I know everyone has an opinion about this, I thought there might be some definitive wisdom on this forum.

Either,
put them under the windows to heat the cold from the window, and stop a convection circuit with cold air from the window sitting on the floor

Or,
don't put them under the windows because of heating the outside through the wall and window.

Everyone agrees, If on an outside wall put insulated reflective strip behind.

Our problem is that the room feels cold whatever we do to the thermostat.

Any ideas?

Thanks,

Peter

Thermals. Anyone who is into the outdoors will tell you a decent base layer is the key to staying warm. Why is it any different in the house?

Thanks for the responses,

The system is balanced according to our heating engineer, and there is no air.

Thermal undies are out, houses are, or should be, different from the outdoors.

Tony, why not use reflective strip IF on the outside wall, and why not put on the outside wall?

Peter

The primary purpose of domestic heating system is comfort, not saving the planet nor minimum cost. Maximising the comfort/cost ratio might be achieved by burning refuse in an open fireplace....

For comfort, put your rads where max cooling occurs - firstly next to external doors, secondly windows, thirdly external walls. Humans object to temperature gradients aka 'cold spots' in rooms/houses. A quick test is to see if the rad is too hot to touch; if it is, then it is probably undersized or possibly wrongly positioned. If only warm rather than really hot, and does not provide comfort, check (1) no system malfunction (2) rads are balanced ie the hot water flow is not being stolen by other rads (3) the ch design is correct ie rad is properly sized, the heat loss calculation is correct, the supply pipes are adequate size and the water temperature is correct (4) excessive draughts

If none of these gives an obvious line of enquiry, it is probable that heat losses have been underestimated, as assumed insulation values in real life are error prone. Try replacing the rad with a larger output rad.

Tony: sorry, but I think your technical analysis is wrong. If you have a sink with no plug, you can keep it full of warm water but undisturbed by feeding a suitable inflow of cold water direct to the wastepipe, therby preventing the water in the sink escaping. We've all witnessed similar events when two sinks/baths or whatever are coupled to the same wastepipe and discharged simultaneously....

Your proposal results in uncomfortable temperature gradients across the room as heat is transferred from the rad side to the opposite external wall side. The room under your proposal is not a simple box at one homogeneous temperature.