As housing developers race to satisfy SAP 10.2 requirements under Part L, they often default to high-cost interventions such as solar panels or triple glazing.
But a more understated alternative, Waste Water Heat Recovery (WWHR) has proven itself to be a cost-effective, low-impact solution, and it’s now gaining a reputation as a simple way to significantly enhance SAP performance at a fraction of the cost of other techniques.
The SAP Challenge
In the past, one of the main challenges with WWHR has been how it is modelled within SAP. The methodology quite rightly prioritises the building fabric first. In other words, if insulation, glazing, airtightness and thermal bridging are not addressed properly, then no amount of renewable or recovery technology will make a building genuinely efficient in SAP terms. Poor fabric performance effectively masks the value that WWHR can deliver.
Once a development has been specified with strong fabric performance, with walls, roofs, floors and windows all optimised, the picture changes. At that point, incremental technologies such as Zypho WWHR can be modelled effectively.
Because Zypho directly reduces hot water demand, it delivers a measurable and repeatable uplift in SAP scores, often achieving the extra compliance margin that developers need without costly upgrades elsewhere.
This is why today, as fabric standards have improved across the industry, WWHR is moving from being a “nice to have” to a highly strategic measure. It provides a huge incremental benefit at relatively low cost, while also aligning perfectly with Part L and the Future Homes Standard’s emphasis on reducing energy use at source.
SAP Calculation Example with Zypho
Full Zypho Product Range in SAP & Part L Calculations
Zypho is one of the most cost-effective products that can be used to increase a building’s SAP score, and pound for pound installing a Zypho can be some of the cheapest SAP points gained, compared to other technologies.
| Zypho Product | Type | Efficiency* | Best Floor Setup | Typical SAP Gain | Use Case Summary |
|---|---|---|---|---|---|
| PiPe75 | Vertical | ~82% | 1st floor showers | +5 to +7 pts | Highest efficiency, ideal for detached and semis |
| PiPe65 | Vertical | ~67% | 1st floor, riser space | +4 to +5 pts | Common in 2/3-bed homes with vertical stacking |
| Slim50 | Horizontal | ~48–65% | Mid-depth shower trays | +3.5 to +4.5 pts | Compact profile, replaces iZi30 when space is limited |
| iZi30 | Horizontal | ~25–39% | Shallow trays (<80mm) | +1.5 to +2.5 pts | Ideal for flats, modular builds |
Full Zypho Product Range comparing to other technologies
The table below shows the comparable cost against other SAP products.
| Product | Est. SAP10 Increase | Product Cost | Installation Cost | Maintenance required? | User Interaction needed? | Cost per SAP 1% |
|---|---|---|---|---|---|---|
| Zypho | 15% | £500 | £100 | £40 | ||
| Solar PV (1.5kW) | 15% | £4,000 | £500 | £300 | ||
| Insulation (increase by 50mm to 150mm) | 2% | £500 | £0 | £250 | ||
| Air Source Heat Pump | 70% | £5,000 | £1,500 | £93 | ||
| Biomass Boiler | 65% | £10,000 | £2,000 | £184 | ||
| Solar thermal | 15% | £3,500 | £500 | £266 | ||
| MVHR | 3% | £1,000 | £500 | £500 |
Zypho® offers the cheapest cost per SAP percentage against other technologies
Get in touch with us today to see how we can help you boost your SAP rating and reduce costs.
Email shower@zypho.uk or call 01525 647220.
