Radiators - are they worth changing?

[sparklins]

We have used more gas this year than expected (or average for a house the size of ours) and are looking at making our home more efficient, windows would be the first stop however it is not something we can do right now for a myriad of reasons.
I was wondering if someone could advise if radiators are worth looking at.

I am not sure how old they are as there seems to be a mix throughout the house and we have only lived here for just over a year but one of them is old, flat and very large (single convector i believe?) probably about 2m wide at least in one of the bedrooms which gets extremely hot even when turned down.
There is another in the lounge which is again over 2m wide and does not look great.
I might be wrong since I know nothing about radiators but some of them are definitely over 10 years old.

The question is would new radiators make a big difference when it comes to energy efficiency? Or should we leave the radiators alone?

The priority is stopping heat leaving the house, so I would look at windows, insulation, curtains, doors etc. before radiators.

Thermostatic valves are worth looking at and you can get WiFi ones now that you can control from your phone. It would mean you could switch them on and off easily so you would be heating an empty house when you are out. You can swap them yourself but it involves draining the system and refilling it. There should be plenty of you tube videos. It is reasonably straight forwards DIY job.

I think they all have thermostatic valves looking from a quick google. The issue with the large one in one of the bedrooms is that even when it's turned down to 1 it makes the room boiling! Can't turn it off completely as then it gets freezing and its one of the kids rooms.

I changed all mine from old singles to new doubles and it made a big difference.

I too changed all of ours two years ago, from single flat ones to much larger ones which are double width. The different has been amazing.

You're right to look at it because the system will run more efficiently at lower flow temperatures, but I'm afraid I wouldn't know how to do the heat loss calculation you'd need to work out how much saving you would make. Radiators aren't that dear and swapping single for double isn't that hard so could might be worth a shout. I want to do it in our house as part of long term being able to install a heat pump, but we haven't got round to it yet.

Do you have a long term plan to improve glazing, insulation etc?

If you have any small insulation jobs or really bad windows you might be better off spending on those instead.

The thermostatc valve can't be working, get that checked as a starting point.

Before replacing them all, I'd look at getting them flushed:

https://www.homeserve.com/uk/living/heating-and-cooling/powerflush/

Before doing that, and especially with the one that's getting boiling hot, I'd get someone round to check they are all balanced properly.

Apparently it's quite an art. We had a firm do ours, and the next bloke who came along to look at overall problems said that they hadn't done it properly, but that it's absolutely normal for him to come across this, because a lot of plumbers can't!! O_O

Bleed the rads https://www.bestheating.com/info/how-to-bleed-a-radiator-for-optimal-heating-efficiency/

Balance the rads https://www.bestheating.com/info/a-best-heating-guide-how-to-balance-radiators/

https://www.bestheating.com/info/are-your-radiators-too-hot/ might be helpful?

Also, check your boiler heating flow temp (not room or rad thermostats temp)
systemhttps://heatable.co.uk/boiler-advice/boiler-flow-temperature#:~:text=While%20a%20range%20of%2060,for%20efficiency%20in%20most%20households.

The one that is stuck on probably needs a new valve, we had one of ours stuck on just recently so gas engineer put a new piece of pipe on underneath the trv to fix it, ours was done under BG Homecare but it was only a small quick job so wouldn't be expensive, I wouldn't think

you could buy a new TRV from Screwfix and try that, it might fix it but usually it's the valve underneath which is the problem

You can check if the valve is stuck on by removing the trv (they just unscrew) and seeing if the little metal pin sticking up in the middle is stuck. If it is then a bit of wd40 and gentle taps with a hammer should be sufficient to unstick.
Given you can actually turn it totally off I wouldn't expect this to be the case though.

There are tons of online calculators that will tell you the size of radiator required in the room. Be careful that you don't exceed the capacity of your boiler by making the radiators too large. I swapped my old cast iron ones for newer double panel radiators which can be smaller physically for the same thermal output.

Also, you can do your own mini powerflush if you are feeling brave. Pop each radiator off and run it through with a hose until the water runs clear. There will be a load of sludge at the bottom. You can also flush the whole system by opening the drain plug and running fresh water through the whole system turning all radiators off bar one, and rotating through each radiator in turn. Don't forget to put inhibitor back into the system if you do this.

We changed ours as they'd all sludged up. The plumbers tried a high pressure clean out of the system but it was all too old and there were microbore pipes too.

It's made a big difference and wasn't that expensive. Though we were redecorating every room and renovating at the time so the redecorating and having the floorboards up wasn't a chore.