New radiators... or not?

CharlieT130

I am going to be replacing my combi boiler in the new year and starting to get a few quotes. My question is whether to replace the radiators at the same time or not? They are 21 years old and it takes 2-3 hours for the house to heat up to 19 degrees with the current boiler set at 65 degrees (the house is also 21 years old as as well insulated as it can be). My hope is that new radiators would heat rooms more efficiently and quickly. I don't want to be replacing pipework so would be limited to new rads in the same locations and dimensions.

I've received one quote so far and the engineer said that the radiators don't need replacing as long as they're getting hot and that replacing the boiler is the main thing, which seems logical, but the house is so cold! I will be asking other companies the same question and googling turns up a mixture of opinions. So I thought I'd ask here as well...

victor2

A new boiler should involve flushing the existing system, so that should improve the performance if it hasn't been flushed for several years, if ever.

ThisIsWeird

Does your existing system actually work ok, Charlie? Ie, when your boiler is firing out 65oC, are the radiators actually 'hot', too hot to keep your hands on them? And are they 'hot' all over, top and bottom?

If the answer is 'yes', then there is no 'need' to replace the radiators (but you may still wish to do so, at least for some - see below.)

The current outdoor temp is unusual (tho' normal for this time of year) and a lot of folk are noticing that their perfectly 'ok' CH systems are suddenly struggling to cope. Since your boiler and rads can get your house up to 19oC in a few hours when I presume it's below zero outside, then it's doing just fine, and you should have to expect to be running your boiler for longer in order to achieve and maintain this. And 65oC is actually not a high output temp for a more traditional boiler, so tweak it up to ~70oC if the cold snap continues; the important thing is to be warm enough. Turn off (*frost*) rads in any room that is not being used.

***When the outdoor temp climbs again, then turn your boiler back down too***

So, seemingly nothing unusual to report here, 'guv

There is another reason to consider 'up-sizing' some radiators, tho', and that is because a larger radiator will give the same output on a lower water temp that a smaller rad will with a hotter water temp. And that is important because the cooler you can run your boiler, the more efficient it will be (this applies to 'condensing' boilers). Also, if you change to another heat source such as ASHP, then these can only output 'coolish' water. So, by up-sizing your rads, you are potentially saving future energy, and also future-proofing your system.

That does not mean you 'should' upsize your rads, tho', because you also need to consider the cost of doing so - £150-200+ a piece? - and how much energy costs this will cover.

Bear in mind that the cold temps usually only last a week or so, and just a few times a year. If your system otherwise works just fine, then it's working 'ok'.

What to do? If there is a 'living' space - sitting room, snug, other reception room - that you really do want or need to be cosy, then I'd give serious consideration to upsizing that rad. Not only will it give you a warmer room, but these will be the rads that will be 'on' for more of the time, so should provide the greatest energy efficiency savings by being runnable on a lower water temp. So if you currently have a single-panel, do 'double'/ if you currently have only one set of convector fins, go twin - that sort of thing. A larger - more powerful - rad in the living area will therefore give you extra heat when you need it in deep winter (but you'd need to turn up the boiler temp to suit), and will also provide you with a more efficient boiler when the outdoor temps allow (but you'd need to lower the boiler temp to suit).

For rooms such as bedrooms, I doubt I'd bother (unless they need replacing anyway). That is because bedrooms only need heating for - what? - one hour in the evening and one in t'morn?, so are not used a lot. And they just don't need to be that warm anyway. For most of the year, they'll be fine, and for the colder spells you just get dressed more quickly...

An exception would be if a bedroom is used for other purposes during the day - a study, work-from-home, a second reception room, that sort of stuff. So, if a bedroom needs to be properly heatable (~20+oC) for longer periods, then do consider up-sizing them too.

To answer your Q - it's yes and no :-)

diystarter7

Hi OP

If you rads look dated etc, your chocie if you want new ones. We've had designer rads for about 18 years, the ancharite cloured ones and chrome in every house we have lived in since but they are not as heated efficient as some of the others
Before that I think we used to have Myson or barlow could be the same I cant recall or something like that, rolled tops - these are all very expensive and stuff is not built like before IMO. If you have heavy-duty rads and are warming up nicely and can be cleaned well, I'd just change the tVR's on them or have them put on if you don't all ready as TVr's can save you loads of money, EG, heat the rooms to temps you want.

Good luck

CharlieT130

victor2 said:

A new boiler should involve flushing the existing system, so that should improve the performance if it hasn't been flushed for several years, if ever.

Thank you. I found some old paperwork showing that the system was flushed when the current boiler was installed 12 years ago by the previous owners. I will confirm that the quotes I get include a system flush.

Thanks ThisIsWeird for the very comprehensive reply. 

ThisIsWeird said:

Does your existing system actually work ok, Charlie? Ie, when your boiler is firing out 65oC, are the radiators actually 'hot', too hot to keep your hands on them? And are they 'hot' all over, top and bottom?

If the answer is 'yes', then there is no 'need' to replace the radiators (but you may still wish to do so, at least for some - see below.)

The current outdoor temp is unusual (tho' normal for this time of year) and a lot of folk are noticing that their perfectly 'ok' CH systems are suddenly struggling to cope. Since your boiler and rads can get your house up to 19oC in a few hours when I presume it's below zero outside, then it's doing just fine, and you should have to expect to be running your boiler for longer in order to achieve and maintain this. And 65oC is actually not a high output temp for a more traditional boiler, so tweak it up to ~70oC if the cold snap continues; the important thing is to be warm enough. Turn off (*frost*) rads in any room that is not being used.

***When the outdoor temp climbs again, then turn your boiler back down too***

So, seemingly nothing unusual to report here, 'guv

The system works at 65c as the rads do get hot all over (except one room), but I can keep my hands on them for a while. The boiler needs to be at 75c before they're too hot to handle (I have asbestos hands though  ). I've been experimenting with how low I can keep it and still be vaguely comfortable and 65c seems to be it. It's forecast 12c on Monday so hopefully the cold snap is over.

ThisIsWeird said:

There is another reason to consider 'up-sizing' some radiators, tho', and that is because a larger radiator will give the same output on a lower water temp that a smaller rad will with a hotter water temp. And that is important because the cooler you can run your boiler, the more efficient it will be (this applies to 'condensing' boilers). Also, if you change to another heat source such as ASHP, then these can only output 'coolish' water. So, by up-sizing your rads, you are potentially saving future energy, and also future-proofing your system.

We really want to switch to a more energy efficient system like an ASHP (I actually wrote my uni dissertation on GSHPs), but that will be reserved for our final home. My partner is in the military so we will be moving in the future and this house will become a rental. We do want to future proof it to a certain degree for future tenants, but not to that degree as we know we don't want to return to our current town.

ThisIsWeird said:

That does not mean you 'should' upsize your rads, tho', because you also need to consider the cost of doing so - £150-200+ a piece? - and how much energy costs this will cover.

Bear in mind that the cold temps usually only last a week or so, and just a few times a year. If your system otherwise works just fine, then it's working 'ok'.

What to do? If there is a 'living' space - sitting room, snug, other reception room - that you really do want or need to be cosy, then I'd give serious consideration to upsizing that rad. Not only will it give you a warmer room, but these will be the rads that will be 'on' for more of the time, so should provide the greatest energy efficiency savings by being runnable on a lower water temp. So if you currently have a single-panel, do 'double'/ if you currently have only one set of convector fins, go twin - that sort of thing. A larger - more powerful - rad in the living area will therefore give you extra heat when you need it in deep winter (but you'd need to turn up the boiler temp to suit), and will also provide you with a more efficient boiler when the outdoor temps allow (but you'd need to lower the boiler temp to suit).

For rooms such as bedrooms, I doubt I'd bother (unless they need replacing anyway). That is because bedrooms only need heating for - what? - one hour in the evening and one in t'morn?, so are not used a lot. And they just don't need to be that warm anyway. For most of the year, they'll be fine, and for the colder spells you just get dressed more quickly...

An exception would be if a bedroom is used for other purposes during the day - a study, work-from-home, a second reception room, that sort of stuff. So, if a bedroom needs to be properly heatable (~20+oC) for longer periods, then do consider up-sizing them too.

To answer your Q - it's yes and no :-)

We've already decided that one of the two rads in the lounge diner will be replaced as that room is large, north facing and at least 2-3 degrees colder than the rest of the house. The other one cannot be upsized due to lack of space, but we will replace the broken gas fire as well (it's safe though!). The rad in my home office (I WFH 4-5 days / week) also needs replacing as it doesn't get properly hot and has an annoying whistle, which I'm hoping will reduce the need to put my plug in electric heater on so much.

I'm leaning towards not bothering to replace the bedroom rads, but is there a point at which we will need to? 30 years old? 40 years old? As I mentioned earlier this house will be become a rental for potentially 10-20 years so I'd like to avoid needing to do it in future when it's got tenants living there.

BUFF

CharlieT130 said:

victor2 said:

A new boiler should involve flushing the existing system, so that should improve the performance if it hasn't been flushed for several years, if ever.

Thank you. I found some old paperwork showing that the system was flushed when the current boiler was installed 12 years ago by the previous owners. I will confirm that the quotes I get include a system flush.

Thanks ThisIsWeird for the very comprehensive reply. 

ThisIsWeird said:

Does your existing system actually work ok, Charlie? Ie, when your boiler is firing out 65oC, are the radiators actually 'hot', too hot to keep your hands on them? And are they 'hot' all over, top and bottom?

If the answer is 'yes', then there is no 'need' to replace the radiators (but you may still wish to do so, at least for some - see below.)

The current outdoor temp is unusual (tho' normal for this time of year) and a lot of folk are noticing that their perfectly 'ok' CH systems are suddenly struggling to cope. Since your boiler and rads can get your house up to 19oC in a few hours when I presume it's below zero outside, then it's doing just fine, and you should have to expect to be running your boiler for longer in order to achieve and maintain this. And 65oC is actually not a high output temp for a more traditional boiler, so tweak it up to ~70oC if the cold snap continues; the important thing is to be warm enough. Turn off (*frost*) rads in any room that is not being used.

***When the outdoor temp climbs again, then turn your boiler back down too***

So, seemingly nothing unusual to report here, 'guv

The system works at 65c as the rads do get hot all over (except one room), but I can keep my hands on them for a while. The boiler needs to be at 75c before they're too hot to handle (I have asbestos hands though  ). I've been experimenting with how low I can keep it and still be vaguely comfortable and 65c seems to be it. It's forecast 12c on Monday so hopefully the cold snap is over.

ThisIsWeird said:

There is another reason to consider 'up-sizing' some radiators, tho', and that is because a larger radiator will give the same output on a lower water temp that a smaller rad will with a hotter water temp. And that is important because the cooler you can run your boiler, the more efficient it will be (this applies to 'condensing' boilers). Also, if you change to another heat source such as ASHP, then these can only output 'coolish' water. So, by up-sizing your rads, you are potentially saving future energy, and also future-proofing your system.

We really want to switch to a more energy efficient system like an ASHP (I actually wrote my uni dissertation on GSHPs), but that will be reserved for our final home. My partner is in the military so we will be moving in the future and this house will become a rental. We do want to future proof it to a certain degree for future tenants, but not to that degree as we know we don't want to return to our current town.

ThisIsWeird said:

That does not mean you 'should' upsize your rads, tho', because you also need to consider the cost of doing so - £150-200+ a piece? - and how much energy costs this will cover.

Bear in mind that the cold temps usually only last a week or so, and just a few times a year. If your system otherwise works just fine, then it's working 'ok'.

What to do? If there is a 'living' space - sitting room, snug, other reception room - that you really do want or need to be cosy, then I'd give serious consideration to upsizing that rad. Not only will it give you a warmer room, but these will be the rads that will be 'on' for more of the time, so should provide the greatest energy efficiency savings by being runnable on a lower water temp. So if you currently have a single-panel, do 'double'/ if you currently have only one set of convector fins, go twin - that sort of thing. A larger - more powerful - rad in the living area will therefore give you extra heat when you need it in deep winter (but you'd need to turn up the boiler temp to suit), and will also provide you with a more efficient boiler when the outdoor temps allow (but you'd need to lower the boiler temp to suit).

For rooms such as bedrooms, I doubt I'd bother (unless they need replacing anyway). That is because bedrooms only need heating for - what? - one hour in the evening and one in t'morn?, so are not used a lot. And they just don't need to be that warm anyway. For most of the year, they'll be fine, and for the colder spells you just get dressed more quickly...

An exception would be if a bedroom is used for other purposes during the day - a study, work-from-home, a second reception room, that sort of stuff. So, if a bedroom needs to be properly heatable (~20+oC) for longer periods, then do consider up-sizing them too.

To answer your Q - it's yes and no :-)

We've already decided that one of the two rads in the lounge diner will be replaced as that room is large, north facing and at least 2-3 degrees colder than the rest of the house. The other one cannot be upsized due to lack of space, but we will replace the broken gas fire as well (it's safe though!). The rad in my home office (I WFH 4-5 days / week) also needs replacing as it doesn't get properly hot and has an annoying whistle, which I'm hoping will reduce the need to put my plug in electric heater on so much.

I'm leaning towards not bothering to replace the bedroom rads, but is there a point at which we will need to? 30 years old? 40 years old? As I mentioned earlier this house will be become a rental for potentially 10-20 years so I'd like to avoid needing to do it in future when it's got tenants living there.

Ideally, you  want to be at the point that your room(s) can be heated by the boiler running at a flow temperature of 55C or lower (now mandated for totally new installs). lower is better.
Bear in mind that as ThisIsWeird said you can also "upsize" a radiator in terms of output by adding another panel of more fins (you can now get T33s with 3 panels & 3 rows of fins) - this comes at the cost of increased depth rather than increased width or height.

n.b. unless they are very recent when you replace your combi also look at whether replacing your controls is worthwile. Control upgrades will usually more than pay for themselves over the life of a boiler by way of energy savings.

FreeBear

BUFF said: Bear in mind that as ThisIsWeird said you can also "upsize" a radiator in terms of output by adding another panel of more fins (you can now get T33s with 3 panels & 3 rows of fins) - this comes at the cost of increased depth rather than increased width or height.

n.b. unless they are very recent when you replace your combi also look at whether replacing your controls is worthwile. Control upgrades will usually more than pay for themselves over the life of a boiler by way of energy savings.

A type 22 radiator will stick out from a wall by about 145mm, a type 33, around 200mm - In small rooms, either is going to look real ugly (in my opinion). When replacing radiators here from type 10 (flat panel, no fins), most of them were type 21 with a single type 11 in the hallway.

As for modern controls, certainly worth doing. A smart programmable thermostat has the potential to deliver 10-15% savings. In reality, a 5-8% saving would be more likely.

BUFF

FreeBear said:

BUFF said: Bear in mind that as ThisIsWeird said you can also "upsize" a radiator in terms of output by adding another panel of more fins (you can now get T33s with 3 panels & 3 rows of fins) - this comes at the cost of increased depth rather than increased width or height.

n.b. unless they are very recent when you replace your combi also look at whether replacing your controls is worthwile. Control upgrades will usually more than pay for themselves over the life of a boiler by way of energy savings.

A type 22 radiator will stick out from a wall by about 145mm, a type 33, around 200mm - In small rooms, either is going to look real ugly (in my opinion). When replacing radiators here from type 10 (flat panel, no fins), most of them were type 21 with a single type 11 in the hallway.

The rad that "cannot be upsized due to lack of space" is in the lounge so presumably not a small room.
I have a small (500x600) T22 in my smallest room, I don't find it ugly let alone "real ugly".
You have to work to the constraints, if you can't go wider then go taller or deeper. As we don't know what is fitted currently that may be a simple upgrade e.g. T21>T22 but in extremis a T33 is a valid solution imo. 

ThisIsWeird

CharlieT130 said:

The system works at 65c as the rads do get hot all over (except one room), but I can keep my hands on them for a while. The boiler needs to be at 75c before they're too hot to handle (I have asbestos hands though  ). I've been experimenting with how low I can keep it and still be vaguely comfortable and 65c seems to be it. It's forecast 12c on Monday so hopefully the cold snap is over. If it's 'vaguely comfy' at 65oC boiler output (which is quite low for current standards), then your system is 'fine'. All you need to do is to turn the output to 70oC+ for the zero spells, and back down when mild resumes. So, your system appears to be perfectly ok by current standards, but will pale somewhat as time goes on. I would suggest that such future issues are addressed when the time comes, becuase no-one really knows for certain what's going to happen. For instance, anyone who chucks out their gas boiler and fits an ASHP on an older property is almost certainly going to rue the day. Such change can only occur if and when folk are also given the funds to improve their insulation levels to a suitable standard. I can't see many folk being able to dip into their pockets and find £10k+ to do this, at least not unless it's done as part of a house purchase that allowed for 'updating'.

ThisIsWeird said:

There is another reason to consider 'up-sizing' some radiators, tho', and that is because a larger radiator will give the same output on a lower water temp that a smaller rad will with a hotter water temp. And that is important because the cooler you can run your boiler, the more efficient it will be (this applies to 'condensing' boilers). Also, if you change to another heat source such as ASHP, then these can only output 'coolish' water. So, by up-sizing your rads, you are potentially saving future energy, and also future-proofing your system.

We really want to switch to a more energy efficient system like an ASHP (I actually wrote my uni dissertation on GSHPs), but that will be reserved for our final home. My partner is in the military so we will be moving in the future and this house will become a rental. We do want to future proof it to a certain degree for future tenants, but not to that degree as we know we don't want to return to our current town. It's good to always have an eye on the future, and to take advantage when changes need to be made - like, possibly, now. But if a change of rads don't make a tangible improvement to your new boiler, then - imo - it just isn't worth doing at the moment. Ie, if you DO need to swap a rad, then go 'big'. If you don't, then don't bother; the difference will likely be just a few %, and who knows what the future holds? Your future tenants will be in the same posiiton as most other householders in the UK, waiting to see what happens. You swapping all your rads might save them £100 per year in energy costs, but you will be £2k+ out of pocket. If, on the other hand, the next UK Gov males insulating homes/ a Green 'push' a priority, then your tenants will likely save many £100's per year, and you hardly out of pocket at all. In essence - but this is only my take - if you DO need to replace rads, then go 'big'. If you don't, then don't. Just wait and see.

We've already decided that one of the two rads in the lounge diner will be replaced as that room is large, north facing and at least 2-3 degrees colder than the rest of the house. The other one cannot be upsized due to lack of space, but we will replace the broken gas fire as well (it's safe though!). The rad in my home office (I WFH 4-5 days / week) also needs replacing as it doesn't get properly hot and has an annoying whistle, which I'm hoping will reduce the need to put my plug in electric heater on so much. And that is the gist! If it NEEDS doing, then do it. If it doesn't, then it's unlikely to be cost-effective, so hold off for now. (The whistling rad sounds as tho' it's being restricted by a too-closed-off lockshield, so could be an easy fix - possibly worth a thread of its own...)

I'm leaning towards not bothering to replace the bedroom rads, but is there a point at which we will need to? 30 years old? 40 years old? As I mentioned earlier this house will be become a rental for potentially 10-20 years so I'd like to avoid needing to do it in future when it's got tenants living there. Rads in a reasonably-well maintained system - ie has inhibitor added - should simply never rust. So, if the rads are performing fine, then there should never be a 'need' to replace them (except to up-size for future heat sources). If your system is currently fine, and as efficient as current systems are - which it will be - then you don't need to anything more for the moment for tenants, just as you wouldn't for your own house. As requirements change, and better efficiency becomes a requirement, then you move with this.

FreeBear

BUFF said:

FreeBear said:

BUFF said: Bear in mind that as ThisIsWeird said you can also "upsize" a radiator in terms of output by adding another panel of more fins (you can now get T33s with 3 panels & 3 rows of fins) - this comes at the cost of increased depth rather than increased width or height.

n.b. unless they are very recent when you replace your combi also look at whether replacing your controls is worthwile. Control upgrades will usually more than pay for themselves over the life of a boiler by way of energy savings.

A type 22 radiator will stick out from a wall by about 145mm, a type 33, around 200mm - In small rooms, either is going to look real ugly (in my opinion). When replacing radiators here from type 10 (flat panel, no fins), most of them were type 21 with a single type 11 in the hallway.

The rad that "cannot be upsized due to lack of space" is in the lounge so presumably not a small room.
I have a small (500x600) T22 in my smallest room, I don't find it ugly let alone "real ugly".

"ugly" is personal opinion - I prefer a slim look that doesn't protrude from the wall too much, so a T21 is about my limit.

fenwick458

Just putting on bigger radiatorss isn't necessarily going to future proof it, you'd need bigger pipes too, and better insulation. I'd focus on the better insulation