Electric combi boiler for underfloor heating and rads - off the grid

[serfer]

I'm listening but i get confusing information. I am told that a communism expensive because it needs to heat water instantaneously, but then i am also told that combi boilers have a store and just need to trickle heat in to keep the store nice and hot... The advice is also conflicting about what type and number of boilers i may need too. So while I am listening, when a question mark appears based on that advice, I will follow it up as best i can. I hope rather than personal remarks we can focus
more on answering the questions raised.

 

[Dotty]

Not seen any conflicting advice on this thread, you've been told countless times what you want cannot be done and why.

Have you ever heard of confirmation bias?

 

[SimonG]

I hadnt heard it as confirmation bias before, I normally hear it as 'wont be told'.

 

[lame plumber]

dont you mean, thats not the answer I want, so go away

 

[chris watkins]

We do our best, free of charge to help people, there is no confusion its the laws of science as I have already stated & tried to explain.

Its not our fault you can't take what you are being told onboard & don't know what a combination boiler is.
Sorry me old fruit but I am out of here!!! :waving:

 

[serfer]

I'm just confused as there are different models mentioned above, one mentions a a smallish amptec would suffice, another mentions having 2 inline, one serving each distribution method. Another mentions not even a powerful gas combi would cope. So its a bit confusing!

 

[Masood]

Heating water instantly?
I was hoping to find a combi with an internal store of 50-150 litres that is kept ticking over at a good temperature...

Guess what you've just described? Yep, you got it - a cylinder!

 

[serfer]

If a combi has an internal store - then why would i go for a cylinder? Or rather, if I want a cylinder, then why is the combi a bad idea? I was lead to believe by a plumber not on this forum that a combi would have a store... So i dont know what to make of it all!

 

[Deleted member 64964]

Guess what you've just described? Yep, you got it - a cylinder!

No its a electric combi boiler with thermal store and an immersion to heat it, its completely different to a cylinder. This think you can get in different sizes and is cylindrical in shape. :blush5:

 

[serfer]

thanks Therm! can you sense my confusion? Masood tells me I'm talking about a cylinder. you like his comment, then you say i'm talking about something completely different.

I'm going to look into the cylinder option, unvented direct, as suggested above, but then chris' comment worries me! Chris seems to be saying that i don't have the electricity supply to deal with an electric boiler of any type?

:disappointed:

 

[SimonG]

The irony of it.

 

[Deleted member 64964]

thanks Therm! can you sense my confusion? Masood tells me I'm talking about a cylinder. you like his comment, then you say i'm talking about something completely different.

I'm going to look into the cylinder option, unvented direct, as suggested above, but then chris' comment worries me! Chris seems to be saying that i don't have the electricity supply to deal with an electric boiler of any type?

:disappointed:

Direct unvented cylinder is your best option. Don't worry about any other posts about hot water. That's your best option without doubt.

It's the most cost effective way and once it's hot it's just a matter of a tickle ro get back to temperature.

 

[chris watkins]

Direct unvented cylinder is your best option. Don't worry about any other posts about hot water. That's your best option without doubt.

It's the most cost effective way and once it's hot it's just a matter of a tickle ro get back to temperature.

I know, I know, I said I was out of here but just a word of warning serfer what you have been told a number of times is correct storing hot water in a cylinder is the way to go cos you can use the energy over a longer period & so it doesn't have to be so powerful, most immersions are 3kW you just have to have em switched on for a good fuse hours.

You started by saying you are on a tight budget but you must understand that the installation of an un-vented cylinder (well any actually) is subject to the Building Regulations AD Part G & as such it is both illegal & dangerous to try to install one yourself "YOU HAVE BEEN WARNED"

Get a plumber in who has their ticket & can self cert the install, they can advice you of the best options & limitations.

Bye CW

 

[cr0ft]

If a combi has an internal store - then why would i go for a cylinder? Or rather, if I want a cylinder, then why is the combi a bad idea? I was lead to believe by a plumber not on this forum that a combi would have a store... So i dont know what to make of it all!

I will try my best to explain. As far as electricity goes you have 2 options available to you. Use cheap off-peak electricity to heat your house (last time I checked this was available for as little as 6p/KWh compared to around 15p/KWh for peak rate electricity). There are even Economy 10 tariffs now available that give you 3 off peaks in the afternoon. Use this electricity to power immersion heaters during this time to heat the largest hot water cylinder you can fit in your property. The energy in this is then stored and used when required to run normal central heating, underfloor heating (plumbed not electric) and heat hot water on demand. These modern cylinders are very heat efficient and will retain nearly all of their energy over a 24 hour period.

As you've mentioned already, cylinder installs are more expensive so you would save money initially by not purchasing a cylinder. This saving will be eaten away in no time at all by paying 15p/KWh vs 6p to heat all your hot water and run your central heating. I can't really make this any clearer so I hope it makes sense!! Effectively your cylinder is like a giant energy battery that stores up off-peak energy and uses it in the peak times.

This is the only cheap way to run an all electric house. If you size the cylinder correctly it will be cheaper than any other fuel type except mains gas. If the cylinder is too small you end up using peak rate electricity and the system costs a fortune to run.

My experience in this? We fit these systems fairly regularly and so I know they work and how cheap they can be to run.

At present a 60A incoming supply to your house isn't sufficient to run one of these systems though (they nearly all draw 52A, running 4 immersion heaters at once usually) which doesn't leave enough left to boil a kettle. Ask your supplier to upgrade you to a 100A supply. This is often free if you can demonstrate why you need it.

 

[village idiot]

Phone up any of the major underfloor heating company manufacturers (Uponor, WarmUp, etc) and provide them with your scenario. They are better able to assist you. Good luck

 

[serfer]

Thanks croft! Really useful and very much appreciate your time and patience!
I was lead to believe that economy 7 or 10 would increase my peak rate by quite a lot. So instead of 10p per unit 24/7. I pay 6p for 10hrs and 15p for 14 hrs. My business will be using quite a lot of electric to power the equipment so i wasn't sure about going economy 7 or 10...

 

[serfer]

also, one more question: why direct cylinder? If i am getting a boiler, wouldn't an indirect be an good option?

 

[SimonG]

Have you ever heard of the horse, the water trough and the two bricks?

 

[serfer]

Not yet, no!

 

[Chalked]

Not yet, no!

dont mean to be blunt but! For example.
Why would you use a 3kw boiler to heat a cylinder with pumps etc. that you can heat with a 3 kw immersion heater?

the op needs to realise that electricity is 100% efficient, but costs 3 times per kw than natural gas.