Model chillers on cost and carbon before the lock-in.
Model up to six chiller options across their expected lifetime: capital, energy, refrigerant leakage, embodied carbon and — if you choose to price it — the cost of offsetting what is left, stress-tested over thousands of simulated futures. Adjust any assumption and every figure updates instantly.
This free tool compares the total cost of ownership and lifetime carbon of up to six chillers over a 15 to 25 year life. You enter installed capacity, capital cost, NPLV, refrigerant type and charge, along with your electricity tariff and equivalent full-load hours. It returns net present value, actual lifetime cost, scope 1–3 emissions and the marginal abatement cost of each option, with P10–P90 uncertainty bands from a 10,000-run Monte Carlo across energy price escalation, grid decarbonisation, run hours and, optionally, the carbon credit price.
Held at today's performance as the baseline for comparison. Its capital is already spent, so every dollar and tonne shown against it is attributable to the upgrade.
Pick the machine type, then overwrite the name and figures with what you are actually quoting — Powerpax, Daikin, York. Whatever you type carries through to the report. The type defaults are illustrative, not recommendations.
Year-by-year cost and emissions tables, a cost waterfall decomposing your reference plant into the winning option, cumulative net benefit with the payback year marked and P10–P90 bands, sensitivity tornado, marginal abatement cost and a written recommendation. Reply to the email and we send back the live-formula Excel workbook behind it.
| Option | Capital | Energy saved | Year-1 saving | Simple payback | Discounted payback | Lifetime saving | Emissions avoided |
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Every option is one dot — hover it for the figures behind it. The vertical axis is always a cost measure and the horizontal always an energy or carbon measure, so each view shows a trade-off rather than the same quantity twice. The shaded region is everything that beats the reference on both.
P10 / P50 / P90 per option and the cost per tonne avoided. Unlocks here as soon as you enter your email above, and it is all in the PDF too.
Total cost of ownership combines capital cost, energy cost over the analysis period at forecast tariffs, refrigerant leakage counted as emissions, and embodied carbon counted once at year zero. Carbon is always reported in tonnes; whether it also reaches the dollars is your choice. Leave carbon credit pricing off and the comparison sets cost against tonnes side by side, with leakage never touching the money. Switch it on, set a credit price and pick the scopes you offset, and the cost of offsetting the residual emissions joins every option's total — including the embodied carbon at year zero if you select scope 3 — so a leakier or thirstier machine is charged for it. Future costs are discounted at a real rate to give a net present value; the calculator also reports undiscounted actual lifetime cost, because the two answer different questions.
Both IPLV and NPLV weight efficiency across the part-load conditions a chiller actually runs at, rather than a single full-load rating point — which matters because central plant spends most of its life between 30% and 80% load, where nameplate COP tells you very little. The difference is the conditions the weightings are applied at. IPLV uses the fixed test points in AHRI Standard 550/590; NPLV uses the same weightings at your project's design conditions — your tower water temperatures, your flow rates, your climate. Since that is what a manufacturer quotes when selecting for a specific job, NPLV is the number you will have on the table, so it is the one this tool asks for. Variable-speed machines separate from constant-speed ones precisely here: their full-load numbers can be close while their part-load figures are not.
Annual scope 1 emissions are charge multiplied by the annual leak rate multiplied by the refrigerant’s 100-year global warming potential. A 320 kg R-134a charge leaking 4% a year is 12.8 kg of refrigerant, and at a GWP of 1,430 that is about 18 tCO₂e every year — before the machine has drawn a single kilowatt-hour. Low-GWP refrigerants such as R-1233zd(E) at a GWP of 1 make that line effectively vanish.
By default at 75 kgCO₂e per kW of installed cooling capacity, counted once in year zero and reported under scope 3, following the CIBSE TM65 approach of estimating from equipment mass and material mix where a manufacturer EPD is not available. It is fixed on this page and editable in the workbook, and the existing plant carries none because it has already been built.
NPV discounts every future dollar back to today, which is how capital decisions are normally judged and the right basis if capital is scarce. Total lifetime cost is the actual cash that leaves the building undiscounted — a larger, blunter number that suits a sustainability or budget-envelope conversation. A high discount rate favours the cheaper machine; a low one favours the efficient one. Both bases are one click apart in the tool for exactly that reason.
Three things as the page loads: energy price escalation, grid decarbonisation rate and run hours. Switch carbon credit pricing on and it varies a fourth, the credit price, which carries the widest spread of any of them because offset markets are the least predictable input on the page. Each one is drawn lognormally on the growth factor rather than as a bell curve on the rate. That keeps the average and the spread the same, but leans the shape to the right: a bad year lands further from the middle than a good one, which is how energy and carbon markets have actually behaved. It also keeps the growth factor positive, so a falling price is still perfectly possible — real electricity prices have fallen in both countries this tool serves. Each simulation draws one value for each and runs the full life on it, and critically every option faces the same drawn future, so each run is a like-for-like comparison. Ten thousand runs give the P10 to P90 band. The bands matter more than the central number: two options whose bands overlap heavily are not meaningfully different, however different their midpoints look.
Magnetic-bearing oil-free centrifugals are typically the most efficient chillers available today. In a recent Australian tender for a 1,100 kW water-cooled replacement, the highest part-load figure quoted by any manufacturer, 11.5 COP, was an oil-free magnetic-bearing machine, and oil-free operation avoids the efficiency drift that oil migration causes in flooded machines over a life. Cheapest to own over 20 years is a different question, and it no longer has the same answer. A good variable-speed screw is close on part-load efficiency — the defaults on this page are 9.5 COP against 10.5, about 10% less energy for the centrifugal, not the wide margin a comparison against a constant-speed machine would suggest — so the capital premium has much less energy saving to pay it back. Which machine is cheaper to own therefore turns on the specifics: equivalent full-load hours, your tariff and its escalation, and how much premium the quotes actually in front of you carry. Enter both and read the P10 to P90 bands rather than the midpoints, which is what this page is for.
No. It is a comparative desktop estimate built to make a trade-off visible before capital is committed. Real numbers depend on your load profile, your plant configuration and your tariff structure. In delivery engagements Exergenics simulates the shortlisted machines inside a calibrated digital twin of the actual plant and verifies savings to IPMVP Option B.