Temperature set back?

[BinaryBob]

On my 3rd spa. Last one lasted 15 years. Harsh MN winters tend to take their toll.

The install tech told me not to bother dropping the set temperature during non-use - It won't do me any good. I was surprised by this comment, obviously contrary to indoor thermostats however there is a big difference in energy usage between making up 6 degrees indoors, and pushing a spa up 10 degrees when ambient is near zero. The new spa is much better insulated than the last.

Thoughts on this?  I should also say that I use the spa every day, or perhaps every other day.

Thanks

[cranbiz]

If your usage will be that frequent, the tech was correct. It won't be worth it.

If you run at 102 deg, the heater will come on when it see's a drop of 1-2 degrees. It will run for some time, could be 5 minutes or so and shut off. With a well insulated spa and a good cover, it won't be all that frequent.

My spa is in an unheated enclosed screen porch. It is set for 102 deg and no setback temp. Ut does not run very much at all. However, I also don't live in MN either. 

[Couch67]

Hi, I would agree, unless you are set up with Time of Use (TOU) rates for electricity.  Here, our electricity rates are cut in half from 7pm to 7am on weekdays. With that, it makes sense to set back the hot tub (assuming you dont use it from 7am to 7pm).  

I have a gecko remote system and its incorporated into my Home Assistant setup. Its configured to set back temp to 80F from 7am to 7pm during weekdays, then go back up to 100F at 7pm. Its set to 100F all weekend.  

I'm not really sure yet how much this is saving.  I do have a few years of 'before' data, so I will do a comparison after this winter.  I know its saving (mostly due to time of use savings, as all heating is with cheaper electricity), just dont know how much. 

Attached is a chart showing hot tub temperature from a day last week. Red areas are heating events, blue are cooling.  You can see the tub got to 93 F after cooling all day, then took about 50 minutes to get back to 100F.

[CanadianSpaTech]

Every spa will have different results. To many varying factors.

If you have a non circ system and the spa runs 2- 2 hour filter cycles a day I would run the spa in Econo mode. Usually the filter cycle start time is determined when you flip the breaker on. Then the second cycle 10 hours later after the first cycle ends. In Econo mode the 10 hour period in between filter cycles if the temp drops the heater will NOT bring the water temp back up to the set/desired temp until the next filter cycle has begun. Once the filter cycle starts if there has been 2 degrees or more of heat loss it will then run the heater for a short period of time and bring it back up to the set temp.

If you have a typical pattern of use and like to go into your spa each night at 8pm then reset the breaker at 6 am or pm. That way when you go out to the spa at 8pm it has run the 2 hour filtering/heating cycle and the spa is at your desired temp.

Turn off air injection jets and water features when not in use. The system draws cooler air from inside the cabinet and can have a cooling effect when not in use.

If you ever need to replace the cover go 6"-4" thick and has an end to end center steam seal and a long (5") side skirt. Like your home most heat loss is through the roof.

If your spa has side vents in the cabinet to cool the pumps you might want to consider restricting them in the Winter months. 

Add rockwool insulation to any voids inside the spa... leaving enough room for the pumps to breath.

Enjoy

 

[BinaryBob]

Thank you all for responding. I will use eco-mode and reduce the temp when away for extended periods.