Can anyone advise me on electric heating. I have the luxury of economy 15. I need to install electric heating in a flat of one large lounge/kitchen and two bedrooms.  I do not like storage heaters.

You may have an E15 meter but does anyone offer a E10 or E15 tariff? I haven't looked at multiple rate tariffs for some time but couldn't find much on this. Some E7 tariffs seem to be available but most comparison sites seem limited to E7?

Standard daytime rates make Electric heating relatively expensive compared to other sources such as gas or oil. Per KWH Electricity is three times the cost of mains gas. If you have mains gas available and plan to live in the house for awhile I would consider that instead of electric.

There are only two ways I know to reduce the running cost of Electric heating..

1) Some form of heat storage. Could be storage heaters or a thermal store feeding wet rads/UFH. Both work by using the cheap night rate and releasing the energy during the daytime.  A typical thermal store would be a big tank of water. Has to be correctly sized and well insulated. Perhaps too big for a flat?

2) A Heat pump. These use electricity to move heat from outdoors to indoors. Similar principle to a refrigerator or air conditioner in reverse. They typically have a performance gain of 2-4 so reduce your bills by a similar amount making the running coat comparable to mains gas. However they are expensive to buy and the design and installation is critical. Perhaps not suitable for a flat due to the noise they make.

It's worth understanding that the amount of energy you need to heat a house depends mainly on how well it's insulated, how warm you want it and for what percentage of the time (eg Is the house empty during the day?).  This is because virtually all modern heating systems are 80-100% efficient.

I would look at some sort of storage system, either storage heaters or a thermal store.

If you discount storage then there is little to choose between the various standard electric heaters. All electric heaters are 100% efficient in that they all convert 100% of the electricity into heat. What matters most is that the system is controllable to suit your lifestyle so that they are only consuming and delivering energy when needed.

Some people/companies claim that UFH saves energy because it produces a warm comfort zone near the floor where people are rather than heating the whole room (or some similar argument). I have wet UFH and I'm not entirely convinced by this argument but others are.

One problem with UFH is that it takes time to heat up and cool down. This leads some companies to suggest you leave it on 24/7 (possibly with a set back thermostat). Thats fine if someone is at home in the daytime but I suspect it's wasteful if your house is empty because everyone is out at work. In that case I feel the fast reaponse of standard heaters/rads would be better.

In the past I have complained to the ASA about outrageous claims made by a manufacturer of electric rads and have had my complaints upheld. Take any claims that their particular design saves energy with a pinch of salt.