I have a horsfield who lives indoors, she has a uv light (one the energy saving ones) that has a high emitance. am I meant to get a red heat lamp too?
the temperature is above 25 in the day and 20ish at night.

that sounds a little cold.
you should have a UVB light and a heat bulb (normal house bulb will do) for day time. Temps under the heat lamp should be around 30º to 35ºC (90º to 95º F) and 20º ond the oposite side of the enclosure. If temps are to low, the tort will slow down or sleep all the time.
What else do you have her set up with?
If you can, post some pics.

forgot to mention: 20ºC for night temp is just fine. It's your day temps you need to worry about, it seems.

It is so cold here (even inside) that we have the 110watt power sun and a 50 watt redlight to help raise the cool lend temps to healthy levels.
I am sure in the summer we can turn off the red light but it is on now 24/7 for our Greek.

I read on the Bearded Dragon forum that it has been found that those coil bulbs are causing a lot of trouble with critters' eyes and causing medical problems. Just to be on the safe side, you might want to change to the tube type.
Patsy

You are right. We had the issue with our guy (rankin beardie). After we got the 10.0 coils that were supposed to be so great our guy lost his appetite and seemed to be hiding. Out of curiosity I replaced those with the Power Sun and...what a surprise within 2 days he was back to his curious hungry self.

This site has a plethora of information and statistics

http://www.uvguide.co.uk/mercuryvapourlamps.htm