Self Build Advice Please - consumer units, sockets & switches...

[davesparks]

Do you keep a kettle of boiling water ready at all times for those few times during the day when you want a brew ?

No, but a 12kW water heater to fill the kitchen sink is also a little ridiculous when far lower powered instantaneous water heaters exist which will serve the same purpose.

You can now get a tap with a built in 3kW instantaneous heater to provide boiling water on tap, so why would you need a 12kW heater to get water at a around 60degrees?

 

[sean_ork]

No but I don't start up a small nuclear reactor to boil a couple of pints of water either.
And unlike a kettle the type of heater I described is very well insulated so once the thermostat temp is reached the water will stay hot for a long time without further current being drawn.

10l maximum ? then its 10? minutes wait till for more hot water - that's the reason folks want high current instantaneous heating

 

[Dave OCD]

10l maximum ? then its 10? minutes wait till for more hot water - that's the reason folks want high current instantaneous heating

Isn't 10 litres enough to wash your hands, have a shave or wash a few dishes then ?

 

[sean_ork]

You can now get a tap with a built in 3kW instantaneous heater to provide boiling water on tap, so why would you need a 12kW heater to get water at a around 60degrees?

What's the flow rate ?

How many litres does the average kitchen sink hold ?

 

[sean_ork]

Isn't 10 litres enough to wash your hands, have a shave or wash a few dishes then ?

Probably, but doing a few sinks worth of dishes could get tedious

 

[Dave OCD]

Probably, but doing a few sinks worth of dishes could get tedious

Well you shouldn't be lazy and let them build up like that.

 

[davesparks]

What's the flow rate ?

How many litres does the average kitchen sink hold ?

How on earth should I know? You'd need the flow rate at the point of connection to find out what it will be out of the tap!
From experience the boiling water is not noticeably slower than the regular hot from a tap.

Again how the hell should I know the average volume of a kitchen sink?

I'm only asking why such a large amount of power is necessary to achieve the same result as can be achieve with much less power?

 

[davesparks]

Probably, but doing a few sinks worth of dishes could get tedious

I thought the whole point of this was energy efficiency?
Using a few sinks worth of dishes to cook a meal is not very energy efficient when meals can be cooked with far fewer dishes!

 

[Deleted member 26818]

I prefer instantaneous heating over tanks.
RedRing do one that is suitable for 2/3 sinks, or one sink and shower, cost me £145 when I purchased it.

 

[Midwest]

Probably, but doing a few sinks worth of dishes could get tedious

Get a dishwasher :smiley2:

 

[sean_ork]

How on earth should I know? You'd need the flow rate at the point of connection to find out what it will be out of the tap!
From experience the boiling water is not noticeably slower than the regular hot from a tap.

Again how the hell should I know the average volume of a kitchen sink?

I'm only asking why such a large amount of power is necessary to achieve the same result as can be achieve with much less power?

Post a link please, I'll find its flow rate - there's no point getting excited over it if its flow rate is 2 dribbles a fortnight.

 

[sean_ork]

I thought the whole point of this was energy efficiency?
Using a few sinks worth of dishes to cook a meal is not very energy efficient when meals can be cooked with far fewer dishes!

Maybe some folks want a meal that doesn't just consist of toast and beans

 

[davesparks]

Post a link please, I'll find its flow rate - there's no point getting excited over it if its flow rate is 2 dribbles a fortnight.

Quooker is the best known one, but there are other brands out there.

 

[davesparks]

Maybe some folks want a meal that doesn't just consist of toast and beans

??? That's just daft, you can cook a while roast dinner with just a few pots and pans if you know what you are doing.

 

[sean_ork]

Quooker is the best known one, but there are other brands out there.

I suspected you'd say that - you do know there's a small tank hidden away feeding it ? The only advantage of these £1200 taps over the £145 versions is boiling water and a very fancy tap.

3kW just isnt enough to heat water instantaneously for the flow rate required

http://www.quooker.co.uk/enuk

 

[sean_ork]

??? That's just daft, you can cook a while roast dinner with just a few pots and pans if you know what you are doing.

OK let's assume you can do what no one I've ever known has been able to do ........

So what about the 2,4 or 6 folks who sit down to scoff that roast - will they be using any plates, knives, forks, spoons, then there's pudding, that's maybe 6 more bowls and spoons, then there's a cuppa afterwards, then the cheeses and more drinkies ... that's a good few sinks of washing up, average domestic sink capacity of say 25 litres ?

rough calculation - 10 litres of water, say its incoming at 10 degrees, 90 degrees rise required - 3kW element - that's nearer to 20 minutes to raise that volume to near boiling

 

[Leesparkykent]

Why not just have a unvented cylinder with an immersion or even twin immersion? and you could run the shower off it. Small solar thermal setup on the roof to keep it topped up throughout the day with something like the solar iboost so when the pv is producing more than what's being used it also heats the hot water.

 

[davesparks]

OK let's assume you can do what no one I've ever known has been able to do ........

So what about the 2,4 or 6 folks who sit down to scoff that roast - will they be using any plates, knives, forks, spoons, then there's pudding, that's maybe 6 more bowls and spoons, then there's a cuppa afterwards, then the cheeses and more drinkies ... that's a good few sinks of washing up, average domestic sink capacity of say 25 litres ?

rough calculation - 10 litres of water, say its incoming at 10 degrees, 90 degrees rise required - 3kW element - that's nearer to 20 minutes to raise that volume to near boiling

You do your washing up in boiling water?

 

[sean_ork]

You do your washing up in boiling water?

No, but that's an argument against having a tap that produces boiling water

 

[sean_ork]

Why not just have a unvented cylinder with an immersion or even twin immersion? and you could run the shower off it. Small solar thermal setup on the roof to keep it topped up throughout the day with something like the solar iboost so when the pv is producing more than what's being used it also heats the hot water.

Great, until the sun doesn't shine - and then you've got heat loss from the cylinder and the dead legs - which most folks don't seem to mind wasting their money on living in their conventional energy inefficient home, but that's not what the OP wants to build.

 

[davesparks]

Great, until the sun doesn't shine - and then you've got heat loss from the cylinder and the dead legs - which most folks don't seem to mind wasting their money on living in their conventional energy inefficient home, but that's not what the OP wants to build.

Solar hot water setups are surprisingly good even with minimal available sunlight.
With some careful thought as to the layout you could get the dead legs to be fairly short. And a thermal store rather than a conventional cylinder would presumably help too? (they must have come up with something better than the gledhill heaps of junk by now)

I don't think it's so much a case of not minding about living in inefficient homes, but more a case of not knowing and not being able to do much about it if they did.

 

[Leesparkykent]

Great, until the sun doesn't shine - and then you've got heat loss from the cylinder and the dead legs - which most folks don't seem to mind wasting their money on living in their conventional energy inefficient home, but that's not what the OP wants to build.

A well insulated cylinder/thermal store in a well insulated house the the loss of heat is going to be minimal surely? Same applies to the dead legs...pre insulated pipe and legs as short as possible. Solar thermal works well even on the not very best of days, you would be surprised.

 

[janner43]

OK - someone said I had lost interest in the thread. Nope. I'm just not willing to debate the often ill informed comments that have been posted along with the insightful ones.

Only Sean and spinlondon apparently have any real experience of this type of build. Other than the eminently sensible electrical design advice that has been given which I have already said is making me seriously consider changing the rating of the water heaters, 80% of the posts are just argumentative and "you don't want to do it like that". I said I didn't want to debate the design scenario, but there appears to be a lot of interest (or maybe not).

I understand the reasons why folks don't know or haven't considered alternative build or design scenarios. I also understand the uselessness of many of the alternatives that are out there which are only really useful in two cases.
1) Where the environment is harsh and requires it
2) Where the technologies are being fitted as part of a refurb rather than a new build.

Where we live the average winter temperature doesn't fall below 3.7° - Plymouth, England Climate Plymouth, England Temperatures Plymouth, England Weather Averages
As a result, high levels of insulation and air tightness coupled with an efficient MVHR should mean no heating is required over that generated naturally within the home.

These things are calculated properly and scientifically and do not require opinion. If top up heating does prove a requirement, I think you'd agree that adding a 1.5kw panel heater somewhere shouldn't prove too challenging!!!

As it is my home, my opinion on the quantity and frequency of hot water that will be required is such that showering and hand washing are all that should take place. We wash our clothes in a washing machine. We wash our dishes in a dishwasher. What you might do is a matter for you.

We are trying to build a 21st century home - not an 19th century one. We are using state of the art knowledge and techniques. Only one other home has been built in the UK to date using the build method we are using. That was the proof of concept in Scotland. Ours will be the first commercially built home after that.

I have also effectively been called a liar - the first time it was reasonable and put in a polite way and I understood and answered it. After that it is just offensive.

In short, while you guys unquestionably know more about electrical science than I. I am not going to take lessons in the overall design concept or in day to day living paradigms from you, thanks very much.

Finally, again my genuine appreciation to the posters who have helped with their constructive suggestions and observations.

 

[Octopus]

OK - someone said I had lost interest in the thread. Nope. I'm just not willing to debate the often ill informed comments that have been posted along with the insightful ones.

Only Sean and spinlondon apparently have any real experience of this type of build. Other than the eminently sensible electrical design advice that has been given which I have already said is making me seriously consider changing the rating of the water heaters, 80% of the posts are just argumentative and "you don't want to do it like that". I said I didn't want to debate the design scenario, but there appears to be a lot of interest (or maybe not).

I understand the reasons why folks don't know or haven't considered alternative build or design scenarios. I also understand the uselessness of many of the alternatives that are out there which are only really useful in two cases.
1) Where the environment is harsh and requires it
2) Where the technologies are being fitted as part of a refurb rather than a new build.

Where we live the average winter temperature doesn't fall below 3.7° - Plymouth, England Climate Plymouth, England Temperatures Plymouth, England Weather Averages
As a result, high levels of insulation and air tightness coupled with an efficient MVHR should mean no heating is required over that generated naturally within the home.

These things are calculated properly and scientifically and do not require opinion. If top up heating does prove a requirement, I think you'd agree that adding a 1.5kw panel heater somewhere shouldn't prove too challenging!!!

As it is my home, my opinion on the quantity and frequency of hot water that will be required is such that showering and hand washing are all that should take place. We wash our clothes in a washing machine. We wash our dishes in a dishwasher. What you might do is a matter for you.

We are trying to build a 21st century home - not an 19th century one. We are using state of the art knowledge and techniques. Only one other home has been built in the UK to date using the build method we are using. That was the proof of concept in Scotland. Ours will be the first commercially built home after that.

I have also effectively been called a liar - the first time it was reasonable and put in a polite way and I understood and answered it. After that it is just offensive.

In short, while you guys unquestionably know more about electrical science than I. I am not going to take lessons in the overall design concept or in day to day living paradigms from you, thanks very much.

Finally, again my genuine appreciation to the posters who have helped with their constructive suggestions and observations.

Probably because you did little of nothing to persuade the masses that you actually have a sparky involved.......

 

[janner43]

Probably because you did little of nothing to persuade the masses that you actually have a sparky involved.......

Look, I do understand why you and others may be dubious - but then again I have stated that there is an electrician and given you all sufficient background to perhaps trust my word on the matter. I don't have the time or inclination to attempt to convince people who are not going to be convinced in any case.

Neither do I have the time or inclination to, as someone put it "argue with an idiot as they will drag you down to their level and beat you with experience".

Neither am I going to debate further than this reply my personal integrity. The facts I have posted in the OP are true, the whole truth and nothing but the truth.

 

[Octopus]

Back to a sensible question - you made a statement about the property being "sealed" or similar - how do you get rid of unwanted moisture?

 

[telectrix]

Back to a sensible question - you made a statement about the property being "sealed" or similar - how do you get rid of unwanted moisture?

and what happens when all the air has been used up, and he's breathing in CO2?

 

[sean_ork]

and what happens when all the air has been used up, and he's breathing in CO2?

Clearly you don't know what MHRV is, or how it works.

 

[sean_ork]

Back to a sensible question - you made a statement about the property being "sealed" or similar - how do you get rid of unwanted moisture?

It's mechanically recovered by the whole house ventilation system.

 

[DPG]

I think people need to look towards these new ideas rather than ridiculing them and sticking to how things have always been done. If we didn't progress like this then we'd still be living in houses with no cavities and no loft insulation. And we'd still have houses full of 60W and 10W lamps. Daz

 

[janner43]

Back to a sensible question - you made a statement about the property being "sealed" or similar - how do you get rid of unwanted moisture?

and what happens when all the air has been used up, and he's breathing in CO2?

https://en.wikipedia.org/wiki/Heat_recovery_ventilation

Heat Recovery Ventilation the best way to remove and replace stale, moist and unwanted air from your home

:waving:

 

[telectrix]

I think people need to look towards these new ideas rather than ridiculing them and sticking to how things have always been done. If we didn't progress like this then we'd still be living in houses with no cavities and no loft insulation. And we'd still have houses full of 60W and 10W lamps. Daz

best thing since the hindenburg. a bit of savings through heat loss. £3000 to replace corroded wall ties and repoint half the house.

 

[janner43]

best thing since the hindenburg. a bit of savings through heat loss. £3000 to replace corroded wall ties and repoint half the house.

You got that right. On south / western UK exposures, ie West Scotland, West Wales, Cornwall and parts of Devon no-one should install cavity insulation - especially if they have exposed brick.

In other parts of the U.K. it should be alright, but I could take you to two houses I personally know of where the houses are colder after the cavity insulation. One has failing internal plaster because of penetrating damp. The cavity insulation gets wet, the house gets cold.

Not good

 

[sean_ork]

Yet builders are still throwing up shoeboxes faced with brick, just enough FG to satisfy the building inspector, dense block inner, and glueing PB to it.

That's so 1960s

 

[Leesparkykent]

Yet builders are still throwing up shoeboxes faced with brick, just enough FG to satisfy the building inspector, dense block inner, and glueing PB to it.

That's so 1960s

More often your find they are now mostly timber framed. As they are manufactured off site.

 

[sean_ork]

More often your find they are now mostly timber framed. As they are manufactured off site.

Most of them are up here, the kit goes up in two days, but even then there's still the daft preference for a brick outer, sticking to what they know.

 

[davesparks]

Yet builders are still throwing up shoeboxes faced with brick, just enough FG to satisfy the building inspector, dense block inner, and glueing PB to it.

That's so 1960s

That's because the overriding decider in mass built houses is cost, the less it costs to build the more money the developer makes.

Houses built for an individual customer can be built far better if the customer is willing to pay for it, but again people don't like to spend money on sensible things.
It's the same situation we come across as electricians, people begrudge spending a few hundred on improving electrical safety but will happily spend thousands on fancy gadgets to plug in to the ancient sockets etc.

 

[davesparks]

Most of them are up here, the kit goes up in two days, but even then there's still the daft preference for a brick outer, sticking to what they know.

But a brick skin has worked for us for hundreds of years, so we kind of like it.
It does beg the question of what alternatives are readily available?

 

[sean_ork]

That's because the overriding decider in mass built houses is cost, the less it costs to build the more money the developer makes.

Houses built for an individual customer can be built far better if the customer is willing to pay for it, but again people don't like to spend money on sensible things.
It's the same situation we come across as electricians, people begrudge spending a few hundred on improving electrical safety but will happily spend thousands on fancy gadgets to plug in to the ancient sockets etc.

Yep, developers don't care what the ongoing costs are to keep it warm, as long as it takes longer than 10 years to fall apart they are alright jack.

 

[Octopus]

That's because the overriding decider in mass built houses is cost, the less it costs to build the more money the developer makes.

Houses built for an individual customer can be built far better if the customer is willing to pay for it, but again people don't like to spend money on sensible things.
It's the same situation we come across as electricians, people begrudge spending a few hundred on improving electrical safety but will happily spend tens of thousands on a fancy new kitchen

corrected that for you!

 

[Andy78]

Yep, developers don't care what the ongoing costs are to keep it warm, as long as it takes longer than 10 years to fall apart they are alright jack.

And even if there are problems within the 10 years they still don't give a .....
Every new build house less than 10 years old that I have been round to in the last 4 years have been in some sort of years long dispute with the developer.

One of the electrically related ones was a couple who had requested chrome accessories throughout as an upgrade to the standard white plastic. The guy who fitted them was apparently a site sweeper upper. Yeah you guessed it, he chopped all the CPCs off behind all the switches.

 

[Midwest]

Lived in a new house since the late eighties, standard brick construction, cavity (now full of insulation). Never had any issues with it, apart from it wasn't big enough. Gas central heating, and hot water. Not a log cabin in the forest by a lake. Wouldn't float Kevin McCloud's boat, but I couldn't afford his prices.

 

[Midwest]

I'm all for new building designs & systems. My eldest has a heat recovery ventilation system in his flat, not very impressed, albeit probable bodged in. Noisy main box, fan boost for kitchen, bathroom is pants, ensuite is always full of moisture after the shower is used. And I'm used to having the bedroom window open at night, not just to get rid of the fumes!

 

[M-Ty]

I have been abusing a 9.5-kW Redring Powerstream as my whole-house water heater (including bath, takes 20-25 minutes to fill) for 20 years.
A single 12-kW one would be even better. It is fine for washing-up. There would be no need for a separate electric shower. Position it nearest the most frequently-used outlet to minimise waste of cold "dead" water and plumb it to everything else in well-insulated microbore for the same reason would be my recommendation.

 

[davesparks]

Yep, developers don't care what the ongoing costs are to keep it warm, as long as it takes longer than 10 years to fall apart they are alright jack.

Actually it only needs to stand for 7 years before the Nancy warranty runs out [emoji12]

 

[janner43]

I have been abusing a 9.5-kW Redring Powerstream as my whole-house water heater (including bath, takes 20-25 minutes to fill) for 20 years.
A single 12-kW one would be even better. It is fine for washing-up. There would be no need for a separate electric shower. Position it nearest the most frequently-used outlet to minimise waste of cold "dead" water and plumb it to everything else in well-insulated microbore for the same reason would be my recommendation.

Now that is very interesting indeed. Thank you for posting.

I have decided that 3 x 12kW heaters is most definitely overkill & an unnecessary design "risk" and have arranged for them to be returned. Fortunately I am still within the window to receive a full refund on them.

I'm keeping the Gröhe shower, mind you

I'm minded to get 2 x 9.5kW Redring RP1s one for the two basins in the bathroom & one for the utility room & cloakroom.

The kitchen is another story...

Currently I'm thinking this way...
1) Hand clothes washing in the utility will only happen once a week at most. The cloakroom might get used once or twice a day.
2) The basins in the bathroom, certainly for 6 months of the year get used during "non-daylight" hours exclusively and for the shorter days, only once a day when it is light. IE 75% of their use pa will be in the non-daylight hours.

As a result, none of that hot water usage is going to make much use of the Solar PV

3) The kitchen, however, is likely to see 90% of its use during daylight hours, and "she who must be obeyed" is quite concerned that she has hot (50° - 60°) water for pre washing greasy dishes if required. In view of that, we might end up with a 5litre unvented 2/3kW heater for the kitchen. Stiebel-Eltron do one as do Hyco. In both cases, they say they take 12 minutes to heat from cold and then use 500 watts in 24hours to keep hot. That sort of usage is going to make full use of the Solar PV while being negligible as far as design impact is concerned.

 

[1Justin]

Hi Janner..If you are still here.
I got to this thread late. I've been fitting out all the electrics in a Passivhaus this year. I have also installed MVHR. i completely (almost) understand where you are.
I have failed though, reading through things, why you see the need for instant water heating? -The future for our energy grid will only be possible with storage for smoothing. That may be batteries, but it will most certainly require hot water tanks since heating loads are so large. (Obviously crap for all those households which only have the space for stupid combi gas boilers, but they'll feel the pain one day) - So storage also means hot water tanks.

Plus you have PV, - Only a financial consideration, but why not make use of that with a diverter, rather than exporting it at 4p a unit? Solar thermal is also very good indeed. It's not often installed but is about three or four times as efficient as current technology PV (area for area on your roof)

 

[sparksburnout]

Blimey, i have just spent far too long reading this thread. I don't like the sound of this sealed up clinical environment too much, i bet all you can hear most of the time is "shut that bloody door". All this rubbish about not using gas appliances in 20 years time, what a load of crap, what do some people think the average person lives in in the country? Me, I like sitting in front of my roaring open fire, with plenty of stored hot water and a few draughts here and there to keep all the moisture and damp out. The way some people talk you might as well live in a space station. I wouldn't want to rely on me and the missus generating enough heat to keep warm some nights, well most nights, all this smacks of some grand designs none sense to me, designer crap for boring folks with nothing else to do.

 

[janner43]

Hi Janner..If you are still here.
I got to this thread late. I've been fitting out all the electrics in a Passivhaus this year. I have also installed MVHR. i completely (almost) understand where you are.
I have failed though, reading through things, why you see the need for instant water heating? -The future for our energy grid will only be possible with storage for smoothing. That may be batteries, but it will most certainly require hot water tanks since heating loads are so large. (Obviously crap for all those households which only have the space for stupid combi gas boilers, but they'll feel the pain one day) - So storage also means hot water tanks.

Plus you have PV, - Only a financial consideration, but why not make use of that with a diverter, rather than exporting it at 4p a unit? Solar thermal is also very good indeed. It's not often installed but is about three or four times as efficient as current technology PV (area for area on your roof)

Hi Justin,

Glad someone else actually understands what I'm on about - clearly not everyone does or even understands the remotest concept of not wasting the resources we have...

I'd opt for battery storage if it wasn't so expensive. When it comes to immersion heaters I loath them. They seem to me to be a daft way of heating lots of water that we'll never use. As I have said previously, clothes washing happens in a washing machine, dishes in a dishwasher. The amount of hot water we will use in a day isn't likely to be more than 30 litres on a "bad" day. The smallest type of tank is normally 4 times that size!!

No, the water heating is an experiment, I'll grant you, but I believe that the concept is sound. When it comes to export quantity, I am hoping to have a Smart Meter if I can get one, so the typical estimate of 50% for the export tariff shouldn't apply.

Our budget isn't endless and I have tried to only spec the tech that actually works with a cost-benefit analysis - which is why, even though we are in the most expensive area of the U.K. for water, we are not having rainwater reclamation for use in the house. The numbers are just not worth it - nowhere near.

Cheers

 

[Leesparkykent]

Hi Justin,

Glad someone else actually understands what I'm on about - clearly not everyone does or even understands the remotest concept of not wasting the resources we have...

I'd opt for battery storage if it wasn't so expensive. When it comes to immersion heaters I loath them. They seem to me to be a daft way of heating lots of water that we'll never use. As I have said previously, clothes washing happens in a washing machine, dishes in a dishwasher. The amount of hot water we will use in a day isn't likely to be more than 30 litres on a "bad" day. The smallest type of tank is normally 4 times that size!!

No, the water heating is an experiment, I'll grant you, but I believe that the concept is sound. When it comes to export quantity, I am hoping to have a Smart Meter if I can get one, so the typical estimate of 50% for the export tariff shouldn't apply.

Our budget isn't endless and I have tried to only spec the tech that actually works with a cost-benefit analysis - which is why, even though we are in the most expensive area of the U.K. for water, we are not having rainwater reclamation for use in the house. The numbers are just not worth it - nowhere near.

Cheers

30liters on a bad day....do you an your partner not shower at all then?