Central heating radiators come down to three checks: output, size and how the unit sits on the wall. More panels or convector surface usually give you more heat from the same footprint, while single-panel options suit tighter spaces and lighter loads. If the pipework and wall space are fixed, dimensions matter as much as output - the wrong size is the one that causes the call-back.
Halcyon by Stelrad K2 Compact Double Panel Radiator - 400 x 1600mm
White Type 22 compact double panel radiator, 400 x 1600mm, 2014W (6873 BTU/h)
Center Type 11 75SC30 Single Panel Single Convector Radiator - 750mm x 300mm 125…
750x300mm Type 11 steel radiator with 1259 BTU/h heat output
Type 11 Single Radiator - 600 x 1600mm 5092 BTU
Type 11 single panel radiator, 600 x 1600 millimetres, white enamel, 5092 BTU
Stelrad Softline Compact K1 Radiator - 450mm x 1600mm
450 x 1600mm single panel compact radiator in white
Center Type 21 75DX50 Double Panel Single Convector Radiator - 750mm x 500mm 274…
Type 21 double panel convector radiator, 750x500mm, 2740 BTU
Stelrad Compact K1 Single Panel Single Convector Radiator - 300mm x 1500mm
Compact K1 single panel single convector radiator 300mm x 1500mm
Center Type 11 Single Panel Single Convector Radiator - 750mm x 400mm 1679 BTU
White Type 11 single-panel convector radiator, 750mm x 400mm, 1678 BTU
Stelrad Elite K1 Single Panel Radiator - 600mm x 1200mm
White single panel radiator 600mm x 1200mm, Type 11, tested to BS EN 442
Stelrad LST Standard K2 Radiator - 800 x 1160mm
LST K2 radiator 800 x 1160mm, white, compliant with NHS safe surface temperature…
Prorad Double Panel Double Convector Radiator Type 21 - 700mm x 1100mm White
Type 21 double panel radiator 700mm x 1100mm, white, 10-year warranty
For central heating radiators, start with the system and the job spec, not the finish. A standard wet system usually keeps you in the same family of product, but the real checks are output, depth, and whether the pipework and wall space will take the size you want. On a tight swap, a slimmer panel can be easier to land. If the room needs more heat, you may need a deeper unit or a larger footprint. The install package matters too. Flue route, filter requirement, fuel type, and who’s signing it off all change what you should be buying.
Flat panel central heating radiators are the usual pick when you want a straightforward swap and do not need much depth off the wall.
If you need more output from the same footprint, a double panel or double convector version gives you that. The trade-off is depth. It sits further out and can be tighter on pipe centres and clearance.
Single panel units are slimmer and easier to place where space is awkward, but you give up output. Once you have fixed the room layout, Radiators is where you step back and compare the wider range against the job.
The first check is output against space. A deeper unit gives you more capacity, but it also stands further off the wall and takes more room around pipework, skirting and furniture.
On a straight swap, that often matters more than the finish. For tighter spaces or lighter loads, a slimmer panel is usually the cleaner fit. Column Radiators suit jobs where the look is part of the brief and you can live with the extra depth. Designer Radiators come in when appearance is driving the choice, but you usually give up some simplicity and sometimes some output for that.
Once you’ve picked the unit, the next call is what sits around it. If the room needs a cleaner finish, radiator covers are the usual add-on, but they do reduce output a bit and make access tighter when you’re back for a valve change.
Radiator foil is worth considering on older external walls where you want heat back into the room rather than into the masonry. For a neater install, radiator valves and the right parts and accessories matter more than people think - it’s usually the small mismatches that slow you down on site.







