Going fully electric - Do you have to change your shower?

waqasahmed

Let's say you've got a heat pump, and heat cylinder

You've moved away from gas entirely, and are now using electricity only for everything. 

Do you have to change your shower to an electric one? Or can it pull "heat" from the pipes, kinda like your taps would?

Would it also be more efficient to simply replace it to a proper electric one anyway? Even though either way, the heating source would still be electric? 

Coastalwatch

We have one of each but prefer to use the one from the cylinder on most occasions as having heated the water it only seems sensible to use it. As to whether it's more efficient than the 8 kW electric I couldn't begin to calculate as it possibly depends on time of year and by how much the cylinder was heated by surplus PV!

Solarchaser

We have moved from electric showers to water cylinder supplied showers.

Negatives would be that there will be heat lost in the pipes just like there is when you run the hot tap.

Positives, much much better water pressure, being able to switch the shower off to soap up and switch back in with instant hot water instead of having to wait on the electric element cycling again, and as an all electric house you have to be mindful of your 100a fuse.
A 40a shower takes quite a bit of this.
If you are also heating cylinder, charging batteries and charging an ev, there will not be enough headroom for an electric shower

Reed_Richards

You can heat a hot water cylinder with a heat pump and perhaps get an average of 2.8 kWh of heat for every kWh of electricity - then use that hot water for your shower.  Or you can use an electric shower to heat cold water and get 1 kWh of heat for every kWh of electricity.  So using the DHW cylinder for your shower is much cheaper if you have a heat pump.  Think of the shower as just another hot tap.

Now with the cylinder there will be some hot water that is trapped in the pipes after you finish your shower and if nobody else takes a shower shortly afterwards that's a bit of heat wasted, but not very much unless you have long pipe runs (unlikely in your house).  Also the hot water in the cylinder will lose some heat gradually, which will be wasted in summer but may heat your house in winter.  But that would happen whether or not you use the hot water in the cylinder for showers.       

mickyduck55

I have both, the 10 kWh shower is used in winter when I have little to no solar excess to divert, the power shower from HW cylinder used when I have an excess of solar so water heated for "free"  The downside of the power shower is that a relatively large amount is wasted, I can be in and out of the electric shower in about the same time as it takes to get the other at temperature.  The downside of the electric shower is that no matter how sunny or charged my batteries are I still import from the grid when its in use.. 10 kWh exceeds my solar and batter delivery capability.

Hexane

mickyduck55 said:

The downside of the electric shower is that no matter how sunny or charged my batteries are I still import from the grid when its in use.. 10 kWh exceeds my solar and batter delivery capability.

Do you mean 10 kW, not 10 kWh?

waqasahmed

mickyduck55 said:

I have both, the 10 kWh shower is used in winter when I have little to no solar excess to divert, the power shower from HW cylinder used when I have an excess of solar so water heated for "free"  The downside of the power shower is that a relatively large amount is wasted, I can be in and out of the electric shower in about the same time as it takes to get the other at temperature.  The downside of the electric shower is that no matter how sunny or charged my batteries are I still import from the grid when its in use.. 10 kWh exceeds my solar and batter delivery capability.

I do intend on getting more batteries anyway tbf, so I'd hope that with batteries, I could basically run off electric

I do currently have 

One electric shower 
One shower powered by gas 

I can easily shower in five minutes but the gas one takes longer to heat up

waqasahmed

Reed_Richards said:

You can heat a hot water cylinder with a heat pump and perhaps get an average of 2.8 kWh of heat for every kWh of electricity - then use that hot water for your shower.  Or you can use an electric shower to heat cold water and get 1 kWh of heat for every kWh of electricity.  So using the DHW cylinder for your shower is much cheaper if you have a heat pump.  Think of the shower as just another hot tap.

Now with the cylinder there will be some hot water that is trapped in the pipes after you finish your shower and if nobody else takes a shower shortly afterwards that's a bit of heat wasted, but not very much unless you have long pipe runs (unlikely in your house).  Also the hot water in the cylinder will lose some heat gradually, which will be wasted in summer but may heat your house in winter.  But that would happen whether or not you use the hot water in the cylinder for showers.       

Thanks. That is indeed a fair shout. I guess it'd be a good idea to "convert" my existing electric shower into a non electric one first then

mickyduck55

Hexane said:

mickyduck55 said:

The downside of the electric shower is that no matter how sunny or charged my batteries are I still import from the grid when its in use.. 10 kWh exceeds my solar and batter delivery capability.

Do you mean 10 kW, not 10 kWh?

10 kW sorry

Reed_Richards

At current prices the running cost of a heat pump is similar to the running cost of mains gas heating, maybe just a little less if you achieve a good COP.  So if you currently have the option of using an electric shower or a shower using gas-heated hot water then the gas-heated water will be a lot cheaper.  Therefore it would indeed be a good idea to "convert" your electric shower into a non-electric one now, before you invest in a heat pump.

waqasahmed

Reed_Richards said:

At current prices the running cost of a heat pump is similar to the running cost of mains gas heating, maybe just a little less if you achieve a good COP.  So if you currently have the option of using an electric shower or a shower using gas-heated hot water then the gas-heated water will be a lot cheaper.  Therefore it would indeed be a good idea to "convert" your electric shower into a non-electric one now, before you invest in a heat pump.

Yeah. I figured that though realistically, I have to also upgrade my pipes too, so if I do I'd upgrade all my (tiny) pipes. It's in the pipeline, to use the pun

Also, this is interesting. it's "Heat Geeks" one

https://emoncms.org/heatgeek

I guess unlike heating, you need a shower daily, and maybe twice daily in summer but you probably won't be using much heat then

 It looks like if you search against all of time, their heat pump has averaged a COP of 3.22 which is perhaps not the true story when it comes to a storage cylinder (Ie: you have that inside the house, and not outside the house)

So it'll probably at the very least be "on par" with gas, using a heat pump cylinder

My plan is this:

- Reinforce my roof
- Add 8 more solar panels + batteries
- Make my house air tight
- Add an MVHR
- Add triple glazing
- Upgrade my piping
- Change electric shower to non electric
- Upgrade my radiators (That require power flushing anyway)
- Replace gas cooker with induction
- Add heat pump cylinder
- Add heat pump