Unvented cylinder size

[Notagainpike]

200/210 or 250l indirect unvented cylinder...

Pros and cons of both please guys, whats the thinking??
Better to go bigger, or are there other considerations to be thought of....?

 

[king of pipes]

Depends on your usage really and how many adults and children in the property usually 45 litres per person.

 

[Timmy D]

You also might want to consider ACV tank in tank cylinders. You can get away with smaller because of their rapid reheat ability.

 

[Notagainpike]

Depends on your usage really and how many adults and children in the property usually 45 litres per person.

Only 2 adults atm!....but we seem to run out of hot water regular....

 

[king of pipes]

Oso cylinders are also a good choice recently fitted this one I'd of thought 210 litres would be enough for 2 people but if your taking long showers and baths stagger the heating and primary heat times or get your system wired for priority hot water . Kop

 

[Last Plumber]

How many bedrooms (how many people could comfortably live there)
Is it likely to increase from the two of you?
Do you both shower or use the bath? If you use the bath is it daily?
Would you shower one after the other?
Average shower time in UK is apparently 7 minutes although personally I can't see how you can be in there that long.
Would you say that's correct?
What boiler is heating this cylinder? Is it a modern condensing boiler?

 

[Enthalpy]

There is a sizing guide on page 12 of the Gledhill STAINLESSLITE PLUS UNVENTED INSTRUCTION MANUAL - DESIGN, INSTALLATION & SERVICING:

https://www.gledhill.net/uploads/StainlessLite-Plus-Manual.pdf

 

[Notagainpike]

Oso cylinders are also a good choice recently fitted this one I'd of thought 210 litres would be enough for 2 people but if your taking long showers and baths stagger the heating and primary heat times or get your system wired for priority hot water . Kop

Looks nice and compact, id not seen these....wired for priority hot water...is this just a change in the control box wiring??

 

[Notagainpike]

How many bedrooms (how many people could comfortably live there)
Is it likely to increase from the two of you?
Do you both shower or use the bath? If you use the bath is it daily?
Would you shower one after the other?
Average shower time in UK is apparently 7 minutes although personally I can't see how you can be in there that long.
Would you say that's correct?
What boiler is heating this cylinder? Is it a modern condensing boiler?

4 bedroom, maybe will at somepoint, yes, both shower, and usually after each other, probably spend way more than 7 mins at a time tbh!
Boiler is a 330i...i think....badged as a british gas...

 

[Notagainpike]

Is the genaral oppinion, that it is better to go for a smaller unit and rely on the fact that they heat recovery is quicker or go for a larger unit and heat more than maybe required, on the basis that heat loss is better than it use to be....

 

[ShaunCorbs]

On a 10 min shower at 10lpm it’s 67l hot etc so even if your doing 20 mins or 20lpm over 10 mins it’s 134l etc

Have a look at eph hot water priority kit

 

[king of pipes]

We should all be trying to conserve water not waste it there will for definite be a water shortage again this year as the weather has been to dry with no rainfall , and global warming 10 - 20 litres a minute is wasting water in my book I always install a 8 litre flow restrictor in shower heads and handsets it enough for a good shower, and save my customers money over the year, priority hot water is a good option as below but your boiler must be compatible to use this type of control and electricians often struggle to wire them mainly because there's not enough wires installed at the boiler or wiring centre . Kop

 

[Last Plumber]

A 150 is plenty in my opinion. Even if there were 4 of you it would probably cope working on 10 litres per min over 7 minutes each shower. Reheat times are quick 70% in around 18 min, full in 26 min depending on make. Don't forget, you are mixing hot and cold. Varies a bit depending on cold temperature and hot store temperature, needs assessing by installer.

I see whopping cylinders in houses these days where there is absolutely no need. Some houses have more hot water than hotels and nursing homes I have worked in.

No point heating large volumes of water just for them to sit losing heat.

 

[Notagainpike]

We should all be trying to conserve water not waste it there will for definite be a water shortage again this year as the weather has been to dry with no rainfall , and global warming 10 - 20 litres a minute is wasting water in my book I always install a 8 litre flow restrictor in shower heads and handsets it enough for a good shower, and save my customers money over the year, priority hot water is a good option as below but your boiler must be compatible to use this type of control and electricians often struggle to wire them mainly because there's not enough wires installed at the boiler or wiring centre . Kop

Valid points taken on board...
So are you saying the smaller cylinder is the best option??

 

[king of pipes]

Yes with the correct control to heat it for 2 of you its plenty .👍

 

[Notagainpike]

Yes with the correct control to heat it for 2 of you its plenty .👍

I see. Thanks for the advice, how would i tell if my boiler is able to be set up for priority hot water?

 

[ShaunCorbs]

With the above kit any boiler is

 

[Notagainpike]

A 150 is plenty in my opinion. Even if there were 4 of you it would probably cope working on 10 litres per min over 7 minutes each shower. Reheat times are quick 70% in around 18 min, full in 26 min depending on make. Don't forget, you are mixing hot and cold. Varies a bit depending on cold temperature and hot store temperature, needs assessing by installer.

I see whopping cylinders in houses these days where there is absolutely no need. Some houses have more hot water than hotels and nursing homes I have worked in.

No point heating large volumes of water just for them to sit losing heat.

A 150l...🤷 really??

 

[Chuck]

A 150l...🤷 really??

That should be enough. Whether it is or not depends on details of usage patterns that only you know, e.g. how many people you have in the house needing showers of what duration and what flow rate and how the demand is distributed over the day.

 

[Notagainpike]

With the above kit any boiler is

I find this stuff well interesting tbh...makes my day job seem well boring

 

[EvilDrPorkChop]

I have 170l on HW Priority and well, it's not enough (Cylinder was existing in house when we bought). 2 People at 20lpm showers. It reheats rapid (Maybe like 10 minutes), but personally if you've got the physical room i'd go with a minimum of 250l. Especially in a 4 bed house.

You don't need fancy controls. You can do it quite simply with a relay that costs £15.

 

[Timmy D]

How many bathrooms?

If 1, another option is to put in a plate heat exchange and go instantaneous with no store of hot water...

 

[Notagainpike]

How many bathrooms?

If 1, another option is to put in a plate heat exchange and go instantaneous with no store of hot water...

1 bath, 1 ensuite, maybe a 2nd ensuite at some point...
Bungalow, so head height is an issue...hww pressure is poor

 

[Notagainpike]

I have 170l on HW Priority and well, it's not enough (Cylinder was existing in house when we bought). 2 People at 20lpm showers. It reheats rapid (Maybe like 10 minutes), but personally if you've got the physical room i'd go with a minimum of 250l. Especially in a 4 bed house.

You don't need fancy controls. You can do it quite simply with a relay that costs £15.

Intetesting, im listening....
🤪

 

[EvilDrPorkChop]

1 bath, 1 ensuite, maybe a 2nd ensuite at some point...

Definitely 200+ then. As I said i'd go 250l.