economy or standard mode?

[teach]

I have a new hot tub and tub in a cold climate.  Right now its in the 20's.  I have a question pertaining to what is the best mode to have the hot tub in as far as electrical usage.  I use the hot tub 3 to 5 times per week and like around 104 degree water temp.  Would it be more energy effecient to keep a constant temp. even when tub is not use or to use what is called "standard in economy mode" on my tub.  The spa is heated to a set temp. usuallly lower than the standard temp. then when you want to use the spa you push a button and the temp. raises to your standard temp. setting and then reverts back to "Economy mode "  lower temp setting after one hour.  You can also have the tub revert back to economy mode immediately by the press of a button.   Do you save on your electric bill by cutting your water temp. back while not in use and then heat it up before use or is it better to keep a constant temp. regardless of the water temp. setting.  Hope you understand this, its a little confusing to a novis hot tubber.     Thanks in advance for your opinions.        

[J._McD]

Let's see if we can simplify this issue.

First set your temperature at the useful temperature, let's say 104°.  Dial the temp request down to 80° effectively disabling your heater and come back in 24 hours to see how low the temperature has gone down.  That is how much temperature you loose in a day, or how much you buy electrically each day.  To see how much heat you produce in one hour, set the temp up and come back in 1 hour to see how much heat went up in the hour.

Determine how much you lose in 24 hours and how much you recover in one hour, you can tell how long it takes to replace the heat loss in 24 hours.  the electric consumption of your heater, 5.5kw multiplied by the cost of your electric per kw hour.

All spas are different and it would be difficult for us to speculate on your energy consumption without knowing details about your spa.

It is ususally recommended to set it and forget it if you use the tub regularly.

[Brewman]

You might save some money- it costs more to keep your spa water at 104 than at a lower temperature.  

Your trade off is having to wait to have your spa water heated.

Savings will vary based on the temperature swing, how often you use the spa, things like that.

I don't use economy mode because I can't predict that precisely when we'll use the spa, and I don't want to wait the time it takes to heat up the water.  Our spa takes about an hour to raise the temperature 4 or 5 degrees.  

I don't really think in our case we'd save enough to make it worth the effort.  If I realized a 10% savings that would only amount to 3 or 4 dollars a month.  I have trouble believing we'd save much more than that.

[Rayman]

If you have a 24 hour circ pump then it doesn't matter, the heater runs when it is needed.  Economy only runs the heater when the filter cycle is on and since the circ pump runs 24 hours Economy is Standard.  If you don't have a circ pump then Economy works, but then you may have to wait for the tub to heat up unless you set the timer for the filter to correspond to when you use the tub the most..

Ray

[Brewman]

My understanding on how the economy mode works on my spa is basically what you said.  
The circ pump runs 24 X 7, and the heater will come on as needed to hold the set temperature- in standard mode.
In economy mode, the circ pump still runs, but the heater will only come on when the filtration cycles are set- but at no other time, thereby letting the water temperature drop a certain amount.  So I'd have to synch up my tub use with filtration cycles, or switch the heater to standard and wait for the water to warm up.
Sounds like too much work to me.

[johnvb]

Actually, on the my Sundance, if the 24 hr. circ pump is set for 24 hrs, but the four filter cycles are set for 0 minutes duration,... and....the mode is in economy, the heater will stay off,  no matter what the set point is.

I use this set up in the summer; the cir pump's heat gain by itself is enough to maintain a 95-96 degree water temp. To turn the heat on, I simple switch from economy to standard.