Here is a check list of what you need to properly care for a SINGLE Sav. Keep in mind these are MINIMUM requirements.
1: A water proof solid topped 8 x 4 x 4 enclosure for an adult and about half that for a juvie.
2: 2 feet or more of a nice moist dig able soil is best. You can buy top soil and play sand from home depot or any garden center and mix it in about a 50/50 ratio. Your going to have to get your hands dirty to find the right amount of water to add. You want it to make a dirt ball in your hand but still fall apart when you poke it with your finger. Cypress mulch is a very, very distant second since it will not hold a burrow but will retain a good amount of moisture . It is NEVER recommended for females. For females you should ALWAYS use a dirt mix. The importance of proper substrate can not be stressed enough.
3: A 130F+ MINIMUM basking spot (Realize we are NOT talking about air temps. We are talking about the temp. of a SPOT in the cage. In this case a raised plywood board. This can be provided with a single or couple of 45 watt halogen FLOOD lights suspended about 8"-12" over an elevated wood "Retes" stack (Named after the great Frank Retes of the Goanna Ranch) like in these pics



That juvie Sav is basking on a surface temp. of over 150F!!!!!look!!!!

4: Air temps ranging from 85F or so on the warm end down to 70F on the cool. The best part is in a solid topped water proof cage with that nice dirt in it, all the heating(basking and ambient air temps) can be achieved with just the basking flood lamps (ha ha! To the guy using that 150 watt what ever, with the screen lid and still cant get the right temps and humidity!). In a setup like this your basking lights can be run 24/7 for providing heat and basking opportunity's on the monitors schedule not yours. All in all the total temp range should be from 130F+ down to 70F+
Here is a pic of a raise up cage of mine

Its 4’x2’x2’ and is constructed of melamine way over sealed with poly. and silicone. The top is plexi. The substrate is a foot of topsoil/playsand and all heat is provided by one 45watt halogen flood set to provide a basking temp. of 125F.
This pic shows very clearly the benefits of using deep dirt as a substrate

Now this adult male savannah monitor setup



It is made from 2x4’s and plywood sealed with linoleum sheeting and LOTS of silicon. Its 7’x4’x4’ and the hinged top is plywood with plexi cut outs. Heating is done with three 60 watt floods run through rheostats for one basking spot set to 155F and a second basking spot of 130F and a 3rd basking spot set at 120. The substrate in the pics 200lbs of topsoil, 200lbs of playsand and 200lbs of cypress mulch all topped of with some leaf litter. Again these are minimum requirements. When keeping varanids bigger caging and more choices for the lizard is always best.