Combi boiler dying - what next?

[vcps2021]

Hello,

 

I live alone in a 45sqm flat that's about 25 years old and doesn't seem to take a great deal to heat using gas central heating.

 

The boiler is old and dying - I need to decide what to replace it with pretty quickly and given low usage and environmental concerns, I'm seriously considering all electric, knowing it will cost some more to run, but also has some benefits. I hoped to hear other people's thoughts before I take the plunge....

 

So basically I've ruled out an air source heat pump (even with the proposed £5000 grant) as I live in a flat and the people in charge of deciding how we alter our properties are conservative and slow to say the least. This decision needs to happen in days and weeks rather than months (years!).

 

 What I am thinking of doing is getting an instantaneous water heater for the 2 sinks and shower (again, low usage) such as: https://www.stiebel-eltron.co.uk/en/products-solutions/dhw/instantaneous_waterheater/compact_instantaneouswaterheater/dce-x_premium/dce-x_10_12_premium.html

 

For heating, I'm planning on electric radiators or infrared panels, ie https://rointe.com/uk/d-series-wifi-radiators/ or https://www.herschel-infrared.co.uk/

 

My thought process is that although gas is significantly cheaper to run, it's more expensive upfront and takes more yearly maintenance. When your boiler dies it's 4k in one pop but hopefully the electric radiators will have some decent longevity(?) and hopefully can be replaced in a staggered fashion. The higher unit cost is slightly offset by higher efficiency versus GCH and more chance to do zoning out the box. I'm also hopeful (delusional) that our dear leaders will subsidise renewable electricity to make this kind of decision easier to make. As my electricity is from renewable sources, it should be a pretty green setup.

 

If anyone can see holes in my logic, has some opinions on this or knows any grants available for ditching gas, I'd be happy to hear. There's a lot of research for me to do here but experience of others is more valuable than research alone. 

 

Thanks!

[SteamyTea]

Be wary of IR heating.

If it was so brilliant, we would not have panel and fan heater.

Have you considered storage heaters, they have moved on since the 1980s.

 

Maybe discus with landlords again  tell them there is free money to be had.

[Conor]

Sounds like a candidate for economy 7 overnight water heating and storage heater charging. Lived in an apartment just like you describes and there were only two storage heaters and a small, well insulated hot water tank. Worked perfectly and bills were very low. 

 

I think you'll need to maximise use of off peak electric - it's the cheapest and least carbon intensive.

[TonyT]

Sounds like you would be better off just installing a new boiler.

 

if you clarify who the people make changes are slow etc as  you will need additional cabling/ equipment to go electric and if that’s the attitude of say a landlord the cheapest option is straight swap with a new boiler.

 

 

 

 

 

[vcps2021]

Thanks for all the replies - I more or less decided against economy 7 (and therefore storage heaters) as I'm working from home more now and use electricity through the day too - that's a shame as I think it would be a good solution.

 

Yes, the electrics needing to be upgraded is something I haven't costed yet or thought about what the landlords attitude will be.

 

I'd likely be better off financially with another gas boiler but not by a huge amount when you factor in maintenance, large upfront cost and inherent inefficiency of a GCH system. I'm interested in the green perspective at least as much as the financial....

[TonyT]

Landlord should pay the maintenance!

if you are the tenant why are you doing all the coatings?

strange 

Edited October 19, 2021 by TonyT

[ProDave]

Can you clarify the term "landlord" used in this discussion.

 

Are you really a tenant?  Or do you own the leasehold of the flat and the "landlord" you refer to is the freeholder?

[vcps2021]

Sorry for confusion, yes ProDave, I meant freeholder.

[Mr Punter]

With Economy 7 the night rate is 41% less but the rest of the time it is 16% more.  Nobody in a flat wants to cook their meals or do the laundry at midnight so it can often end up costing more.

[SteamyTea]

2 hours ago, Mr Punter said:

Nobody in a flat wants to cook their meals or do the laundry at midnight so it can often end up costing more.

My house is a similar size to the OPs flat (48m²).

I do my laundry at night, and I sleep though it.

5 hours ago, vcps2021 said:

I'm working from home more now and use electricity through the day to

How much do you think you use during the day?  I work evenings, only use a couple of kWh during the day, and often less.

80% of my energy is at the night rate.

[Mr Punter]

3 hours ago, SteamyTea said:

My house is a similar size to the OPs flat (48m²).

I do my laundry at night, and I sleep though it.

 

But if you were in a converted flat or even purpose built over 15 years old your neighbours would not thank you.

3 hours ago, SteamyTea said:

only use a couple of kWh during the day, and often less.

 

Lots of people work at home.  Up, shower, breakfast kettle toaster, kettle again hairdryer lunch, microwave, fridge, computer printer, TV, lighting, cooker.  Face it there is no way a normal person consumes 80% of their electric between midnight and 7:00 AM.  Post up your last 3 bills and it will either prove me right or prove that you are not normal.

[Temp]

12 hours ago, vcps2021 said:

When your boiler dies it's 4k in one pop

 

How big is this boiler? 

 

A 25kw combi is £820 from screwfix. Plus fitting obviously.

 

Oh and British gas will let you pay monthly (9% interest).

Edited October 19, 2021 by Temp

[vcps2021]

I'm typically in front of my computer by 8, till 6  with all the toaster/kettle/lighting/fridge stuff mentioned by Mr Punter.

 

Probably the quote for nearly 4k is a bit of a one off as I'd planned to put the flue through the roof this time to make positioning the boiler higher up more simple. It would be 24w.

 

Does anyone have any experience with devices like this?: https://www.stiebel-eltron.co.uk/en/products-solutions/dhw/instantaneous_waterheater/compact_instantaneouswaterheater/dce-x_premium/dce-x_10_12_premium.html

 

It looks like such an easy solution for 2 sinks + 1 shower and if it has reasonable performance and lasts then I think it might work well for me....

 

For me it's not just about the running cost but balancing that with doing a greener option and still living comfortably,

 

Thanks!

 

 

[Carrerahill]

On 19/10/2021 at 11:34, vcps2021 said:

Hello,

 

I live alone in a 45sqm flat that's about 25 years old and doesn't seem to take a great deal to heat using gas central heating.

 

The boiler is old and dying - I need to decide what to replace it with pretty quickly and given low usage and environmental concerns, I'm seriously considering all electric, knowing it will cost some more to run, but also has some benefits. I hoped to hear other people's thoughts before I take the plunge....

 

So basically I've ruled out an air source heat pump (even with the proposed £5000 grant) as I live in a flat and the people in charge of deciding how we alter our properties are conservative and slow to say the least. This decision needs to happen in days and weeks rather than months (years!).

 

 What I am thinking of doing is getting an instantaneous water heater for the 2 sinks and shower (again, low usage) such as: https://www.stiebel-eltron.co.uk/en/products-solutions/dhw/instantaneous_waterheater/compact_instantaneouswaterheater/dce-x_premium/dce-x_10_12_premium.html

 

For heating, I'm planning on electric radiators or infrared panels, ie https://rointe.com/uk/d-series-wifi-radiators/ or https://www.herschel-infrared.co.uk/

 

My thought process is that although gas is significantly cheaper to run, it's more expensive upfront and takes more yearly maintenance. When your boiler dies it's 4k in one pop but hopefully the electric radiators will have some decent longevity(?) and hopefully can be replaced in a staggered fashion. The higher unit cost is slightly offset by higher efficiency versus GCH and more chance to do zoning out the box. I'm also hopeful (delusional) that our dear leaders will subsidise renewable electricity to make this kind of decision easier to make. As my electricity is from renewable sources, it should be a pretty green setup.

 

If anyone can see holes in my logic, has some opinions on this or knows any grants available for ditching gas, I'd be happy to hear. There's a lot of research for me to do here but experience of others is more valuable than research alone. 

 

Thanks!

Get another combi boiler.

[Iceverge]

On 19/10/2021 at 11:34, vcps2021 said:

So basically I've ruled out an air source heat pump (even with the proposed £5000 grant) as I live in a flat and the people in charge of deciding how we alter our properties are conservative and slow to say the least. This decision needs to happen in days and weeks rather than months (years!).

 

There are options for a heat pump with only ducting to the outside, No need for an outdoor unit.  

https://www.jouleuk.co.uk/victorum-exhaust-air-heat-pump-pre-plumb-system/

 

 

To be honest I think your idea is fine. You may struggle to get large flow rates with an instant water heater, but if you can live with it you will avoid annual inspection charges which will forms a large part of your set up as is. 

 

If you have a record of your average usage with gas it's simply a matter of doing the maths for electric and/or heat pump. 

 

 

  

[Carrerahill]

On 19/10/2021 at 11:34, vcps2021 said:

Hello,

 

I live alone in a 45sqm flat that's about 25 years old and doesn't seem to take a great deal to heat using gas central heating.

 

The boiler is old and dying - I need to decide what to replace it with pretty quickly and given low usage and environmental concerns, I'm seriously considering all electric, knowing it will cost some more to run, but also has some benefits. I hoped to hear other people's thoughts before I take the plunge....

 

So basically I've ruled out an air source heat pump (even with the proposed £5000 grant) as I live in a flat and the people in charge of deciding how we alter our properties are conservative and slow to say the least. This decision needs to happen in days and weeks rather than months (years!).

 

 What I am thinking of doing is getting an instantaneous water heater for the 2 sinks and shower (again, low usage) such as: https://www.stiebel-eltron.co.uk/en/products-solutions/dhw/instantaneous_waterheater/compact_instantaneouswaterheater/dce-x_premium/dce-x_10_12_premium.html

 

For heating, I'm planning on electric radiators or infrared panels, ie https://rointe.com/uk/d-series-wifi-radiators/ or https://www.herschel-infrared.co.uk/

 

My thought process is that although gas is significantly cheaper to run, it's more expensive upfront and takes more yearly maintenance. When your boiler dies it's 4k in one pop but hopefully the electric radiators will have some decent longevity(?) and hopefully can be replaced in a staggered fashion. The higher unit cost is slightly offset by higher efficiency versus GCH and more chance to do zoning out the box. I'm also hopeful (delusional) that our dear leaders will subsidise renewable electricity to make this kind of decision easier to make. As my electricity is from renewable sources, it should be a pretty green setup.

 

If anyone can see holes in my logic, has some opinions on this or knows any grants available for ditching gas, I'd be happy to hear. There's a lot of research for me to do here but experience of others is more valuable than research alone. 

 

Thanks!

4K in one pop sounds an awful lot based on your demands.

 

A boiler for your house will be about £800-1200 - allow a day to fit plus materials, maybe £250-350 -  Total cost best: £1050 - worst £1550.

 

https://www.screwfix.com/p/worcester-bosch-greenstar-28cdi-gas-compact-combi-boiler/446KP?kpid=446KP&ds_kid=92700055281954502&ds_rl=1249404&gclid=CjwKCAjw_L6LBhBbEiwA4c46uot8sKvS-1z55CQdbyDHMPm-Uzw9UyHz90IdPmFU3kQs6oXGSEQOehoC4RsQAvD_BwE&gclsrc=aw.ds

 

Anyone who tries to sell you new pipework, new radiators, new everything, is at it and needs to be removed from your list of potential installers.

 

Get onto some local plumbers with some good reviews and talk to them, tell them you want a boiler out and a boiler in, that is what you want nothing else, when they start to tell you what else you will need politely decline and move on. If you get the nonsense about gas line size them do your own research, even phone the manufacturer and ask for the spec to be confirmed. Often 22-28mm pipes are talked about these days, however a short run of say 15mm with radiused bends, not 90° elbows, may be suitable. I cannot remember the figures but for every bend they say add a metre or something like that, gentle radiused bends can be ignored. Apparently I needed a 22mm gas pipe, I did the calc and needed a 15mm!

 

A good number of my neighbours have had new C/H systems installed over the past 5-6 years. The majority of the jobs start with piles of copper pipe going in and lots coming out. When I speak to them and ask about the new pipework most of them have said, "Oh well the company told me I needed it as the piping was over 20 years old and it will be clogged and they cannot guarantee the new boiler because Viessmann or Bosch etc. won't allow a new boiler on an old system." At that I am usually left angry they have been ripped off.

 

I realise there are sometimes times where new rads and pipework are needed.

 

I was at a building industry seminar/fair type thing for housing associations a number of years ago, I was there giving a talk but the rest of the time I was just wandering about, looking at the stands, and mainly asking businesses like Tesla and Wylex and Vent-Axia about products with an eye for my own build. I went to the Worcester Bosch stand and asked them about replacing boilers, explained the whole new systems being installed thing and they looked at me blankly and said, nope, nothing we spec, they just recommend a flush IF the system shows signs of dirty water/sediment and then a filter is retrofitted. Viessmann were the same. They agreed it was just greedy contractors pulling the wool. 

 

Boilers are funny things, people get very serious about them, it's like the big bad monster in the room no one dares to question and people just blindly go with what they are told. The fact is they are just a gas burner, heat exchanger a pump and some pipework with some controls. They are simple beasts.

 

I think you will regret electric heating in the longer run. 

 

Have you also taken into consideration the cost of the 6-12kW (depending on model) supplies you will need run in around your house for the instantaneous hot water heaters? You say you live in a flat, is there good easy access to run the potentially 10mm^2 cables about your house and does your consumer unit have spare ways for 2 No. additional high current circuits? 

 

Also note your electricity is not only from renewable sources, your supplier only buys from renewable sources so they are buying renewable, but you will still use Nuclear, Coal, Gas, Oil etc. it all comes from the same cable, please be under no illusion you are getting solar or wind or tidal generated electricity coming into your house because you have signed up to a renewables only supplier.

 

It is like buying eggs, the egg suppliers go and buys eggs from farms, some are organic, some are organic freerange, some are battery, some are organic battery, some from ultra happy hens living in a small holding with 4 other hens and get to run about the warm kitchen in the winter. Then everyone buys 10 eggs from the egg suppliers, however, everyone just then goes to the skip and takes out 10 eggs at random...

 

You did ask if anyone saw holes in your logic so I hope this is not seen as being too critical!

 

 

Edited October 20, 2021 by Carrerahill

[Temp]

4 hours ago, vcps2021 said:

Does anyone have any experience with devices like this?: https://www.stiebel-eltron.co.uk/en/products-solutions/dhw/instantaneous_waterheater/compact_instantaneouswaterheater/dce-x_premium/dce-x_10_12_premium.html

 

They are rated at 10/12kw so performance should be similar to a 10/12kw electric shower.

[Nickfromwales]

Replace the boiler. Combi out > combi in should be change of £2k with new TRV’s + stat, magnetic filter and a gas pipe upgrade etc ( post-code allowing ). I’ve not yet seen MI’s ( in over 20 years of heating that allow a 15mm pipe to a combi as they’re so gas hungry in DHW mode. They used to say it’s ok to do a gas rate check at the appliance, ergo a short-ish run of 15mm before the appliance would be permissible. They binned that and now ask for 22mm to the appliance as other gas-burning appliances that share the same gas run may not be taken into consideration with the earlier prescribed methods. These days it is 22mm ( or larger depending on the length of the run vs boiler kW rating ), so you are guaranteed the gas delivery that is sufficient for the stated max hot  water rates. 

The radiators you linked to are going to heat linear with demand so you won’t he able to completely strategise your off-peak heating during winter. Bad idea IMO. 

The instant water heater will be pathetic on a good day, and completely useless when any other tap is open anywhere. Seriously bad choice. Conversely I have recently fitted the 3-phase brother of that ( the 27 ) and it is staggeringly good for an instant. uses 32a per phase!!!! If you had 3-phase I would recommend one of these in a heartbeat. Amazing bit of kit. ?. 
 

Fit a new gas boiler, and if you want to show off get a WB unit which can be Hydrogen Ready. 

[vcps2021]

Thanks for all replies.

@Nickfromwales - is this the one you got?

https://www.elementshop.co.uk/stiebel-eltron-dhe-27-204285-set-three-phase-touch-instantaneous-water-heater-4i-technology#reviewsTab

This is all new tech to me and I have no idea what the difference really is and what the 3 phases mean. It sounds good and I'm open to this one if it'll better suit my needs, although I live alone so rarely will run into the shower and tap running at the same time issue.

@Carrerahill - more than happy to hear the flaws in my thinking.....at least before I take the plunge! I realise there are not 2 separate grids for green elec and coal/gas powered elec but by choosing a renewable plan, the electricity is purchased from a renewable source and put into the grid, thereby increasing the amount of green electricity in the grid overall - I think that's a good thing.

@Iceverge - thanks for this - I'll go through the gas bill next

[SteamyTea]

10 minutes ago, vcps2021 said:

but by choosing a renewable plan, the electricity is purchased from a renewable source and put into the grid

Or they have bought carbon offsets from companies like Tesla.

Customer choice has little effect on RE generation capacity. Legislation is what is driving this.

 

3 phase is basically 3 separate electric supplies (they are connected, but offset by 120⁰, at the generator). So expensive to  install and pay the ongoing meter rental.

 

You can get an instantaneous, inline heater that can take a hot water supply. So a small cylinder, heated at night on E7 (or other time of day) may be possible.

But look at reduction first.

Not many people really need a half hour shower at 20 litres/minute flow rate. 3 minutes at 8 l/min would get the normal dirt off.

 

[Nickfromwales]

4 hours ago, vcps2021 said:

@Nickfromwales - is this the one you got?

Yup. Same supplier too. 
If you have a single phase electricity supply ( the most commonly found type ) and no 3-phase then you cannot install that unit I’m afraid. 

Edited October 21, 2021 by Nickfromwales

[vcps2021]

On 21/10/2021 at 13:54, SteamyTea said:

On 21/10/2021 at 13:37, vcps2021 said:

but by choosing a renewable plan, the electricity is purchased from a renewable source and put into the grid

Or they have bought carbon offsets from companies like Tesla.

Customer choice has little effect on RE generation capacity. Legislation is what is driving this.

 

I need to read up on this more but seems like Octopus energy are one of the better companies - hope I'm right there....

 

 

On 21/10/2021 at 13:54, SteamyTea said:

You can get an instantaneous, inline heater that can take a hot water supply. So a small cylinder, heated at night on E7 (or other time of day) may be possible.

But look at reduction first.

 

Do you know of such an instantaneous heater? I'm googling but not sure I'm using the right search to be honest...

 

Thanks!

[SteamyTea]

4 hours ago, vcps2021 said:

Do you know of such an instantaneous heater

I think our old mate Jeremy Harris had a Stiebel Electron one that was plumbed in after his cylinder.

 

I think he found he did not need it and someone on here had it off him. @ProDave I think.

Edited October 23, 2021 by SteamyTea