David Hansen wrote:
On 14 Aug 2006 03:25:41 -0700 someone who may be "mkkbb"
wrote this:-

I have a solid concrete floor which we are ripping up and going to
re-lay.

In addition to operating the underfloor heating at a lower
temperature to radiators, so that people can stand on the floor,

So that the floor is not destroyed...

underfloor heating also has different time characteristics. It can
be turned off earlier than radiators (because the floor provides
thermal storage) and will probably need to be turned on earlier.
Thus it should be on a separate time control, have a room thermostat
and ideally the pump and mixing valve should be arranged to
compensate for outside temperature. All this is no great hardship as
controllers are available to do all of this.

Yes to all of that.

I run about a three hour lead on hours..strangely enough it only takes
about half an hour from switchoff before you notice that its off..the
heating is SO constant and even that the slightest change - a door
opening etc - makes you realise its changed. In deepest winter I run it
24x7 anyway, because we have so much thermal mass it scarcely makes any
difference to the cost.

We find that we don't have any hot or cold spots though - apart from
under the sofa. THAT is up to maybe 35C sometimes..the pets LOVE UFH.