nereocystis

Yes. As I find out information, I have been adding it to the Wikipedia "Hot tub" article. The URL is at http://en.wikipedia.org/wiki/Hot_tub. The list of approved spas is at http://www.energy.ca.gov/appliances/applia...e_elec_spas.zip. I talked to the Gary Fernstrom of PG&E today. He was responsible for the 2004 document. I'll try to summarize Wednesday. He had some interesting points.

Marquis will be pretty quiet when the pump is not running at all. I have also heard that circ pump spas need to run an hour or two a day at high speed to skim the top. Is this really true?

Yes, the need varies, but the problem is getting numbers. If I run the filter for this many hours, how much energy do I consume. How does this compare with 24 hours of a recirculating pump. Numbers are required, and almost impossible to find in the industry. Also settings for reducing the energy usage are nice. The Marquis, for example, let's you set a mode where the heater is only working when the filter mode is on. Do I really need 102 degree water at 4AM. I don't. Then why keep it that hot? Tiger River has a setting which also turns off the heating for a few hours a day. How much energy is used when the tub isn't doing anything? Televisions need to reduce this number to be energy efficient, but I haven't seen this number for hot tubs.

I'm confused about buying an energy efficient model. I know, hot tubs use lots of power, no matter what. I may add more solar panels to offset the additional usage. Does anyone have reliable information about energy efficiency of the tubs? I'm comparing the Marquis's filtering at a few hours a day with the lower power recirculating pumps which are on 24 hours/day. I want real numbers, not a discussion of Marquis's employee buyout. I include some of my calculations below, but my confidence isn't that high. The California Energy Commission established standards for hot tubs. These standards were supposed to take effect January 1, 2006. The hot tub industry complained that the standards were not quite correct. The standards correct for volume and surface area of the tubs. This is reasonable, but the standards don't include a minimum constant. A tub needs a certain amount of energy, regardless of size. The energy should increase in a way related to volume and surface area after that. Volume for heating, surface area for cooling. In short, the standard still are not in effect, and I want to buy a tub. Many manufacturers use an 85W circulating pump which runs 24 hours/day. This pump filters; much of the heat produced by the pump is recovered and used to heat the water. The Marquis tub, by contrast, uses a higher powered pump for filtering, the same pump used by the jets. It uses 3.2A at 230V. The official recommendation uses this pump for about 6.5 hours a day, for filtering, testing the heat, heating the water. Probably, I can cut this back to 3-4 hours a day or so. This is still 2.2-3kWh/day. I can keep the heat off except for a short while before I use the tub. With insulation, the temperature will be close to correct, and just need a small amount of heating. I can cut the filtering down from 2 hours twice a day to 4 hours a day, plus one hour after use. The 85W pump *might* be better, but I don't quite have enough details to decide.

If everything were equal, then running an 85W pump for 24 hours a day will use the same amount of energy as running a 1000W pump for 2 hours a day. 24 * 85 / 1000 almost equals 2. Of course, everything isn't quite equal. On a Marquis, then the pump runs in low speed, for either heating or filtering, how many Watts does the pump use? How much of the power is put back into the water as heat? I suspect that 1000W is too much, but I don't know. Now, let's do a quick calculation. 85W * 24 hours each day is 2.040 KWh each day. 2 Standard for Marquis is 2 hours twice a day on low for filter. This is 4 hours a day. SmartClean filters 1 hour after each use. Let's say 1 hour each day. Every 30 minutes, in standard mode, the temperature of the spa water is checked by turning on the pump at low power for 2 minutes. That's 96 minutes a day. Probably a few extra minutes for heating the water when the temperature is too low. That's a total of 4 1/2 - 5 hours/day. So if running the pump in low speed uses 400W or less, then Marquis comes out ahead. If running the pump in low power uses more than 400W, then the Marquis loses the race. 85 * 24 / 5 is about 400, just to complete the explanation. I'm considering buying a Marquis, but I'm still a bit concerned about energy use. I understand why they are not yet listed with the California Energy Commision, though I wish that they were. They have done some of the tests, but disagree with the CEC's current standards.