Underfloor heating

Kirkmain

So i've bitten the bullet and turned on my electric underfloor heating for the winter. Can someone clarify, is it more or less expensive then gas central heating per heat supplied? I know electirc is more expensive then gas, but isn't heating the room up from the floor more efficient than a plumbed radiator sat in one corner of the room?

Also is the most cost effective way really to just leave the matts on round the clock? or to turn off and then on as required?

Netexporter

In crude terms a resistance electrical heater is 100% efficient, a modern condensing gas boiler should be about 90% efficient, if the system is correctly set up. Gas is about a third of the price of on-peak electricity, so gas wins hands-down.

If you have a smart meter you could go on a TOU (time of use) tariff, to reduce your electricity price at certain times but unfortunately the cheapest times probably won't coincide with when you want the heat.

QrizB

Kirkmain said:

So i've bitten the bullet and turned on my electric underfloor heating for the winter. Can someone clarify, is it more or less expensive then gas central heating per heat supplied?

More expensive, typically 3x more expensive (depending on a whole lot of variables).

Kirkmain said:

I know electirc is more expensive then gas, but isn't heating the room up from the floor more efficient than a plumbed radiator sat in one corner of the room?

No, not really, although you'll have nice warm feet with electric UFH that you wouldn't have with a plumbed radiator!

Wet UFH is different, as it lets you set a lower water flow temperature (vs. radiators) and potentially improve the efficiency of the boiler. But you don't get that with electric UFH.

Kirkmain said:

Also is the most cost effective way really to just leave the matts on round the clock? or to turn off and then on as required?

The most cost effective way is to turn them off and use your gas CH instead. I'm assuming that isn't an option!

Otherwise, turn them off when not required. Electric UFH is no different to any other direct electric heating - panel heaters, IR panels, electric combi boilers, oil-filled radiators, fan heaters, magic German clay - in that respect.

matelodave

Actually leccy is now around four times the cost of gas unless you are on something like an E7 or E10 tariff. This is directly from the Eon-Next website

From 1 October the price per kilowatt hour (KWh) for customers on the default tariff will be 27.35p per KWh for electricity and 6.89p per KWh for gas. Ofgem has raised the daily standing charge slightly to 53.37p for electricity and 29.62p for gas.

Depending on what sort of underfloor heating you've got, proper stuff buried in the floor screed usually works like storage heating and should be using off-peak leccy to charge up over night and then slowly let it out during the day.

Overlay matting under the tiles is generally much more expensive to run as it tends to be used "on demand" and therefore runs on peak rate leccy.

To get a better answer the OP needs to specify what sort of heating they have, what tariff and what sort of controls before anyone can give a reasonable answer

Rodders53

MUCH more expensive.  Check your own supplier's  prices for Gas units (per 1 kWh energy, not cu.m or cu.ft the meter reads) versus Electric unit 1 kWh.  EDF suggest that from 1st October it will be 10.3 p gas and 34 p electric on average...

There's some that suggest having warm feet means you can run the room(s) at lower temperatures than with convector radiators.  But electric is 100% efficient and condensing gas boilers slightly poorer (90-99% claimed) but even so gas is still far cheaper.

Electric UFH is quicker to respond cf wet system with concrete screed UFH. So likely it won't need to run all the time.  You'll have to experiment with controls to find out how you like it, and if yours allow a choice of temperatures at different times... or not.  Use a smart meter or similar energy monitor to record what the UFH is using!!

Our oil fired wet UFH won't be going on until it gets a lot colder here as it takes hours to get 'warm' (heating the slab up first) then overheats the rooms if we get any sun (solar gain).  We have ashp to warm the main rooms in the 'shoulder' months (that produce 3 kWh of heat for 1 kWh of electric input so roughly 'matching' gas prices).  This thread has made me a tad less concerned that my Kerosene looks likely to be around 8p/kWh when I order 1000 litres next week (I still regret not ordering 900 litres in Summer when it was cheaper, though).