'Anti-scale' covers several technologies that do NOT do the same job. Polyphosphate conditions the water without removing hardness; a salt softener actually removes calcium and magnesium; CO₂ injection lowers the scaling potential by gentle acidification; reverse osmosis produces very pure water at a single point of use. Choosing well starts with your goal and your water hardness.
Indicative 20-year cost comparison
Order of magnitude for a household consuming 150 m³/year (France, 2025–2026). Prices come from published catalogues; use them as a reference, not a quote.
| Technology | Main service | Investment | Opex/year | 20-year cost | Key point |
|---|---|---|---|---|---|
| Polyphosphate | Light anti-scale & anti-corrosion conditioning | 87 € | 19 € | 466 € | Cheapest, but does not remove hardness |
| Salt softener | Hardness removal | 1275 € | 150 € | 4275 € | Most robust on hard to very hard water |
| CO₂ injection | Anti-scale by gentle acidification | 1600 € | 50 € | 2600 € | Interesting if you want to avoid salt |
| Reverse osmosis | Very filtered drinking water at the tap | 200 € | 39 € | 984 € | Point-of-use only — does not protect the whole plumbing |
Reverse osmosis is shown here as a point-of-use economic reference, not as a whole-home anti-scale substitute.
How to choose
- Moderately hard water (up to ~30–35 °f) and your goal is to protect a boiler, water heater or appliances → polyphosphate: compact, low-cost, no salt discharge.
- Hard to very hard water (> 35 °f) or you want to remove hardness across the whole home → salt softener.
- Anti-scale without salt → CO₂ injection.
- Only very pure drinking water at one tap → reverse osmosis (not a substitute for whole-home scale protection).
In short: polyphosphate is the economical, simple, local option; the softener is the robust choice on hard water; CO₂ is the salt-free middle ground; reverse osmosis targets drinking water, not your plumbing.
Not sure which fits your water? Ask our technical team or explore our anti-scale solutions.