Sterra's purchase prices run $599–$1,999, and because every current model publishes a filter price and interval, a complete five-year total can be computed for each: $1,850 to $2,915. Velta's purchase prices run $1,588 (HydroForm+) to $2,988 (HydroSpark+), but velta.sg's own filters/service page marks every relevant cartridge, for all three models, "Price being finalised — Contact us for the confirmed price" as of this check, so filter cost is excluded from every Velta total and all three are flagged incomplete. Velta's five-year figures ($1,588, $2,188, $2,988) are purchase price only, not a genuine cost of ownership. Because none of Velta's models has a complete total, the cheapest complete five-year cost in this matchup is necessarily a Sterra model — the Y Tabletop, at $1,850.

Velta names reverse osmosis on all three current models' product pages ("RO membrane" in each). Among Sterra's four, the X Standing, X Tabletop and Y Tabletop name ultrafiltration ("UF Membrane"); the Sterra 8 doesn't name its filtration technology at all. Neither brand publishes a scoped certification for any model. Velta cites a one-off third-party lab test (SGS Malaysia, on a single submitted water sample) for the HydroSpark+, but its own product page explicitly states "this is not product certification or a guarantee for every installation" — recorded here in notes, not as a certification, because Velta itself disclaims it as one. Sterra cites no equivalent third-party test for any model.

Velta HydroSpark+ is the only model in this entire dataset that outputs sparkling water — a genuine and singular differentiator. HydroForm+ is tankless hot/cold/ambient; HydroView+ is a tankless undersink system with a dual-outlet faucet (RO-filtered drinking water plus a separate composite-filtered rinse stream), a form factor Sterra doesn't offer. Sterra's four models split tankless (the 8) and tank-based (X/Y), all hot/cold/ambient, with no undersink or sparkling option.

Velta HydroForm+ (180×425×380mm, 7.3kg, tankless countertop) is a close class match to Sterra 8 (150×370×392mm, 6.7kg) — Sterra's is marginally smaller and lighter. HydroView+ (165×381×435mm, undersink) has no Sterra equivalent. HydroSpark+ (220×508×436mm, 21.7kg, tabletop) and Sterra X Standing (300×365×1115mm, 22kg, floor-standing) are similar in weight but very different form factors. On installation fee, Sterra states $0 for all four models; Velta states none for any of its three.

Velta states a two-year warranty for all three current models, but doesn't publish what that warranty covers or excludes — its own policy page directs buyers to purchase documentation that isn't published online. Sterra publishes the exact coverage and exclusions for every model (filters, hoses and wear-and-tear excluded throughout) alongside terms of three years (Sterra 8) or one year plus a paid extension (X/Y). Neither brand states whether its installation/service technicians are in-house staff or contracted.