eletric bill just in

[goingwarp]

I had posted last month about my eletric bill being really high and I had concerns about the tub wasteing too much eletricity, well my newest eletric bill came in. This month the bill was 115.00 last month the bill was 143.00 so that sems more like it, last year my bill was 83.00 so this is within the 20-30.00 it takes to run the tub.

[Steve]

Glad to hear you're not "going warp" over your electric bill anymore!

Steve

[Chas]

First month is always the highest. And no, it's not because you start with cold water - the bill doesn't seem to jump after a water change down the road.

I don't know why this happens, but I figure it has to do with watching the tub heat, checking the chems every five minutes, lots of extra towels in the dryer, more lights on, more people over, more cold ones in the fridge.....

[Bigbender]

This thread is a coincidence...

A friend stopped by the other day and we got to talking about our hot tubs. He works long hours so the only time he uses his tub is on the weekends. It surprised me when he said that he turns his heat back to 72 degrees on sunday night and then turns it back up to 102 on saturday morning so it's ready for him in the evening.

As soon as I responded with "Why"?, I realized his obvious answer would be "to save electricity". Since it's below freezing in Pa. right now, maintaining 30 less degrees might save him some money through the week, but when the heater kicks in for five hours every saturday to get it back to 102, wouldn't this actually cost him more in wear and tear and electricity ?

Can anyone provide some answers from experience or  from meter tests ?

[Brewman]

I dont' have any meter proof, but generally you can save money by doing this.  People set back their home thermostats all the time to save money.

It's all a matter of how long the heater runs to heat the water to operating temperature, vs how long it would have run to maintain the water temperature during the same time period.

If your heater consumes 5,000 watts, and your electric rate is $.07 per kwh, it costs about $0.35 per hour to run the heater.  If it takes 5 hours to heat the water, it will cost about $1.75 to heat the spa water once per week.  The spa will also consume power that week for filtering, and for whatever the heater needs to keep the water at 72.

If the heater needs to run more than 5 hours per week to keep the water at 102, then your friend may be saving money.

I just keep my water at full temperature all the time.  I've heard that certain spa chemical routines may not function as intended at low water temperatures.

Brewman

[Steve]

I dont' have any meter proof, but generally you can save money by doing this.  People set back their home thermostats all the time to save money.

 It's all a matter of how long the heater runs to heat the water to operating temperature, vs how long it would have run to maintain the water temperature during the same time period.
 
 If your heater consumes 5,000 watts, and your electric rate is $.07 per kwh, it costs about $0.35 per hour to run the heater.  If it takes 5 hours to heat the water, it will cost about $1.75 to heat the spa water once per week.  The spa will also consume power that week for filtering, and for whatever the heater needs to keep the water at 72.

If the heater needs to run more than 5 hours per week to keep the water at 102, then your friend may be saving money.

I just keep my water at full temperature all the time.  I've heard that certain spa chemical routines may not function as intended at low water temperatures.

Brewman

They say with a programmable thermostat, that cooling the temperature at night more than 4 degrees will not save on electricity as the cost to reheat the home negates it.

If you are going away for 10 days or more, I suggest cooling the spa to 80 or 85 but to do this regularly will not provide any savings. Reheating to 100+ degrees when dealing with 400+ gallons causes the heater to operate longer than maintaing a steady temperature.

Steve

[Drewski]

Hmmmm...

I gotta think about this one. I suppose I'd look at it from the standpoint of thermal effeciency (NO, this is not a full-foam vs. TP response).

If you have "highly effecient" insullation properties, would a tub expend MORE power to keep water at a HIGHER tempurature than a lower one?  I'd think not, but then again??

Also, does cooling occur FASTER than heating? I'd say YES, because I think more factors contribute to cooling (during the winter) than heating.

Assuming there is NO difference in the cost to maintain at high vs. low temperature, and assuming that it takes MORE energy to heat back from 80 to 102 than is saved by NOT heating while going from 102 to 80, then YES, it would seem to be more expensive to do this.

I'll bet the savings are in the margins as Steve indicated.

For what it's worth (if anything)...

Drewski

[Chas]

Some tubs will save money this way, others will cost more. It all depends upon how long your tub will retain heat.

You can do a simple test with some complicated math to figure out if this would save money or not.

Turn off the heat in your tub and check the temp in 24 hours. Repeat for five days. Find out how many degrees the thing loses per night, but don't expect it to be the same number of degrees every night: it will lose faster from 100 to 90, less from 90 to 80 and so on, and then you have to average things out to get a number. Keep an eye on the weather: it will cool faster in cold than warm weather, and it will cool faster in a wind than calm, and if you have to lift the lid to test water temp, chems etc. you can throw things off.

Turn the power back on and carefully monitor how long it takes to get back to your normal temp. This will give you an average rate at which your tub heats. Most tubs of around 350 - 400 gallons can do about 9 degrees and hour with 5KW heaters. Very roughly.

Once you know how long it takes to cool and how long it takes to reheat....

Sorry, my wife is ready to go to breakfast. You'll have to finish this yourself....

Aloha

[goingwarp]

Hey steve great to see you back, thanks for the helpful advise you gave me the first time around I also think that changing the filter times to be around the same time I am in the tub will help as well, now I can and will be changing the water soon. Speeking of water change what should I use to clean the tub itself (not that it's really dirty) but just to make sure before I put in the new water. I don't want to run into any problems.

[Steve]

Thanks warp.

As far as cleaners for the acrylic, most dealers offer a non abrasive cleaner designed for this purpose specifically. There are many brands out there but most work very well to remove scum or calcium deposits.

Let us know how things go with your water change.

Steve

[Max78]

I purchased an Optima in September of 2004.  I hadn't paid much attention to the electrical cost until it started gettting really cold outside (I live in central IL where it can get pretty cold).  My last electrical bill from 12/20/04-1/20/05 was $109.00.  My electrical bill for the same period last year (without a hot tub) was $89.00.  So $20.00 for a pretty cold period with moderate use isn't too bad.  I keep my thermostat set at 98 most of the time.  Sometimes turn it up just a bit while in the tub but end up turning it back down.

[Constance]

This winter we were out of electric for 2 days!!  I live in Ohio and we're having a cold, long winter.  I was concerned about how long my new tub (purchased Aug 04) would be OK before I be in trouble with freezing.  When i purchased it, The dealer said it should last about 4 days.  Yes--I know the outside temp would effect this alot.  I figured I'd wait until the end of the 3rd day to check the temp.  In the mean time i kept the lid closed.
I was very pleased to find that after 2 days when the electric came back on, my full foam spa was 89'.  I routinely set it for 102'.
I was very lucky our power can back after 2 days.  Some people were out for a week.  I plan on keeping my tub at 102 in the winter--just in case we loose power, I'll have more of a cushion with the water temp.  It was not a good feeling thinking about what i was going to do if we remained out of power and my tub started to freeze!!

[im45us]

The heater just went on my 11 year old Hot springs tub with a 5 year old cover in need of replacement. My tub sits outside in Massachusetts and I keep it at 102 . The tub was without heat 8 days total but pumps did work but only kept circ pump going. When I repaired the heater the temp was 76 degrees .

Ivan