120v vrs 240v

[watzup]

I am still on the 'fence' so to speak on the benefits disadvantages of 120v or 240v hot tubs.  The one disadvantage of 120v systems is that the pump and heater cannot run at the same time.  Here in Florida, I do not think the heat loss would be that much for an average 30 minute use??? nor would the need for 'fast recovery' be in my case.  Then the cost issue, 120v/20amp circuit would seem to require less wattage than a 240/50amp.  I had one dealer comment that his factory study indicated that the 120v system, over time, would consume less power.  Appreciate any comments on factual studies etc.   TIA

[dpgtech]

depending on the ambient temperature heat loss can be minimal in a 30 minute or less soak.  if fast recovery time is not a concern and you don't feel like you will lose much heat during a soak then there shouldn't be a problem.   Any electrician I have spoke with claims that 240 is more efficient than 120, but thats not based on any factual studies that i know of.   There are so many variables involved in calculating energy consumption of a hot tub that it can be an imperfect science. in terms of less wattage. typically your intial heat time with 240 is about 6 hours from cold to hot while your time with 120 is 24 hours approximately.  and 120 will typically draw about 13-15 amps while heating depending on your system, while 240 will typically draw about 21-24 amps while heating. so even though you are drawing more amperage you are doing so for about 1/4 the time. maybe an electrician out there can back me up or shoot me down.   I believe that you can figure out kwh used by this formula amps x volts= watts. divide by 1000 gives you kilowatts.  kilowatts  times hours used = kw hours.  so for example 15a x 120v= 1.8 kw.  1.8 kw x 24 hours = 43.2 kwh.  
25a x 240v= 6kw.  6kw x 6 hours = 36 kwh.  so 240 actually uses less kwh.  all of those numbers were approximate.  really you need to take an amp reading and voltage reading to get accurate calculations. and tose were only based on the spa heating not while in use with everything running.

[Chas]

The cool-down is minimal in high-end tubs. They insulate the plumbing well, some even recapture heat from the jet pump motors. Some tubs with air blowers will cool more.

As to any cost savings: it depends on the system your chosen tub has. Just using 220 is not automatically more efficient than 110. There are very tiny little gains to be had by running the higher voltage, but that alone will NOT translate into a savings you can see on your bill.

You have to move water through the heater to get the heat into the tub, and that is done with a pump. Some tubs only run the pump when the heater needs to be heating, and in those tubs it is better to have 220 since the 220 tubs have larger heaters and heat faster. Some tubs have small dedicated heating pumps which run all the time - Sundance, Caldera, HotSpring, Tiger River and D1 all do this. I'll talk about HotSpring since I sell it and know it:

HS uses a small circ pump (85 watts) which runs all the time. keeping the water temp even throughout the system is a huge bonus. You don't get in, hit the jets and have the temperature go up or down. You don't find cold spots in some low corner or other. Plus they filter all the time, but that's another topic.

As a result, there is no cost savings between 110 and 220. See, you pay for Watts. Watts are voltage multiplied by Amperage. A 110 spa will have a 1500 watt heater. A 220 spa will have around a 6000 watt heater. But the key is, the 6000 watt heater will do in 15 minutes what the 1500 watt heater takes an hour to do.

Four time 1500 watts is 6000 watts, so your tub heats slower but costs exactly the same amount. Again, the pump in these spas runs all the time, so that is not part of the equation - and the small amount of power it takes to run that pump around the clock amounts to pennies - and the benefits outweigh the cost.

Now if you want to talk about jet power, you can have much bigger jet pump motors when you go with 220 volts. As a result, in the same model spa, in the same climate, a 220 spa will cost you more to run. But you can run more jets at the same time, or in some cases you get more power out of the same jets, so it is generally considered OK to pay a little bit more for power.

Installing a 220 volt spa usually costs a bit more than  110.

A 110 volt spa cannot just plug into any old household outlet. In fact, you may end up installing a dedicated, 20 amp outlet for your 110 volt spa. That may very well cost just a couple hundred bucks less than having 220 put in.

Some houses don't "have" 220 volts, or don't have room in the main house electrical panel for a 220 volt appliance to be added. Those houses are generally ready to have the electrical system upgraded anyway, and I have yet to meet a person who wasn't glad to have upgraded once it was all said and done.


Having the 220/upgraded electrical adds to the value of the home at resale whether or not you leave the tub for the new owners.

[SurgTec]

I can't claim any technical expertise but I can comment on being a former 110 circuit spa owner and now a 240/50 amp circuit spa owner.

The old spa took FOREVER to reheat after a water change - or when power goes out (yes we do loose power often in FL).  My new Marquis spa - with the 240 / 50 amp circuit - heated from 60 to 104 in 6 hours.  Nuf said?


Yes it does draw more amperage when it is running - but it needs to run less.  Apples and oranges I guess.  I happen to feel that all the 'bells and whistles' that a high end spa offers - also require the higher power demand.  Once we commit to spending this much on a personal luxury - kibitzing over amps and volts seems petty.  I for one am willing to pay whatever it costs to keep my spa running properly!

[Chas]

Yes it does draw more amperage when it is running - but it needs to run less.

Due to your larger pumps, you are most definitely paying more to run a 220 than an identical 110. But who wants to give up the mega pumps for a couple of bucks a month?

[SurgTec]

EXACTLY - if this was all about a couple bucks a month - I wouldn't have a spa in the first place!  

Owning a spa is about personal luxury, pleasure, relaxation and fun - not penny pinching.

[sms392]

Hi all,

Found this on a house wiring FAQ site and thought I'd pass it along:

Subject: Is it better to run motors at 110 or 220?

     Theoretically, it doesn't make any difference.  However, there is a difference is the amount of power lost in the supply wiring.  All things being equal, a 110V motor will lose 4 times more power in the house wiring than a 220V motor.  This also means that the startup surge loss will be less, and the motor will get to speed quicker with 220V.  And in some circumstances, the smaller power loss will lead to longer motor life. This is usually irrelevant unless the supply wires are more than 50 feet long.

[salesdvl]

Thats interesting info but doesnt apply to this situation.  Wiring a spa 110 or 220 does not change the wiring of the individual motors.  A 220 spa means it has 2 "hot" leads rather than 1.  The electricity is split up inside the control box and supplied to the individual motors, light bulbs etc  as 110.  The heater will get hotter on a 220 than on a 110, and as mentioned, there is enough juice to fire the heater and the pump motors (usually).

[Guzz]

Some spas use an air induction system to divert the hot air from the pumps into the spa, Hotsprings is one of them, this is particularly beneficial in 110v spas where the heater will not operate when the jets are in use.

[socal]

just to further comment on what chas mentioned about pump power........................

Marquis spas that run on 110v have a "max flow" pump of 120gpm (gallons per minute) where the 220v pump can push out up to 160gpm.
i wil use the Quest for this example (its avail as 110 or 220) and try not to be a salesman about it  
120gpm out of 27 jets @ 110v compared to 160gpm out of 27 jets @ 220v. that should give you a decent idea comparing output.
as far as efficentcy, like others have mentioned, the time it takes to heat up a spa initially takes alot longer on a 110v system. i have seen little difference in maintaining temp with 110v vs. 220v. i have had a couple of 110 models running in the showroom (as i am sure other dealers have done even if it was "just to check them out").


hope i didnt add to your "fence riding"  

socal

[watzup]

Wow....this is great info.  It is my understanding, in regards to motors only, that yes a 240 motor drawing half the amps of a 120 motor (same watts) still would cost less because the efficiency is slightly greater in a 240 system.  I do not believe this to be true of heater elements.  Watts are watts.  So what I think then that everybody is saying, the difference would be recovery time and to a lesser extent power from the jets.  All my kids have moved out and so my usage will be two adults 90% of the time and I am looking at a 3-4 person size.  The 120v models I have looked at so far 'seem' to be robust.  I am going to meet with my city electrical inspector tomorrow to explore the requirements for electrical, both 120 and 240.  Typical wiring requirements from different hot tub vendors seem to have conflicting requirements and I am going to try and get a handle on it.  Again....thanks for the great info.  

[socal]

good luck with the city, and a good idea as well. you'er welcome for the input. anymore question, just ask away.
just for general knowledge.....what brands are you looking at?

[watzup]

I

good luck with the city, and a good idea as well. you'er welcome for the input. anymore question, just ask away.
just for general knowledge.....what brands are you looking at?

In the area that I want to place the HT, a size of approx 70"x84" would fit the best, so I have looked at:
1. Marquis- 315 a little to small 60x84, Quest
2. HS Jetsetter, Prodigy, Sovereign (very nice but 2 big)Sumatran
3. Vita-Alero (perfect size 67.5x84x34), Image.

[Chas]

The Jetsetter is a convertable spa. It runs very well on 110 or 220.

You can make the change at any time, now or later.

The Jetsetter doesn't cool when the jets are running on 110, even though the heater is disabled at that time. The tub is relatively small, well insulated, does not have an air blower, and recaptures the heat off the jet pump motor.

[salesdvl]

Chas or whomever,  When you guys are referring to HS "recovering" heat from the motors, are you talking about the fact that the air inlets are in the motor cabinet and that the air would be "warmed" prior to being injected back into the water at the jet?  Since the idea of the pump shroud is to actually vent the heat out of the motor compartment, I am confused.  Has something changed in the last year?  thanks.