAR) | Cumulative (SAR) | Discounted cumulative (SAR) |
|---|---|---|---|
| — | — | — | — |
| Source | SAR per year |
|---|---|
| Gross profit change from throughput | — |
| Operating cost change (energy and servicing) | — |
| Cost of poor quality change | — |
| Net annual benefit | — |
Total cost of ownership — breakdown
| Item | SAR |
|---|---|
| Acquisition (equipment and civil works) | — |
| Operating across the horizon (energy, servicing, filters) | — |
| Training and commissioning | — |
| Residual value | — |
| Total | — |
| ROI across the horizon | — |
Cost of poor quality, energy and effectiveness
| Item | SAR per year |
|---|---|
| Rework cost today | — |
| Rework cost after the change | — |
| Difference | — |
| Item | Value |
|---|---|
| Equipment units | — |
| Total connected load (kW) | — |
| Annual consumption (kWh) | — |
| Total investment (SAR) | — |
| Annual energy cost (SAR) | — |
| Item | Value |
|---|---|
| Current OEE | — |
| OEE after the change | — |
| Additional productive hours per year | — |
Method
The equations in full, and where each figure comes from
Nothing is calculated behind the interface. The four equations below are what the browser executes, and you can work them on paper yourself.
Layer one — total cost of ownership
TCO = acquisition + (annual operating x years) + training - residual value
Acquisition is not the purchase price alone: in the full facility scenario it carries the civil works as well. Operating covers energy, servicing and filters multiplied across the horizon. Residual value is deducted at the end, and it enters the cash flow in the final year rather than the year of purchase — because that is when it is realised.
Layer two — cost of poor quality
COPQ = jobs per year x rework rate x (job cost x rework cost share)
Rework is charged against the cost of a job, not its value, because redoing a job consumes cost and does not consume revenue. Job cost is job value less the gross margin. The model asks you for the rework rate before the change and after it, and both are your figures — we promise you no particular reduction.
Layer three — overall equipment effectiveness
OEE = availability x performance x quality
An optional layer, switched off by default. It runs only once you confirm you hold availability, performance and quality figures that were actually measured. The model assumes no failure rate on your behalf and publishes no benchmark OEE, because we hold no documented measurement to publish.
Layer four — decision metrics
payback = the year the cumulative cash flow crosses zero (interpolated)
NPV = sum of [ cash flow(t) / (1 + r)^t ]
IRR = the rate r at which NPV = 0 (solved by bisection)
ROI% = (total benefit - total cost) / total cost x 100
Payback is interpolated inside the crossing year rather than rounded up to it. IRR is solved by bisection rather than Newton–Raphson, because bisection cannot diverge once a scenario mixes staged capital with a residual value in the final year. Where the cash flow contains no sign change the panel prints an em dash, not a zero.
Why a range rather than one number
A single figure implies a precision no calculator running on assumptions actually holds. Every result is therefore shown in three cases — conservative, expected and optimistic — derived from the uncertainty band you set. Read the conservative case first: if the decision holds there, it holds.
Where every default in this calculator comes from
| Figure | Default | Source and classification |
|---|---|---|
| Electricity tariff | 20 halalas/kWh | Official external source. Saudi Electricity Regulatory Authority — industrial rate. Commercial is 22 halalas up to 6,000 kWh per month and 32 above it. Read 2026-09-05, excluding VAT. |
| Booth connected load | 11 kW | From our technical team — the general connected load of a paint booth, and the low end of the published 11–50 kW range at 380 V three-phase, 50 or 60 Hz (family page). ⚠️ Connected load, not metered consumption. |
| Load factor | 60% | Editable assumption. A machine does not draw its full connected load for the whole cycle. We hold no documented average — set it from your own meter reading. |
| Discount rate | 8% | Editable assumption. Not a rate we recommend — set it to your own cost of capital. |
| Uncertainty band | ±25% | Editable assumption. Generates the conservative and optimistic cases around the expected one. |
| Throughput gain | 0% | Zero by default, deliberately. Not a figure we promise for any model, so it stays out of the result until you raise it. The out-of-the-box result therefore rests on your figures alone. |
| Rework rate before and after | 15% → 6% | Your estimate in both states. We promise no particular reduction. |
| Residual value | 0% | Zero deliberately. We hold no documented resale value, and printing an estimate would lift the result without support. |
| Current energy and servicing bills | From your invoice | Your own inputs — the most reliable figures in the model. |
| Annual servicing and filters per booth | 4,000 SAR | From the technical team — an operating figure for the standard paint booth. Treat it as a starting point and adjust it to your contract and your filter interval. |
| Expected operating life | 10 years | From the technical team. It is context for choosing the horizon, not a promise about the life of the unit on your floor, which follows running hours and routine servicing. |
Anything absent from this table is not assumed by the calculator at all. Where no documented source existed we left the field to you rather than filling it with a silent estimate.
Common objections
What buyers raise before signing off the capital
Purchase price is one line in an equation of four
The sticker shock is real, but it compares a figure paid once against figures paid every month. Total cost of ownership puts energy, servicing, filters and rework on the same scale, and the question becomes: what does not upgrading cost me over five years?
Switch to the upgrade scenario and enter your current invoices to see the cumulative gap.
Which is why the output is a range, conservative case first
This model does not hand you a saving percentage. Energy is computed from connected load and the published regulator tariff, the rework rate before and after is written by you, and residual value defaults to zero. Every assumption without external support is named as one in the ledger.
Raise the uncertainty band to 40% and read the conservative case alone.
Its cost never arrives as a single invoice
It is spread across three separate ones: more energy for the same cycle, filters replaced at a rising cadence to hold airflow, and a rework rate that climbs slowly enough for the team to treat it as normal. Layer two exists to put an annual figure on the last of those.
Enter your real rework rate and read its annual cost on its own.
Downtime is counted once; rework repeats every month
Downtime is a genuine cost and is not dismissed here. The difference is that it is a one-off entry inside acquisition, while excess energy and rework are recurring entries in every year of the horizon.
Installation and commissioning run 7 days on average, and the scope for your site is fixed at the survey before supply.
Frequently asked
Questions about the model and its output
Are the results binding?
No. They are indicative and not binding. The calculator applies the equations printed in the method section to your inputs and to the assumptions listed in the ledger, both of which you can edit. Binding figures come from a quotation built on a site survey and a fixed internal dimension.
What separates the four scenarios?
One engine, different inputs. Single product and equipment package compare your current state with that state plus the new machines. Upgrade opens a full before-and-after comparison against your current invoices. Full facility build starts from zero: there is no current state, so the output becomes break-even from the start of the investment rather than a saving, and a civil works layer is added above the equipment.
Where does the default electricity tariff come from?
From the Saudi Electricity Regulatory Authority: 20 halalas per kWh for the industrial sector, and 22 halalas for commercial up to 6,000 kWh per month with 32 above it. Read on 2026-09-05, excluding VAT, because a registered business recovers input VAT. Check which band your account sits in and edit the field if it differs.
Why is there no energy saving percentage?
Because a saving percentage is a claim about equipment performance, and we hold no documented measurement to publish. What is implemented is tighter: energy cost after the change is computed from the machine’s connected load, its running hours and the regulator’s tariff, while current energy cost comes from your own bill. The difference between the two is the saving — calculated rather than asserted.
Why does residual value default to zero?
Because we hold no documented resale value for this equipment family in the Saudi market, and putting an estimate there would raise net present value without support. The field is yours to use if you have a figure you trust, and it enters the cash flow in the final year of the horizon.
Does this work for equipment other than paint booths?
Yes. None of the four equations assumes a machine type: enter the unit cost, connected load and annual servicing in the equipment table, and your volume and job value in the main fields. That is why the equipment table accepts multiple line items in the package and full-build scenarios.
How do I keep the result or send it to procurement?
The mini feasibility study button opens your print dialogue, where Save as PDF produces the file. It carries the tables, the assumption ledger with its sources and the print date, and its text stays searchable and selectable. The WhatsApp button opens a direct chat with the sales team and sends none of your figures.
Can the purchase be financed or paid in instalments?
Financing and instalments are not provided by us. They are arranged through independent third-party finance providers. Our part is to supply the quotation and the specifications those providers ask for, while the terms and the approval itself rest with them rather than with us.
You have the figures — the next step is a site survey
Send us your calculator output, the nature of the work, the space available and the largest part that will enter the machine, and we will propose the configuration on a quotation built from a fixed dimension rather than an estimate.