Tumblers per year = guests × drinks per guest × events per year (events), or people × drinks per person per day × days open per year: 220 for schools, 365 for hospitals, and the working days you enter for offices (default 250). You choose what share of those drinks are served today in new plastic tumblers; the rest are assumed to come in shared glasses washed by hand.
Plastic waste = tumblers × the tumbler weight you pick (default 3 g).
Hygiene: every drink is served in a glass that GILAS has spray-washed, ultrasonically cleaned and UV-C disinfected, a cycle designed to cut pathogens by 99.9% (independent validation under way). Shared-glass reuses replaced = drinks served in shared glasses today. Staff hours freed = those drinks × hand-washing seconds per glass ÷ 3,600. We do not estimate illnesses avoided, because that depends on many factors we can’t measure.
CO₂e avoided = plastic weight × (making factor + disposal factor) − tumblers × 0.005 kg per GILAS wash. Making factors, including forming into a product, are 2.569 kg CO₂e per kg for PP, 4.367 kg CO₂e per kg for PS, 3.855 kg CO₂e per kg for PET; landfill is 0.0089 and recycling 0.0064 kg CO₂e per kg, from the UK Government GHG Conversion Factors for Company Reporting 2024 (DESNZ). Burning releases the carbon in the plastic as CO₂: 3.14 kg per kg for PP, 3.38 kg per kg for PS, 2.29 kg per kg for PET (from each plastic’s carbon content; open burning also releases other pollutants not counted here). We give no credit for recycling, and treat GILAS washing and hand-washing of shared glasses as equal, so shared-glass drinks add no CO₂e either way. The GILAS wash figure is a placeholder until we measure it.
Savings = tumblers × (your tumbler cost, default ₹2, − ₹0.3 per GILAS wash) + staff hours freed × your staff cost per hour − shared-glass drinks × ₹0.3 per GILAS wash. This excludes the cost of buying, leasing or renting GILAS and of the GILAS glasses.
Payback = the GILAS price you enter ÷ monthly savings. It is shown only when you enter a price, and ignores maintenance, consumables and financing.
Water = tumblers × 100 ml per cycle (claimed, pending validation).
Results are rounded to whole numbers. The emission and cost factors are placeholder assumptions that will be replaced by figures from an independent lifecycle assessment. Real-world results depend on your cups, electricity source and how often glasses are reused.