Geek Wants A Hot Tub - Any Programmable Thermostat Options?

[rontl]

Everyone seems to agree that if you want your house to be 70 when you come home in the winter, the most efficient way is to have a programmable thermostat that keeps the house cool during the day and then heats it up by 5:30 when you come home, and then cools it down while you sleep, etc. One thing a lot of people have said is that you want your tub hot all of the time, so you can get in it whenever you want, otherwise, you won't use it.

Here's my question. Is there any way to get my spa to not attempt to keep it hot all night long, or during the day. I'm going to use my spa mostly in the evening, so if it would keep it hot for 6 hours at night, and then just turn off the heater at midnight, it'd never interrupt my use.

Given the price of fuel and rising concerns about energy consumption that in a few years we won't have spas with programmable thermostats that can keep them cool during the weekdays, and hot during weekend days.

The geek in me would love to be able to remotely turn it up a few degrees from the comfort of my PC, and then go get in it.

Thanks,

Ron

[Goodwing]

Ron,

Great question. I hope that somebody with some expertise will comment/respond. I have NO idea - but I'm guessing that MAYBE a reason they don't have them yet is the idea that heating-up water from (for sake of arguement) 90 to 100 degrees costs more money and takes more energy/time than maintaining it at 98.

That's my guess.

Cheers,

Mike

[rontl]

That's the argument you hear, but I know I saved money when I put a timer on my electric hot water heater, when I had one of those, which is obviously somewhat relevant. In the case of your house furnace, you can fairly quickly heat up a house full of air fairly quickly. Water doesn't heat up as quickly, I know. But in say the summer, if the spa thermostat shut down at midnight, I wonder how much it would cool down by 6pm the next night, given the state of insulation today. Suppose, for the sake of argument, it got down to 90. With a smart thermostat, (not the dumb programmable ones we have today), it could say, "hmm, I'm supposed to be at 101 at 7pm. Time to fire up!" But if it had only gone down to 95, it would start heating at 6:30 (or whenever, I obviously don't know how long it takes to heat). Also, I assume you could set it to hold at 92 all day, and then go up to 101 from 6-12, etc.

I've heard people say there wouldn't be much in the way of savings, but I've never seen anything remotely quantitative about it. I'm hoping someone can either

A. Tell me of someone who's doing this now or selling an aftermarket kit, or

B. Point me to some hard numbers that convince me that the savings would be trivial.

BTW, sorry there accidentally ended up with two of these postings. If anyone knows how to get rid of the second one, please do it or tell me how. Thanks.

[benalexe]

My spa has an economy mode. Will only heat the water when the filter is on. and will get the tub go 15 degrees below set temp.

[Dr. Spa]

Are the laws of physics quantitative enough?

Newton's law of cooling;

According to Newton's law of cooling, the rate of change of the temperature of an object is proportional to the difference between its initial temperature and the ambient temperature.

[rontl]

Unfortunately, that doesn't account for the insulation, whose job it is to protect my precious hot water from the cold world outside. And now that I think about it, I guess my question also comes out of ignorance of how long it takes to heat up a spa from a given temperature.

How long for most tubs to go from 90 to 100? 95 to 100? 80 to 100?

Ron

[Hillbilly Hot Tub]

Unfortunately, that doesn't account for the insulation, whose job it is to protect my precious hot water from the cold world outside. And now that I think about it, I guess my question also comes out of ignorance of how long it takes to heat up a spa from a given temperature.

How long for most tubs to go from 90 to 100? 95 to 100? 80 to 100?

Ron

The new tubs have an economy mode that only allows them to heat during a filter cycles. Adjust the filter cycle to come on "x" hours before you use the tub and it will be up to temp to use. It will do this twice a day, 12 hours apart.

There is a ststem (or maybe a few) that works from your computer. Its called aqua link. It is costly, but we put one in for a homeowner that lives in NJ and has a second home in NH. He monitors his hot tub via this system. It is hooked into his security system for his home.

Depending on insulation quality, ambient air temp, wind and what size heater you have, typically spas heat up about 5 degrees an hour.

[rontl]

That looks like exactly what I was looking for. Thanks! I didn't see the kind of remote that could be controlled via the computer, when I was looking on their website, but I thought I'd try to call them. Unfortunately, as you said, the prices are not cheap.

Do you know of anyone who offers something simpler (ie cheaper) that would just offer me the kind of functionality I get from my $40 home programmable thermostat, without the remote accessability?

Also thanks for the heating info. We knew that our local HS shop had been able to heat up a tub from room temp (say 70) to 100 between the time we called at 10, and 5, so 5 degrees per hour seems reasonable.

Thanks again.

Ron

[jdskycaster]

I am just chiming in on this as I have no specific expertise in this area but I would think part of this equation comes down to reliability. If you live in a cold climate with below freezing temperatures you want as bullet-proof a system you can get that will not allow your water to get to the point where freezing occurs. I am not sure about you but I have had an experience with cheap set-back thermostats that have failed in the middle of winter. Not a big deal if you are home or not away from home for an extended period of time but you get the idea.

This is an excellent theory and is one that should be explored with the rising costs of energy, but there is no substitute for a system that you can completely rely on and cost is always a factor.

JD

[rontl]

Well, since I plan on being in it every night, it shouldn't ever have a chance to get that cold!

I haven't heard anybody estimate the costs yet, but it still seems to me that letting it drift down to no lower than say, 75,(80, whatever you want) during the day, and then heating it up to 100 in the evening would use less energy that trying to keep it at 100 for 24/7.

Ron

[Hillbilly Hot Tub]

Well, since I plan on being in it every night, it shouldn't ever have a chance to get that cold!

I haven't heard anybody estimate the costs yet, but it still seems to me that letting it drift down to no lower than say, 75,(80, whatever you want) during the day, and then heating it up to 100 in the evening would use less energy that trying to keep it at 100 for 24/7.

Ron

Does the HS you are looking at have the ability to put it into an Economy mode? By the sounds, this is what you are looking to do. Tubs with Balboa systems can be put into an economy mode that only allows them to heat during set times, like a house programmable thermostat.

Also, a well insulated spa wont drop to 80 degrees (unless it is BITTERLY cold) in less than 24 hours. In the cold part of winter, on windy days here in NH, I only lost 5-6 degrees in my tub in a 12 hour period.

[spatech (the unreal one)]

Does the HS you are looking at have the ability to put it into an Economy mode? By the sounds, this is what you are looking to do. Tubs with Balboa systems can be put into an economy mode that only allows them to heat during set times, like a house programmable thermostat.

Also, a well insulated spa wont drop to 80 degrees (unless it is BITTERLY cold) in less than 24 hours. In the cold part of winter, on windy days here in NH, I only lost 5-6 degrees in my tub in a 12 hour period.

If the spa has a circ pump the "economy" mode made no sense to me. The only good the economy mode does is to reduce the amount of time the 2 speed pump runs by having the filter and heat time run simultaneously. Its intent is not to reduce heater on time as the heater will have to come on sooner or later anyway to get back to temp. Therefore, if the spa has a circ pump running in economy mode is useless. It won't hurt it to run it in economy mode with a circ pump but its pointless IMO.

[spatech (the unreal one)]

Well, since I plan on being in it every night, it shouldn't ever have a chance to get that cold!

I haven't heard anybody estimate the costs yet, but it still seems to me that letting it drift down to no lower than say, 75,(80, whatever you want) during the day, and then heating it up to 100 in the evening would use less energy that trying to keep it at 100 for 24/7.

Ron

If your spa is well insulated it'll take multiple days to drift that low. To find out how well insulated your spa is run a little test after using it by dropping the temp down to 90º and closing it up. Check it the next morning and later the next day. A fully insulated spa will hold the heat very well and it'll drop negligibly overnight and over a couple days it'll still hold the heat well. This would show you that you can leave the temp right where it is and not play the temp game. You won't be saving anything by raising and lowering the temp setting, you'll only be making it less convenient to use.

[Hillbilly Hot Tub]

Does the HS you are looking at have the ability to put it into an Economy mode? By the sounds, this is what you are looking to do. Tubs with Balboa systems can be put into an economy mode that only allows them to heat during set times, like a house programmable thermostat.

Also, a well insulated spa wont drop to 80 degrees (unless it is BITTERLY cold) in less than 24 hours. In the cold part of winter, on windy days here in NH, I only lost 5-6 degrees in my tub in a 12 hour period.

If the spa has a circ pump the "economy" mode made no sense to me. The only good the economy mode does is to reduce the amount of time the 2 speed pump runs by having the filter and heat time run simultaneously. Its intent is not to reduce heater on time as the heater will have to come on sooner or later anyway to get back to temp. Therefore, if the spa has a circ pump running in economy mode is useless. It won't hurt it to run it in economy mode with a circ pump but its pointless IMO.

Clearwater has circ pump and economy mode. It confused me at first, but is not useless. How it works on Clearwaters...the circ pump still runs 24/7, filtering with ozone. If you set a "filter cycle" and put it into economy mode, it only allows the heater to come on during the set "filter cycle" It is still filtering and ozone via circ pump, but not allowing the heater to come on untill it thinks its going into a filter cycle, then it allows the heater on and starts heating too. It is not useless at all. The big pumps still do not come on (except to purge) and it makes it so the heater only comes on during times you want it to.

Balboa tech classes do wonders in training you a bunch of tricks like this, sub level programming is even better ( we learned how to trcick the system and get the tub to set for 105 also)

[spatech (the unreal one)]

Clearwater has circ pump and economy mode. It confused me at first, but is not useless. How it works on Clearwaters...the circ pump still runs 24/7, filtering with ozone. If you set a "filter cycle" and put it into economy mode, it only allows the heater to come on during the set "filter cycle" It is still filtering and ozone via circ pump, but not allowing the heater to come on untill it thinks its going into a filter cycle, then it allows the heater on and starts heating too. It is not useless at all. The big pumps still do not come on (except to purge) and it makes it so the heater only comes on during times you want it to.

Balboa tech classes do wonders in training you a bunch of tricks like this, sub level programming is even better ( we learned how to trcick the system and get the tub to set for 105 also)

What I was saying is if you have a spa where either circ pump does the filtering alone then economy mode has no point. So the question becomes whether you need more filtering than the circ pump provides.

It may make sense if your main pump is used to supplement the filtering of the circ pump but if you have a circ pump why would you need the main pump for filtering other than to occasionally run it after a party or something. If I had a spa with a circ pump and a main pump that supplements filtering and I wanted to redcue energy costs I would probably just zero out the filtering of the main pump and let the circ pump do the work and see how that performs before I'd bother with the economy mode.

[Hillbilly Hot Tub]

Clearwater has circ pump and economy mode. It confused me at first, but is not useless. How it works on Clearwaters...the circ pump still runs 24/7, filtering with ozone. If you set a "filter cycle" and put it into economy mode, it only allows the heater to come on during the set "filter cycle" It is still filtering and ozone via circ pump, but not allowing the heater to come on untill it thinks its going into a filter cycle, then it allows the heater on and starts heating too. It is not useless at all. The big pumps still do not come on (except to purge) and it makes it so the heater only comes on during times you want it to.

Balboa tech classes do wonders in training you a bunch of tricks like this, sub level programming is even better ( we learned how to trcick the system and get the tub to set for 105 also)

What I was saying is if you have a spa where either circ pump does the filtering alone then economy mode has no point. So the question becomes whether you need more filtering than the circ pump provides.

It may make sense if your main pump is used to supplement the filtering of the circ pump but if you have a circ pump why would you need the main pump for filtering other than to occasionally run it after a party or something. If I had a spa with a circ pump and a main pump that supplements filtering and I wanted to redcue energy costs I would probably just zero out the filtering of the main pump and let the circ pump do the work and see how that performs before I'd bother with the economy mode.

As I said above, the main pump does not come on for filtering. You are just telling the computer that there is a filter cycle, but that pump does not come on except to purge (all pumps come on for 2 mins) so the economy mode is just used for the heater in this system. I can set the filter cycle for whatever I want, the main pump does not run, just the heater. If I take it out of economy mode, the spa heats everytime I lose 1 degree.

Its actually a neat system.

[Hillbilly Hot Tub]

Clearwater has circ pump and economy mode. It confused me at first, but is not useless. How it works on Clearwaters...the circ pump still runs 24/7, filtering with ozone. If you set a "filter cycle" and put it into economy mode, it only allows the heater to come on during the set "filter cycle" It is still filtering and ozone via circ pump, but not allowing the heater to come on untill it thinks its going into a filter cycle, then it allows the heater on and starts heating too. It is not useless at all. The big pumps still do not come on (except to purge) and it makes it so the heater only comes on during times you want it to.

Balboa tech classes do wonders in training you a bunch of tricks like this, sub level programming is even better ( we learned how to trcick the system and get the tub to set for 105 also)

What I was saying is if you have a spa where either circ pump does the filtering alone then economy mode has no point. So the question becomes whether you need more filtering than the circ pump provides.

It may make sense if your main pump is used to supplement the filtering of the circ pump but if you have a circ pump why would you need the main pump for filtering other than to occasionally run it after a party or something. If I had a spa with a circ pump and a main pump that supplements filtering and I wanted to redcue energy costs I would probably just zero out the filtering of the main pump and let the circ pump do the work and see how that performs before I'd bother with the economy mode.

As I said above, the main pump does not come on for filtering. You are just telling the computer that there is a filter cycle, but that pump does not come on except to purge (all pumps come on for 2 mins) so the economy mode is just used for the heater in this system. I can set the filter cycle for whatever I want, the main pump does not run, just the heater. If I take it out of economy mode, the spa heats everytime I lose 1 degree.

Its actually a neat system.

[spatech (the unreal one)]

Clearwater has circ pump and economy mode. It confused me at first, but is not useless. How it works on Clearwaters...the circ pump still runs 24/7, filtering with ozone. If you set a "filter cycle" and put it into economy mode, it only allows the heater to come on during the set "filter cycle" It is still filtering and ozone via circ pump, but not allowing the heater to come on untill it thinks its going into a filter cycle, then it allows the heater on and starts heating too. It is not useless at all. The big pumps still do not come on (except to purge) and it makes it so the heater only comes on during times you want it to.

Balboa tech classes do wonders in training you a bunch of tricks like this, sub level programming is even better ( we learned how to trcick the system and get the tub to set for 105 also)

What I was saying is if you have a spa where either circ pump does the filtering alone then economy mode has no point. So the question becomes whether you need more filtering than the circ pump provides.

It may make sense if your main pump is used to supplement the filtering of the circ pump but if you have a circ pump why would you need the main pump for filtering other than to occasionally run it after a party or something. If I had a spa with a circ pump and a main pump that supplements filtering and I wanted to redcue energy costs I would probably just zero out the filtering of the main pump and let the circ pump do the work and see how that performs before I'd bother with the economy mode.

As I said above, the main pump does not come on for filtering. You are just telling the computer that there is a filter cycle, but that pump does not come on except to purge (all pumps come on for 2 mins) so the economy mode is just used for the heater in this system. I can set the filter cycle for whatever I want, the main pump does not run, just the heater. If I take it out of economy mode, the spa heats everytime I lose 1 degree.

Its actually a neat system.

I guess I just don't see any advantage to delaying the heater's operation in that scenario. In the end the heater has to turn on to get the spa back up to temp.

Economy mode on a spa that solely uses a circ pump for filtering obviously causes no harm other than the temp may drop a slight bit when you go to use it but in the end I see no gain in that scenario so I can't see bothering to use it.

[Hillbilly Hot Tub]

Clearwater has circ pump and economy mode. It confused me at first, but is not useless. How it works on Clearwaters...the circ pump still runs 24/7, filtering with ozone. If you set a "filter cycle" and put it into economy mode, it only allows the heater to come on during the set "filter cycle" It is still filtering and ozone via circ pump, but not allowing the heater to come on untill it thinks its going into a filter cycle, then it allows the heater on and starts heating too. It is not useless at all. The big pumps still do not come on (except to purge) and it makes it so the heater only comes on during times you want it to.

Balboa tech classes do wonders in training you a bunch of tricks like this, sub level programming is even better ( we learned how to trcick the system and get the tub to set for 105 also)

What I was saying is if you have a spa where either circ pump does the filtering alone then economy mode has no point. So the question becomes whether you need more filtering than the circ pump provides.

It may make sense if your main pump is used to supplement the filtering of the circ pump but if you have a circ pump why would you need the main pump for filtering other than to occasionally run it after a party or something. If I had a spa with a circ pump and a main pump that supplements filtering and I wanted to redcue energy costs I would probably just zero out the filtering of the main pump and let the circ pump do the work and see how that performs before I'd bother with the economy mode.

As I said above, the main pump does not come on for filtering. You are just telling the computer that there is a filter cycle, but that pump does not come on except to purge (all pumps come on for 2 mins) so the economy mode is just used for the heater in this system. I can set the filter cycle for whatever I want, the main pump does not run, just the heater. If I take it out of economy mode, the spa heats everytime I lose 1 degree.

Its actually a neat system.

I guess I just don't see any advantage to delaying the heater's operation in that scenario. In the end the heater has to turn on to get the spa back up to temp.

Economy mode on a spa that solely uses a circ pump for filtering obviously causes no harm other than the temp may drop a slight bit when you go to use it but in the end I see no gain in that scenario so I can't see bothering to use it.

In the winter months it keeps my tub from coming up that 1 degree everytime it drops, I just have it heat the water up once, the 5 degrees I may lose, during the time I want to use it. I understand what you are saying, how much does it save to run the heater an hour to come up 5 degrees or let it run 4 minutes several times a day to keep it set at the same temp. Since I do not have a meter on the tub, I can not tell. My dad, who is retired from the electricity buisness says it does not save much to do this, but I will say that having the programable thermostat for out house saved me about 100 gallons of oil this year ( i only normally use 600 gallons so this was a lot) I wonder why the savings on a house opposed to a hot tub, I think this is what people are asking

[spatech (the unreal one)]

In the winter months it keeps my tub from coming up that 1 degree everytime it drops, I just have it heat the water up once, the 5 degrees I may lose, during the time I want to use it. I understand what you are saying, how much does it save to run the heater an hour to come up 5 degrees or let it run 4 minutes several times a day to keep it set at the same temp. Since I do not have a meter on the tub, I can not tell. My dad, who is retired from the electricity buisness says it does not save much to do this, but I will say that having the programable thermostat for out house saved me about 100 gallons of oil this year ( i only normally use 600 gallons so this was a lot) I wonder why the savings on a house opposed to a hot tub, I think this is what people are asking

I think in the end you'll save about $2/month with that method on a well insualted spa by doing this but you'll also risk the chance that you go to use the spa and its dropped 2º or 3º or... from the setpoint you like to soak in. Therefore, I don't see any advantage over turning the heater on just once/day (or twice) to let it heat versus letting it heat as it so desires with the circ pump (which is the key here because if there is no circ pump then I do see the sense in using the economy mode).

Its a non-issue to me and I'm just being argumentative if it is being described as advantageous.

[rontl]

I think you've understood my question, and I guess the good news is how very well spas are insulated these days. We're still debating between the Caldera C45 and the Geneva, so I didn't realize how little heat they lose. It seems that my question is pretty much moot, which I think is a good thing for all of us, in the long run.

Thanks, everybody.

Ron

[rontl]

I think you've understood my question, and I guess the good news is how very well spas are insulated these days. We're still debating between the Caldera C45 and the Geneva, so I didn't realize how little heat they lose. It seems that my question is pretty much moot, which I think is a good thing for all of us, in the long run.

Thanks, everybody.

Ron

[zroger73]

After my warranty is up, I'll might rip out the control system and replace it with a small PLC and touch-screen HMI. Add analog inputs for water temp, heater temp, circ motor temp, jet motor temp, cabinet temp, ambient temp, and water level. I'll write a program that compares all the temps to determine the most efficient and safest operation. When the water level gets low, a solenoid valve opens topping off the water level. Chemical sensors could be added for automatic chemical dispensing. Turbidity sensors could be added to analyze water clarity and automatically filter the water as needed - or even open another solenoid valve to empty then refill the tub. Pretty much the entire tub could be automated and monitored and controlled over the Internet. Might relocate and redesign the filter system so the control system could automatically initiate a "backwash" routine when low flow is detected. Tons of possibilities!

Parts list

PLC

HMI

analog input modules (for temps and water level)

analog output module (for control signal to SCR-controlled heater)

relay output moduled (to energize motor contactors for circ and jet pumps)

power supply

several Type-K thermocouples

4-20ma water level sensor

4-20ma pressure transducer

Ethernet communication module

30A SCR

Cost? Probably as much or more than the hot tub itself. Value? Only "cool" for us geeks! Will I actually do this? Nah, but it's neat to dream about.

[Cedric]

Hi everyone,

Is there  something new since 2008 on this topic? I'd be interested!

Thanks

Cedric

[chrispomeroy]

I have a pretty basic Spa Controller and topside panel that do not expose any configuration options to the end user as far as scheduling goes, however this all changed when I bought a compatible balboa wi-fi controller.

The app allows you to create a schedule and alternate the state between normal mode and economy mode.  According to balboa, economy mode just means "20F less than the normal setpoint."

So using this wifi controller + app I can set a schedule as you would with a home thermostat. 

The one big flaw in this design:  When in economy mode, the touchpanel is inoperative.  This could be incredibly frustrating if you have a family or multiple people using the tub, and you set the schedule while someone else is home and wants to turn up the heat.  They would literally have you call you to adjust the temp in the app on your phone, to take the spa out of economy mode. I haven't found a workaround for this.