A panic room is build to prepare for the extremely unlikely event of a home invasion.**
A more likely event would be a weather event (storm, tornado, etc.) or a loss of power/ heating.
It would make more sense to prepare a room with backup heat/ cooling systems to survive a power out or similar situation.
Solar/ wind/ generator power and some insulation...

Definitely a good idea.

My parents are older, and with the heat and humidity of the south power outages can be dangerous for them. For about a month our central air was out of action in the middle of the summer, though we still had power, and a little window AC unit was a lifesaver by making one room bearable. I've since purchased a small generator, nothing fancy but enough to run it in case the power did go out. The alternative was to have them hang out in the car most of the day with the A/C running, and it's good IMO to have tiered PACE like contingency plans that start at your familiar standard of living, then if something happens (like weather or power outage) you can change gears seamlessly to the next level down, and then down further as the event extends in time or severity and supplies have to be stretched. In addition to the generator we have the car, a small inverter for the car, plenty of battery banks and small solar panels to cover things like basic lighting and personal electronic power, we can transition from electrical stove to grill or camp stoves to cook food in the freezer if needed, an alternate source of water, etc.

Puerto Rico post Maria was an eye opener for me when it came to preparedness, when you may face extended durations where you're simply on your own without power, and COVID was another eye opener, illustrating just how difficult it is to self isolate even for just two weeks without having to venture out for resupply. It was mostly an inconvenience with COVID, but a pandemic on this scale could have easily been far worse.

We had a tornado a few years back, our station was called out for the recovery effort that night. I shot a video the morning after:

https://www.youtube.com/watch?v=FfkCe0I6Xso

They really do skip some houses and completely obliterate others (like you see near the end of this video). Luckily no one seriously hurt, but it got me thinking about building a classic tornado shelter out of cinder blocks like the old FEMA manuals

Simply wearing wet cotton drops your temperature dramatically. As we all know.
In the right circumstances 'death cloth' becomes 'life cloth'.
Wet with tepid water. Too cold a drop is dangerous.
Qjs

some recommendations from a 73 year old, living on the central Gulf coast of Florida since 1955

inverter generator and either small shaker style window A/C or a portable A/C... the portables are around $400 and the small units around $125.. adapt the inverter to run off bulk 5 gallon fuel cans

I very seldom lose city water pressure, but my hot water tank holds for about 2 days... a dedicated black painted garden sprayer is used to provide warm water to shower and shave... source (stored) of fresh drinking water, and back up option (filter/pool shock/boil)... access to non potable water to flush toilet (directly into bowl)

my flat Asian style grill (mine is a Gas One)runs on both butane and propane... heats water for bathing or coffee... a small portable tail gate style grill cooks bamboo skewered meat and foil packet burgers... hot water bath warms hot dogs, and warms canned style soups provides hot water for clean up

battery powered construction fan or camping fan to provide air flow... a dedicated power strip to control all your charging devices

7 day cooler to hold frozen and perishable foods... 3 or 4 frozen gallon jugs can hold for multiple days... if possible pre chill prior to a forecast weather event... I try to transfer prior to power going out... it most likely will happen

standardize re charge batteries... for task light(headlamp), area lamps, and weather radio

have cash on hand and secure transport case for important documents in case you need to evacuate... keep auto fuel tank as topped as possible

quick dry clothing, brimmed hat, and foot wear... patio or camping chairs for out of door relaxing... there is no clean up worth a heart attack

a trailer hitch ball on a riding mower allows you to attach a utility trailer for cleanup... I use an electric chain saw

just some thoughts off the top

Lights, a bed or cot, water, radio...

If you have a basement, it will stay more temperature regulated than the rest of the house.

If you are planning for the possibility of evac, most everyone has a suitcase of duffel or backpack, keep it ready with a few items like change of clothes, spare underwear and sicks, spare USB cable and 12v and 120v plugs to charge your phone from, spare toiletries and medicines.

We have three basic plans for weather.

1) Most weather, we don’t do much other than close the windows. We don’t have a lot of launch hazards; if high winds are called for we’ll secure a couple things in the back yard.

2) We do get tornados. When the sirens go off we take all the people and dogs and pile into the bathroom in the basement. Structurally it’s our best bet.

3) Our default posture for weather-related problems is to bug-in. I have a generator — it’s not big enough to run our AC but could take care of the fridge and several other things. In a hard rain during a power outage we’d need to run both sump pumps, that’s something we’d have to manage carefully. This year I added an indoor-safe propane space heater (and I do have CO detectors). Worst case in cold weather is pile everyone in one room, seal it with plastic drop cloths, and run the propane space heater but only while there is an adult on watch.

I have eyes on a larger multi-fuel generator and a transfer switch, but for now I’m holding off.

We fill gas tanks when severe weather threatens, so we can leave, siphon gas to run the generator, and so on.

If we were to lose power, water, and natural gas, it wouldn’t be long before we decided to leave.

I've thought about a manual boat/kayak bilge pump for sump pump backup for when we are bugging in, keep meaning to get one and test it.

I agree with Eugene
In our hot region, people used to have a basement in almost every house. It was a primitive application of geothermal air conditioning. Now, building costs and leaking water has made this option problematic.

Off course, it is not a wise choice in easily flooded area.

Speaking of basements

A few years back I saw a few episodes of "Doomday Preppers" on TV. And one of the "preppers" had a twisted idea of saving his family which was bugging-in a basement under s commercial building in the downtown part of a city !!! I was surprised to say the least, what was he thinking when he drew this plan. The only entrance to this basement was from the footpath itself. His wife was upset and didn't like their "test run", and I didn't blame her. At the very least, some debris from the building itself could have closed their entrance shut and they will have no way of escaping. Not to mention you need to stay away from downtowns , not go IN.