What belongs in the oven savings figure?

Everything the oven costs that a UV cell does not. Fuel or electricity, exhaust and make-up air, the building cooling load it creates, maintenance, the floor space it occupies, and the working capital held in cure-time work-in-progress. Most cases are built on the first item alone, which is why they usually understate the project: the space and the WIP are frequently larger than the energy.

Why add a discount rate?

Because payback and NPV answer different questions. Payback asks how long the money is at risk, which is a fine screening question; NPV asks whether the project creates value at the cost of the capital it uses, which is the question that approves it. Here the two differ by 44% of the headline benefit, and a case presented on payback alone will be re-appraised on NPV by someone else anyway.

Will my parts cure under UV?

That is the question to answer first, and it is not a cost question. UV cures where light reaches, so thick sections, filled or heavily pigmented systems, and parts with shadowed features can be entirely routine in a thermal oven and impossible under a lamp. Trial the actual parts with the actual chemistry before building any of this arithmetic; discovering it afterwards is the most expensive way an oven conversion fails.

What does this page not capture?

Three things, any of which can dominate. Throughput, where cure time falling from minutes to seconds often removes a bottleneck and the extra contribution exceeds every saving here. Substrate range, where losing the thermal limit makes heat-sensitive materials possible. And tax, depreciation and utility rebates, which for an energy-reduction project can be large and are entirely jurisdiction-specific.

Why does the NPV equal the net cash at a zero rate?

Because that is what a zero discount rate means. A dollar in year five counts as a dollar today, so five equal annual amounts are worth five times one of them. Running it once is worth doing: it makes the assumption behind undiscounted payback explicit and confirms both rows are working on the same cash flows.

Is five years the right horizon?

It is the earlier version's convention, kept so the figures stay comparable with what the old page published, and it is defensible for curing equipment that will normally last considerably longer. A longer horizon flatters the project and a shorter one penalises it, which is exactly why the discount rate matters more than the horizon does. It prices the timing rather than truncating it.

UV Curing calculator

Oven vs UV Cure Payback Calculator: Simple Payback and Discounted NPV

Appraise replacing a thermal cure oven with a UV cell, on the basis everyone quotes and the basis a finance function will apply. Enter the installed cost, the annual cost the oven imposes that UV removes, the UV cell's own running cost, and your discount rate. The calculator returns simple payback, net annual savings, five-year net cash and ROI as the earlier version computed them, plus the discounted present value of the same flows. Set the rate to zero and the NPV collapses onto the net cash figure, which shows what an undiscounted payback assumes without saying so.

What this calculator does

Appraise replacing a thermal cure oven with a UV cell on both bases: the simple payback everyone quotes and the discounted value of the same cash flows.
Use it for screening a thermal-oven replacement before committing engineering time, presenting a capital case that will face a hurdle-rate test, showing how much of a payback claim is undiscounted arithmetic, testing sensitivity to an oven savings figure, comparing UV conversion against an oven upgrade.
Appraise replacing a thermal cure oven with a UV cell on both bases: the simple payback everyone quotes and the discounted value of the same cash flows.

Formula used

Net annual savings = annual oven savings − annual UV operating cost
Years to payback = UV cell installed cost ÷ net annual savings
Five-year net cash = net annual savings × 5 − installed cost
Five-year ROI (%) = five-year net cash ÷ installed cost × 100
Five-year NPV = net annual savings × (1 − (1 + r)^−5) ÷ r − installed cost

Inputs explained

UV cell installed cost: Everything spent before the first good part: equipment, integration, electrical work, controls, guarding, commissioning, and the trial material used to prove the process.
Annual savings vs thermal oven: Everything the oven costs that the UV cell does not: fuel or electricity, exhaust and make-up air, building cooling, maintenance, floor space, and the working capital tied up in cure-time WIP.
Annual UV operating cost: Electricity, lamps or array provision, cooling, and any nitrogen. Build it from the energy, lamp-replacement and nitrogen pages rather than estimating it.
Discount rate: Your cost of capital or hurdle rate. Set it to zero to reproduce the earlier version's undiscounted figures, which is what the old page assumed without saying so.

How to use the result

Best suited to screening a thermal-oven replacement before committing engineering time, presenting a capital case that will face a hurdle-rate test, showing how much of a payback claim is undiscounted arithmetic, testing sensitivity to an oven savings figure, comparing UV conversion against an oven upgrade.
Assumes the parts can cure under UV. Thick, filled, pigmented or shadowed parts that an oven handles routinely may not cure at all, and that is a feasibility question rather than a cost adjustment. Ignores tax, depreciation, grants and utility rebates, which are jurisdiction-specific and can be substantial for an energy-reduction project. Prices no throughput change, and an oven-to-UV conversion usually delivers one. Cure time falling from minutes to seconds often removes a bottleneck outright, and that benefit can dwarf every line on this page. Excludes the value of substrates that become possible once the thermal limit is gone, which on some products is the real reason for the project. Assigns no residual value and no allowance for lamp or array degradation raising UV operating cost over the horizon.

Current U.S. benchmarks

As of 2026-08-20, the U.S. prime lending rate is 6.75% (Federal Reserve via FRED). Equipment loans and lines of credit typically price at prime plus a spread, so use your actual borrowing rate when you have it.

Common questions

What belongs in the oven savings figure? Everything the oven costs that a UV cell does not. Fuel or electricity, exhaust and make-up air, the building cooling load it creates, maintenance, the floor space it occupies, and the working capital held in cure-time work-in-progress. Most cases are built on the first item alone, which is why they usually understate the project: the space and the WIP are frequently larger than the energy.
Why add a discount rate? Because payback and NPV answer different questions. Payback asks how long the money is at risk, which is a fine screening question; NPV asks whether the project creates value at the cost of the capital it uses, which is the question that approves it. Here the two differ by 44% of the headline benefit, and a case presented on payback alone will be re-appraised on NPV by someone else anyway.
Will my parts cure under UV? That is the question to answer first, and it is not a cost question. UV cures where light reaches, so thick sections, filled or heavily pigmented systems, and parts with shadowed features can be entirely routine in a thermal oven and impossible under a lamp. Trial the actual parts with the actual chemistry before building any of this arithmetic; discovering it afterwards is the most expensive way an oven conversion fails.
What does this page not capture? Three things, any of which can dominate. Throughput, where cure time falling from minutes to seconds often removes a bottleneck and the extra contribution exceeds every saving here. Substrate range, where losing the thermal limit makes heat-sensitive materials possible. And tax, depreciation and utility rebates, which for an energy-reduction project can be large and are entirely jurisdiction-specific.
Why does the NPV equal the net cash at a zero rate? Because that is what a zero discount rate means. A dollar in year five counts as a dollar today, so five equal annual amounts are worth five times one of them. Running it once is worth doing: it makes the assumption behind undiscounted payback explicit and confirms both rows are working on the same cash flows.

Last reviewed 2026-08-25.