Here I go again ….

QrizB

Swipe said:

Try to shower at off peak if you can.

And consider shorter showers

Swipe said:

7.2kW is on the lower power scale of electric showers.

Indeed it is. Those 10.5kW monsters must make the red LED on a meter flash like crazy.

Qyburn

30 minutes is a long shower.

Scot_39

You dont need to actually use the meter and the power draw test after buying / fittnig a device to see roughly what it would cost to run - the shower / almost any electrical device should have a rating if on the mains - from 5W for say an old basic USB charger - to 10kW plus for a more powerful shower.

If you (or the fitter) tossed the shower box - the shower will normally have a rating label - look on underside.

A mid level (8.5/9.5 are popular rating sizes - so take average) 9 kW rated shower - for instance - in 10 minutes would use 1.5 kWh

Energy in kWh = Power in kW * Time in Hours

So Energy = 9 [kW] x 10 [min] / 60 [min/hr] = 1.5 kWh  

Cost about 40p at SR - less at offpeak - more at day rate on Snug iirc

For half an hour - and my elderly disabled mum before needed asistance - could take over 20 minutes - so its not a fanciful question - when we had to put it on before and off after - 

9 kWh x 30/60 = 4.5 kWh.   At SR c26 = more like £1.10

7.5kW nominal shower would be lower.  

There should be info on the box - or a label - maybe on the bottom - so difficult to read for some.

7.2 kW - with a little bit (100-200W) of background use though does seem surprisingly low for an electric shower.

The lowest at Screwfix where got my cheapish Triton 8.5kW model is 7.5kW and theirs only 2 out of dozens ( 30+ 8.5s, 43 at 9.5kW their most popular rating - but exceeeded my supply limits).  

At 230V though - a 7.5kW nominal at 240V if that was the rated point - could pull less.

Rosie1001

It’s just been installed , wasn’t on high heat , just a medium temp so didn’t draw that much power 

I like a hot shower thou , lucky my off peak is going off around 6.36 am or 7.09 am 

it varies 

wrf12345

94p for an hour but only 1.5p per minute...

Spoonie_Turtle

Rosie1001 said:

It’s just been installed , wasn’t on high heat , just a medium temp so didn’t draw that much power 

With our shower, the power draw is constant regardless of the temperature.  The temperature changes by having the water flow over the element at a quicker or slower rate, so quicker = cooler and slower = warmer.  I don't know if there are different types of electric shower but you'll be able to work out if your does the same by whether the flow rate changes with different temperatures.

Of course if it has an eco mode as well as the normal mode then that will use less power, I think it heats the element less so the flow rate is slower for the same temperature than it would be on the full mode. 
(To illustrate: with our old shower that did have two modes, you'd have to turn it to 8 or 9 on eco mode to get the same temperature as 5 on full, and in winter the hottest in eco mode resulted in not much more than a dribble but still didn't get warm enough.)

QrizB

wrf12345 said:

94p for an hour 

94p for 30 minutes. £1.88 for an hour.

wrf12345 said:

 but only 1.5p per minute...

I will leave correcting this as an exercise for the reader.