Future "conventional" boiler (tank setup) replacement?

[413x]

Obviously we all know energy is a hot (lol) topic at the moment. I've been surprised by the claims of what efficiency gains can be made as well.

A heat pump is a no go. Too expensive. Refitting radiators etc is just never going to be a full ROI with this house.

I believe our boiler is very old. It could be as old as the house? (20 years). Not even sure I can find out. Which means savings could be significant.


From other threads people have suggested that keeping the tank is potentially sensible with things like solar and this heating water via this a consideration.

However for us I think a tank is a huge waste.

There's only 2 of us. We aren't high use on hot water. A combi makes much more sense.

I can probably work through picking a boiler spec on my own. But combi replacement (getting rid of tank) vs replacement (keep tank) is not a clear choice.

Its only a three bed house so I doubt it will ever be a high consumption house.

I'm sure many of you guys are going through this now. But stuck on what to do on this one. But at present it's probably the best next high cost project.

 

[Deleted User 298457]

The cost of conversion could outweigh any material savings. What tank do you have right now? An older vented one or a newer unvented one?

 

[katie279]

Shwmae!

I looked into this when we got our current house, which sounds similar to yours.

Agree I'd ignore heat pumps (at least low temp ones which are pretty dreadful tech) - keep half an eye on high temperature heat pumps, these effectively produce heat at same temperature as current boilers, so no replaced radiators etc, just swap it in.

Modern hot water cylinders are pretty darn efficient, so you should definitely get one that suits your usage, but they're highly insulated so lose heat pretty darn slowly.

Solar is a great option and would highly recommend looking at it - hot water is something you'll use regardless of season (unlike heating), so with a reasonable solar install you can easily take free hot water from April-October.

Just a few thoughts!

 

[peterwalkley]

Household of 4 people here and were in similar situation about 18 months ago. The existing boiler was just over 20 years old and we also had a hot water cylinder + cold tank in the loft. We switched to a combi and got the hot water cylinder and header tank removed. It also meant the pump we'd had installed to get decent water pressure for showers could also go as main pressure was good enough. In your situation I suspect you can the same. The combi is brilliant - its pretty much instant hot water when needed and no problem with showers or baths. Keeping a tank of hot water around is just pointless with modern combis.

Talk to a decent plumber - stuff local to you like water pressure, hard/soft water and where you'd need it installed are all considerations. Total price for us was a bit over £2800, £1100 of which was the boiler. It was 3 days work and he also did a magna cleanse of the system which brought a high pile of accumulated cack out of the pipes. Also changed from an utterly garbage thermostat (accuracy was +/- 5 degrees if your were lucky !) to a hive.

I didn't measure energy cost savings, but things like the house heating up much faster, piping hot water in 30 seconds to a minute (depending on pipe run), far simpler pipe work to reduce leak potential, we gained a cupboard and useable loft space all made it worthwhile. No regrets at all.

 

[413x]

The cost of conversion could outweigh any material savings. What tank do you have right now? An older vented one or a newer unvented one?

How would I know?
I know theres a tank in the upstairs cupboard.. But no idea further than that

 

[throwaway4372]

I'll be switching from tank to combi when my boiler dies. The tank leaks heat into the house which is so well insulated it's gets uncomfortably hot for me. Talked it over with the heating guy, it's just a case of paying for time, simple enough to switch.

 

[413x]

Household of 4 people here and were in similar situation about 18 months ago. The existing boiler was just over 20 years old and we also had a hot water cylinder + cold tank in the loft. We switched to a combi and got the hot water cylinder and header tank removed. It also meant the pump we'd had installed to get decent water pressure for showers could also go as main pressure was good enough. In your situation I suspect you can the same. The combi is brilliant - its pretty much instant hot water when needed and no problem with showers or baths. Keeping a tank of hot water around is just pointless with modern combis.

Talk to a decent plumber - stuff local to you like water pressure, hard/soft water and where you'd need it installed are all considerations. Total price for us was a bit over £2800, £1100 of which was the boiler. It was 3 days work and he also did a magna cleanse of the system which brought a high pile of accumulated cack out of the pipes. Also changed from an utterly garbage thermostat (accuracy was +/- 5 degrees if your were lucky !) to a hive.

I didn't measure energy cost savings, but things like the house heating up much faster, piping hot water in 30 seconds to a minute (depending on pipe run), far simpler pipe work to reduce leak potential, we gained a cupboard and useable loft space all made it worthwhile. No regrets at all.

Yes. We use the tank so little.
Our current shower is electric too.

Only time I use hot water is rare occasion I don't put something in dishwasher or rarer. A bath treat.

So end up heating the tank mainly for leigonella (spelling?)



The only reason to not go combi is future potential. And tbh. I don't think we will be in this house long enough for solar or anything else worth utilising a tank for.

 

[413x]

I'll be switching from tank to combi when my boiler dies. The tank leaks heat into the house which is so well insulated it's gets uncomfortably hot for me. Talked it over with the heating guy, it's just a case of paying for time, simple enough to switch.

Do you think you'll wait until it does die?

 

[throwaway4372]

Do you think you'll wait until it does die?

My boiler is 10 years old and the guy said there's probably another 5 left in it, I'd rather get the full value from it and not cause unnecessary waste. Don't necessarily have to wait until it dies, but get the full expected life from it, I'd say you've already satisfied that requirement. I might end up moving before then, so that's part of my calculation.

 

[Deleted User 298457]

My boiler is 10 years old and the guy said there's probably another 5 left in it, I'd rather get the full value from it and not cause unnecessary waste. Don't necessarily have to wait until it dies, but get the full expected life from it, I'd say you've already satisfied that requirement. I might end up moving before then, so that's part of my calculation.

100% this. Never swap an old boiler unless it is broken IMO. You could go from 5 boilers in your life to 6 for no reason.

How would I know?
I know theres a tank in the upstairs cupboard.. But no idea further than that

Take a picture of it and post it. If it is unvented it's reasonable modern and worth keeping IMO.

You should consider swapping your electric shower for a hot water tank fed system/mains fed system too.

 

[413x]

100% this. Never swap an old boiler unless it is broken IMO. You could go from 5 boilers in your life to 6 for no reason.


Take a picture of it and post it. If it is unvented it's reasonable modern and worth keeping IMO.

You should consider swapping your electric shower for a hot water tank fed system/mains fed system too.

I think its vented.

There is a tank in the loft. So looks like that means vented? Saw a YouTube that said tank = vented

I'll get a pic later.

 

[Deleted User 298457]

I think its vented.

There is a tank in the loft. So looks like that means vented? Saw a YouTube that said tank = vented

I'll get a pic later.

Yeah probably vented. Still decently efficient and should only need 30mins twice a day to heat up. Odd your shower is being pumped out of it. You could have a mega power shower. It was glorious in my last place.

 

[413x]

Yeah probably vented. Still decently efficient and should only need 30mins twice a day to heat up. Odd your shower is being pumped out of it. You could have a mega power shower. It was glorious in my last place.

The shower I assume is cold fed? Well. I assume it is! It's a 10kw electric shower.

 

[Deleted User 298457]

The shower I assume is cold fed? Well. I assume it is! It's a 10kw electric shower.

Yeah you'll have a cold feed but then be paying mega $ to heat the water (relatively speaking). Odd as unless you have a bath I doubt you're emptying that hot water tank at all.

 

[413x]

Yeah you'll have a cold feed but then be paying mega $ to heat the water (relatively speaking). Odd as unless you have a bath I doubt you're emptying that hot water tank at all.

Nope. The hot water tank is basically not required with our current setup.

Dishwasher, washing machine cold fed.
Shower electric.

 

[Mercenary Keyboard Warrior]

I would rate unvented > combi > old vented system boiler.
Thats based on cost and quality of life.

I've had combis in last 2 houses prior to this one and yes they are probably the cheapest to run, but even specced at the top end you can tell when the demand is high. Not so much an issue in a house with 2 people thats for sure.
Your problem is likely to be that vented to unvented is not recommended unless your willing to run the risk of leaks. The vented put much more pressure on the pipes that may have been fine, you will also be fine with a combi.

Its a strange combo you have for sure though having a hot water tank and no hot water to the shower. Is it possible to make that change as well?
A modern well insulated cylinder will lose very little heat so dont rule out a replacement boiler and water tank switch. The savings from hot water to being gas heated as opposed to electric heated is significant, normally. But...

Solar opens up possibilities, but really you need to think, renewables and pricing.
If as is starting to sound more and more likely there will be more time of use tariffs etc having a tank allows you to heat with electric as well opens that up.
I will be switching to heating my tank overnight on 7.5p units mainly once my install is completed, when there isnt excess solar to do that, which will probably only limited days per year realistically.
The boiler will then basically just be to top hot water up and run the heating, I expect i will probably turn the boiler off completely in future from roughly March-Oct.

 

[DXP55]

I have had two houses with hot water tanks - I moved into this bungalow and water pressure was low so went combi - 13 yrs on I am still regretting getting one - As regards not changing boiler till it breaks down is daft - I rented a 1982 house and asked boiler engineer who serviced it what was efficiency - He said 60% so for every £100 -£40 was going out the flue.

For me it's hot water tank any day.

 

[413x]

Yeah I thought this might happen. Seeing as we are at a point of fundamental change the choice isn't clear cut.

Combi seems much easier. I've lived with combis before, and the whole system has been simpler.

But I don't want to make the wrong call. As above. Once it's done its done.
Of this was a long term home it might be different. But as its not planning on to be its a short ROI time, but also timing of whats best for the property.


Tank seems a faff. Seems like having it on is an incredible waste at the moment.
If I want to wash up the odd pan is it better to have the tank on every day? Or boil the kettle?

I certainly don't need hot water more than 3 times a week. If that.

 

[Journey]

But as its not planning on to be its a short ROI time, but also timing of whats best for the property.

If you won't get ROI on solar as you've said many times due to not being there long enough, you are never going to get your money back in the savings by changing a perfectly functioning boiler. You'd be lucky to pay less than £3k fully installed, and you might see 10% of that back against the value on the house when you sell it.

My advice get it serviced (if you haven't already), contact the manufacturer and get the specs for it and look at what the efficiency should be, and then look at what improvement you'll make by changing it, I think you'll realise that its not a good investment

 

[413x]

If you won't get ROI on solar as you've said many times due to not being there long enough, you are never going to get your money back in the savings by changing a perfectly functioning boiler. You'd be lucky to pay less than £3k fully installed, and you might see 10% of that back against the value on the house when you sell it.

My advice get it serviced (if you haven't already), contact the manufacturer and get the specs for it and look at what the efficiency should be, and then look at what improvement you'll make by changing it, I think you'll realise that its not a good investment

This is what I am potentially leaning to. It was what I was leaning to. But some of the efficiency claims are significant. Significant enough that if I did change it, and had to stay an extra year or 2 (who knows way things are going) than its very near ROI.

But I do think (kind of hope) you are right.

It was serviced when we moved in. The engineer liked it. Said it was the type that never go wrong

Apparently, specs say 77pc efficient. New! So it's potentially significantly less efficient than a new combi?