Vented direct hot water cylinder options

[BennyS]

Hi,
I'm currently purchasing a flat that has a direct, vented, hot water cylinder. Due to it's age I'm looking to replace it and wondered what is my best option, as well as what size would people recommend?

The flat only has electricity (no gas) and is on an economy 7 tariff. The current system has a separate cold-water tank but I was thinking whether a combination cylinders was any better?

In terms of my use; we are a young family so would require about 3 bathroom-sinks full of water in the morning, maybe a kitchen-sink full during the day and a shallow filled bath (about 10cm deep) in the evening for the kids; everything else in the flat heats its own water (washing machine, electric shower, dishwasher).

I was wondering:
Is a hot water cylinder my best option for getting the water I need?
If so, what size should I go for and are there any specific types to look out for?
Do I need any timer device set-up to help me (in terms of the economy 7 tariff)?
Would water I heat up during the small hours of the morning still be hot for the bath about 14 hours later?

Any help would be most appreciated

 

[Madrab]

Economy 7 works overnight, heating with cheaper electricity. 2 immersion heaters, bottom one heats the cylinder on Economy 7, top one is a booster top up, usually on normal rate.

1) With electric heating and a busy family with children then economy 7 with a hot water tank is probably the better option, though there are other options with instantaneous heating but with electricity it is all pretty costly
2) Approx 30-40 Litres of hot water per person per day is a good starting point for a busy house.
3) You should have one circuit for the main immersion heater working off of Economy 7 overnight, and a separate 1/2, 1, 11/2 hr booster control allowing an additional top up, connected to the top immersion heater. There should be a separate circuit for the economy 7 that the main immersion heater is connected to, that will energise when economy 7 kicks in usually between 11 and 12pm, that element should have a thermostat that will shut it off when hot enough so normally not timed.
4) Any modern cylinder has to have a minimum of insulation by law, that will keep the water hot. An older cylinder may require a jacket to enhance it's insulation.

If you have a modern, well insulated cylinder, heating that overnight should give you 3/4 of a tank of hottish water later that day, you should then have the top up immersion heater that will give you the ability to top it up. You will work out a routine of how and when you need to top up as you use it over time.