Underfloor or Rads – Heat Emitters – Heating

This is a quazzy energy question… but it comes up a bit, so…

So first, the principles. Underfloor heating and Radiators are “Heat Emitters”, which have the job of transferring the heat from the hot water, that was heated by your boiler, to the room. Rads systems generally operate using water systems at 55C. Under floor systems use water at 35C.

Installation cost

Radiators are cheap – Underfloor is expensive

Space they take up

Underfloor is out of site. Rads take up space, and some might even say are quite ugly.


Underfloor is fairly danger free. Rads are hot to touch, so might cause an accident

Heat up time – Response time

Rads can heat up a room quickly (since the water in them is hotter). With underfloor, it takes longer, so you need to have switched on the heating earlier to get the same effect (though being on for longer will not mean more cost, just longer at a lower setting)

Retaining heat

Underfloor is better for keeping a background level of heat in the house. See thermal mass


Lower temperature water is more efficient, so underfloor

If badly controlled, underfloor heating can be waste lots of energy, so rads

Modern Condensing boilers (the most efficient boilers available), work better with lower temperature systems, so underfloor

If properly insulated, the walls, and floor are a similar heat loss, so nothing here

Room Flexibility

Underfloor allows you to put furniture wherever you want. With Rads, that can be a problem

Rads allow you to have any floor covering you want. With underfloor, heavy carpets are a problem

Alternative technologies

Some alternative technologies, such as Geothermal Heating only work with lower temperature systems.


I think it is likely that the lower temperature thing will become bigger and bigger in the future. The hotter you need to get the water, the more challenging. So in my dream house… underfloor

Other points

Underfloor doesn’t leak (if put in correctly day one)… something which can’t be tampered with by people… is usually less demanding on maintenance. In fact… rads are more likely to leak. (just don’t hammer a nail into the floor)

Underfloor won’t burn your feet

Retrofitting underfloor = money pit


One Response to Underfloor or Rads – Heat Emitters – Heating

  1. I have both underfloor heating and radiators in my old farmhouse (ie. cold, damp and draughty however hard I try!). I love the underfloor heating but my hot water is heated by wood burning stoves, so the equation goes like this:
    option 1 turn on underfloor heating, keep the stove at top temperature all day and enjoy
    option 2 have a bath and run the washing machine with the bath water, let the fires go out
    option 3 turn on the rads in the sitting room and the bedroom later and if the stoves are kept running might even get a shallow bath!

    You get the idea, the underfloor just sucks heat, but it is soooo nice.

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