Advice on plumbing a new house

Combi boilers are not compulsory & not always the best solution. Electric showers are usually just about acceptable in terms of flow rate.
If water pressure and flow is decent (20 ltr/min) have a think about unvented dhw.
The trick with pipes in wall (from what i've seen) is to have them emerge behind the rad then terminate to valves with elbows at the bottom. Bend radius in placcie is quite big & best not having elbows in the wall..
 
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oldbutnotdead said:
Combi boilers are not compulsory & not always the best solution. Electric showers are usually just about acceptable in terms of flow rate.
If water pressure and flow is decent (20 ltr/min) have a think about unvented dhw.
The trick with pipes in wall (from what i've seen) is to have them emerge behind the rad then terminate to valves with elbows at the bottom. Bend radius in placcie is quite big & best not having elbows in the wall..
Click to expand...

Why go for unvented? i dont know anything about them tbh but surely a combi boiler is cheapest to run
 
gwebstech said:
Why go for unvented? i dont know anything about them tbh but surely a combi boiler is cheapest to run
Click to expand...
That depends on your lifestyle. If you live on your own and are out all day @ work then probably, if you have a houseful (teenagers especially) then not so sure plus you get all the issues with shower running cold cos someone in the kitchen is running the hot tap.
Combis are space efficient, if you've got space they are less attractive
 
The 2 main options are stored hot water or a combi. You are correct that a combi will only effectively feed 2 hot water outlet at a time, if someone is in the shower and another hot water tap is turned on then there's an issue. If that can be managed within the household then fine.

Alternatively if you want copious amounts of hot water and the ability to run 2 powerful showers and other hot water outlets at the same time then stored hot water would be more efficient and an unvented is the better of those options if your mains has a sufficient supply and you have the space.
 
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Thanks for that guys, you just made my job more complicated lol. The 2 showers is the thing that im most concerned with, also does running hot water affect a combi shower even if the flow rate is higher ie on a higher KW boiler?
 
You're getting into physics here a bit. Consider- the standard combi with its 30-odd KwH DHW heat exchanger is adequate for 1 shower. If you want 2 adequate showers at the same time you'll need a 60 KwH heat exchanger and pipework to suit. Which may not work very efficiently when you only want 1 shower and will defintely cost more to buy. One for you to research really...and there's nothing wrong with combining the systems.
For instance, let us suppose that some of the time there's only you (or you + partner) in the house. For most purposes you'll be using the ensuite. And then some of the time (school holidays, odd weekends, whatever) you have a houseful. One efficient setup for you could be a standard (30KwH HW) combi boiler with the combi bit running the ensuite and the kitchen hot tap, the 'family' bathroom DHW fed by an unvented cylinder (or vented with pump if your water supply isn't up to much). The cylinder can be heated by the heat side of the boiler via a zone valve & programmer so easy to fire it up when its going to be needed, as far as the boiler is concerned it is another radiator.
There's plenty to think about and you're in the ideal situation- blank paper, no current system to consider.....NB You'll need a decent sized cylinder if you want it to run 2 proper showers at the same time- look at 200 litres minimum.
 
oldbutnotdead said:
The cylinder can be heated by the heat side of the boiler via a zone valve & programmer so easy to fire it up when its going to be needed, as far as the boiler is concerned it is another radiator.
There's plenty to think about and you're in the ideal situation- blank paper, no current system to consider.....NB You'll need a decent sized cylinder if you want it to run 2 proper showers at the same time- look at 200 litres minimum.
Click to expand...

Great idea but if im only using the tank for the bathroom shower for example ( the combi powering the ensuite) i can surely do with a smaller tank?
 
gwebstech said:
Great idea but if im only using the tank for the bathroom shower for example ( the combi powering the ensuite) i can surely do with a smaller tank?
Click to expand...
Indeed you can, that's one of the bonuses of using both technologies.
That 200 litre plus note applies if you were going to run the whole house off the cylinder (which depending on your use pattern) might be more efficient (ie cheaper) than the combi plus setup. Modern cylinders (with the moulded jackets) hold heat much better than the old coppers with a loose wrap on top.
You need to check the water supply at the house before making your boiler decision- if the mains pressure/flow is only the statutory required (1 bar 9 ltr/min IIRC, not sure where I read this) then combi and unvented hot water will be disappointing, start looking at big cylinders and big header tanks.
 
oldbutnotdead said:
Indeed you can, that's one of the bonuses of using both technologies.
That 200 litre plus note applies if you were going to run the whole house off the cylinder (which depending on your use pattern) might be more efficient (ie cheaper) than the combi plus setup. Modern cylinders (with the moulded jackets) hold heat much better than the old coppers with a loose wrap on top.
You need to check the water supply at the house before making your boiler decision- if the mains pressure/flow is only the statutory required (1 bar 9 ltr/min IIRC, not sure where I read this) then combi and unvented hot water will be disappointing, start looking at big cylinders and big header tanks.
Click to expand...

thanks, ill check with the water board when they fit it
 
no.

what made you think a combi is cheaper to run?
 
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