Electric Immersion Heater Options

littleteapot

learner21 said:

I have a 120 litre tank - which is well insulated - I also had a leaking drain valve at bottom of tank - so now I have 2 valves.
I cannot post links yet - but fitted a new immersion heater - a Tesla T-Smart Immersion Heater which I control with an app, but most importantly lets me see the tank temperature on my phone. I would say takes 30 minutes to heat to 55degC. 
The fitted immersion is also unlikely to have a faulty thermostat - which means it's on all the time - as the water would be hot all the time. 

Good choice - old or even new standard copper immersion cylinders are rubbish even those with a think layer of foam on the outside. Ours is  Gledhill Stainless Lite double-walled with very good insulation from 2014 (inner stainless steel tank, thick insulation, then plastic outer shell). I'm sure the Tesla one is even better.

When I bought the house it had a standard copper cylinder with a cold water tank on top (I think these were known as Telford cylinders) which meant I had to have a pump to give a proper shower as the top of the cylinder was not buch above shower head height. But by 2014 this was leaking like a seive despite only having been installed in 2004. So I decided to splash out on the stainless steel cylinder which was capable of holding mains pressure along with the associated paraphenalia such as expansion tank, pressure reducing valve, one way valve, over-pressure and temperature blow-off valves etc. The insulation is so good we get hot water even in late evening from the last overniight charge, and the benefit of no noisy shower pump.

yakuzakitty

Stubod said:

..could you not fit an "instant" shower....ie one that heats the water as you use it?

I was looking into this but it turns out to be much more complicated than I initially thought. We'd need a new circuit and a new mains electricity supply to our bathroom, and we'd need to retile in between this being installed and the shower unit being put in.

yakuzakitty

doodling said:

Hi,

Stubod said:

If the hot water tank is used to feed a power shower it will be quite large? May be better to get a self heating shower and replace the hot water tank with a more modern (ie better insulated), smaller one?

The right solution for the OP depends on the selection of the right electricity tariff.

The flat is all electric so ideally it would be heated with a heat pump system of some sort and in that case you would expect the hot water to be most cost effectively heated by the heat pump.  Such a configuration remains relatively rare however.

The next most cost effective heating arrangement would be the use of storage heaters on economy 7, with hot water also heated at cheap rate. In that case it is probably cheaper to accept the small heat loss from the tank as the overall cost will still be cheaper than an electric shower at daytime rates.

Only if the heating uses non-storage heaters at normal rates (at vast expense!) is an electric shower likely to be a cost effective solution.

Can't have a heat pump unfortunately. Another problem is that the boiler doesn't have a timer - it's either on or off, and we need to manually do this. So taking advantage of night-time prices isn't practical with the current set-up.

yakuzakitty

Jonboy_1984 said:

This echoes my experiences of a 25 year old scaled up tank in a hard water area.

Having replaced elements 4 times in two years as they died, it developed a leak on the drain valve and was replaced. New tank took less than half the time to heat to the same level (unit of measure used being hot enough for the wife to enjoy a bath…!).

Did you have a new immersion heater and tank installed or was it another system?

doodling

Hi,

yakuzakitty said:

doodling said:

Hi,

Stubod said:

If the hot water tank is used to feed a power shower it will be quite large? May be better to get a self heating shower and replace the hot water tank with a more modern (ie better insulated), smaller one?

The right solution for the OP depends on the selection of the right electricity tariff.

The flat is all electric so ideally it would be heated with a heat pump system of some sort and in that case you would expect the hot water to be most cost effectively heated by the heat pump.  Such a configuration remains relatively rare however.

The next most cost effective heating arrangement would be the use of storage heaters on economy 7, with hot water also heated at cheap rate. In that case it is probably cheaper to accept the small heat loss from the tank as the overall cost will still be cheaper than an electric shower at daytime rates.

Only if the heating uses non-storage heaters at normal rates (at vast expense!) is an electric shower likely to be a cost effective solution.

Can't have a heat pump unfortunately. Another problem is that the boiler doesn't have a timer - it's either on or off, and we need to manually do this. So taking advantage of night-time prices isn't practical with the current set-up.

I don't believe you've told us how the flat is heated?  As my post said, the cheapest way to heat water using electricity it to do it overnight on E7, but this is only sensible if you can take advantage of the E7 rates for a significant proportion of your electricity usage (heating being the obvious big part of that).

Getting a timer fitted for the immersion heater is not expensive if you do want to use E7.