Cold water tank size to service a 300L cylinder

lostinashford

Installing a 300l unvented cylinder, I have an existing 80 gallon (360l) cold water tank which I want to reuse.

Solar people telling me it will just about do but 100g would be better and builder and architect telling me it fine.

Going with unvented hot water at 1.5/2 bar. One bath and two showers servicing 4 people.

Any advice on size of cold water tank very welcome

Outkast_IRE

Cold water cistern is usually sized based on occupancy.
How many people in the House and do you expect this number to change soon.

lostinashford

Two adults and two children (though they are growing) fulltime. Not going to change apart from occasional short term visitors

Outkast_IRE

Well put it this way, would it be easy to add another cistern later if necessary or swap to a bigger size?

If the mains pressure is strong and refills the tanks quickly then you will be fine, usually there is only trouble when the mains is slow and refilling takes awhile.

Also usage patterns come into it, sometimes you have a person who likes a half hour long shower

lostinashford

Thanks Outkast_IRL