[Closed] New boiler musings.....

Is it broken?

No it still works and I generally take the view that the most environmentally friendly decision is to keep what you have but it hasn't been serviced for some time as parts are difficult to find plus I suspect it is very inefficient (although difficult to know) I suspect I am pushing that theory to its extreme!

It'll work with 8mm but I'd strongly recommend changing it for 22mm on the main runs from/to the boiler and 15mm to the radiators. The performance difference in getting heat to the radiators quickly is huge.
I'd normally agree with keeping existing setups but copper is easily recycled, the plumber won't throw it away he'll weigh it all in as along with the cylinder will be worth a small fortune.

I wouldn’t take a hot water cylinder out given the moves on decarbonisation of heat.

The tank simply gives you more options going forward.

Replace it with a modern tank? Maybe.

Solar water, PV dump to heat, heat pumps, off peak electric heat - all work more easily with a modern hot water tank.

In a similar position here so watching with interest.

Was advised against installing one on 15mm pipes!

Our Combi recently packed-up after 12 yrs service due to being badly furred-up (very hard-water area). The manufacturer's own engineer advised against having a new boiler installed on old 15mm pipes.

They couldn't and wouldn't issue a warranty on their new boiler knowing it was installed on old (1980s?) 15mm pipes...

For a new CH system (new pipes and rads) to be installed we were told would be c.£10k.

We replaced our 'standard' boiler & cylinder last September for a combi.

Our boiler was very old & we'd had a couple of faults where parts were hard to come by.
After struggling to decide which way to go for ages, we ended up choosing a combi. The reasons for this were mainly so we could get rid of the cylinder & move the boiler from the kitchen to the airing cupboard & liberate some space in the kitchen.
Most people we spoke to (including both people we got to quote) said that a combi was definitely a better option, which I think also swayed us.

So far my thought are a bit, meh. I feel that we perhaps should have stayed with a 'standard' boiler & cylinder. It feels like we are still 'learning' to live with the boiler. It takes quite a while for the hot water to come through & we just find it not as good as the previous system.
I am not sure the idea of having a permanent tank of hot water in the house is a great one either, considering the fuel costs. But, the combi isn't quite living up to expectations.

We haven't been able to work out any cost savings, as it was right around the time our energy provider (OVO) went bust & the prices went up across the board.

Also - not related to the boiler, but the thermostat.
We went with a Google Nest thermostat. Don't bother. It is crap. Looks nice, but just doesn't work very well. I think we'd be better off with just a standard programmable controller.

plumber won’t throw it away he’ll weigh it all in steal it as along with the cylinder will be worth a small fortune.

FTFW

You seem to be getting into this boiler lark.

Mind you, I have heard its quite immersive.

I already use a Tado which is useful and probably change to Hive at the same time.

Interesting. That would be spending money to switch to an inferior system (IMHO etc.)

I've got a new one going into my flat on Tuesday. It's a rental which changes things.
I would have preferred to get it fixed - not sure how old it was but at least 9years - but plumbers seem to work on a trial and error basis and don't have the time or knowledge to really diagnose the problem. I just thought I was going to end up throwing good money after bad.
Having said that it's a small flat so, although a cost I could have done without, not crippling.

No idea about the 8mm pipes sorry.

Some boiler supply is very limited, pcb shortages.
Ideal ok, others not so good
So have various options within a framework to choose from

theres a new boiler being fitted as I type nearly finished. We decided against a combi and went for a like for like + condenser, not giving up my power shower for anyone, not no way ;). It's also nice to have a hot water option should the gas get turned off. And I don't like the combi at my mums. Though I must say it's a hefty old box!

Also got this to do soon with a 32+ year old Baxi boiler. Thinking sticking with conventional boiler. I don't think the water tank is a big heat loss. Our tank is relatively modern with foam type insulation rather than a jacket. Keeps the airing cupboard warm without feeling like there is a huge amount of heat.

There was a place that did online quotes here a while back. Also anyone know any good plumbers worth getting quotes from in the East Dunbartonshire or northwest Glasgow area?

The last major work on our system was 15 years ago and the guy, though excellent, has retired.

We've got something called a 'storage combi' which has a (100l) tank built in and a rapid recovery coil. the theory is you get mains pressure showering without keeping a large tank of water hot (most tanks are about 300l or so I think - so you're reducing the losses by 2/3). Will run more two showers at the same time (or no impact if someone runs a tap). Once you've exhausted the 100l you still get combi flow rate but the theory is that unless you're running multiple outlets for a long while simultaneously it's topping it up in between AND while in use.

I think we had about 8 people showering in quick succession one Christmas and no noticeable change in pressure or temperature.

For a new CH system (new pipes and rads) to be installed we were told would be c.£10k.

I was told similar. Then whilst it's all in bits you might as well do a rewire. And then of course you'd need extensive redecorating. So I fixed it all with a new house.

Mind you, I have heard its quite immersive.

Delete your account. 😁

Some interesting comments thanks. Ref the Tado to Hive swap I havent looked into it yet but seemed a bundle deal with the supplier. I assumed they were similar (but would have done my home homework before pressing the button) The Tado has been quite good and wouldn't be without it now.

We have 2 bathrooms so some years ago I installed a pump which transformed the shower experience. I did expect more love for the Combi boilers so maybe a like for like swap which removes the 8mm pipe issue is the answer...

8mm pipework is rubbish regardless of boiler type.

As discussed above. It is is a tricky time to replace a boiler. Heat pumps are supposedly the way forward. However, many (including myself) are not convinced by air-to-water heat pumps as viable for most. However, if you go down this route, an air-to-water heat pump will require a hot water tank. There will be £5k grants available imminently to install but that is probably less than half the cost even without extensive pipework changes.

Currently gas is around 5x the price of electricity but air-to-water heat pumps are only around 3x more efficient than gas boilers so the economics don't' stack up. The flux in energy prices makes it difficult to know if this will be the case going forward. I can envisage a situation in 5 years time where the gap between and off-peak electricity widens considerably - expect to see more time-of-use tariffs. In addition the gap between kwh price for gas and electricity will also narrow. Mainly as a result of increased supply of renewable energy. Which might tip the balance in favour of heat pumps in the next few years. The current Russia situation might accelerate the transition.

My current thinking is to install an air-to-air heat pump (air conditioner) for our main living room and keep our gas system for the time being but use it far less. Install cost is around £1700. Efficiency is around 400% compared to 300% for an air-to-water heat pump. Unfortunately, no government grants available as they can also be used as air conditioners. However, it will work well in tandem with our solar panels in the summer.

Slightly different circumstance as we are on oil CH, but our boiler is packing up.

Thats going to be a very expensive job for OP by the sounds of it, basically taking the house apart to change all the piping.

My only advice would be get smart heating system with each room controllable, eg. we have EvoHome

Also can you future proof ie get bigger rads for when you have to move to Air Source or Ground Source Heating?

Alternatively would it be cheaper to put under floor heating in, rather than rip all the walls apart?

All sounds very expensive. We have just been quoted £3.7k for a new boiler that requires very little pluming change!

Thats going to be a very expensive job for OP by the sounds of it

Suppose it depends if I go for combi. If I go like for like then the old 8mm piping can be replaced as I go along. I can do this myself and with the same boiler there is no urgency. As above there doesnt seem a lot to recommend the Combi. Like for like is only around £2.200 fitted.

My current thinking is to install an air-to-air heat pump (air conditioner) for our main living room and keep our gas system for the time being but use it far less. Install cost is around £1700.

This is exactly what a chap I know has done. Seems to work really well for him.

This is exactly what a chap I know has done. Seems to work really well for him.

To some degree central heating is a function of poorly insulated houses. In a well insulated house the temperature variations between rooms (and between night and day) are much less. I am certain two air-to-air heat pumps for the whole house would be sufficient for us.

Watching with interest.

In the process of buying a 1930's Semi with no central heating apart from two gas fireplaces in the living room and dinning room and an electric bathroom heater.

I have no idea what to do. Going on price it seems installing a Combi and radiators is the cheapest at the moment.

Watching with interest.

In the process of buying a 1930’s Semi with no central heating apart from two gas fireplaces in the living room and dinning room and an electric bathroom heater.

I have no idea what to do. Going on price it seems installing a Combi and radiators is the cheapest at the moment.

Insulate! Insulate! Insulate!
In rough order of ROI:
Loft insulation
Cavity wall insulation
Underfloor insulation
Double glazing

As I have banged on about above. Once you have done that I would seriously consider air-to-air heat pumps for a new installation.

Thanks martin_t

Loft insulation is the first thing we are getting done as it hasn't got much at the moment. Luckily it's already got recent Double Glazing.

I understand what Cavity wall insulation is, but is there a chance that filling in the cavity with insulation that damp comes through because the wall ties can't do their job?

Loft insulation is the first thing we are getting done as it hasn’t got much at the moment. Luckily it’s already got recent Double Glazing.

I understand what Cavity wall insulation is, but is there a chance that filling in the cavity with insulation that damp comes through because the wall ties can’t do their job?

There are a lot of scare stories about this and old houses needing to breath etc. Personally, I think most are caused by other factors or general deterioration. We also have a 1930s semi and had cavity wall insulation installed 12 years ago. Energy use dropped by 20%.

There is good practice to for installation e.g. not blocking vents etc. I would also suggest treating external brickwork with weather seal to avoid water penetration. To be honest wall ties in a 1930s house could be corroded by now anyway. Replacing with stainless steel at the same time isn't a bad shout.

Also check that your cavities are not full of crap. Lime mortar would have originally been used. Typically this has been replaced with concrete mortar. However, in the absence of moisture, the lime mortar inside dries and crumbles down into the cavity. This can end up bridging the damp proof course (with or without cavity wall insulation). So it is good practice to clear the cavities anyway.

Tiny pipe rads in our house. Big 440cdi combi, no leaks in the last 10 years.

Thanks martin_t for the extra info. Will look into getting the Cavity wall insulation done at some point. Cheers