Electric Boiler for domestic only (not C/H)

[dylan1]

Hi

I'm completely renovating and, because of house position, am unable to use either oil or gas.

Wondering if there are any electric boilers that would be suitable.

It would be supplying - kitchen sink, Utility sink, Bathroom basin and bath.
(No shower and not a 'combi' - no central heating required)

I know that's quite a lot, especially the bath, and I have looked at 'under sink' heaters even thinking of having 2, one for kitchen and one for bathroom, but the flow rate from even the largest seems quite low.

Is there a solution? One that would give flow rates similar to an oil or gas burner or am I stuck?

Thanks

 

[plumbplumb]

Depending on mains pressure your best option is a direct unvented cylinder.

You would get hot water at mains pressure.

 

[rich4nancy]

Hi
An option if you have space is install a hot water cylinder with cold water storage above. Higher the better. You could then heat the water via immersion heater. This would give you a bulk store of hot water and offer the same flow rates as a gas boiler/tank fed system. It also gives flexibility in the future if you wanted to add pumped showers.

Just Another idea ??

 

[Onetap]

Is there a solution? One that would give flow rates similar to an oil or gas burner or am I stuck?

Thanks

Hot water storage cylinder & 3 kW immersion heater? An 'instantaneous' electric heater wouldn't be practical if you want a reasonable flow rate from a bath tap. The immersion heater would heat some or all of the cylinder in 30 minutes or so. Maybe economy 7 if that's still going, heat the water at cheaper rate overnight and store.

 

[plumbplumb]

Price of copper cylinders/tank/pipework it's probably like for like with a vented system.
Plus there is no need to have an extra tank/lagging/overflow etc etc.

Unless however the mains pressure is poor

 

[rich4nancy]

You could use stainless steel cylinder with price of copper being high.
Basic 900x450 direct from sc###fix 175 quid.

 

[dylan1]

Thanks for all replies.

You've convinced me not to look for 'instantaneous' but go for a cylinder. Best, because of space, would be a direct unvented but you've all worried me a little with talk of water pressure. Is mine enough? What are the implications if it's too low? Using a cheapo meter it reads 4 Bar (I'm away in the hills and the end of the line.) Is this enough? Could I also run a mixer type shower off this?
Sorry for multiple questions.

 

[TicklyT]

4 bar static pressure sounds like a good starting point, but you also need to know the flow rate, and the residual pressure at that flow rate before deciding on the best system.

It is possible the water pressure may dive dramatically if you draw off more than the smallest trickle of water. If that does happen, a vented hot cylinder and cold storage cistern could perform better than an unvented cylinder.

Easy enough to measure the flow rate by how long it takes to fill a bucket of known capacity. For example, filling a 2 gallon (9 litre) bucket from the kitchen cold tap in 30 seconds equates to a flow rate of 18 Litres per minute.

If you connect your pressure gauge to another tap, and read the pressure whilst filling the bucket, you will get the residual pressure at whatever flow rate you fill the bucket at.

LPG, LNG or oil are all likely to offer lower running costs than electric water heating.