This is an interesting topic. I've been thinking about building a hot tub heater control for mine with an ESP32, a high voltage/high current DPDT relay, plus a couple Dallas 1-wire temp sensors. I'm already using ESPHome and Home Assistant for various DIY controls and monitoring. While this won't do anything to reduce the total electrical consumption, I'd use it to shift when the heater runs to avoid importing from the grid during peak rates and make better use of our grid-tied solar as export tariffs continue to drop. Setting up the relays normally closed will be a fail safe so things run factory-normal if my project goes offline, as well as using the temp sensors to prevent temps from going too low. In addition to monitoring, this would allow some additional automation opportunities too. If I get around to this project I'll try and remember to post up a thread here.
My hot tub uses 49% of my electricity per month...lets fix that.
- Thread starter tmprof
- Start date
Osmethne
Solar Enthusiast
I would definitely use a heat exchanger to separate the hot tub water from heater water.
Osmethne
Solar Enthusiast
And this idea of draining it for the winter I don't get. I think winter is the best time to use a hot tub.
yes please do! I would be very interested to see how that goes for you and what your final setup looks like
James Getman
New Member
I think the coldest I used the hot tub was 17 Fahrenheit, your hair would freeze if you were not wearing a hat. Putting dish soap in there was fun, 2 to 3 feet of frozen suds. Getting too old for that adventure.
My favorite is when my hair is frozen and I'm in the hot tub.
yep I love that, also jumping in the snow and then running back in the hot tubs.
Up in vail / steamboat springs in colorado there are places we go out at 0F/-17C many of the hotels keep them running all year outside.
k490
Solar Enthusiast
I have had a hot tub for 10 years now bought it used from a friend who lost their house to foreclosure and divorce. Didn't pay much for it since then I have gone through 3 control modules and a new pump from Acura Spa in Riverside, CA. It's a power hog put a amp meter on the wire watch it pull 50 amps at 240V. Even my hot water heater doesn't pull more then 20 amps. I turn it down to 80F we heat it up on the days we want to use it. Sometimes the clock gets flipped so it's heating during peak hours I'm getting a demand charge now in the winter.
We haven't even filed it yet this year been so warm here in AZ we still hitting 80's. I might fill it we do like using it when it gets down into the 40F degrees. Most of the year it stays drained spa store told me it might cause it to crack not keeping it filled if that happens ill just trash it. We been draining it for at least 5 years now I open the connection to the pump drain the water out of the lines.
We haven't even filed it yet this year been so warm here in AZ we still hitting 80's. I might fill it we do like using it when it gets down into the 40F degrees. Most of the year it stays drained spa store told me it might cause it to crack not keeping it filled if that happens ill just trash it. We been draining it for at least 5 years now I open the connection to the pump drain the water out of the lines.
crack just from being empty? that's a new one, what commission percentage do the sales guys get there?
It'd crack from your extreme temps etc way before just magically sitting empty
k490
Solar Enthusiast
That is what he was saying because summer gets to 119F here it being drained might cause it to leak because dries out. I haven't had that issue with it we had a pump go out and the control board died 3 times. I'm not sinking any more money into it if it dies give it away first who hauls it away. Lots of them in FB marketplace, or CL for free all the time here. People buy them don't realize how much work it is keeping the chemicals perfect and draining refilling. They leave them full of nasty water all summer turn green eventually just want it gone. The cost to have it wired into the house is also not cheap I did it myself I know a co-worker who spent $2500 for a contractor to run wire underground. He put in a 16-person hot tub cost him almost $20k I told him he was nuts in AZ just sit in the pool 92F water in the summer.
Yep had one 20 years ago massive pain in the ass. That's why I went with a stock tank build. Also can rotate water through UV lamp for well pumps that kills bacteria and don't eve need chlorine in it. IDC about PH either anymore.
holy shit that is a lot to run some wire, but 16 person damn!
if it's just you two I recommend going stock tank, there are a million videos on youtube too. I'd went with the oval one above, 8ft by 3ft wide by 2 deep is massive. It is nice to sit across from each other. Circle one is kinda dumb imo
salt water hot tubs / pools still require chlorine =[
All the ones around here are using salt to replace adding chlorine.
How does the system work? All salt systems I've ever seen just have way less chlorine but still have it.
Only way I've seen to get rid of it entirely is to use UV sterilization like usually used on well systems. Lots of Europe does it to clean drinking water too. Which is why I made my own to do that for my tiny tub
Salt water chlorination is a process that uses dissolved salt for the chlorination of swimming pools and hot tubs. The chlorine generator uses electrolysis in the presence of dissolved salt to produce chlorine gas or its dissolved forms, hypochlorous acid and sodium hypochlorite, which are already commonly used as sanitizing agents in pools.
yea so still chlorine in the water, still easy to test and see it has it. People that get rashes from chlorine get less of a rash but still get one. Chlorine tablets also produce chlorine gas in the water
yea salt would be even worse in my stock tank. chlorine also eats the zinc off the galvanized steel but a lot slower.
Salt pools also get a chlorine generator. Guess what salt is made of? Anyway the generator separates the ions and suddenly there is active chlorine. Then muriatic acid is needed to balance the pH as chlorine is used up. It is quite a chemistry project.
Balrog006
Solar Enthusiast
22kw a day!?!?!? That’s just nuts. Is there a setting on the controller to put it into economy or power save mode, out of its standard mode for heating?
I have a 330gal 6 person Viking and its balboa controller has a standard mode that I assume is a lot like what yours is running. We keep it in the EC mode though, where it only heats the water 2X a day on a 12 hour schedule. I have it set for 8 o’clock, so at 8 am it runs and heats and filters (2 hours of low speed filtering) and uses at most 6kWH. And then again at 8pm it runs again and is ready for when we usually take our dips in it about 9 pm. It runs the same and uses about the same. These are winter numbers, where the ambient is sometimes down in the teens but usually 20-30f. In the summer it’s the same schedule but it only used 3-4 kWH each cycle. This also avoids the Peak Use Charge times of 2-7pm in the summer
For the winter at my rates the extreme max of 15kWH would be a little over $2 a day, in the summer it’s less than $1.
It's all about the tubs insulation and how the top is designed (more insulation!) too.
It's ugly but the best thing to do is just buy a lot of foamular insulation and wrap stuff.
(It is resistant to basically everything)
Only home depot sells it (several sizes):
Owens Corning FOAMULAR 150 2 in. x 4 ft. x 8 ft. R-10 Unfaced Squared Edge Insulation Sheathing 6W - The Home Depot
FOAMULAR Extruded Polystyrene (XPS) Rigid Foam Insulation offers a comprehensive product line of insulation boards in a wide choice of sizes, thicknesses and edges with a Lifetime Limited Warranty for
www.homedepot.com
Balrog006
Solar Enthusiast
I need an arctic cover for this one, it’s fairly new and haven’t sprung for it yet. I have packed much of the free space inside it with more insulation and spray foamed all the joints.It's all about the tubs insulation and how the top is designed (more insulation!) too.
It's ugly but the best thing to do is just buy a lot of foamular insulation and wrap stuff.
(It is resistant to basically everything)
Only home depot sells it (several sizes):
One old tub we had we had 6 inches around it and then laid brick around the outside of the tub which made it look niceOwens Corning FOAMULAR 150 2 in. x 4 ft. x 8 ft. R-10 Unfaced Squared Edge Insulation Sheathing 6W - The Home Depot
FOAMULAR Extruded Polystyrene (XPS) Rigid Foam Insulation offers a comprehensive product line of insulation boards in a wide choice of sizes, thicknesses and edges with a Lifetime Limited Warranty forwww.homedepot.com
Hadn’t considered sitting it in a bathtub of more insulation ?
Balrog006
Solar Enthusiast
That’s a big one. Mine is pretty standard and it has a 5kW heating element and 2 240v pumps.
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