Cost of replacing radiators?

[BrumJim]

Don't know the effect on thermal efficiency of a new radiator. They are certainly more efficient in terms of heating output per sq m of radiator.
Have you thought about Electronically controlled TRVs? We've just had them fitted, and it means that you can have your lounge cold in the morning when you are not using it, and the bedroom cool in the evening when you are in the lounge. Also have the bedroom warmer in the morning to persuade me to get up, and cooler at night when I am heading into bed anyway. You can get 6 odd settings per day, with different settings for each day of the week, or week days and weekends.
I managed to change all my radiators (except one - didn't fit) to TRVs in my old house, and that was without there being an obvious drain cock on the system. However some re-designing of the pipework was required in my new house, and got my local house removals box supplier to do all the work. Except flushing and inhibitor filling.

Remember do not fit a TRV to the radiator in the room with the main thermostat, and in any case, have at least one radiator without a TRV.

 

[Over The Hill]

I am just pricing up a new rad in my loft conversion and an new rad to replace a broken one (bleed valve rusted in). Start at £20 up to £80 so say £300 for six. Valves are a pair for £10 (one thermo one plain) so £360 all done. Sometimes the sizes dont quite add up but you can get a really handy telescopic extender to make the new one grow a bit longer for a few quid.
Do in the summer when not needed and take your time - save £900 for 2 days work.
If you are keen you may decorate the wall before putting the new one on.

 

[djmc]

We have recently replaced our oil fired central heating with a geothermal system. All our radiators are cast iron of an ancient vintage. All the plumbers : central heating people we had estimates from thought that cast iron radiators were much better with a geothermic or aerothermic system than the more modern radiators.

 

[Globalti]

Yes, they will hold the heat for longer and release it more slowly.

 

[threebikesmcginty]

We have recently replaced our oil fired central heating with a geothermal system.

We replaced our oil-fired CH with an air-to-water heat pump with underfloor heating, it works extremely well and we've found it's nice not having radiators as they always seem to be in the wrong place!

 

[Black Sheep]

How old is old ?

You can swap out the valves for TRV's fairly easily. The rads on your walls have been bought to suit the size of the room and the amount of external walls, and efficiency doesnt really come into it if they are not clogged.

In theory, yes.

none of the radiators in our house were the size they should have been, rather than solve the problem, extra radiators and external pipework had been added to each room resulting in the systems water getting cold (extra radiators plumbed in tandem with the other in the room) before it reached the boiler for a second pass making the boiler work harder yet not really achieving much.

So, if your system was fitted by a professional, or someone who took the time to research what he was doing then, yes, your radiators should be the right size,

however, if you are replacing a single panel radiator with no fins on the back with a double panel you may find you can get a physically smaller radiator.

Bathrooms seem to be where we differ from the above, people have often fitted towel rail radiators into bathrooms as they look good, offer good practicality and, in the case of my bathroom, leave it bloody freezing due to it not being possible to get a towel radiator big enough to heat the room! (plumber looking at what he could get for me that met the requirements he'd worked out) This is mainly due to the high ceilings of my house.

 

[Globalti]

Since doing two bathrooms in our house I have felt the warm patches on the floor where the pipe runs are and now I really regret not having run the radiator pipework under the floor in a zig-zag pattern down the middle between the joists; this would have made lovely warm bathroom floors and supplemented the towel rails.

 

[summerdays]

We didn't have radiators in two of the rooms when we moved in - a bedroom and bathroom, so we got them installed and replaced one old radiator for a much smaller modern one in the living room. I think it was about 600 pounds, and done in under a day - I wasn't in so I don't know exactly how long it took.

 

[snailracer]

In theory, yes.

none of the radiators in our house were the size they should have been, rather than solve the problem, extra radiators and external pipework had been added to each room resulting in the systems water getting cold (extra radiators plumbed in tandem with the other in the room) before it reached the boiler for a second pass making the boiler work harder yet not really achieving much...

Hmm can't really see how that would affect efficiency. In principle, fitting a single new finned rad would also result in the water in the return loop getting colder compared with a single old rad, cos the fins cool the water more effectively. Two old rads in tandem would result in return loop water being colder than with just one old rad - in other words, just like with a single new finned rad.

Compared to a single finned rad, two old rads in tandem would present more back-pressure to the circulating pump, but that only affects power output (i.e. it would take longer to heat up the room) and not efficiency, because circulating pumps take negligible power to run. In other words, radiators are all pretty much 100% efficient, old or new. The newer ones just heat the room faster.

 

[Black Sheep]

The issue with my house is, the heating system that was in was an old single circuit system which, when put in with the original radiators probably worked ok if a little chilly - adding the extra un-finned radiators did nothing to help except on the first couple of rooms on the loop. The house has about 10 rooms in total so you can imagine a couple of those rooms were slightly chilly on the old system.

I've had, since moving in, a completely new system fitted which is much better.

 

[subaqua]

The issue with my house is, the heating system that was in was an old single circuit system which, when put in with the original radiators probably worked ok if a little chilly - adding the extra un-finned radiators did nothing to help except on the first couple of rooms on the loop. The house has about 10 rooms in total so you can imagine a couple of those rooms were slightly chilly on the old system.

I've had, since moving in, a completely new system fitted which is much better.

thats a balancing issue rather than rads.
the radiators closest to the boiler are stealing the heat from the water . the return valve (lockshield) only needs to be cracked open a little and opened progressively further the further from the boiler you get . helps if you have a idea of how it was piped. ideally a temp difference of 10 degrees C between flow temp and return temp when the system boiler is running at full pelt and all temp control valves are wide open. good commisioning engineers and CH installers can do it by feel I use an IR thermometer as I have one for other reasons ( I did it once using a thermal imaging camera but thats just excessive TBH ) but i can do it by feel.

 

[Beebo]

Bathrooms seem to be where we differ from the above, people have often fitted towel rail radiators into bathrooms as they look good, offer good practicality and, in the case of my bathroom, leave it bloody freezing due to it not being possible to get a towel radiator big enough to heat the room!

The trouble with towel rails, as we have found to our cost, is that they are, by their very nature, covered with towels, so the heat never gets out.

 

[Black Sheep]

thats a balancing issue rather than rads.
the radiators closest to the boiler are stealing the heat from the water . the return valve (lockshield) only needs to be cracked open a little and opened progressively further the further from the boiler you get . helps if you have a idea of how it was piped. ideally a temp difference of 10 degrees C between flow temp and return temp when the system boiler is running at full pelt and all temp control valves are wide open. good commisioning engineers and CH installers can do it by feel I use an IR thermometer as I have one for other reasons ( I did it once using a thermal imaging camera but thats just excessive TBH ) but i can do it by feel.

It wasn't a balancing problem, there was no return pipe, it had been plumbed as a string of radiators coming off the one pipe, so the return flow from a radiator was going back into the hot water flow and onwards through the rest of the system, not heading straight back to the boiler through a separate return pipe.

The trouble with towel rails, as we have found to our cost, is that they are, by their very nature, covered with towels, so the heat never gets out.

even with no towels on it wasn't doing the job by a long way.

 

[subaqua]

It wasn't a balancing problem, there was no return pipe, it had been plumbed as a string of radiators coming off the one pipe, so the return flow from a radiator was going back into the hot water flow and onwards through the rest of the system, not heading straight back to the boiler through a separate return pipe.



even with no towels on it wasn't doing the job by a long way.

thats a balancing problem . closest radiator to the boiler has the outlet open a gnats crack . thats how schools etc used to have systems piped- really easy to add a radiator and once balanced runs lovely. not as easy to do it by temperature of return pipe. it gets balanced by getting the rad temps similar.

reverse return systems are apparently self balancing but thats just a theory made up by engineering consultants who have shares in pipework manufacturers

 

[Over The Hill]

We have recently replaced our oil fired central heating with a geothermal system. All our radiators are cast iron of an ancient vintage. All the plumbers : central heating people we had estimates from thought that cast iron radiators were much better with a geothermic or aerothermic system than the more modern radiators.

All that happens is the more water you have in the radiator, the slower it is warming up and cooling down. We have half victoran cast iron rads and half modern thin ones. Cast ones stay warm for 2 hours after heating is off whereas the modern ones are cold in 30 mins. This could be seen as less efficient as it is harder to warm the house for a limited time (say first thing before going out to work). But overall I dont think it makes much difference.