Adding a radiator with too much BTU?

Zola.

Our hallway never heats up too much unless the heating is on for a long time. Its an old double radiator - 140mm wide. Its positioned beside the front door area (3 bed semi house).

The rads in the house are mostly old, and bled when required. The living room and bedroom ones are fine however.

Would there be any danger in adding in a new radiator that was very powerful, in an attempt to make the hall and landing etc a bit more cosy?

Gloomendoom

It would depend on the output of your boiler. If it’s maxed out already, your hall might get a bit warmer but the other rooms would be correspondingly cooler.

Zola.

Boiler is only turned up a little over half way. I didn't want to stick it up full if it meant burning all the fuel up in no time.

Nick_C

Do you really want a very warm hall? Do you spend much time there?

Is the thermostat in the hall? If the hall starts getting warmer, you will need to adjust the thermostat to get the same temp in the lounge that you do currently. (I'm sure you assuming you don't have TRVs)

Zola.

If the hall was warmer it would filter up to the landing etc. As its the first room people will enter its good to have a warm feel also.

TRVs are in the living room and spare bedroom only. The rest are all old radiators, which get piping hot, but I am just not convinced they are pumping out a lot of heat into the rooms.

We have a wood burning stove which burns away in our living room. We knocked in the adjacent dining room into one big room, and the stove does a great job of heating this open plan room.

The trouble is when you leave the room on a cold night and step into the hallway to go to the kitchen, it can feel like stepping outside!

Zola.

So no real danger if I put in something about 6000+ ?

jamesd

No danger but you should have a thermostatic valve on it so it stops heating once the hall reaches whatever temperature you set.

A boiler temperature setting controls how hot the water sent to the radiators is. Hotter lets the radiators get hotter and put out more heat. The fuel consumption should be controlled by thermostat or thermostatic radiator valves that turn off the individual radiators once the area they are heating has reached the temperature you set. It's normal to turn the boiler temperature higher in winter and lower in summer, that's a big part of what that control is for.

If there aren't any thermostats you can use the water temperature as a crude way to regulate the temperature but it produces problems like the one you have now.

If you can afford it, getting TRVs and maybe other updated controls would be the way to go, as well as a radiator that can put out more heat - higher btu rating.

There is a cheap trick you could try: have a fan set to blow at the radiator. That will increase its heat output. Not a permanent solution but handy for a little while.

Another cheap thing to try is setting the boiler temperature control to maximum. The hotter circulating water will increase the heat output of all of the radiators. You can use the TRVs in the living room and spare bedroom to avoid those rooms getting too hot, just turn down the TRV if necessary. This will probably help with the hall temperature but also make some other place too warm. A towel over the radiator can cut the output into that other place. If this lets the hall get to a comfortable temperature that would suggest that the radiator there already can put out enough heat and adding TRVs to the places which get too warm at the higher boiler temperature would be the way to go.

It's also possible that as part of the original balancing of the system the flow control valve on the hall radiator has been turned down. Less water flow means lower heat output, more means more. Adjusting that may need a cover to be removed on one end then a screwdriver used to adjust. Can be done DIY.