Temperature Decrease when the Cover is on

[twok99]

Has anyone tracked the decrease in temperature with the cover on along with the ambient temperature.  I am starting to track mine and wanted something to compare to.  

[bosco0633]

Vinny and I did a study last year, but I dont believe that there is anything that is out there currently to assist you.  Good luck and it is all in the name of science

[twok99]

For example I just tracked my temperature change over the past 4 hours.  I have a remote sensor so I can do it from from inside of my house.  Results are I lose approximately .75 degree F per hour with an outside temperature of 69 degrees.  I have Jacuzzi J-370 tub with 485 gallons.  I am somewhat disappointed in these results and am thinking about getting a new cover for the winter.  However it would be nice to get some type of a comparison.

[tileman]

Wow that seems abnormal to lose .75 degreea an hour w/ your cover ON.. I also have a Jacuzzi. It was 28 degrees the other night  and I soaked for 1 hour with cover off and temp. remained constant.
Today temps reached the upper 50s and my water remained at 103 all day. Check to see if your cover is tight all the way around.

[bosco0633]

I would agree, that seems to be a big temperature drop.

[grumpy]

 Results are I lose approximately .75 degree F per hour with an outside temperature of 69 degrees.  

Is that loss with the heater turned off?

[Vinny]

What Bosco and I did last year is available to read somewhere here.

Bosco's tub lost 0.0 degrees in 2 1/2 days while my tub lost 16 degrees.

So in 64 hours my tub lost 16 degrees which is 0.25 degrees an hour in 20 to 30 degree temps. New cover may  work or you might consider a Arctic like Bosco's.

Doc sells covers and he has an extreme cover that's 6" to 4" taper and a R-21. I'm planning on getting one when my cover goes!

I would also not trust a wireless device unless you know for a fact it is 100% accurate. My wireless goes blank every so often which means it lost the signal, they may not be accurate to the actual degree ... the only true readings I would trust is from a certified calibrated themometer.

[bosco0633]

Vinny I cant find that post anymore.

[anne]

When you guy did that experiment, was the power totally off, so no filtering or anything? I know I could search that thread, but I am being lazy.

I unplugged my tub at the GFCI the other day to work on something at about 9 am. Promptly forgot that it was off. At about 11pm as I was contemplating a soak, I remembered my error, and the tub had lost 4 degrees in those 13 hrs (100 deg to 96). It was a really cold day for CA in October, so it must have been 60-ish? The only reason it started as low as 100 is that I added a little water. Normally its 102-104.

[Vinny]

Bosco here it is:

http://www.whatsthebest-hottub.com/cgi-bin/yabb/YaBB.pl?num=1141403389/28#28

Anne, we didn't shut off the tubs, it was done while it was low temps, we kept the heaters off though. Basically the concept of TP is that your tub uses it's pump motors to heat the air in the cavity and this gives you extra efficiency as the tub uses that heat effectively. What happens when the pumps are off as in your case is where full foam may have an edge in keeping the actual tub warmer but the equipment bay is out in the cold ... not a big deal at temps to 33º but as it gets below that is where the problem can happen. As I said, I was really impressed at how the Arctic heated the water with just the pump motors filtering.

I know this is going to open something up. Quite honestly I didn't buy my tub for when I lose power, I have a house full of water pipes to worry about if that ever happened. But it's a good feeling knowing that if my heater ever goes in the winter (or Bosco's and yours) that my tub has days before it freezes.

[anne]

Thanks Vinny. That makes sense. One thing I could not figure out is that with my Arctic (perhaps this is common) if the current temp is 2 degrees above the set temp, the pumps will not come on (so no filtration) so that the tub will not go too much higher than it was set to be at (the pumps definitely do increase the tub temp). So I wonder how Bosco set his so the heater would not come on, but it would still have pump cycles?

[Vinny]

Thanks Vinny. That makes sense. One thing I could not figure out is that with my Arctic (perhaps this is common) if the current temp is 2 degrees above the set temp, the pumps will not come on (so no filtration) so that the tub will not go too much higher than it was set to be at (the pumps definitely do increase the tub temp). So I wonder how Bosco set his so the heater would not come on, but it would still have pump cycles?

So what your saying is perhaps Bosco cheated?  

My tub never shuts it's circ pump off no matter what temp, it's been as high as 105 with the temp set to 100. I know that some tubs will shut down their circ pumps if the temp is over 2 º. I just assumed that all tubs without circ pumps will filter, reguardless of settings. Quite honestly I think that that is a dumb feature ... what happens if you go on a vacation and decide to lower the temp? Your tub theoretically may never get filtered - YUK! I would check this out with your dealer if you didn't already.

[bosco0633]

anne you are right about the 2 degrees.  I thought of dropping my temp to, but then I realized this would happen.  So I opened the compartment and unplugged the heater.  

This is like running a circ pump because I dont have one.

So the tub does its thing and stayed at the set temp without losing heat.  Lid closed of course.  From what I remember, I was strongly encouraged not to trip the breaker so this is what I did.

I believe one posted that it was not a fair comparison because of the heat generated from the pumps in the TP shell.  

Vinny no cheating maybe confusion, I belive I was overly sensitive during this expierement fighting a battle what now looks like with myself!!

[Vinny]

I thought you might have been cheating after what anne said about her tub. I think I remember you saying that you did unplug the heater.

I can't fault you for being sensitive around here. Sometimes these battles get too heated. We (they?) forget that there are many brands of good tubs and sometimes it becomes a brand contest. I have said in the past - don't bash all brands but give people info about the bad ones, but it continues.

I find it amusing that some claims go unchallanged but don't let someone else claim something.

Now everybody go soak!!

[Gomboman]

Wow that seems abnormal to lose .75 degreea an hour w/ your cover ON.. I also have a Jacuzzi. It was 28 degrees the other night  and I soaked for 1 hour with cover off and temp. remained constant.
Today temps reached the upper 50s and my water remained at 103 all day. Check to see if your cover is tight all the way around.

I believe they were assuming that you cut off your power during this time Tileman.