How to reduce running costs?...

[iceno9]

So....i have my spa installed on a wooden decking, filled, running....enjoying 

However i expected about 50p to £1 per day running costs in electricity and this appears not to be the case. In fact it is more like £2-£2.50 per day. Thats like £800+ per year and right now its summer!!!!!!
For reference the tub is a Hydra Spa Millenium, it has a new circulation pump, new lid which is not water logged, about 7ft square.

So what things have people tried to reduce running costs? What works?
For example -
 - I have added a 1 inch thick foam with aluminium on each side (called Kingspan in the UK) to 3 of the 4 sides of the tub. i.e. removed the panels and filled the gaps between the wooden structure.
 - What difference would lowering the temperature by 1 degree make?
 - I have seen some people have a 'bubble wrap' floating on the water surface and then the lid on the top. Does this really help minimise losses?
 - Are there settings changes i can make that might help? For example - changing the filter cycle? (Its a Balboa GL2000 system with ML700 control)
 - If i use the tub once per day (always evening), is it worth using economy mode and then have a single heat cycle 1-2 hours before i use the tub? Or should i just keep standard mode that maintains the tub temperature all the time?

Any other ideas?
Maybe wire in to next doors meter!!!!

[Chartreux]

By Bubble wrap do you mean a solar cover/blanket?
Here in Texas/USA those might work, not sure how much sunshine you get in the Summer, they even reduce the heat on a hot tub during the Summer.
So just depends on how much sunshine and how hot you get, for the solar covers/blankets...
Others will come by with more info as far as the insulation under the hot tub. 

[iceno9]

I talk about the thermo blankets you can get that float on the water underneath the spa cover. The idea is to stop evaporation whereas the cover stops convection. I know it will help....but i dont know to what extent and i dont know if "any old bubble wrap" is good enough or if it needs to be a special kind for some reason....for example, an aluminium foil version might stop radiated heat escape too!??

But of course i am after other ideas too....what can i change/modify on the tub to improve it?

[Dr. Spa™ Ret.]

Some preliminary testing by a major spa manufacturer showed that a floating blanket (under the hard insulating cover) increases the total R value of the covers(s) by R-10.

[Quickbeam]

I am a fairly new spa owner and noticed that for the first couple of weeks of ownership, due to evaporation, I was adding water to my spa once per week. I have since added a spa blanket and have not had to add any water since. Not sure how this equates into actual savings, but I’m pretty sure there has to be something there.

[buzzsaw90]

Not sure if that is a lot compared to mine. I've had a tub for 10 months now (Caldera Cantabria) and have been tracking my electric bills. Over the 10 months that i've had it, i've used 3800 more Kilowatt-hours of electricity than for the same period last year. At 13.5 cents per KwH, that works out to about $50 a month, assuming all extra usage was caused by the tub. Since the last 2 months are July/August, that average will go down a bit.

[Spatech_tuo]

- Are there settings changes i can make that might help? For example - changing the filter cycle? (Its a Balboa GL2000 system with ML700 control)

Any other ideas?
Maybe wire in to next doors meter!!!!

I'd try the economy mode for sure. Also, when that filter cycle is on the spa will draw in air from the outside into the water if you leave your air valves open. Close all your air valves when you exit the spa so that you're not adding that colder air into the water during times when the spa is not in use.

[aeajr]

A spa enclosure may help reduce costs.

Here is my 1 year report on my installation which includes an enclosure, a greenhouse.
http://www.whatsthebest-hottub.com/forum/index.php/topic,17809.0.html

I did not do a 1 year test with a 1 year second to record any differences.  However my hot tub is outside in NY.  This winter we had a lot of days under freezing but we used our hot tub all year round.   For us, any energy savings is a bonus.   I have no hard numbers to quote but I guestimate that I will save enough power for the greenhouse to pay for itself in 5 years.  But even if it never zeros out, the comfort of using the tub in rain, snow, wind and cold makes the improvement well worth it.  And keeping the bugs away is wonderful.

During the summer, when the tub is not being used the temp inside the greenhouse gets up to 100 to 115 degrees F.   That is close to or above the temperature of the hot-tub so the heater does not have to run to maintain the temperature of the water.   Even at 70 degrees F you have a 33 degree delta to the 103 degree temperature of the water in the tub.   That means the tub is losing heat to the air.  If there is a breeze the heat is lost faster.   Insulation helps but does not totally stop heat loss or your heater would not need to run, but it does.

In the winter, if the temperature gets to 32 degrees F, 0C now you have a huge temp differential and the tub is losing heat much much faster.   When you open the tub to use it the heat loss goes through the roof at 70 degrees and is huge when it is colder.   Having an enclosure helps retain some of that heat and block the wind that would rob even more heat from the tub.   In the winter that retained heat helps warm up the greenhouse to make it more comfortable for winter use.  It may be 25 degrees F in the greenhouse when you open the tub but it will be 50 degrees F when you get out.

Note that we put the greenhouse enclosure in to make the hot tub more comfortable to use in rain, snow, wind and cold weather.  I have a screen door on the greenhouse so it also keeps the flying insects away from those in the tub.  During the time we are actually in the tub in the summer we leave the doors open so the temp inside and outside the green house quickly equalize, but the screen keeps the bugs out.