The Dash Away From (Natural) Gas

[Black Hole]

Coincident with the announcement of grants for heat pump heating systems, my gas combi boiler has been declared beyond economic repair (radiators seem OK, but it's struggling to supply consistent hot water). Granted it's over 20 years old, but I threw £1400 at it for a major rebuild less than 5 years ago. This puts me right at the spearhead (when I prefer to be behind the curve - let other people be guinea pigs).

I shall be getting a second opinion on the boiler, but...

Replace: Moderately expensive; relatively quick and easy; not future-proofed; subject to gas price hikes.​

​

Air-sourced heat pump: Very expensive; significant engineering and adaptations required; high-maintenance.​

​

Ground-sourced heat pump: Enormously expensive; significant engineering and adaptations required; high-maintenance; probably not enough space available for the necessary groundworks; opportunity to replace the patio.​

​

Per-room heat/cool aircon: Noisy, and I guess expensive to run.​

​

Electric combi boiler (is there such a thing?): Quick and easy; expensive to run?​

​

Electric hot water (reinstall hot cylinder system?) + electric rads/heaters: Least maintenance! No more corroding radiators, thermostatic valves, diverters, circulators... Can add roof-mounted solar collectors to heat a hot cylinder at later date.​

Input/discussion welcome.

 

[4ndy]

I was surprised to hear on Radio 5 this morning that air source heat pumps use quite a lot of electricity. Fewer kw than gas boiler, but currently about 5 times cost per kw, so no financial gain to offset higher installation cost.

Also need hot water tank, so not easy replacement for combi boiler system.

Sent from my SM-G991B using Tapatalk

 

[MikeSh]

Per-room heat/cool aircon: Noisy

And a heat pump for warm water won't be?
Lot of complaints about about noise, not least from neighbours.

TBH at the current state of development I'd stick with a gas boiler for now. In 10 years things will be different, hopefully better, and you can revisit it if you are still alive. (Even if they are still noisy at least then you won't be the first to be a local pariah )

 

[EEPhil]

I always wondered whether there is an electric combi boiler. Just replace the gas one with electric and bingo. No mucking about with pipework etc. Still moving mucky hot water around all over the place. Probably more expensive to run if it did exist. With gas providing some electricity generation electricity prices are likely to rise a lot as well. I'm glad that before I moved, when the gas boiler was condemned, I insisted on a replacement keeping the hot water tank. We had hot water nearly on demand just by heating the tank for a couple of periods during the day. Where I am now, on demand heating of hot water. Yeah, right! Turn on hot tap to fill a bowl of water for pot washing. Cold water...wait...cold water...wait...cold water...wait...tepid water...wait...moderately warm water...wait...get fed up, fill the bowl with water not hot enough to do the job. What a waste of water! Can't seem to turn the boiler temperature up (wonder if it has been limited to stop us older people scalding ourselves?). Pre-heating doesn't achieve the aim either. Wish I still had a hot water tank.

In any case, the government hasn't provided enough money to make a significant dent in the boiler population. If I read the story correctly, some of the money is earmarked for insulating social housing. So how many conversion grants will be available?

 

[Black Hole]

And a heat pump for warm water won't be?
Lot of complaints about about noise, not least from neighbours.

Yeah, heat pumps might work if you live out in the wilds with nobody around for miles...

Also need hot water tank, so not easy replacement for combi boiler system.

The hot tank isn't much of a problem, it can go back in the airing cupboard where it always used to be (and where the combi is). But getting pipework (etc) to there from where an outdoor unit would have to be sited would be a whole 'nother ballgame.

With gas providing some electricity generation electricity prices are likely to rise a lot as well.

Dependence on gas for electricity should decrease over time, but we had a major issue with renewables when the wind wasn't blowing and the sun wasn't shining either.

The old combi which was replaced about 20 years ago had very little to go wrong, but relied on an electric circulator for the rads. It annoyed me that if there was a power cut there was no heating. The "new" combi won't even ignite if there's a power cut! So it's not like the gas provides fall-back. I can't help thinking a dry heating system is the way to go, even if it does cost more to run.

 

[RobH1]

TBH at the current state of development I'd stick with a gas boiler for now. In 10 years things will be different, hopefully better, and you can revisit it if you are still alive. (Even if they are still noisy at least then you won't be the first to be a local pariah )

I agree.

 

[4ndy]

​ Dependence on gas for electricity should decrease over time, but we had a major issue with renewables when the wind wasn't blowing and the sun wasn't shining either. Do you think so? Won't we all be charging our electric cars? Particularly overnight, when solar is not working. The TV ad says can charge car overnight for less than a fiver. A fiver is about a day and a half extra usage in my house. Multiply that by perhaps 2 charges a week and there is clearly going to be more demand than renewable sources can meet, even discounting cloudy skies and periods of low wind.

 

[Ezra Pound]

the government hasn't provided enough money to make a significant dent in the boiler population. If I read the story correctly, some of the money is earmarked for insulating social housing. So how many conversion grants will be available?

They have set a maximum of 90,000 5K grants - and the number of gas uses is 25 million

 

[MartinLiddle]

Electric Combi boilers exist; see for instance Link to Screwfix ; I have no idea how useful they are in practice. In Black Holes situation I would be tempted to fit one of the cheaper gas combi boilers with the idea of being able to review the situation in ten years or so. A recent Which review suggest an Ideal boiler might be suitable.

 

[Ezra Pound]

Now I know why we don't see much in the press about electric heating boilers, not only is it 5 - 6 times the price to run, it also looks like domestic premises aren't capable of supplying the power, the biggest single phase (63 A) boiler in the link above only supplies 14 kW, whereas average gas boilers tend to be 20 - 25 kW or more

 

[everthewatcher]

Cold water...wait...cold water...wait...cold water...wait...tepid water...wait...moderately warm water...wait...get fed up, fill the bowl with water not hot enough to do the job. What a waste of water!

That's odd - combi boilers usually have small tank of hot water to bridge the gap until the heat exchanger comes up to temp. However if there's a long pipe run from boiler to outlet then there's your problem.

FWIW combi boilers can be used with a conventional hot water store - it just needs an installer that knows what they're doing. The combi/instantaneous part supplies the nearest outlet, say kitchen and/or utility room, the hot water store supplies everything else.

 

[Black Hole]

If I did ditch gas it would save me the standing charge.

 

[EEPhil]

FWIW combi boilers can be used with a conventional hot water store - it just needs an installer that knows what they're doing.

That’s what I had installed at the old house.

That's odd - combi boilers usually have small tank of hot water to bridge the gap until the heat exchanger comes up to temp. However if there's a long pipe run from boiler to outlet then there's your problem.

The boiler’s right next to the bathroom and the hot water is ok. The kitchen is not very far from the boiler but it takes ages for the water to heat up. There is a hint of warmth then it goes cold and then it’s as I described. I’ve no idea where the pipes have been routed. Outer Mongolia probably, the time it takes to heat up. I had to have a gas engineer in to commission the boiler when I moved in. Then another one came to check up on the first one. I watched the check and we did see the boiler come on when the hot water tap was turned on. Who knows why I have to waste so much water to wash my pots. At least the water isn’t metered. Not very environmentally friendly though.

 

[MikeSh]

Now I know why we don't see much in the press about electric heating boilers, not only is it 5 - 6 times the price to run, it also looks like domestic premises aren't capable of supplying the power, the biggest single phase (63 A) boiler in the link above only supplies 14 kW, whereas average gas boilers tend to be 20 - 25 kW or more

If you have, or get, a 100A supply it's doable ... just about. People who already have a 7kW/32A shower and then add a 7kW EV charge point can have trouble if they are on an 80A incomer, and it's a non-starter on a 60A of course.
Quite often the actual cabling is good for it and it just needs the DNO to fit a bigger fuse, but it can get very interesting because a lot of it is down to the opinion of whoever is looking at it.
(Oh, and also that 100A written on your main fuse carrier doesn't necessarily mean you have a 100A supply. It's usually the rating of the carrier, so unless there is some other label or documentation (from a test perhaps) someone needs to pull it out out to see what the actual fuse inside is rated.)

 

[Ezra Pound]

You would also need to find a single phase 240V electric boiler that uses 100A, Strom don't make one :-

 

[everthewatcher]

...and it just needs the DNO to fit a bigger fuse, but it can get very interesting....

Particularly if, as here in a '82 link-detached house, it's on a looped service/supply. Main fuse is 80A which was probably OK back in '82 taking taking diversity into account, but these days with >9kW showers it's a different matter. Which is probably why UKPN in their documentation on looped services say that 60A fuse must be fitted.

As for power showers and vehicle chargers on 60A services, there's a load-sharing device available (and probabaly more) that disconnects the charger when the shower is used.

 

[RichFX]

Coincident with the announcement of grants for heat pump heating systems, my gas combi boiler has been declared beyond economic repair (radiators seem OK, but it's struggling to supply consistent hot water). Granted it's over 20 years old, but I threw £1400 at it for a major rebuild less than 5 years ago. This puts me right at the spearhead (when I prefer to be behind the curve - let other people be guinea pigs).

I shall be getting a second opinion on the boiler, but...

Replace: Moderately expensive; relatively quick and easy; not future-proofed; subject to gas price hikes.​

​

Air-sourced heat pump: Very expensive; significant engineering and adaptations required; high-maintenance.​

​

Ground-sourced heat pump: Enormously expensive; significant engineering and adaptations required; high-maintenance; probably not enough space available for the necessary groundworks; opportunity to replace the patio.​

​

Per-room heat/cool aircon: Noisy, and I guess expensive to run.​

​

Electric combi boiler (is there such a thing?): Quick and easy; expensive to run?​

​

Electric hot water (reinstall hot cylinder system?) + electric rads/heaters: Least maintenance! No more corroding radiators, thermostatic valves, diverters, circulators... Can add roof-mounted solar collectors to heat a hot cylinder at later date.​

Input/discussion welcome.

Since 1975 I've had an air heat exchanger running 24/7 for domestic ventilation; warm wet smelly air from bathroom and kitchen goes out, transfers useful amount of heat to clean fresh outside air coming in to bedrooms and living room typically at 16C to 18C for much of the year, except hottest summer when its set to extract only. Two fans using about 20W each, heat recovery up to about 1KW, and we don't need to leave windows open in a draft-free house. I have a three stage filter (particulates, pollen and charcoal layer) on the inlet side. It has gone through a few fan motors, filters need regular attention, and I added silencers to the ducts. It has paid for itself many times over.

In 2017 I bought an Electriq elQ-9WMINV-QC two-part air-con / heat-pump. It has a gain of about 6W/W for cooling and 4W/W as a heat pump depending on outside air temp. However if the air drops below about 8C then the efficiency begins to drop off and eventually it will deliver ordinary electric heat when air is below -7C. So the air heat-pump is a non starter for really cold weather. I improved the sound deadening on the outside unit quite a lot with some appropriate Silent Coat. We tend to only use it for a few weeks in the year, enough in the cold weather to keep the seals etc working as well as keeping us cool in summer. It may not be economical, but it is a luxury worth every penny to keep cool!

The igniter on my heat only (avoid combis like the plague) gas boiler was walking wounded, becoming more stumbling, but it looked like a fan speed sensor fault, fortunately the Vaillant man did an excellent job in diagnosing and fixing the fault, but for the three days waiting for him over last weekend the heat-pump kept quite a lot of the ground floor at 21C and was typically only using about 300W while doing so. However hot water was on an immersion heater, at 3KW for three of us in the house, much more expensive than the gas would have been.

Fitting the 24HXi condensing gas boiler in 2005 dropped the annual gas consumption by 35%. Last week was the first time it had a wearing-out fault that finally stopped it working. The house has three timed zones that can call for heat: upstairs, downstairs, and hot water tanks local to bathrooms (short hot water pipes).

Insulating the ground floor ceilings eleven years ago was another excellent optional improvement we've made to the house. Comfortable cool bedrooms at last despite loads of loft insulation, with comfortable warm living areas below them. Gas consumption dropped another 15%. from the pre-condensing boiler average

 

[everthewatcher]

That’s what I had installed at the old house.

Ah, OK.

Conventional vented hot water cylinder here. I was thinking about a mains pressure one but the old copper cylinder failed unexpectedly so I had to put in a normal but stainless one in a hurry.

On the list of things to do is re-route the pipes to/through the kitchen as the hot water run is 3m longer than it could be, which may not contain that much water but it's still 3m of copper pipe to warm up. The downstairs loo had a similar problem - turn on the tap as you close the door and you'd have warm water by the time you'd done - so there's a 3kW handwash unit going in.

 

[Black Hole]

My Worcester-Bosch Highflow is now inoperable. CH was OK, but less vital than hot water. When trying to provide hot water, it had got to the point where it was going into overheat fault and tripping out, then "rebooting", resulting in multiple ignition cycles and the inevitable occasional ignition failure.

When it goes into ignition fault, it has to be reset by turning a control knob down and up again, but the plastics are so brittle now that the shaft broke. Even power-cycling doesn't clear the ignition fault, it has to have the knob cycled. I went in to (try to) fix it, but it was like an avalanche of mouldings snapping or cracking. I could no doubt engineer something, but the amount of hot water which was being provided between cycles isn't worth the bother.

So that's it, end of the road. I'm having a 35kW hydrogen-ready Ideal combi fitted... but not for three weeks (due to diary conflicts). Anybody want a house guest? I could rig up an electric shower temporarily, but it doesn't seem worth the effort with just me here and I'm away for one of those weeks anyway.

The airing cupboard within which the boiler lives will have to be totally rearranged, losing a large degree of facility (the Highflow was floor-mounted, but the Ideal has to be wall-mounted and reasonably high up the wall). Why not replace like with like?: 1: Reliability (the Highflow has always been a pain in the arse); 2: £1,500. As my (independent) trusted engineer suggested Ideal (as had already been mentioned here), I went with that.

For information: the Highflow is 27kW, and has a small built-in insulated hot reservoir tank which supplies the initial hot water demand, and is then topped up by the actual boiler (which diverts away from the CH to do so). The Ideal has no such reservoir, so hot water demand is not met until the boiler kicks in. However, even with the Highflow there was a delay while the existing cold water in the pipes was displaced, so now it will just be a bit more delay.

 

[everthewatcher]

The Ideal has no such reservoir, so hot water demand is not met until the boiler kicks in. However, even with the Highflow there was a delay while the existing cold water in the pipes was displaced, so now it will just be a bit more delay.

That's progress for you.

When the cylinder failed here there were a few days with no hot water until I could source the correct size SS one. A like-for-like wouldn't fit due to increased insulation thickness, or rather it would fit but there was no room to make the connections. Washing using water from a kettle wasn't a problem but no shower and for a bath I used multiple kettle boilings.

When that kettle failed I kept the element for use as a bath immersion heater should I ever be in the same situation again. And yes, I am fully aware of the safety precautions that would have to be taken.