Last week we shifted the tank stack around, so the kids could better access their pets. The boys were very helpful but it meant a lot of carrying and re-wiring. The task was simplified, however, by our lack of reliance on electronic thermostats. There is no doubt that setup costs for reptile habitats are expensive. You need a decent vivarium, which must include a head source and probably UV light (depending on the species). Even a new 3ft vivarium can easily cost you £100 - £150. Adding on a T5 high output UV system and thermostat will soon rocket that cost towards £250 - 300, but is all of it really essential?
Conventional herpetological wisdom tells us that a tank MUST have a thermostat in order to control the environment and protect the inhabitants from overheating. I think there are exceptions to this rule, however, if you a) live in a temperate country b) keep desert species c) keep species that require relatively cool temperatures. If you tick these boxes then a more effective solution is simply to size the wattage of your spotlight appropriately. You cannot get away from the requirement for UV (if you keep diurnal lizards and other sun loving species of reptile) but you can avoid a thermostat.
Firstly lets look at the types of thermostat on offer: 1) pulse stats - only work properly with ceramic heaters because they would cause conventional bulbs to flash 2) dimming stats - drop the amount of power delivered through the system. This is not a very good solution where standard bulbs are concerned because it can literally drop the visible light to nothing more than a faint elemental glow. Again they are better with ceramic heaters 3) On/off stats - the cheapest variety and it literally switches off the heat source when a defined temperature is reached. This means that the temperature will fluctuate within a wider range but only about 1 - 2 degrees centigrade.
All of these systems have their limitations, as mentioned above, but the biggest problem is the inevitable cancellation of direct basking spots. Let me be clear at this stage - I do not like ceramic bulbs (see pic below) because they emit heat in all directions. This prevents generation of a hot spot, which would frequently be encountered basking in the sun. It is natural for reptiles to seek a bright, saturated area of sunlight where they can rapidly increase body temperature. A ceramic bulb is very good at warming the entire environment and certainly won't make the animal ill, but it limits natural behaviour and activity in my experience. I switched the ceramic bulb out of our monitor lizards' tank and they immediately headed for the new spot lit area, with activity rapidly increasing over the next few hours. This was not coincidence, it simply offered them a better opportunity to raise their body temperature to optimum levels.
When you use a stat the ambient room temperature is no longer a factor for your reptiles, The stat will maintain a temperature within the range you set. If the cool area is supposed to be 30 degrees, then that is what it will be. This is sensible if you live in an extremely cold or hot country and don't have central heating or decent ventilation, but if you live in a temperate climate (as we do in the UK) then you can make the ambient temps work to your advantage and completely avoid the need for thermostats.
It is all about right sizing the spotlight wattage to the size of your enclosure. Now this may mean dropping down to a spotlight no more than 25 watts, but such a bulb can still generate localised basking areas of 40 degrees and will also facilitate an excellent temperature gradient for your animals. As the ambient temperature increases throughout the year, then so too will the temperature of your tank and indeed the basking spot. Mother nature helps to keep your pets in sync with the seasons. For example - we have our pair of cunningham skinks in an enclosure approximately 90cm long x 45cm x 40cm. A 30" UV tube provides a small dose of background heat and of course the all important sun-like UV energy. At the far end is a 25 watt spot light. During winter the ambient room temps can drop as low as 18 degrees at night but at the height of summer you could easily be sitting in 24 degrees during the day. I know - from trial and experience - that the summer temps will never be too hot without a stat. Likewise in winter they will never be too cold. The bulb is sized so that even the most extreme of heat waves will not put the animals at risk. Yet it can stay on 12 hours a day during summer and provide a localised hot spot that closely mimics wild conditions.
A conventional reflector (see pic below) has the added advantage of creating a wider temperature gradient, something that ceramics struggle to achieve in smaller enclosures. So if you live in a temperate country it is possible to avoid the stat completely. Just make sure you get the bulb wattage correct and always use a spotlight design, so heat is focused downwards. As stated earlier I would recommend this approach more for desert species that are used to a wide range of temperatures or those that, in a temperate climate, will require hardly any background heat at all (think New Caledonian Giant Gecko).
At this time we do not have any active stats - they have all been turned off. It is worth mentioning that one clear disadvantage of standard spotlights (halogen or otherwise) is the reduced life span vs ceramic bulbs. Nonetheless they are normally cheaper to purchase. I check the bulbs daily and will switch them every four months, whether they are still working or not.
Our New Caledonian Giant Geckos have only 5 watt bulbs during the day and 7 watt fluorescent night lights. These both push the ambient temperature up about two degrees, which is ideal for increasing their metabolism but - in conjunction with the seasons - maintains a perfect year round temperature range. In winter the daily temp is around 24 - 25 degrees and at night time it varies between 20 - 23 degrees. In summer the daily high is never more than 29 degrees and at night 27 degrees. All this is possible if you size the heat source to the size of enclosure. There is certainly no need for a stat and rather it would be counter productive - preventing the very natural fluctuation that occurs as part of daily changes in external ambient conditions.
So if you live in a place with generally mild weather - like the UK - you certainly do not need a stat :).
