Questions on Spa Energy Usage

[jslost]

Greetings.  I have kind of an interesting scenario I was hoping someone could help me understand. 

We purchased a used Master Spa spa, Legacy Inspire, which is about 10 years old. We had to replace the heater but otherwise it works great and has no issues at all.  We have a new cover on it too.

This thing has been an energy beast though, and we've seen our power bill go through the roof. The spa runs a minimum 4 hours a day for maint. and appears to utilize, per attached, about 5 KwH per hour (20Kwh day - just for maint. cycles).  I've tried to look into whether this is normal, but most data I can find is for new spas.  I understand the heater is the biggest energy such but it's new, so I would expect it to be somewhat efficient and running properly. 

We have already addressed power billing, etc.. the the best of our ability with our local utility.  I am mainly curious of two things:

1) Is this 5kwh about typical for this (older) spa?

2) Would a newer spa be more efficient?

Thank you very much for any help. 

JH

 

[RDspaguy]

The heater is no more or less efficient new or old.

The heater is likely either a 5.5kw or a 4kw. Any time it is on it is drawing the same amount. It will be noticeable when you first fill it and heat it up. Maintaining the temp should not be a huge daily expense.

The pump, running in high speed, is about 1/2 of the power usage as the heater. In low speed it is about 1/3 of high speed. Many spas have a small circulation pump that runs 24/7 for heating and filtration but draws very little power, about as much as an old fashioned 100w bulb.

Radio, wifi, led lighting, ozone or uv, and salt cells also increase power usage to various degrees.

Since heater run times vary with ambient temperature, spa construction, spa location, and use habits it is nearly impossible to pin down what is "normal" usage.

You can remove your side panels and insulation boards and add some fiberglass inside if you choose, just do not insulate around pumps and equipment as you could cause damage. If it is on a deck, you might insulate between the joist underneath the spa with foam board as well.

 

 

[Cusser]

I'm in Arizona, and at this time of year our high temperatures are 65-70F, and gets down to 40F at night.  I have a 1988 CalSpa, set to operate only when water temperature drops, and needs to pump/heat to get back to 104F.

My spa actually runs less than 1/2 hour per day for that, so my costs are low, figure under $15 a month for electricity and chemicals.

[jslost]

Hi. Thanks for much for your responses.  The information on the heater seems helpful.  This seems normal then if I am reviewing the above image and seeing about 5kw per hour (heater plus low speed circ pump).  I chose this specific image example because it was just a maintenance (and heating) cycle day. We didn't use the spa and it doesn't have any other features except an ozonator.

If we went with a newer spa with a circ pump, would we expect to see much lower overall power usage? I'm not sure how the heater plays into that as mentioned. 

Overall, it makes me feel better to confirm this isn't anything unusual. It's still costing us about $75/mo though. If I can get a more efficient spa it might be worth a look if I can cut this back. We are in CA so no big temp swings and it's usually about $2.50 per 2 hour cycle (without using it!).

Thanks again.

 

[ratchett]

12 hours ago, jslost said:

If we went with a newer spa with a circ pump, would we expect to see much lower overall power usage? I'm not sure how the heater plays into that as mentioned. 

Age of spa isn't what counts from an efficiency standpoint, insulation is what does.   Many modern low-cost budget grade hottubs (the type sold on HomeDepot.com, Amazon, etc) have little to no insulation to reduce shipping weight/costs.  These tubs are horribly inefficient and still cost a fortune to run.   To put it into perspective, when shopping for a nice three seater for the wife and I, we reviewed *literally* every make/model 3 seater on the market at every price point.   While the top-tier flagship name brand models were quoting between $10 and $20/month in electrical operating costs, the budget grade ones would never say - however I found more than one person with a budget grade tub paying close to $100/month to keep a smaller 200 gallon tub heated and didn't seem to think there was anything wrong with that.

Instead of buying a new hottub, take a look at the condition of the insulation of your tub.  First, inspect the cover - what condition is the cover? Is it old and worn out? Does the cover fit properly or is it an aftermarket cover roughly the right size but not perfect? A majority of heat loss comes from the top, so a good condition properly fitting cover is necessary to heat retention.  Next is there full foam insulation from the cabinet walls to the shell? Or are there large open voids in the cavity?  With a bit of rockwool stone insulation packed into contractor bags and carefully stuffed into position you can greatly increase the heat retaining capabilities of your hottub (note, leave plenty of space around the electronics and motors - they need room to breath).  This is where a FLiR Thermal Imaging camera is extremely helpful to spot where you have the biggest heat-loss issues, They're such versatile tools I use mine everywhere haha.

That said, my 2019 Hotspring Jetsetter has full spray foam insulation from the shell to the cabinet walls (HUGE pita for weekend warriors without proper tools to service a spa like this themselves, I'll admit) and with that cover on it will retain heat extremely well to the point where I'm basically paying for the electrical costs to run the circ pump, ozonator, LED lighting, etc and thats it lol.   Most of the time I'm averaging around $10/month to keep my tub heated to temp (goes up to about $12/month in the winter time when temps drop into the 40's).   But I'm also in Florida next to the Launchpads,  which hasn't seen snow since the 70's haha - I don't *need* this full foam insulation in my climate, but it doesn't hurt

[Cusser]

Yes, amount and type of insulation is very important.

When Mrs. Cusser and I had a bathtub installed into our home, we asked for additional insulation to be added around it before the "pony" walls were built, and it does help keep the heat in.  Because we have the exact same bathtub in our place up north (was installed before we bought the place).

[jslost]

This is all super helpful. I will inspect the insulation and report back my findings. The cover we have is new. We got it aftermarket but it was custom fit and I selected the higher density option to retain heat better. 

I am starting to get this now. Basically, the heater is the main draw and if I can decrease the amount of time it runs I should see the usage decrease.  Makes sense. 

I am still curious about whether a higher end new spa would do better, especially one with a circ pump and that I can control how often it runs (min 4 hours a day seems too much).  I intentionally purchased this used one as a bit of a "test", mainly to see if myself and my family would use it. So, upgrading to a newer spa was always on our radar at some point. 

 

[Cusser]

I should add that my 1988 CalSpa required and uses a 40-amp 240 VAC circuit, for a 7-foot, approximately 350 gallon unit.  I believe that many newer spas use 50-amp or 60-amp circuits for similar sizes/water volumes.  To me, that somewhat indicates that newer spas might require more heat to reach and maintain 104F temperatures, maybe in the past 3 decades there's been less insulation added as cost-savings, out of sight strategy....

A good quality cover will also retain more heat.

[castletonia]

An energy efficient hot tub will be efficient regardless of age.  Nothing against Master Spas, but I have never considered them to be a leader in energy efficiency.  They typically are lacking in insulation and use powerful, more energy conserving pumps.  While it's true that a good cover will make a difference, it's not going to change your $75 a month into $30-$40 a month.

Circulation pumps are more efficient than jet pumps operating on low speed.  If you want to get more technical than necessary, there are two types of circulation pumps, high flow and low flow.  A low flow, like Hot Spring and Caldera use will run 24/7.  A high flow like Jacuzzi uses will move more water and cost more to operate, but you have the option to reduce your run time.  Personal opinion is I prefer a circulation pump that runs 24/7, regardless of size.  Constantly filtering water is better than water that can sit stagnant and if the hot tub you purchase has an ozone, that ozone will only operate when the circulation pump is running.

If I were you and I convinced myself that upgrading was going to happen, I would start looking now because hot tub inventory is nearly non-existent and lead times are really long.  Just make sure you are actually upgrading and make sure that you really want this.  Spending $10K on a hot tub is a lot of money just to save $30-$40 a month in operating costs.  

[rmcderm313]

 

Sorry posted on the wrong thread.  Can't delete entirely...

 

 

 

Edited January 12, 2021 by rmcderm313
Wrong post

[PNW Soaker]

Many people will disagree with this because it can be counter-intuitive, but lowering the temp of your tub by 5 degrees for times you're not using it will save you quite a bit of money. I have mine lower every day at midnight to 99 degrees then at 12pm next day it goes back to 104. I could plainly see this reflected on my usage graphs, it was cut by about a 1/3rd. Some people will say it costs less to "maintain" temperature but that's not how it works, all things equal, heater time will still be less with this method.

All the other recommendations you're getting here are good too.

[jslost]

Thanks everyone for the tips and recommendations. I have a much better handle on this now, including how I might improve it.  

[dsss]

Hi everyone,

We are in a similar situation and trying to determine how much energy our 2008 Sundance Cameo 880 is using. For context, we keep it at 104 usually, live in the Bay Area, so a temperate climate with cool nights. We have kept the spa up with regular maintenance and factory service. We have an aftermarket (high density) cover that overlaps a touch on the spa (we are considering replacing it with one that would lock in more snug). 

Below is my energy usage across two days, as you can see, the hot tub spikes are huge. We run the tub in economy mode which means there are four filter/heat cycles (6am/Noon/6pm/Midnight) for 30 minutes. I just tried reducing those cycles to 15 minutes to see if that lessens the power usage (though I am concerned that may not be long enough?)

Any thoughts or insights into how I can adjust my settings and/or usage patterns or if I'm in the right ballpark with my current setup, would be greatly appreciated