80x40x40 terrarium heating

Hi, I'm buying a new terrarium for my ball python. Terrarium's dimesions are 80x40x40 [cm]. What kind of heating device would be the best? So far I have been using a heat mat and it served me good, but I don't know what size and voltage terrarium this size requires to keep optimal proper temperature.
Sorry for my bad English, I'm a foreigner.

Well, you're definitely going to need an additional heat source. Your UTH (under tank heater/heat mat) is there solely to provide a hot spot, primarily to aid with digestion. Heat mats aren't made to supply ambient temps.

This is where it becomes a matter of personal preference...

A) Heat bulbs in a heat lamp are your cheapest way to go. They are cheap to buy, but fail fairly regularly and draw a decent amount of electricity to run.

B) CHEs (ceramic heat emitters) run through a heat lamp are a bit more expensive, but are not going to break or die.
They also draw a decent amount of electricity to run.

C) RHPs (radiant heat panels) cost more initially, but run more efficiently. Once you buy one, it should last pretty much forever too.

Just an important reminder: ALL heat sources should be run through a thermostat. This can prevent dangerous heat spikes which can cause burns or even death to your snake. It also makes regulating temps pretty simple.

Thanks for your answer!
So I should use heat lamp and heat map?
Also I'm using a thermostat.