A Central Air Heating Element, A PID and a Sauna

[JayPoorJay]

What could go wrong...?

I'm not sure if this is the right sub category or even the right forum but here goes,,,

I'll just dive right in. I want to see if it's possible and what it would take to use a PID Controller (or 2) to run a central air conditioning heater element (the kind that goes into an air handler) and a small blower fan... The application is a DIY Sauna... Am I nuts? Mean, these components could be had for around 100 bucks.

What do I need to be thinking?

Of course I will go to Vevor and order one of their 200$ sauna heaters so I can have some stones to pour water over for steam and such,,,

But is this idea feasible?
Is it worth exploring?
Open to thoughts and ideas 🙂

[sam_sam_sam]

Maybe it will depend on what you are trying to achieve meaning what temperature range are taking what swings are going to be acceptable how much time are you going to allow for temperature recovery or over/under temperature swings are going to be happy with limitations of heating elements

The size of the room are you planning on having how well will the room be insulated are you going to glass window all of these things need to look at to determine whether or not it would be feasible or cost effective to build your own sauna room or buy one that all the calculations have already worked out and then you just do heating elements and temperature controller or better yet see if you can just buy the sauna temperature controller you just need to know what amperage the temperature controller can handle and choose a heating element that is suitable for your current limitation of the temperature controller

I hope this helps you out on what you thinking about doing

One note about using air conditioning heater elements you need to have a enclosure for the heating element to be able to hook up a blower assembly to it and that there is no way for a human to be able to get in contact with the heating element this is going to be must do for safety reasons do not be tempted to bypass or not use the temperature high limit cutoff device because if you this will make this device dangerous to use

One other note you also need to make sure that you have enough air flow across the the heater element to not trip the high temperature limit switch because some of these heating element assembly have a one time extreme high temperature fuse and if you blow this one depending on the style of the heater assembly it might be replaceable although some styles are incorporated in the heater element and are not replaceable just be aware of this potential issue with them

One last note that you need to be aware of is if you want this is going to be a mobile unit you will need to have a tilt device mount on it if could accidentally flipped over also if it is a mobile unit you also need to have a GFCI outlet for safety reasons as well you can get them for 220 volt systems but they are going to be electrical panel type of meaning a breaker type device / you should do this even if it not going to be a mobile unit just for safety reasons

[JayPoorJay]

Saaaam! Thank you.

All of your points are spot on and well taken. Very much so. And although I have a good ways to go with my thinking about this many of the ideas you raise I have been thinking about as well...

Please know that safety is first and foremost. This is my wife and I's first new home, our dream home, and I would never,,,. I would scrap this idea in a second if it couldn't be done with great measure of safety.

What I am leaning about the PID is that it has the ability to really govern the in off times of the element. 40%, 50% 60, 70 80 for on of times. And, in that, a way to have the fan run only when and if the element is operating. The elements and associated ac systems are already designed that way.

And a BIG YES to a safe and isolated enclosure for the element and it's ducting. It's also part of the design and what the air handlers achieve normally, so it must be doable.

How do I wire and dial in the PID Controller?

For the element. Not this, but something like this. It's all wired up.(see attached link)

[JayPoorJay]

Oh. And for average temperature,,, I would say around 150 to 180 degrees. Far more than a home heater usually achieves but I think possible for an element of this type with a blower and air moving over it,,, running at like 40 or 50 percent....?

[JayPoorJay]

Another quick point, Sam... It will not be difficult for me to make a basic all wood construction Sauna, cedar is what I've been planning, with a vapor moisture barrier and heavy insulation...no glass. Minimal heat loss.

I think/believe that if I am able to figure out this heating and controller set up it would be possible to get the space (max 200sq feet) up to 160 170 degrees using the blower/coil element device and with the Vevor Sauna Heater pretty much keep it there, also making it so I can pour some water for steam. Basically supplementing the main heater.

One might wonder WHY I would go thru all this trouble so let me explain. COST - the cost of a good sauna heater for the size room/sauna I would like is ridiculous... I know the Vevor Sauna Heater I posted doesn't seem that way,,, but the Vevor Sauna Heater (as far as I know) would never do what I need reliably...

Then, for the cost, they take huge amounts of time (and energy) to get the Sauna space to reach temp and hold it. I believe this issue can be solved with the idea I/we are exploring. People report noticable increases in their energy bills.

I think bringing a sauna to temp this way, and regulating it with a smart PID Controller might be a big deal for a whole wave of DIY people (give a look at YouTube) who are installing and trying to figure out installing personal home Saunas and Steam rooms.

I need y'all's HEEEEELP, lol.
Even if it proves impossible it's worth a shot.

[stj]

this all sounds like a great way to die.

why not use a 3KW thermal curtain or fan heater and a cold-steam generator?

[JayPoorJay]

this all sounds like a great way to die.

why not use a 3KW thermal curtain or fan heater and a cold-steam generator?

Thanks for the reply STJ...

Honestly and seriously... Please describe the DIE factor. The reason I posted this idea here is exactly for that reason. Would you elaborate on the potential dangers you see...

I'm looking at a lot of stuff on the net and people are using PIDs and it's feedback set up to control various heating elements to do all sorts of things. From smoking meat to powder coating rims, to running heating in stills.

I'll get to googling thermal curtain, fan heaters and cold steam. There has to be a way to-do this without breaking the bank. Maybe even doing it in a way that is better than the more traditional ways.

I'm all ears.

[JayPoorJay]

this all sounds like a great way to die.

why not use a 3KW thermal curtain or fan heater and a cold-steam generator?

By the way STJ,,, I don't know if I wasn't clear enough or if you misunderstood my OP... Water is MEANT to be poured over commercial sauna heaters like the ones made by Vevor and a dozen other sauna heater companies. It's a sauna thing.

I am NOT suggesting running water over the element/coil set up I am trying to make. That part of this would be in a separate insulated ducted housing with a blower a fair ways away from the interior of the Sauna... Basically I am trying to make a controlled heating unit for a Sauna... I guess this strikes people as a scary idea...?

[stj]

building your own heater housing without all the safety's or running a homemade controller without feedback and mutltiple cutouts is dangerous.
much cheaper to get a themal curtain used from a comercial auction.
they only cost 100-150 new, but shops replace them sometimes and they are very reliable.
a cold steam generator - mostly a cheap $5 chinese product simply uses ultrasonics to vaporise water into a cloud using low voltage.
or you can buy a complete cased digital controlled unit sold as a "humidifier" that does the same thing

[JayPoorJay]

building your own heater housing without all the safety's or running a homemade controller without feedback and mutltiple cutouts is dangerous.

Absolutely. I know it can be dangerous (electricity and heat both are) going outside of the box. It's why I'm asking for y'all's guidance.

This is a Goodman unit (photo) and it does have fail-safes and controls built in. $93 bucks and has the capacity to heat large areas - houses... And for feedback, the PID with a thermocouple inside the sauna to track temperature. Set the coils to run at 40% let's say, no more, with air moving over them in a well made housing. Air housings for air handlers from the factory are simple things, just made up of a heavy sheet metal for the most part...

[diif]

Oh. And for average temperature,,, I would say around 150 to 180 degrees. Far more than a home heater usually achieves but I think possible for an element of this type with a blower and air moving over it,,, running at like 40 or 50 percent....?

fail-safe. max temperature. unless you remove it, then you're into dodgy territory.

[JayPoorJay]

fail-safe. max temperature. unless you remove it, then you're into dodgy territory.

Hello D... When you say "remove it",,, what's the it? Fail safes from the coil unit I purchase? Is that what you mean?

[diif]

You're taking a device that heats to about 30c and want it to heat to 150c. It won't do that by design for safety reasons.

[sam_sam_sam]

You are going to have issues doing it this way because those heating elements are inot designed to get that hot the temperature cutout will be around 150* to 180*F and not only that the type of heating element wire used on most of them if gets over heated it most certainly will fail

I would highly recommend that you but a commercial made heater made for this purpose even if you do not buy the controller that made for but it might end costing you just as much as just buying the controller as well because it should have the safety device already incorporated into the design of the system and probably UL listed as well

I thought you were only going up to around 100*F and what you have in mind would probably work but you would have to be careful about the CFM across the the heating element not get so low that you overheating the heating element wire but what temperature you are looking for is not going to work with what you have in mind and something else to keep in mind is that if you had a major failure and you burn your house down and when the investigation was conducted and they find out that it was home made you will be in trouble with the insurance company and I can promise you will not collect a dime

I will tell you a little story about a situation that I had with above ground pool and commercial made pool timer and loosing power and having to reset the timer clock this is a pain in the ass so I built my own pool timer with a Basic Stamp from Parallax the controller is not that expensive and my routine for the timer was very simple

I used a Basic Stamp controller
I used a time chip that you can put a super capacitor for the time keeping function which I had done before on another project but for this particular project I did not used this function because it was not necessary

The routine was very simple one hour ON and two hours OFF and kept repeating this routine from sunrise to sunset and for that I used a regular green LED light to detect the sun light

So even if you lost power and it came back on a few minutes to hours later did not matter because the routine was written to first look and see if the sun was out playing if so run the routine

The reason I mentioned this story is that I used commercial made components and it put into a water resistance enclosure that the front cover was transparent with a gray tinted so the sun light would hit the sensor and if I wanted to I probably could have gotten it UL listed if I was willing to pay the money for it

I ran this for several years until I took down the above ground pool because of it getting to experience to keep it up

Now if you insist on doing with the air conditioning stile heating element if you were to put the temperature sensor on top of where the high temperature cutoff sensor is and keep your temperature controlled at a temperature no higher than 120*F maximum you might be able to get the to work but my suggestion to you would be as follows

You need to do this with a 120 volt version space heater that the heater element glows when running with the fan in it a temperature controller sensor mounted right next to maximum temperature switch and keep the maximum temperature below the temperature switch cutoff temperature you will have to experiment with this and once you have determined what your maximum temperature that you can have with out tripping the temperature switch then you know if this possible or not in other words “ a proof of concept “ and then you know what the limitations will be with type of heating element and a lot less expensive if you find out that it not feasible for cost effective to make your own

Now there might be another option but you would have to do a proof of concept that is to use something like this device
https://www.ebay.com/itm/174448494486?hash=item289df0c796:g:oB4AAOSwvltfa2C A&amdata=enc%3AAQAIAAAA8Lzyp9rVaRjns%2F1vfmbXyTa 6Q YIzdd%2Fyz52euw3ALNjpVVhLE17YS%2FIoLfL4z%2BRyGWfo6 KJ0%2B1rGCQDqyhgBj47oIDb4VlNueyxsTBxlPDXpiyITARz2g eFgsAVPWF%2FqDM5FbZwQkVrTRYIHTLSToG9kYRDeimTlh%2Bp GqVNrIoi8IAXBKMfeVGrsKYtC8Lyg4TzN0TJThK3kWOf%2B5EL uV3ZkPx1vtNi%2BdlizmX7JQAYIdStyRJlh4dW0gGppVuzfNRw jtwjogm8VAr0SLFyg8vEq1PBeKhCwCyw26rhOLBNw54rU10Ui3 TZF9YRRiF3D%2Bg%3D%3D%7Ctkp%3ABk9SR_KnwLifYw

This is how I approach this idea and do a proof of concept
I would use two of these controllers one for the heating element and one for fan and what you want to do is use a single speed fan and preferably with out a capacitor on the fan motor which is going to be hard to find but not impossible to find it might have to be a 120 volt fan motor and maybe a smaller squeal cage for the blower the idea here is to determine what fan speed would be desirable and then adjust the maximum temperature to just under the maximum temperature switch being triggered and I would highly recommend that you tap the switch a few times to make sure that it not on the verge of triggering you do not need to have the temperature switch controlled by 220 volts you can just use the temperature controller voltage the idea here is not to defeat the maximum temperature switch but to use it a different way to control it and how and what it controls it should turn the heater element wire off until it cools down and by the way the maximum temperature switches on this type of heater element is controlled by the 24 volts ac so we are really doing anything different in this respect or you could just use the fan that comes with the heater element housing and just use the lowest fan speed and adjust the heater element accordingly and then could use a temperature controller for the room itself and turn the heater element off when the room gets to the temperature that you want

One thing to keep in mind is that the heater element should not be glowing real red hot it should just getting red hot so that you can just seeing it getting that way for best results out of the heating element

[JayPoorJay]

Sam_Sam_Sam! Maaaan,,,, I cant tell you how appreciative I am for how willing you are to walk me thru alllllll of these ideas and information. Responding, I almost feel CHEAP or like I'm cop-ing out because my response cant get close in comparison to the amount of effort it must have taken you to put all of these ideas together.

Based on what you all have said, I'm going to shift a litte bit...

Of course safety is the chief concern which out weighs any other consideration in moving forward at every step in this idea. I want to state that clearly and I am SUPER grateful for it seeming to be y'alls primary concern too! That said,,,

Let me put forward another idea or possible approach.

In thinking about the element/coils to be used I (obviously) was NOT aware of all of the dangers and limitations of the central heater air handler style element. So I think I will scrap that idea all together. Toooo complicated, tooooo many things to think about and tooooo many limitations - wrong equipment - wrong application... I have been watching guys on YouTube building all different kinds of PID controlled ovens and what they are using is just basic household oven elements. Designed to operate for hours (if need be), glowing cherry red at high temperatures, and surviving. Not even requiring air flow for cooling. A couple of guys I've watched made their own coils/elements out of wire to heat Kilns, Heat Treat Ovens with temps of 1400 and 1500 degrees. Another guy using two electric oven elements for a large powder coating oven. Gets to 400+ degrees in 7-8 minutes. At 400 degrees for extended periods - there are loads of videos. Ill attach a couple.

YOUTUBE VIDs
HOW TO WIRE PID FOR SINGLE OR MULTIPLE HEATING ELEMENTS
BUILDING A 240 VOLT 20 AMP PID CONTROLLER
MAKING A BURNOUT OVEN

So, heres my "new" thinking. First there is these products (or ones like them) I see on Amazon -
a Fire place blower motor.
stove top elements.
Then this stuff
Then this stuff
Then this stuff is a possible direction for the heating element....
Then a couple hand fulls of these...

The idea is to (like the guy in the Heat Treat YouTube video) to encase and suspend the stove top elements in a tunnel of fire brick made to smartly support the elements while creating a tunnel for air to be pushed/forced thru. Blower would be connected to the brick tunnel with sheet/duct, to and thru brick tunnel with elements, back to sheet metal duct and then defused in to a well insulated sauna structure. I think this would heat a sauna MUCH faster than the 45-60+ minutes it takes even the BEST pre-fabed sauna heaters to reach temp.

Then, there is wiring the PID, setting the limits (limiting the elements at 40, 50, 60% to achieve desired temps), powering the blower fan so it comes on automatically. Breakers, SSR's (how many???)

I think y'all must be able to see where I am going with this.

Ill also say.... I'm sure you are thinking - why doesn't this guy just drop the 2000$ and get the proper premade heater??? Here's the thing, the prices for what you are actually getting are crazy... Then, this being a new house and a fixer-upper the BILLS are already coming in, then - I like to MAKE things... But clearly I need help and there are a million things I don't know.

So, what do folks think about this new approach?

[diif]

The commercial heater sits in the enclosed sauna heating the air, it has safety features built in.
i think you want to blow air you are heating into the sauna ? You're taking it out as well to recirculate ?

[sam_sam_sam]

Here is a thought that you might want to consider what about finding a commercial unit that is not working anymore and buying it for a reasonable price and then you take it apart and see how and what was use and try to fix it now this might not an option because it might hard to find one and I get this

To use one from a wall mount oven you will have another set of issues to deal with because on these units do not have ANY SAFETY devices whatsoever so this is even worse in this scenario and respect so might feasible but it is not going to be easily done because now you are going to have known how to use a micro controller and how to program one and here is reason why I say you should to know how to use and program one

You must have a way to monitor the temperature of the heater element that is this style because if you allow this element to get to hot one of two things is going to happen one you will cause the element will open up and stop working if you are lucky which is the best outcome that you can ask for

The second senecio is the worst case scenario because this is dangerous at best because in this situation is that the heater element short to ground and if you are lucky you will trip the breaker and this is assuming that the device is properly grounded if not grounded properly then you will have shocking situation that you will very possibly shock if you touch the enclosure if not properly grounded safely hazard

You have to continually monitor the temperature of the element and keep it under control because you do not want to have thermal runaway stimulation because this will cause thermo damage to the element and cause the situation that you want to avoid at all cost no matter how difficult this situation might be

This situation must be thoroughly tested and you will need to try to make the device to fall and see if your safety procedures actually work properly do not assume that they work test them to make sure that they work properly this where program a micro controller comes in play

I personally would not even attempt to build something like unless I completely understand what the hazards are and know how to control them and deal with them

I going to tell you a story where I had to deal with a situation similar to this and what you are considering doing because of cost but you want to save money I completely understand because I been down this road many times myself but I have one consideration that I always keep in mind how safe can I do something I want to do

I had a water heater go bad and decide to go down the road and get a tankless water heater and would live happily ever after well not so quick that not quite what happened because there are a few things that I learned very quickly about the limitations of a tankless water and first one that if have one handle water valves ( hot and cold ) this is going to cause you issues you were not prepared for because the hole principle behind a tankless water is that you have a tube with a heater element and flow meter and a current limiter that is based on flow so how this is done is two or more heater element which reduces your water flow somewhat but you also have to the water flow metering device also restricts flow as well so this also restricts water pressure as well and this type water valve is setup is that if you have an unbalanced water pressure on the hot water side the valve shut down the hot water side considerable and is very noticeable and you can not control the water temperature very well this is an issue that can not be tolerated by me what so ever so there has to be a solution but this is not the only issue that you face the second issue is that you can only have a certain amount of water flow through the tankless water heater because then have a over flow error and the tankless water heater shut down and it goes cold water only this situation is not acceptable either so I got the brilliant idea to buy a second tankless water heater and put it in parallel to the first tankless water well this is great idea except for one problem now you have another set of issues that you were not aware of and you are not prepared for

Now the story gets really interesting and complicated because now you still have the flow issues and now you have one more issue that you did not know anything about which is when you have two different models of tankless water heaters you have two different restrictions issues to deal with each one has a different flow restrictions to deal with so I got the brilliant idea to use one way valves because you also have an issue where because the flow restrictions are different the water back up and causing one of the tankless water heater to go into an error that is basically a temperature over loading issues which tells controller your heater element current control circuit is out of program limits and will cause it to shut down and you get cold water again not acceptable either

So now the story gets even more complicated because now I had another brilliant idea to use two shut off valves to control the water flow to each tankless water heaters to the water supply lines to each tankless water heaters now this fixed the problems that I was having and solve all the issues that I was having but I had to figure out how this tankless water heater functions and I had to guess how the program was setup and how and what it was looking for the type of limitation it was looking at this particular part of the equation was very important to understand other wise you are not going to make this work correctly

Now I did get these tankless water heaters to work together correctly but it was not easy and it took several months to get it to work properly with out any issues not an easy under taking

I was getting desperate at one point that I was considering going down a certain rabbit hole and this not good place to be because it might force you to take chances that you might not otherwise consider doing or going down this rabbit hole but I would not consider using it unless I could do it safely in the end of hole process because I said earlier in the end of the day it has to be safe to use

And this was built my own controller and using the device that I mentioned earlier in this post that would control the current to the heater element but this would take a lot of time and testing to make sure that it would work properly as you intend to work

So when you are considering doing something you need to understand how the system should work and what the limitation of the system are and the limitation of any device that you plan on using to control the system or any device that is going to do the work that you want to accomplish this part is very important to consider and completely understand before you start building and put things together

When I made the comment earlier that I understand that you want to save money so do I when I bought the second tankless water heater I bought a non functioning tankless from EBay a tankless water and fixed it

It had the following issues
a non functioning controller
a bad temperature sensor
the heater elements need to be cleaned

I have one thing that helps me with doing things like this and it this
I have a lot of experience with controls and how a lot of them work and if I do not know how they work I googled them so I can understand how they work

The other thing that I have is that for a little while I also learned how to program a Basic Stamp controller from Parallax
this gave me understanding how micro controller works

The other thing that has helped me a lot is that I also went to school for industrial electrical and automation and learned how some of these systems work which is a great help when you want to modify something ( VFD drives ,Program Logic Controllers “ PLC ” and a introduction to PLC programming which I do not have any real experience in but I do understand programming concepts of which is very important to know and help to be able to troubleshoot issues with them ) plus a lot of things that you learn as well

The other thing that has help is this forum has helped to no end I been on for quite a few years now and I can not begin to tell you how much I have learned on this forum about many topics and devices

Job experience are as follows
Auto Mechanic technician for 5 years ( went to school for )
Air conditioning and refrigeration technician for 8 years ( went to school for )
Industrial Maintenance technician on all kinds of equipment at facility ( Electrical Plumbing and thing else that comes up ) 10 years and now )
Plumping was self taught by trial and error not necessary the best way to learn it

You are not going to believe what I going to tell you next

I also watch as many episodes of “How it is Made “ this is extremely helpful understanding what it takes for how something made but it also helps you understand what is inside of a piece of equipment and most of the time they are accurate but sometimes the terminology that they use are not always completely accurate about that part of it


I hope this helps you understand what you are facing in what you are considering doing but in the end of the day be careful and safe this is very important

[sam_sam_sam]

YOUTUBE VIDs
HOW TO WIRE PID FOR SINGLE OR MULTIPLE HEATING ELEMENTS

BUILDING A 240 VOLT 20 AMP PID CONTROLLER

MAKING A BURNOUT OVEN

Okay let's start with the first one”Building a PDI controller”

He is good explaining how the basic functions and concepts are in part 4 of this project that he is doing

However I have a couple of issues with his presentation one being that he over looks the alarm function if this PID controller has an output pins it should be used as a failure mode meaning that you use two different sold state relays one that functions as your controller would be normally if you were to have an alarm then you want it turn off power to heater element ( I will go into how you go about doing whenever you get to this point )

Another issue I have is that he does not explain what the parameters value are what would happen if you made value higher or lower this is something else that you need to understand as well because more you understand about this the more control you will have the parameters and you will understand it limitations as well

I would highly suggest that you buy one and that you go through each function and understand how it actually works

( This is known as “[ proof of concept ] ” )

[ so you can see the results you can do this very safely with an incandescent light that can act as a heater element you just put the temperature sensor on the light bulb and you can test each function that way safety ]

The most important thing that you want to accomplish is that you completely understand how and what PID can and cannot do this in very important to understand

One note the Basic Stamp control has a chapter in its book on how to do s PDI function with this controller that is how I got my understanding of how a PDI controller works because it has labs experiments in each section for you to do and it gives a very detailed explanation of how it works and you can see it working in real time

One word of caution about the notion about running this type of heating element for hours is that core temperature should never exceed the maximum temperature of this type of element like I mentioned earlier in this post when you plan on putting something on top or over the heater element you will cause the core temperature to rise and it might be over maximum temperature of core temperature of the element at full running amperage you need to be aware of this and take this in account and use caution about what you put above the element now if you put a metal plate that you will be making steam good idea as long as you can accurately control the amount of water is on the plate this will take so experimentation to how much flow you can safely do but this is another subject all by itself

One note at a lower amperage you would have some lead way but be aware that it will take longer for you to get to the temperature that you desire but is some of the limitations I was referring to earlier in this post

Yes you can get heating elements to go to very high temperatures but what you have to understand is that you are using the right type of heating element and the right type of ceramic tile and right type of bricks to absorb heat and distribute it all over the entire enclosure so yes it can be done and safely but the most important thing you have to remember that each device has it maximum operating temperature and you should never come close to it you need to stay in it nominal operating temperature there is a big difference in the two of them

[magistertc]

Well, JPJ,
This post will not address your issues directly. (and has nothing to do with caps or electric heat). But....

Virtually every locale requires a permit to build, followed by inspections. Then add a rider to your insurance, not insuring may be a costly error.

Determine locale. Easiest is outdoors, if you have a safe area separated from other buildings. Indoors is doable, with different caveats.
Outdoors, you can generally use a wood stove designed for sauna, or cobble up something according to requirements
Indoors, it will be electrical, amperage according to size and temperature.
Structure will need floor drain(s)

Materials -- construct shell from whatever wood or paneling. Interior, tongue-and-groove clear heart western red cedar.
You should not use anything that will run sap, or splinter, or deteriorate with heat and time.
Some deadfall trees could possibly be used. Stay away from wood with knots.

Structure should have outer shell, insulation, vapor barrier, reinforced door that opens outward (safety! also, if rugged enough, it could be a tornado shelter).
Add on wiring, a low wattage lamp, a means to ventilate interior when not in use.

A shower and other appliances , refrigerator, TV, computer, table, chairs, etc.. are desirable.

Electric sauna stove will have GFCI, adequate wiring, dedicated circuit breaker for over-current, thermal fuses, timer, temperature control limited to some maximum.

There are numerous sauna kits and bare-bones ready-buillt boxes that simplify the project.

And the But-- all this costs money. Think in terms of thousands. Quit worrying about shoestring adventures. If you don't have the money now, plan instead.
Build the shell first, then you can have a storage area and tornado shelter until you acquire the means for the rest of it.

How do I know this stuff? My wife and I built a new house 25 years ago. And I got my dream sauna. Runs at 195 deg.F once or twice a week.
Some of the money from sale of our old house went to buy the necessary stuff. Say, five big ones. I can add it to the sale price when the time comes.
So, think ahead, Good Luck
Tom C

[JayPoorJay]

Thank you Tom. All great information...
Safety and keeping this thing that way is what all of this hinges on.
I will not go forward (my wife would NEVER allow it) if its is not tight and safe.

Sam, thanks so so much for all of your guidance and ideas..., Ill add a couple of photos (not to scale and drawn quickly) to give a better sense of what I am thinking at this point...

Nothing will be directly above the elements except the next element(s) all encased in fire/furnace brick. They will only be on when the fan is on. There will NEVER be water near any part of this. And, the yet to be determined maximum running percentage, the amperage applied to the elements will not cause them to be powered maxed out. I'm hoping for something like medium 60, 70 or 80 % power maximum. In that they should never get red hot, maybe just slightly glowing. Also, they will be run ONLY on a timer. 60min to 90min max, and will not be able to be powered unless the timer is running.

I want to add - wood stoves and fireplaces can be unsafe. Space heaters and portable heating devices can be unsafe. Pretty much anything can be unsafe if not used properly. Pools can, fast cars can etc etc etc motorcycles. Then, there's children's swing sets.. With that in mind, I view projects like these.

I still have a long ways to go with this idea and again, will not move forward unless it can be dont safely, safely, safely...

I need to know if a PID can be set up to bring a heating element up to heat slowly - rather than coming on full blast at startup to reach set temps?
I need to know if a PID can be set up so that when it is turned on it goes right into its programing OR is there a bunch of fiddling one has to do in order to run the ONE and only program on the device?
I also need to know if a PID needs to be SET and programed every time OR does it have a memory and can HOLD programs when powered down?

A LOT to learn and I am open to all suggestions.