Should you buy the Eco NOVA or Ultra NOVA?
Nova is direct about the relationship between these two seats. The Ultra NOVA is described as building on the Eco, adding automatic lid operation, user presets, an enema wash and a thinner body. Everything else carries over.
That means the features you use every day are the same on both. Unlimited instant warm water, a heated seat, a warm air dryer, adjustable spray pressure and temperature, and a self-cleaning nozzle.
The auto lid is the headline addition and the main reason to pay more. It opens as you approach and closes afterwards, which is genuinely nicer to live with and more hygienic in a shared bathroom.
The enema wash is the feature people either need or ignore entirely. It delivers a targeted stream that some users rely on for medical reasons, and it is rare at any price. If that applies to you, the Ultra NOVA is the only one of the two that offers it.
Two details run the other way, which is worth knowing before assuming the pricier seat wins on everything. The Eco NOVA has a stainless steel nozzle where the Ultra NOVA uses resin, and it carries a four-year warranty against the Ultra NOVA's three. The Ultra NOVA does get the longer trial period at 60 days rather than 30.
For most bathrooms the Eco NOVA is the sensible buy. Step up to the Ultra NOVA if you want the hands-free lid, need the enema wash, or want the thinnest possible seat on the toilet. Both fit elongated bowls only — check the full range of bidet seats if you have a round bowl.