Here’s a question that may help with the bulb issue: Are you using a temp gun to measure the basking surface temperature? Sometimes people rely on those stick-on thermometers, which in addition to only measuring the general air temperature, can be mildly to severely inaccurate (sometimes being off by as much as 20 degrees). If you don’t yet have a digital thermometer, getting one could help us figure out if Lizzie’s lethargy is because her temps are either too cold or too hot. I think you mentioned she’s over a year old, and if that’s the case a good basking temperature gradient falls between 95-105 degrees (babies like it a tad hotter with a basking temp range that can be up to 110). So if you aren’t measuring her surface temperatures with a temp gun I’d get one ASAP. I use the ZooMed temp gun that’s available in most chain pet stores, Amazon, etc., but there are other options available at hardware stores as well. Once you measure her basking surfaces with the temp gun, you’ll know right away if you have a lizard that’s trying to avoid a too sweltering basking rock or doesn’t bother basking because her temps are way too cold. Both of these scenarios can be perceived as brumation and all it takes is getting the temps on track to reverse that behavior. My enclosures are 24 inches high and I find 100 watt basking bulbs work really well for that height. During the summer when our SoCal temps get toasty sometimes I’ll downgrade to a 75-watt bulb to offset the change and keep temps in the cages consistent. So the wattage of your bulb depends on your cage’s height, how high your basking objects are, and the material of the enclosure. The downside of glass tanks is that it can be much harder to retain heat in them, which is why (if you don’t have one) a temp gun is even more crucial to make sure she’s getting adequate heat. When I had my first baby beardie she started her life in a big glass tank, and because I lived in Oregon at the time, I became frustrated with the constant adjustments I had to make on a daily basis to get that tank to maintain decent temperatures. Once I bought a vivarium-style enclosure (three solid walls and a glass front) I was thrilled with how much easier it was to keep the temps on track. I didn’t have to worry about a screen top filtering out a percentage of her UV light, and I learned that beardies actually feel safer/more secure when surrounded by three solid walls (glass surfing was no longer an issue). If you’re thinking about upgrading her enclosure, you can actually build a pretty nice one for less than $150. My beardie collection is on the low side at the moment, but if I ever turn the corner and become the reptile version of a crazy cat lady I’ll probably start building the enclosures myself. There are some really great how to videos on YouTube and there’s also some good info on the enclosures section on this site. Some members have created and shared their cage blueprints and instructions and I’ve been amazed by many of the photos. I’m a huge fan of the 4x2x2 size for an adult beardie, which I think should be the minimum size for an adult. If the thought of building an enclosure is less than appealing, I’ve heard good things about the San Diego company DIY Cages and the line Dragon’s Den makes. I think both of these companies make enclosures that come with a basking bulb and UV tube light fixture. So this circles us back to your current issue. I apologize if this info was already given and I overlooked it, but:
1. Are you measuring Lizzie’s temps with a temp gun? If no, getting one should be a priority. We’ll be able to proceed and pinpoint if this is a temp issue once you’ve got one.
2. If yes, what are her basking surface temp or temps? I like to use staggered basking objects so a beardie can choose from multiple basking temps in the desired range (ex: current basking surface temps in my adults’ cages are 95, 98, 100, and 104). So you may have more than one answer to this question if that’s your situation too.
3. What is your UV light brand and model? Example: Is it a compact bulb or a long fluorescent tube?
4. How high is the cage/what’s the distance between Lizzie’s UV light and her basking surface?
The answers to these last two questions will determine if there’s inadequate UV reaching the lizard. Even if her basking temps are perfect, a UV light that’s too weak or too far away from the lizard could be the problem, especially if you have a screen top filtering out a percentage of that UV light (which isn’t necessarily an issue if you have a really strong UV light like a Reptisun 10.0 T5 tube light, but can render some of the already weak compact UV bulbs that have a low output even weaker/make them essentially useless).
I think we’re getting closer to an answer so any info you could provide on those topics will help immensely.