Triton ENVi shower specs discrepancy

Rarius · Aug 20, 2025

I'm looking at having a 10.5kW Triton ENVi electric shower installed in my new extension. However the specs don't seem to add up.

The specs say 8 L/min and 10.5kW... Now assuming the mains water is at about 7°C and I want a 38°C shower, quick thermodynamic calculation (Q=mcΔT) shows that we'd need 17.3kW to heat that much water by 31°C...

What gives? Does the shower restrict the flow until the water reaches the required temperature? Will my 8 L/m shower actually be only about 4.5 L/m?

Or is my calculation wrong (it has been a few years since I did my physics degree!)

Many thanks for any experience you can share about these showers.

Chuck · Aug 20, 2025

Nope, physics hasn't changed since you did your degree.

As you can see from the table half-way down this page (based on 42°C outlet temp and an optimistic 240V across the heater):

Compare Electric Showers: 8.5kW vs 9.5kW vs 10.5kW – Find Your Perfect Fit

Discover the perfect electric shower for your home! Compare 8.5kW, 9.5kW and 10kW models to find your ideal match. Learn more now!

www.tritonshowers.co.uk

the flow rate for winter inlet temperature, which they seem to have assumed is 5°C, is going to be more like 4.1 litre/min. Their 6.8 litre/min flow assumes an inlet temp of 20°C, which is unusual IME.

4 litre/min will get the job done but it's not exactly luxurious. OTOH, your utility bills will thank you, particularly if you have teens in the house...

Rarius · Aug 20, 2025

Chuck said:
Nope, physics hasn't changed since you did your degree.

As you can see from the table half-way down this page (based on 42°C outlet temp and an optimistic 240V across the heater):

Compare Electric Showers: 8.5kW vs 9.5kW vs 10.5kW – Find Your Perfect Fit

Discover the perfect electric shower for your home! Compare 8.5kW, 9.5kW and 10kW models to find your ideal match. Learn more now!

www.tritonshowers.co.uk

the flow rate for winter inlet temperature, which they seem to have assumed is 5°C, is going to be more like 4.1 litre/min. Their 6.8 litre/min flow assumes an inlet temp of 20°C, which is unusual IME.

4 litre/min will get the job done but it's not exactly luxurious. OTOH, your utility bills will thank you, particularly if you have teens in the house...

Sounds like Triton are sailing pretty close to the wind regarding the trades description act by specifying 8 L/min when that is unobtainable under normal usage. If my calcs are right, you'd only get that if you set the shower to 23°C... Brrrrrr!

Thanks for confirming my suspicions.