Electric water heating

FreeBear

mrsyardbroom said:

Does anyone know what is the smallest vented cylinder you can get? I only need about 30 litres a day. The ones I've seen are much bigger than that.

90l is about the smallest vented cylinder available. You can also get unvented cylinders at around 60l capacity at around twice the price of a vented one. But if you fill a bath on a regular basis, the smallest you want to go is around 120l.

mrsyardbroom

I very rarely use the bath. It's only for washing something big. I use the shower.

MysteryMe

Standard sizes will tend to be cheaper than say a 30 litre tank if one existed.  Also when you have a bath, if you have too small a tank you will a) find you don't have enough water to run a bath and b) by draining it entirely you are then having to heat a whole new tank of cold water from scratch which I would have thought was more costly that having a larger tank that you are only partly draining. I think a standard size tank would work out cheaper all round although obviously you wont gain extra space in the airing cupboard.

mrsyardbroom

I don't ever have a bath. I use the shower.

Section62

mrsyardbroom said:

I very rarely use the bath. It's only for washing something big. I use the shower.

The point is that if the cylinder is too small you may not have enough hot water to use the bath when you want to, without turning the immersion heater on in the day (peak) rate period.

The whole idea of heating water using off-peak electricity is to heat enough that you very rarely need to use peak rate-electricity to top up. The economic cost of heat-loss of the stored water is offset by the fact it has been heated at a cheaper rate.

Although you don't use much hot water (/have few baths) you may have problems when you come to sell the property if the hot water cylinder is seriously undersized for the property - it is something a good surveyor is likely to notice and comment on.  More likely perhaps as increasing energy costs means people are more likely to go for storage-type heating systems to make maximum use of energy when it costs the least.