Gas v Electric shower

The_Village_Idiot

Hi all,  Reading a thread earlier about electric and gas showers and people are looking to go gas showers from the combi boiler.

To my simplistic mind, there is not much in it, i.e.  we have an 8kw electric shower, 2 people showering for total 15 mins is 2 kwh at 45p a kw, 90p.  My 30kwh combi would be 7.5kwh at 15p per kwh,  15 minutes,  112.5p.

Please tell me where I am going wrong, my user name says it all !

TIA 

BUFF

Your combi will give a far better shower - higher flow rates etc. Certainly where I live an 8kW shower in the middle of winter is not going to be very warm.

An electric shower is 100% efficient so 8 kWh (if you actually ran it for an hour) transferred heat to water.
An average combi is probably 80% efficient at transferring heat to water so 30kWh results in 24kWh heat transferred to water - 3x that of the 8kW electric shower. If you restrict the combi to lower flow rates then it will not use 30kWh e.g. half the flow rate, half the gas.

Gerry1

Your combi wouldn't be going flat out at 30kW (not kWh) for those 15 minutes.  If we're pessimsitic and assume it's only 80% efficient for hot water then it would be using 10kW to provide the equivalent of your 8kW electric shower, so it's costing only one third of the price you calculated.

You also seem to be quoting the old gas price before the EPG reduction: gas is probably a whisker over 10p/kWh now.

SAC2334

I ve just had my electric shower and total use of the 8 kw shower was less than 40 seconds..

 Cost of shower 4 p , 28 p a week ..Using the tried and tested  "switch on wet, switch off,  soap up , switch back on to rinse off  "

Beat that gas shower users !
I am taking at least 8 mins to shower but as hot water sprinkling down on a person is not doing any cleaning whatsoever there is no real point in having it blasting away doing nothing just for the sake of it wasting lots of energy 

northernsoul

I have done some tests and found the following
4 minute gas shower 1.88kWh   £0.192   
5 minute gas shower 2.14kWh   £0.219
6 minute gas shower 2.39kWh   £0.244

not had a longer shower than 6 minutes
therefore a rough estimate
 
7 minute gas shower 2.65kWh   £0.271
8 minute gas shower 2.91kWh   £0.297

using a rainforest shower head

BooJewels

@northernsoul that tallies with my own findings when I did a direct comparison of my two options. I think we maybe discussed them at the time.

The gas heated shower is a bit cheaper, but not threefold as is often suggested in this place.  Where gas won for me is that you get a nicer, more enjoyable shower with much better pressure and flow - but if you're metered for water, might use more water and that have a cost implication too, reducing some of the advantage.

My own 8 minute x 9kW showers cost me 40.8p so 37% more expensive and probably not as nice.

northernsoul

Agreed.
My rainforest shower is much better than the 9.5kw electric shower I had many years ago (I am not metered for water , I pay £33 per month whatever I use) 

BooJewels

Me neither on the metering.  I need some work done in my bathroom, so will get my shower swapped as part of that process.  I only did my experiments using a push on shower head to the bath taps, which are unfortunately at the wrong end of the bath, so not a long term solution. 

The_Village_Idiot

Thanks to all who commented.

@Gerry1,  yes old prices quoted just for simplicity.

And the cheapskate I am, only the wife is using the 8kw, I'm on the 4 kw setting and it's a pitiful shower !

Will be converting to a gas shower shortly. 

Yorkshire_Pud

My electric shower is 8.5 kW and now the weather is colder it gives a very unedifyingly weak flow as I have to cut the flow to get the heat up to comfort level. So now use the over bath shower from the taps fed by the gas combi and that is great. 

Looks like it’s gas for the Winter and Electric for the Summer roughly and I do like having a shower that’s not reliant on gas especially as had a period where the gas boiler had to be replaced so could use the electric shower for that time and could do again.

housebuyer143

A lot of people do not have 30kw boilers but more likely 18kw or 20kw. That makes a gas powered shower much cheaper than the electric in a lot of circumstances.
Not to mention electric showers are depressingly weak in the winter.