CH Question

Radiator design hasn't really changed that much in the last 25 years - except that fins are far more prevalent, which increases the output. Other than that, they simply obey the laws of physics - so the output is a function of the surface area and temperature differential.

Until a few a years ago it was common for radiator manufacturers to quote the output at a delta-T of 60 ('cos it gives more impressive numbers!) but many are now quoting at 50 or less - probably with condensing boilers in mind. [I suspect that they have to, in order to comply with some standard or other].

By all means come back with another thread if you can't make your heat loss calcs, radiator capacity and achieved room temperature stack up.

I was thinking materials may be better. We got two towel rads for the bathrooms. They have no panels or vents, just horizontal tubes and boy can they heat a room!

Kostas

Towel rads are not actually renouned for giving out much heat - so perhaps yours only have a small space to heat.

As far as ordinary rads are concerned, a white painted rad is a white painted rad. If you raise its temperature to a given value by passing hot water through it, it will give out the expected amount of heat by a combination of convection (mainly) and radiation. If you put fins on it, it will give out more heat due to the increased surface area for the convection air to pass over.

Stainless steel towel rail rads give a lot more heat out than chrome plated ones, about 40% if I remember.

However the towels which are often hung on these rads ( I wonder why !!) reduce the output by even more.

I have the predecessor of these (the 1100s) for a 5m2 tiled bathroom.