How hot will a tub stay?

[Garyjr]

With much cooler evenings upon us, will most tubs maintain the set temperature on longer soaks (say an hour) with the cover off and the outside temps dropping into the teens?
Mine seems to maintain it right now, but the outside temps are still only in the low 40ies.

Thanks,
Jr

[Vinny]

It's hard to say. My tub will shut off the heater when 2 pumps are on and I've been in it or 40 minutes and it lost 1º in 20 - 30 air temps. I have a 4 KW heater and it can stop the heat loss with the cover open but it's not powerful enough to heat up the water with the cover open.

Some tubs have a 5 KW heater and don't shut their heater off with the pumps on, they're usually the 60 amp tubs and I believe that the tubs maintain their heat and probably heat the water with the cover open.

With that said, I don't find losing 1º a big thing ... my tub is usually 1º above set temp anyway.

[Vanguard]

Depends on insulation, too.  Oooh.  Sorry.  Don't want to start that.  I know, I know, most heat loss is through the open cover.  Just poking some fun.

Anyway, you will lose heat since your heater won't work while the jets are on.  I know Hot Spring and Caldera will do that on a 50 amp circuit.  Most others, as Vinny said, need 60 amps to do that.  I have found that because the heater on my Hot Spring Vanguard stays on, I don't lose heat when its cold.

[Brewman]

The Optima running at 60 amps pretty much keeps the set temperature give or take a degree, all the way down to below freezing temperatures.
 As was said before, the 60 amp setup lets the heater come on anytime it's called for.

[Repeat_Offender]

Same here, my heater will operate regardless of how many pumps I have on or what speed they're running at.

[Hammster]

I have a Sundance Capri and it only requires a 50 amp circuit. I can have all the jets and pump and heater running all at the same time.

[drewstar]

My Tiger River's heater operates independtly of the jet pumps.  I belive it's a 4Kw 230v heater.  I had no problems keeping the tub hot in the dead of a New England winter. However, I like my temps around 101 and have a little bit of room extrra room on the top end if I felt it wasn't hot enough.  Someone who demands the water be kept at peak temp consistenly might notice something.   Weather conditions will make a huge difference.  Wind blowing over the surface of the water will remove heat very quickly, air injectors will also make a difference as well.  But all in all, a quality tub should not have a problem providing hot wter in the dead of winter.  I have a feeling you'll be fine, and develop a wonderful addiction to winter soaking  

[Brewman]

Some Sundances, at least the ones I looked at back a few years ago, have different options for electrical.  The heater is independent as well, it's more a factor of power demand.
 My spa, for instance, came standard with a 50 amp configuration.  In this configuration the heater would come on as demanded by the thermostat, unless both of the main pumps were running at high speed.  Apparently the current demand is too high for a 50 amp breaker when everything is running at full tilt, with the heater.
 So as an option, a jumper can be set on the board to allow the heater to come on anytime, even if both pumps are runniing at full blast.  
 When so set, a 60 amp breaker is required.
Alternatively, the spa jumper can be set for I think 30 amps, which limits the heater and pump running combinations even more, it an option for someone who doesn't have the capacity to run a higher amperage setup.

[spahappy]

I've been in my Coleman in -15 for 45 minutes and lost 1o. My spas has a 5.5kw heater and is on a 60 amp breaker.

[ndabunka]

My Jacuzzi J-370 (3 years old) is running on the 60amp circuit and can heat while running both pumps on high.  It has maintained a 103-degree temp in temps of around 10-degrees above ZERO ferenhiet (about as cold as it get's here)

[Garyjr]

Last night at 41* outside temperature, our tub stayed right on 100* with all 3 pumps running (Note: on our Maxxus, the heater kicks off when all 3 pumps are running.)  We then turned 1 pump off and set the thermostat to 101*, and within 10 minutes it raised the water temp to 101*.

I don't think we will have any problems maintaining our desired temps even in the coldest of weather.

Brewman,
Do all tubs have the option of the setting the spa jumper to run all 3 pumps and the heater at the same time?  I am running on 60amp service.
Jr

[dkersten]

I havent had the opportunity to soak in really cold weather yet, but my tiger river Bengal has a 6000w heater and I know on at least the first speed of the main pump it stays on.. I have not noticed if it stays on when the jets are on full as I am always enjoying the massage and not putting my foot over the hot water return to see if its hotter than the water.  My 50 amp service gets divided at the gfci to a 20 and a 30 amp, and I imagine if the main pump is on full the heater is off or on a low setting because when we first powered it up the heater was drawing 24 amps constant, and its on the 30 amp side as is the main pump.. I dont run the pumps on full for an entire soak though so as soon as it goes off that heater is on again.. I imagine the temp wont drop much even in a prolonged soak.. maybe a degree but I cant imagine a 6000w heater not being able to keep 330 gallons hot unless its below about -10..

[tubbintom]

Side comment to this thread...A few people have mentioned, that they can run their pumps on high or low.  I have a 2006 800 series sundance and I only have the option to turn them on or off with no speed control.  I understand you can adjust the pressure with the air controls.  Is this what you are referring to or do tubs have pump high/low options?

[drewstar]

The pumps themselves are 2 speed.  On my tub, I have 2 pumps for the jets. One is one speed (high) and the other is 2 speed (high and low).

If I push the "Jet" button on my control pad once,  one pump comes on at low speed, and about half the jets in the tub are on a soft, slow  stream.  It's ok.

If I push the "jet" button again, that same pump comes on High and the same jets are now running at full blast.

If I pusht the "jet" button again, the other single speed pump turrs on (at high speed) and now all my jets are blasting at full velocity.

[Repeat_Offender]

Same here, one push for low speed and a second time for high speed. The difference I think with my spa is that one pump is dedicated to one half of the spa and the second pump the other half. I can run one pump on high and still have the jets on half the tub off. I'm not sure if that's an advantage or a disadvantage but I have operated it that way on occassion.