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S

serfer

Hi all,

I'm new here and trying to get my head around the selection of boilers as none of them seem to have very detailed spec sheets. My property is off the mains gas grid, with no space for LPG or oil tanks. I can't afford biomass or air source pumps which leaves me with an electric boiler.

I would like the boiler to run the underfloor system, radiators and domestic hot water for a 3 bed, 2 bath home.
I would like it to be a combi boiler.


Anyone got any ideas of a good model?

Thanks!
 
I have no space even to bury the tank.

Moving house use isnt really a helpful idea! I am looking for advice and assistance. I know electric combi may not be the cheapest option in terms of per unit of fuel, and I dont want to discuss running costs, refuelling, installation or servicing costs.

I am just wondering what electric combi boiler would be suited for ufh and rads and domestic hot water. 🙂

thx all
 
No. Cheap rate isnt an option for me as I have huge amounts of electric running during the day / when the rate would be much higher than usual.

I save hundreds on installation and maintenance and I have very little space so combi electric is the way to go. This much i know and i dont need to hear alternatives thx v much for the input, but i really just would like thoughts on good electric combi boilers for rads, ufh and domestic hot water!
 
Simon is right, serfer. Electric combi will not give you anything like the flow rate of a gas boiler. To heat UFH and rads a smallish Amptec will do the trick. Direct unvented for hot water. It's irrelevant that you use loads of electricity during the day - the cheap rate you use during the night will still save you some money. If you're really not concerned about saving money then just run the immersions 24/7.
 
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Look at the electric heating company based in Scotland I've fitted a few of their units and they seem to be ok that said they have only ever been fitted in flats and one guy moved out 8 months later due to running costs.

To to get the heat load you need your going to need a 3 phase supply to run an average house electrics day to day plus allowance for maximum load in winter.

Personally for what your asking/adamant on doing I'd get 2/3 heatrae sadia inline boilers (tall slim pass through type) in tandem linked with an unvented hot water cylinder fed via a heavy duty water softener.

Id is also get solar panels on the roof. I know you've stated that the cost of renewables is out of your range, but you can get them free you won't earn a penny out of them like the people who own them but youll
be making a start on reducing an astronomical running cost.

And nod although you say there is no room for the alternatives, there is always a way always. How can you live of the beaten track cut off from mains gas and not have space? Equally if you are off mains gas I can't imagine you will have an overly adequate electrical supply
 
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I save hundreds on installation and maintenance and I have very little space so combi electric is the way to go.
This much i know and i dont need to hear alternatives thx v much for the input, but i really just would like thoughts on good electric combi boilers for rads, ufh and domestic hot water!
If this much you know why are you bothering to ask on here?
The bit you clearly don't know is the basic laws of science & the limitation of the domestic house electrical supply.

We wouldn't even be recommend that you install a gas fired combi to supply the hot water to your two bathroom house at around 30kW it would provide a very poor hot water flow & not be able to provide the heating at the same time.
Lets just say you went with an electric version.
30kW = 30,000watts / 230Volts = 130 Amps, have you checked the size of your cut out fuse on the incoming electric supply to your house, if not go take a look.
 
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Thanks everyone for the information! Its really helpful to get pro input. I own a little cottage, for me and family to live in, with no land, out in the country off the grid. There has never been a heating system in place - just a few old wood burners.

I have been been investigating heat source and distribution since November and have resigned myself to having no option other than electric. Or 47kg bottled calor gas. I really don't have much room downstairs (trying to start running a business from home that needs equipment and loads of storage) and the loft is 350yrs old and cant take the weight of a tank up there.

Re the electrics - I have just had the PME update for my earth and I'm running 60amps until my metre gets updated when I could go to 100A. The electric hardware, cabling, sockets and all will be done entirely from new next month.

I imagine the 75sqm ufh will be running a lot. 6 Upstairs rads used sparingly if at all. Really dreading the thought of high running costs. Why is combi no good? Is it because it would always be running?
 
Electric is my only option but... I'm wondering why combi would be very expensive to run when compared to another electric system...
 
Why is combi no good? Is it because it would always be running?
Because it take large amounts of energy to heat water instantaneously (4.186J/degC/Litre).

That 30kW gas fired combi I was talking about will deliver something like 12Litres a minute @ a 35deg C rise in Temp just enough to supply one tap properly. If we took all of your current electrical supply & used it all to heat hot water it would be equivalent to a 13.8kW combi (60Amp x 230V=13,800w).
Get the idea ?
Ever used an electric shower ? they are limited to around 10.5Kw for a reason & you don't get a good shower out of them in the winter do you.
 
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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...
 
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...

you dont seem to be listening to anyones advice at present!!
 
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.
 
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?
 
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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:
 
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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!
 
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!
 
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:
 
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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:
 
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.
 
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
 
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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.
 
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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
 
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...
 
also, one more question: why direct cylinder? If i am getting a boiler, wouldn't an indirect be an good option?
 
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.
 
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Aha. Gotchya! So boiler is eg 9 or 12kw. And immersion in a direct cylinder is 3kw. I see i see 🙂. Thx chalky and all
 
so.. is an immersion heater the same thing as a direct cylinder? last question i promise. probably. 🙂
 
also, one more question: why direct cylinder? If i am getting a boiler, wouldn't an indirect be an good option?

No need to get a boiler. You only need a boiler if you are going to be on mains gas. Off-peak electricity is cheaper than all the other fuel types. You just need the cylinder to be sized correctly so it holds enough hot water (i.e. stored energy) to satisfy your hot water/heating demands in the peak rate times. The cylinders in question work in reverse to normal cylinders. The immersion heaters heat the water in the cylinder. The heating circuit water passes through a heat exchanger in the cylinder and takes energy from the cylinder water itself. Make sense?

You can run underfloor heating off these no problem in fact a UFH system works better on these than a normal radiator setup due to the lower temperatures UFH runs at.

Take a look at this system - this would be perfect for you: -

THERMAflow

Make sure you get someone who knows what they are doing to size and install it for you or it will be the most expensive system to run you could imagine.
 
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.

Off peak electricity is much closer than that to the cost of natural gas though. If he doesn't have access to natural gas in the street an off-peak electric system is cheaper to run than LPG or oil.
 
Thanks for the info croft... The thermaflow link is selling me electric combi boilers... Which was my first plan. But the consensus seemed to be to avoid the electric combi due to run it costs.

What at does anyone else think? Is a direct unvented cylinder enough to run 6 rads, 75sqm ufh and dhw? Would a boiler be needed too? Would 9 or 12kw be best... Loads of fun this plumbing malarky! A fair bit to get me head around and thx again for helping
 
Can you have yourself taken off of a thread ???????? this is starting to do my brain in.

serfer please for the sake of god get a local guy to come in explain the options & give you a quote, you are getting yourself all tied in knots & it is certainly not fun, in fact I am starting to think this is a windup.

You keep using the term "combi" a combi to us is a boiler (gas or oil fired) that heats water instantaneously you turn on a tap and we have done that one haven't we??

What croft has suggested is an electrically heated thermal store, the heat is stored in the primary water & can be used to provide heating for the house &/or domestic hot water (taps) via a plate heat exchanger.

An un-vented hot water cylinder can not be used to provide heating for your house only hot water from your taps.

You are right about the cost of peek rate electric when on an Economy 7 tariff it tends to be higher than if you were just on a standard rate but we can't help you with that can we ?? You need to look at you day time usage & get some quotes.

One thing you have found out is just how much "FUN" it is living & working in a small old property in deepest darkest Devon & if you think you are poor now wait to those bills start to roll in.
There was a good reason why they stuck to logs burners !!!!
Now for the very last time bye.
 
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electric combi boilers are common place - they appear all over the internet, and in Croft's link.. it clearly mentions 'electric combi' on the first page...

these electric combis (their word NOT mine) have an internal store of 150 litres or so. so to me it seems like they call it an electric combi, and you guys call it an electrically heated thermal store and thats fine by me, just want to use the right terms to make sure i'm on the same page as you all.

so i want an electrically heated thermal store AND a plate heat exchanger? never heard of a plate heat exchanger, is that a seperate bit of kit, or does it come inside the thermal store?
 
Get a plumber in to talk to you direct on the job and explain as you are not either listening or grasping the concept

Get an electric boiler to do the heating side
And a direct cylinder to do domestic water
 
Thx Gray. I bet this must be painful for everyone and its great this community exists to help folks like me. Electric boiler and direct unvented cylinder. Yes. Got that agree! Sounds great. I understand.

But chris and croft have mentioned a thermal store.

A) you don't agree with their advice
b) a thermal store is another way of describing either a boiler or cylinder...

Theres so many terms its confusing. I dont know if everyone is using different words to talk about the same things or if you actually have fundamentally different solutions to the problem.


Thx again all, you guys are awesome
 
Hi Serfer

Please don't take offence, but from your posts its clear that you have just enough knowledge to be dangerous - either to life and limb, or more likely to your bank balance. Either settle down and do some serious (non-google) research, or take the guys advice and get an expert in.
 
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I'm not a fan of thermal stores
There ok if a secondary heat source is being utilised but if not just an expensive cylinder

Where all different so we all like different things

But unless your house is very well insulated any and all will cost you to run
 
There ok if a secondary heat source is being utilised but if not just an expensive cylinder

Agreed. By far the best use for a thermal store is to integrate multiple heat sources, or (usually on a large scale) to dump the heat from an uncontrolled source.

For most domestic purposes they just add unnecessary complexity.
 
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As I mentioned in post #4.

Unvented direct cylinder, as long as static pressure, dynamic pressure and water flow are satisfactory. Needs to be installed by a suitably qualified engineer.
Amptec for rads.
Amptec for underfloor. This is a specific boiler that runs at a lower temperature for ufh. Theres no point using a normal boiler and overheating the water to kix it to lower temperatures.

The above will take very little room. I did a direct unvented and amptec for 10 rads in a small airing cupboard.
 
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Hello again Simon, I remember the post. Would really need two boilers? Would one boiler running at low temp and feeding both ufh & large surface area rads suffice?

And Ray... The expert i got in suggested electric combi! I actually had a few in. Almost all just wanted to know what I wanted and didnt come with solutions.
 
The silence is deafening isn't it? Besides some confusion over electric combi storage heaters you've been given sound advice and even some basic calculations that you insist on ignoring, questioning or plainly just don't understand.

I'll try one last time, here's what you wrote...

I have been been investigating heat source and distribution since November and have resigned myself to having no option other than electric. Or 47kg bottled calor gas. I really don't have much room downstairs (trying to start running a business from home that needs equipment and loads of storage) and the loft is 350yrs old and cant take the weight of a tank up there.

Given that you say you have no outside land you can't use ground source but did you dismiss bottled gas because you thought you had to store the bottles inside (including those feeding the boiler)? A bottle cage will have the footprint of about four paving slabs and positioned against the outside wall of your home, all you need internally is space for a wall mounted system boiler and a high pressure vessel (which can be positioned anywhere given the right conditions) that will provide all the hot water you'll ever need for both bathrooms. I'd make room for these whatever it takes because frankly irrespective of your business acumen, if you continue to pursue an all electric course (if it's even feasible) whatever money you make will be going towards your electric bill.
 
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electric combis are so called because they combine an electric boiler and a cylinder in one unit hence the term combi they are not the same as a gas combi which is an instantaneous water heater (heat exchanger) combined with a heating boiler
 
So what do you think markfxy? Electric combi is cheaper to run than amptec and cylinder?

And anydad... You have a pretty poor attitude. If you read the above youll see i have explored all the ideas given, and pointed out some confusion and conflicting advice. Not ignoring anyone. I know i can store calor bottle outside, but at 16p per unit its the most expensive option there is. Thx for your time taken to contribute, and I'm sure you know your stuff, but its the least useful post i have had. I'm stuck with electric, just trying to figure out the best way to deal with this reality. Thx again to all!
 
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Hmm... Yup. When i mention amptec above i meant boiler. Sorry! Electric flow boiler plus direct unvented cylinder costs around £1000 inc vat.
Electric amptec electromax combi has internal storage of 150 litres for example weighs in at around £1500...

so i guess i go with the separate boiler and cylinder. A bigger cylinder probably best.
 
There are electric combination boilers which 'combine' an amptec, or similar electric boiler, and an unvented cylinder. Then there are electric combi boilers along the same lines as a gas combi, an elnur gabarron springs to mind. Looks like a gas combi and has a small hot water store.
 
Doh!> > 16p per unit of calor gas, keep up! LPG is 6 or 7p sure but I cant fit the tank anywhere. I've had loads of teams come to the cottage and 16kw high temp daikin or panasonic or mitsubishi is going to cost just under 10k inc vat. If you can do it cheaper, lets talk!

Simon! THANKS AGAIN! There seem to be some of us here who don't know too much about the electric side of things -or maybe i use the wrong terms or jargon gets in the way... whatever.

Still... I'm not sure whether to get the store and boiler together in one unit (what i call electric combi) - or go for a boiler and direct cylinder as separates.

3 beds, 2 baths, 2 kids under 10... underfloor heating of 75sqm, 4 large area rads and 2 little towel rads. i feel we almost have a resolution... ... ...!
 
maybe lpg is calor... but i cannot fit a huge lpg tank on the property. i can dump a few47kg calorbottles outside = but then i pay about 16p a unit, which is just plain daft but there you go.
 
Air source heat pump will be way cheaper to run and if you get an installer that's MCS registered you'l get the RHI payments reducing the payback considerably against an electric boiler
 
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If you have the space you CAN for sure bury LPG or oil tanks. I have no space. Trust me i checked every possible approach.

Msc and and RHI and greendeal are brilliant and totally the future. Makes brilliant financial sense. But i cant afford the upfront whack of 10k.


Electric Boiler with internal storage or electric boiler with direct cylinder. Thats the choice i need to make
 
Walls are 600mm solid stone. Government will tell you its poorly insulated. But thermal mass must count for something. 500mm in the loft. 50mm celotex on floor. Double glazing. Sounds alright to me but won't know til next winter when i live there properly.
 
75mm minimum under floor, build regs. I have solid walls they bleed heat, had thermal image taken, am in process of dry lining wit h 75mm. One room at a time. Best way to spend money is to conserve heat if you can
Also putting new DG windows in. Old ones not efficient and have triple glazed velux windows and 150mm celotex in roof
 
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Celotex do a new under floor insulation that goes
to 50mm. Hope thats gonna be ok.

600mm wall bleeding heat? I'd like to see it! How hot must the inside wall be in order for the outside wall to lose heat? Its stone and cob. I am just wondering about going for a combined electric boiler and store.. Or going for an electric boiler and direct cylinder. Thoughts on that would really help!
 
Electric boiler with internal storage or with direct cylinder makes no difference give it a couple of months and you won't be able to afford to run either,

It will cost you a fortune to heat your place best thing you can do is insulate as much as you can and get a wood burning stove
 
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Got a couple of those already.
Off peak heating of the cylinder must be affordable. And the underfloor and large rads need a lower than usual temperature, so i would have it would be ok...?
 
image.jpg

Six of these and an electric blanket. Oh and a big kettle.
 
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Celotex do a new under floor insulation that goes
to 50mm. Hope thats gonna be ok.

600mm wall bleeding heat? I'd like to see it! How hot must the inside wall be in order for the outside wall to lose heat? Its stone and cob. I am just wondering about going for a combined electric boiler and store.. Or going for an electric boiler and direct cylinder. Thoughts on that would really help!

600mm walls are terrible for heat loss
Not being funny mate but you do seem to be coming across as a know all
Your house is not well insulated so whatever heating you put in is not going to be efficient in the slightest
 
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not coming across as a know it all from what I have read, more of a ......................end. What you need to do is listen to someone who actually knows their stuff local to you, go to a large well established firm and be prepared to spend some money to get things rght
 
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Thats just lame, lame plumb. No-one can agree. Half of the peeps i speak with tell me its going to be cosy. Half say not. Big thick walls... Cob. Straw and mud. You know the best insulator seems to be bales of straw? Dont want to be a know it all, just sharing my experience. People living in these buildings in the village cant even agree. Some are warm. Some cold. Does me bloody head in. Everyone has garden space for a tank except me and me neighbour who live alone in a one bed shoebox and fuels it with 47kg calor bottles for about £150 a month!
 
lovely and warm on a sunny day yes.the black slate roof gets especially warm, i was thinking of putting ducting in the roof ridge to collect hot air and take it back downstairs. Also thinking of hanging more slate on the side of house and running pipe in between slate and house wall, to capture more heat and warm the water that way. not an end solution, but a little help on a sunny day...
 

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