Modern Radiators are they more efficient...

[rqy99g]

... than their older counterparts?

I'm just replacing the kitchen in a house we moved in to this year (now sick of living in a mess!) and one job leads to another. Looking at the kitchen diner now and the only thing which won't have been replaced is the dining room radiator. it is a double 4' 9" (175cm) x 1' 5" (43.5cm) with no convector fins. Will a modern radiator (say 500 x 1600 double) be more efficient?

Externally the radiator looks in good nick but I'm guessing it was put in when the house was built 40 years ago so may not be as good inside.

 

[Mottie]

If you replace it with a larger double rad with double fins it will definitely chuck out more heat.

 

[Madrab]

If a double panel radiator has internal fins against one that doesn't, it will heat the space more efficiently. It turns a 60/40 convection/radiant radiator into a 90/10 radiator. They have similar heat outputs but heat the space in a different way.

 

[rqy99g]

Cheers

 

[oldbuffer]

Just out of interest, no radiator is any more efficient than any other. Some heat up quicker but cool down more quickly (aluminium). Some give out more heat than others (e.g. those with fins against those without), but use more heat in the process, which the boiler has to supply.
The way to do it is to calculate the heat loss requirements of the room, and size the radiator output accordingly. Anything else is down to aesthetics.

 

[rqy99g]

Just out of interest, no radiator is any more efficient than any other. Some heat up quicker but cool down more quickly (aluminium). Some give out more heat than others (e.g. those with fins against those without), but use more heat in the process, which the boiler has to supply.
The way to do it is to calculate the heat loss requirements of the room, and size the radiator output accordingly. Anything else is down to aesthetics.

Somewhere at the back of my mind I was thinking along these lines and is one of the reasons I asked the question. Thanks.

 

[Madrab]

Radiators with convection fins will heat the space in a different way than those without, rather than actually give out more heat, they just use the heat more efficiently IMO. A radiator with fins will use convection to heat the air space as against radiation and therefore won't need to be on for so long before the room is up to temp, the TRV shuts the rad down and shut the boiler off.

This is why most modern convection radiators have at least one set of fins.

Perfect real life example - Was asked to put a modern column rad with the same output as their older Type 22 double double convection radiator into a room @ 1750w. Recommended against it because in my experience it wouldn't heat their bay windowed, 3.2m ceilinged room properly but they were adamant they wanted the look. Was back a month later to change it to a Stelrad Softline Deco @ 1750W output, huge difference, customer much happier with a much warmer room.

IME it's not all about heat output but more so the way it heats the air space.

 

[rqy99g]

Good stuff Rob, thanks.

 

[ericmark]

My old house I had a rather small Myson radiator with an output of 3.5 kW it must be 30 years old, the new iVector I am sure is better, but more down to automatic speed adjustment rather than more efficient.

What is efficiency? I would say down to speed at which it transfers heat, and to increase that all you need it to paint in mat black, the old Myson the matrix was mat black, OK behind a wood box so you can't see it is black.

But the problem is more down to radiator and controls matching the boiler, if the boiler is setting modulation rate by the temperature of the return water having a radiator where there is no restriction to water flow, and it uses the fan speed to adjust output is not really going to work, unless piped in series not parallel.

One odd fan assisted in the kick space in the kitchen OK, but in the main the boiler is designed to use non fan assisted with lock shield valves and TRV's controlling the flow.

The less water in the system the faster radiators can heat up, and the less heat the radiator stores the better, with the old on/off boiler the old cast iron radiator was good, but not with a modulating boiler.

 

[foxhole]

Rads are available a single, single with fin, double, double with fin , choice is dictated by required heat output and available space.