Painting a radiator is dead easy as long as you prep properly — the heat is the only thing that catches people out.
First rule: turn it off and let it go stone cold. Painting a warm radiator means the paint flashes off too fast, you get brush drag, and the finish ends up patchy. Cold and dry, every time.
Prep is the bit that actually matters. Sugar soap or degrease the whole thing to shift any oils, then give it a key with 240-grit so the new paint has something to grip. Hoover the dust off and wipe down with a tack cloth or a damp microfibre. If there's any flaking, rust, or bare metal showing, spot-prime those patches with Zinsser Cover Stain or a dedicated metal primer like Hammerite before you topcoat — bare metal will let you down otherwise.
For the topcoat, you don't strictly need a specialist radiator paint these days. A good water-based eggshell or satinwood from a quality trim range will cope with central-heating temperatures without yellowing or cracking. Little Greene Intelligent Eggshell and Dulux Heritage Eggshell both wear well on metal and brush out beautifully. Two thin coats beats one thick one — thick coats sag on the curves and trap heat.
The big question people ask: *can I paint it the same colour as the wall to make it disappear?* Yes, and that's exactly what I'd do. A radiator painted in a soft neutral like Farrow & Ball Slipper Satin or Ammonite, or a warm white like Strong White, vanishes into a matching wall far better than leaving it factory gloss-white. If you want it to feel like joinery, go bolder — Down Pipe on a radiator under a window looks proper smart.
Use a small angled brush for the panels and a thin sausage roller for the flat front. Mask the wall behind with FrogTape and pop some card down the back. Leave it 24 hours before you fire the heating back up — rush it and you'll bake in brush marks.