hot water storage in attic

[1razor1]

Is there any reason why the hot water storage tank cant go into the attic?
I dont want to put a combi boiler into my house but I do need to replace the hot water storage tank and wouldnt mind some of advice about choosing one, I want rapid heat, that much I do know. I have two bathrooms and two en suites but they have their own electric showers. I would like to utlise the space used one of the bedrooms by relocating the hot water storage tank (not an immersion heater) and wondered if it could go into the attic, which is large with good height, is there a reason not to do this.....alternatively is there any reason it cant go on the ground floor of the house?
Any info gratefully received

 

[ChrisR]

You need a metre between the bottom of the cold water header tank and the hot water cylinder.
Unless you use Unvented hw store, which also avoids pumps and gives a decent shower assuming decent mains pressure...

 

[1razor1]

thank you for your quick repl, please excuse the naivety of my question but what is the difference tween vented and unvented, I assume the old one I have is vented but why and how? is the unvented one easy to get hold of? and is there a problem with me putting it on ground floor, would I then need a pump?