Selecting wattage for outdoor shelter

[LobsterOfJustice]

I have built a 2' x 4' outdoor shelter which will be located under our deck (although not up against the house) in our outdoor enclosure. I'm planning on running a Vivarium Electronics radiant heat panel on a VE-200 proportional dimming thermostat. I live in North Carolina, zone 8a which technically means average annual extreme minimum temperature of 10-15* F. Typically, throughout the winter we will get lowest lows around 25 - 35. Rarely lower, often higher (50's). Daytime high temps are almost always above freezing, usually 40s - 50s, sometimes as high as 70s. Pictures of the house structure for reference are below. It has R 7.5 insulation (2 x 3.75) and 3/4" boards on the outside and inside (inside boards not seen in construction pics below). Right now I don't have any plastic curtain over the entrance but I'm considering adding it.

This will be for a Hermann's tortoise. My strategy is to allow the tortoise to brumate, so from what I can tell, I really only need to maintain temps around ~45 *F. However, given that we often have weather much warmer than that throughout the winter, the tort may not be in proper brumation some or all of the time (?). So not sure if I actually need to be targeting a higher temp.

1. In general, is my strategy of RHP + proportional dimming thermostat the preferred path forward?

2. What wattage RHP do I need? They offer 28, 40, 80, and 120. I dont mind getting the biggest one since it will be on a proportional dimmer, just to have the capacity in case I need it (especially in the event that the tortoise "wakes" during a mild week in January and then temps drop again when it is not brumated). Any downside to that strategy?

 

[LobsterOfJustice]

Pics

 

[S2G]

Thats something id do more for like a sulcata night box. Hermanns will be just fine without all that. RHP's are sized per cubic ft though & designed for room temps.

Im in AL, but i have a good bit of experience with eastern hermanns. I provide deep double shade & an underground hide for our summers. Winter time I use to use cold frames on a house like you built, but our winters are crazy inconsistent with temps so i always worried about one of them getting out & freezing. I skip brumation if they act funny or i just got them.

What im doing now for is chemnerds brumating process. After they settled down for the season you put them in a box where they can bury & then i keep them at 40F on a temp controller that kills things before it freezes. I have a little fridge setup in the garage now from end of nov to march.

 

[Tom]

I have built a 2' x 4' outdoor shelter which will be located under our deck (although not up against the house) in our outdoor enclosure. I'm planning on running a Vivarium Electronics radiant heat panel on a VE-200 proportional dimming thermostat. I live in North Carolina, zone 8a which technically means average annual extreme minimum temperature of 10-15* F. Typically, throughout the winter we will get lowest lows around 25 - 35. Rarely lower, often higher (50's). Daytime high temps are almost always above freezing, usually 40s - 50s, sometimes as high as 70s. Pictures of the house structure for reference are below. It has R 7.5 insulation (2 x 3.75) and 3/4" boards on the outside and inside (inside boards not seen in construction pics below). Right now I don't have any plastic curtain over the entrance but I'm considering adding it.

This will be for a Hermann's tortoise. My strategy is to allow the tortoise to brumate, so from what I can tell, I really only need to maintain temps around ~45 *F. However, given that we often have weather much warmer than that throughout the winter, the tort may not be in proper brumation some or all of the time (?). So not sure if I actually need to be targeting a higher temp.

1. In general, is my strategy of RHP + proportional dimming thermostat the preferred path forward?

2. What wattage RHP do I need? They offer 28, 40, 80, and 120. I dont mind getting the biggest one since it will be on a proportional dimmer, just to have the capacity in case I need it (especially in the event that the tortoise "wakes" during a mild week in January and then temps drop again when it is not brumated). Any downside to that strategy?

1. The dimming thermostat is not necessary, but also not harmful. Inconsistent winter temps are one of the things that kill tortoises during brumation. It needs to get cold and stay cold. If your box is well insulated, it might stay cold enough when those daytime highs get into the 60s or 70s. Only your thermometer can tell you. I used a 4x4 box and brumated my Chersina outside. We have warm sunny days here in the 60s and 70s through winter, but cold nights in the low 30s usually. My boxes stay an average of these temps. During a few winter warm spells, I have had to put ice bottles in the boxes during warm days, and then crack the lids over night to let cold air in. I was shooting for 45-50 for Chersina, and I was able to stay in that range all winter with a little effort here and there. Using a fridge is much safer, more consistent, and less hassle.

2. Only your thermometer can tell you what wattage to use. There are too many variables. Since it is controlled by a thermostat, I prefer to go with the larger wattage panels. If the extra watts are not needed, the thermostat will keep it off. Having said that, you aren't trying to make it a tropical island paradise in there. It only needs to remain 60ish for a hermanni, and occasionally colder over night won't hurt anything. What I have discovered that is a total game changer is the basking lamp in the box. For years I always struggled with weather extremes while I was trying to get them ready to brumate, and after I woke them from brumation. I needed some warm sunny days for them to empty there gut before brumation, and the weather would turn cold and cloudy too soon. Likewise, we'd get a warm spell in spring for two weeks, so I'd wake them all and get them up and running and eating again, only to have a long spring cold rainy spell set in after their guts were full of food. This drove me CRAZY for years. The heat lamp solves this problem. The RHP maintains ambient so it doesn't get too cold over night, and the heat lamp could be used when I needed them to be able to bask in the "sun", but the sun was not cooperating. On warm sunny days in spring and fall, I simply left the heat lamps off. During unseasonal cold spells, I would run their heat lamps on a timer and this would allow them to warm up and function. It also warmed ambient up in each box on colder days. It works great.

Check this thread out for brumation info:

Tom's Brumation Thread

Every fall we get bombarded here on the forum with all sorts of questions and problems regarding hibernation and tortoises "slowing down" for winter. The purpose of this thread is to talk about all aspects of this subject, to dispel some of the myths and mysteries, and give a "how to" list of...

tortoiseforum.org

 

[LobsterOfJustice]

This temp is if they’re not in brumation, correct?

It only needs to remain 60ish for a hermanni, and occasionally colder over night won't hurt anything.

 

[Tom]

This temp is if they’re not in brumation, correct?

Correct. 40-45 for brumation. I have not experimented with higher or lower brumation temps for this species, so I would not argue with someone who was having success at slightly different temperatures.