Hot Tub Forum

Original => Hot Tub Forum => Topic started by: richopian on December 18, 2006, 11:59:32 am

Title: Hot Tub temp when not in use?
Post by: richopian on December 18, 2006, 11:59:32 am
Hi all,
I'm new to this hot tub thing and was just wondering what temp everyone recommends setting there tub to when not using it.
 
I have no idea myself. The first night I thought I'd better bring it down to 80 degrees overnight (so as not to pay for heating to a higher temperature). It ended up snowing that night and to my surprise in the morning the temp was 100 degrees !! - I guess the circulatino and filter pumps that run must help maintain the temp.
 
Last night I set it to 90 degress, but am now wondering if this is foolish. Should I just leave it set at 100.  
 
Any thoughts and advice...
 
cheers
Rich
Title: Re: Hot Tub temp when not in use?
Post by: PotomacG on December 18, 2006, 12:08:33 pm
If it's a new tub, set it and forget it.  Unless you're leaving it at a vacation house where you are away for long periods, it's not practicle, nor will it save you much (if anything) to play with the thermostat on a daily basis.

You want that baby hot and waiting for you to jump right in!

My $.02
Title: Re: Hot Tub temp when not in use?
Post by: tony on December 18, 2006, 12:11:36 pm
I agree...set it and forget it.  I leave mine at 102.
Title: Re: Hot Tub temp when not in use?
Post by: Reese on December 18, 2006, 12:16:03 pm
If you are going to use the tub regularly, you probably won't save anything by setting the temp down, because water heats and cools slowly, and requires a lot of energy to reheat.  On some tubs, setting the temp down causes the controller to go into "summer mode", shutting off the circ pump or filter cycles to avoid generating any additional heat.  That may not be advisable in the winter, when keeping the water moving helps maintain a uniform temp.

On the other hand, if your use is sporadic, or if you know you will be away for awhile, setting the tub down may save you a little money.  (Remember, if the tub is costing $20-30/month to heat, a 10% savings is only $2.50 a month -- IMO a small price to pay to have it ready to use on a whim).  I'd recommend setting it down to a point where the tub can reheat to normal temp in the lead time you will be able to give it.  For example if your tub heats 4-5 degrees/hour, and you are willing to wait a half-hour for the tub to warm up when you decide to use it, set it down 2 degrees.  If you can wait an hour, 4...etc.
Title: Re: Hot Tub temp when not in use?
Post by: Brewman on December 18, 2006, 12:23:30 pm
It takes less energy to keep water at 90 degress than 100.
 But it also takes energy to raise the temperature from 90 to 100, in my spa, that would probably take close to 2 hours.  

To save money, you have to have the spa sitting at the lower temperature long enough to come out ahead on the energy used to heat up the water.

In most cases, I suspect that savings would be so small as to not be worth the bother.

 
Title: Re: Hot Tub temp when not in use?
Post by: Dr. Spaâ„¢ Ret. on December 18, 2006, 01:30:13 pm
Lets make an assumption that over 24 hours the water will drop from 100 to 90. Now, are you saying it will take MORE energy to raise the temp back up from 90 to 100 than it would to manitain the temp at 100 for the entire previous 24 hours?????
Title: Re: Hot Tub temp when not in use?
Post by: lskarp on December 18, 2006, 01:36:20 pm
I take mine down to 98 when I am not using it.  This way, the kids can go in and spash around a bit wihtuot roasting.  I like it at 102 degs.  IF I am gogin to go in, it takes an hour or so to get all the way to 102 so no big deal.   When I get home, I pop outside and raise it up.

I am sure that I am not saving hege $$ especially out here in South Florida, but up north you will save $$ for every degree.
Title: Re: Hot Tub temp when not in use?
Post by: Brewman on December 18, 2006, 01:54:30 pm
Quote
Lets make an assumption that over 24 hours the water will drop from 100 to 90. Now, are you saying it will take MORE energy to raise the temp back up from 90 to 100 than it would to manitain the temp at 100 for the entire previous 24 hours?????


If you're asking me, I have no idea.  I know how much my heater costs to run per hour, but what I don't know is how often it kicks on for how long to keep the temperature I've set it at.  

 What I do know is that I don't want to wait 2 hours for the water to run up to temperature if I want to use the spa.  

What I suspect is that the amount I'd save wouldn't be worth it to me.

Dollar wise? Don't know.

Title: Re: Hot Tub temp when not in use?
Post by: Dr. Spaâ„¢ Ret. on December 18, 2006, 02:16:16 pm
Quote


 What I do know is that I don't want to wait 2 hours for the water to run up to temperature if I want to use the spa.  

What I suspect is that the amount I'd save wouldn't be worth it to me.


Agreed. If one is using the spa daily, or almost daily, the savings would be quite minimal. For someone only using the spa occasionally, like on weekends, there may be a slight noticeable savings (though I'd tend to go to an even lower temperature).

There's a law of physics that "translates" to, the greater the temperature of the spa, the more heat will be lost in a given period of time. Hence, it requires more energy to maintain a spa at 100 than it does at 90. As a  lower temp loses less energy, it will therefore require less energy to bring the water back up to temperature, that to maintain the higher temperature over a period of time. But again, for a regularly used spa, the savings will probably be negligible.
Title: Re: Hot Tub temp when not in use?
Post by: Jacuzzi Jim on December 18, 2006, 02:29:30 pm
Quote
Hi all,
I'm new to this hot tub thing and was just wondering what temp everyone recommends setting there tub to when not using it.
 
I have no idea myself. The first night I thought I'd better bring it down to 80 degrees overnight (so as not to pay for heating to a higher temperature). It ended up snowing that night and to my surprise in the morning the temp was 100 degrees !! - I guess the circulatino and filter pumps that run must help maintain the temp.
 
Last night I set it to 90 degress, but am now wondering if this is foolish. Should I just leave it set at 100.  
 
Any thoughts and advice...
 
cheers
Rich


 Most people just set it and forget it,but with the J365 you could use the economy mode.  Then it will only heat during a filter cycle,some people (not many) can set the filter cycle to come on 1 hour before you use the spa, now granted this only works if you plan to use the spa at a specific time everyday. But it would work, best way just leave it where you want it then its always ready to go. ;)
Title: Re: Hot Tub temp when not in use?
Post by: Brewman on December 18, 2006, 02:37:04 pm
Yeah, my Optmia has that economy mode too.  Only problem is me.  My spa use isn't all that predictable.  

PS
I did some mental math- my cost to run the heater for one hour is about $0.50, so call it a buck to get that theoretical 10 degree increase.  

Do that once a day, and I'd be paying about $30/month to boost that water.  

But my spa heating costs aren't all that much more than $30 per month, on average.  

So it looks like in this example, I'd be breaking even at best.  I suppose then, that the best use of this would be for those who only use their spas once or twice a week.
Or less often.  







Title: Re: Hot Tub temp when not in use?
Post by: Tatooed_Lady on December 18, 2006, 02:42:38 pm
my hubby and I use the tub sporadically...not at all for a week, then 3 nights in a row, then 1 night next week, and.....you get the picture.  ;) Anyhow, our tub is set at 101, and we don't bother adjusting it, unless we get a streak of warm weather (drop tub temp to about 100), or really cold (bump it up to 102). "Set it and forget it" is the motto in this case. This way, the tub is ALWAYS ready for us, regardless of how well we planned our soak.
Convenience might cost a tad more, but to us, it's worth it.
Title: Re: Hot Tub temp when not in use?
Post by: Gomboman on December 19, 2006, 12:06:52 am
I'm with doc on this one.

Quote
Lets make an assumption that over 24 hours the water will drop from 100 to 90. Now, are you saying it will take MORE energy to raise the temp back up from 90 to 100 than it would to manitain the temp at 100 for the entire previous 24 hours?????
Title: Re: Hot Tub temp when not in use?
Post by: Davidny on December 19, 2006, 03:05:05 pm
My massage therapist has a Snorkel hot tub, which she hops in at 108.  :o
Title: Re: Hot Tub temp when not in use?
Post by: Reese on December 19, 2006, 03:09:20 pm
Quote
My massage therapist has a Snorkel hot tub, which she hops in at 108.  :o
Did you mean to post this in the "What temp..." poll?  Regardless, what is a "Snorkel" tub?  Sounds interesting, very interesting -- especially in the same sentence with "massage therapist". ::)
Title: Re: Hot Tub temp when not in use?
Post by: Jack_L on December 19, 2006, 03:17:14 pm
Our tub sits at 104 all the time unless we go on vacation. Then I will drop the temp down to 90 or so.  
Title: Re: Hot Tub temp when not in use?
Post by: neocacher on December 19, 2006, 03:59:57 pm
Some of you sound like that old Ronco advertisement for a meat rotisserie,
"Set it and Forget it!"
Title: Re: Hot Tub temp when not in use?
Post by: Ehizzle on December 19, 2006, 06:44:31 pm
Quote
It ended up snowing that night and to my surprise in the morning the temp was 100 degrees !!

Sounds like you must have a Hot Spring! ;D No need for the heater to come on since its so well insulated.

I'm very existentialist so I dont care what tempurature the tub is at when I'm not there. It doesnt exist when Im gone. :P
Title: Re: Hot Tub temp when not in use?
Post by: hottub.pool_boy on December 19, 2006, 07:14:05 pm
It costs the same to maintain at 80 as 100.
Title: Re: Hot Tub temp when not in use?
Post by: Reese on December 19, 2006, 07:21:27 pm
Quote
It costs the same to maintain at 80 as 100.
I disagree.  Unless your tub has no heatloss whatsoever, the higher the differential between the ambient temp and the tub, the more it is going to cost to heat.  To make the example simple: during the summer when the ambient temp is 80, if you set the tub at 80, the heater is not likely to run.  If you set it at 100, it will have to.
Title: Re: Hot Tub temp when not in use?
Post by: hottub.pool_boy on December 19, 2006, 07:29:07 pm
In general, it will cost the same.

Specific outside temperatures, different heater amp draws, a new spa cover versus 6-8 years old, full foam spa or not. I guess if you want to pick specific outdoor temperatures and specific water temperatures anyone can make assumptions.

But if you consider 40 degrees outside, when a tub is probably used the most, it will be the same cost to maintain 80 or 100.
Title: Re: Hot Tub temp when not in use?
Post by: Chad on December 19, 2006, 07:38:03 pm
I'm with Reese on this one.

If it's 40 degrees outside and you set the thermostat for your furnance at 80 opposed to 70, it would run alot more. I would think the same would apply for a spa as well.
Title: Re: Hot Tub temp when not in use?
Post by: hottub.pool_boy on December 19, 2006, 07:40:44 pm
Wrong. But you win, you're right.
Title: Re: Hot Tub temp when not in use?
Post by: Chad on December 19, 2006, 07:42:06 pm
Quote
Wrong. But you win, you're right.
:-?
Title: Re: Hot Tub temp when not in use?
Post by: hottub.pool_boy on December 19, 2006, 07:46:52 pm
I may be young, but I learned through being involved with a family hot tub business and marriage that...... when you know you're right and the customer/wife thinks he's/she's right.....It's best to agree and end the argument.  :-?
Title: Re: Hot Tub temp when not in use?
Post by: Chad on December 19, 2006, 07:49:55 pm
Quote
I may be young, but I learned through being involved with a family hot tub business and marriage that...... when you know you're right and the customer/wife thinks he's/she's right.....It's best to agree and end the argument.  :-?

I like the way you think.
I was not trying to argue with you though. I just want to know how you came to that conclusion. I'm just curiuos that's all. :)

ps- were you saying that my furnance analagy was wrong or that furnances don't run more when set at a higher temperature when it's 40 degrees outside.
Title: Re: Hot Tub temp when not in use?
Post by: MostlyLurkingGal on December 19, 2006, 08:47:27 pm
WHY NOT, Is your first name Chad?
Title: Re: Hot Tub temp when not in use?
Post by: Reese on December 19, 2006, 10:19:25 pm
Quote
Wrong. But you win, you're right.
There aren't any winners in a civil discussion.  If you look back at the thread, most everyone agrees that it takes less energy to maintain a spa at a lower temp.  If we're all wrong, that's fine, but please explain how hot-tubs defy the laws of physics. :o
Title: Re: Hot Tub temp when not in use?
Post by: Brewman on December 20, 2006, 09:20:18 am
Quite simply, all other factors being equal, it takes more energy to maintain water at 100 degrees than it would 80 degreees- assuming that all you want to do is hold the water at a constant temperature.  And assuming that you have heat loss to deal with, which would be the case for most of us.

Where it gets more complicated is when you debate the merits of keeping a spa at 100 constantly, or try saving money by reducing the water temperature when not using the spa.  And that entirely depends on a whole lot of variables, so there isn't a pat answer to the question.
Title: Re: Hot Tub temp when not in use?
Post by: drewstar on December 20, 2006, 09:29:17 am
Quote
Quite simply, all other factors being equal, it takes more energy to maintain water at 100 degrees than it would 80 degreees- assuming that all you want to do is hold the water at a constant temperature.  And assuming that you have heat loss to deal with, which would be the case for most of us.

Where it gets more complicated is when you debate the merits of keeping a spa at 100 constantly, or try saving money by reducing the water temperature when not using the spa.  And that entirely depends on a whole lot of variables, so there isn't a pat answer to the question.
 I agree with brewman.

The statment  "It costs the same to maintain at 80 as 100."  as a stand alone statement is incorrect and misleading.

The fact is, it cost less to maintin water at 80 than it does 100, but that's not the whole story. We're not using our tubs at 80.

But as Brewman stated, insualtion, heat retention, heater efficiany, and climate all play a huge roll. Least we forget, brining the temp up to 100, (or 102 or what ever you soak at).  The amount of time you use the tub, surface area, wind conditions, all play a roll.

Given all that,
If you use your tub a few times a week, keeping the temp at a constant is probably better.  However, if you only use your tub a few times a month (perhaps it's at a vacatin house?) then maybe not and I'd experiment with bringing the temps down a bit (say 95).  inversley, I would not keep my tub at 104 constantly, I'd be inclined to bump it down to 101 or so.