In a point-of-use purification system, almost all the energy goes to one job: raising the pressure across the membrane. Everything else — a valve, an indicator, a flush cycle — is rounding error beside it. That single fact decides most of what follows in the design.
The pump is the design decision
A booster pump is added because the incoming supply is assumed to be too weak. Once it is there, it brings a power supply, a transformer, a pressure switch, a source of noise and the component most likely to fail first. A system designed without one has to earn that omission somewhere else: usually in the membrane area and in how little the flow path resists the water passing through it.
Removing the pump does not remove the need for pressure. Below the minimum inlet pressure a system is rated for, a pump-free design will not deliver its rated output — it is not that it runs slowly, it is that the specification no longer applies. That minimum is a per-model number and belongs on the model's own page, not in an article.
What efficiency is usually measured against
Two numbers do most of the work. One is electrical: watts drawn while producing water, which for a mains-pressure system is zero. The other is hydraulic: how much water leaves as concentrate for each litre delivered. A system can be excellent on the first and unremarkable on the second, and a specification that quotes only one of them is quoting the flattering one.
Where this lands in practice
KomiBright's under-sink and commercial systems run on mains pressure, without a pump and without an electrical supply. The A95R is the deliberate exception: it carries a 25W priming pump and is the one model in the range rated for open sources such as a river or a lake, where there is no mains pressure to work with in the first place.
