What size thermal store for hot water only

[scott2hot]

Hello everyone,

I've been asked to fit a thermal store and would like some confirmation on what size cylinder to fit. The thermal store will be a vented direct model (twin immersions only) and will only be supplying hot water, the house is a 3 bedroom with one bathroom. I was thinking a thermal store of arounnd 190/200 litres. Does this sound adequate.

Many thanks in advance.

 

[Gray0689]

What other heat source
If just for hot water

 

[scott2hot]

The only source to heat the thermal store will be the two immersion heaters, the rest of the house is heated by night storage heaters via economy 7, living in the sticks there's no gas!

 

[Gray0689]

Why a thermal store then?
There far more expensive than a standard direct unvented cylinder

 

[scott2hot]

Hi Gray, the customer wants mains pressure hot water, it takes about 30mins to fill the bath - they currently have a combi cylinder as there is no roof space for the traditional vented cylinder set up.

 

[Gray0689]

An unvented cylinder not vented
Unvented is mains pressure hot water
And will probably work out cheaper to run than a thermal store plus you will either need a thermal store with integrated header or a header tank in roof space

 

[Nostrum]

You need a direct unvented cylinder then

 

[scott2hot]

I have suggested an unvented cylinder but the customer doesn't like the idea of the annual servicing/check up. If they choose an unvented system I would have to pass it on as I've not got my unvented ticket - been meaning to do it for a while

 

[Gray0689]

Well it's up to you mate an unvented cylinder would be better and more cost affective for yous customer in the long run imho

 

[ecowarm]

Direct thermal store as long as immersions on economy 7, you could run a towel rail or rad of it as well. No more expensive than an unvented.

 

[Gray0689]

Combination thermal store is more expensive to buy and the heat loss is bad
Personally I would go for unvented but it's an idea with the towel rail ect Eco said

 

[scott2hot]

Thanks for the advice regarding fitting a rad/towel rail, i've priced up a 180ltr thermal store complete with immersion heaters for about £950, how much approximately would a unvented set up complete with all the prv's, trv's, expansion vessel etc cost ?

 

[Gray0689]

Thanks for the advice regarding fitting a rad/towel rail, i've priced up a 180ltr thermal store complete with immersion heaters for about £950, how much approximately would a unvented set up complete with all the prv's, trv's, expansion vessel etc cost ?

At a rough guess about £600 all in

 

[ecowarm]

Something to consider though is the routing of the G3 pipe work if not on an external wall and the cost of having it installed by a qualified installer (Unvented) and you can get a combination thermal store cheaper if you shop arround

 

[Gray0689]

Something to consider though is the routing of the G3 pipe work if not on an external wall and the cost of having it installed by a qualified installer (Unvented) and you can get a combination thermal store cheaper if you shop arround

There also the same problem with overflow from a combination thermal store too mate
Pros and cons with both systems so up to you and your customer to decide what's best for them

 

[ecowarm]

Not the same Gray as the overflow can be run in plastic (cheap) and G3 is Copper 22-28mm plus depending on distance imo

 

[lame plumber]

If they are so keen on a thermal store why not push solar to help reduce running costs esp if they are elec only.