[Greenbuilding] Hot tubs and recirculating pumps (Kevin Dalley)

[Paul Eldridge]

Hi Kevin,

Just to expand on your last point.... Hot Spring Spas use a 
min-circulation pump called the "Slientflo 5000" to clean and filter the 
water 24 hours a day.  It uses 68-watts and approximately 80 per cent of 
the waste heat from its operation is transferred directly to the water 
that passes through it, offsetting at least a portion of the spa's 
heating demand (~ 1.3 kWh/day).  These spas have a "Summer" mode which, 
as you mention, allows the pump to be turned off for eight hours a day 
-- a great feature if you're a time-of-use customer [do NOT use "Summer" 
mode in very cold weather, as this may increase the risk of freeze-up].

In addition, Hot Spring spas have their own, unique GFI panel, which 
consists of a two-breaker system -- one breaker for the heater and 
another for everything (i.e., pumps, lights, ozonator, etc.); a 
five-wire cable connects the GFI panel to the spa.  Since the heater 
operates on its own circuit, an electrician can easily add a mechanical 
or electronic timer circuit to restrict its operation to specific times 
of the day (e.g., off-peak periods); everything else will continue to 
function as normal.

If you plan to use your spa each day, I wouldn't bother to turn the 
temperature up and down  -- these things are so well insulated (at least 
in the case of the better ones), any reduction in power consumption is 
likely to be fairly modest.  But for Hot Spring spa owners with TOU 
meters, adding a timer control to the heater circuit makes good sense.

Cheers,
Paul

>------------------------------
>
>Message: 6
>Date: Sun, 09 Sep 2007 15:30:28 -0700
>From: Kevin Dalley <kevin at kelphead.org>
>Subject: Re: [Greenbuilding] Hot tubs and recirculating pumps
>To: geoedb at idiom.com
>Cc: Greenbuilding at listserv.repp.org
>Message-ID: <87myvveakb.fsf at kelphead.org>
>Content-Type: text/plain; charset=us-ascii
>
>Thanks for the analysis, George.  And healthy is fun, perhaps.
>
>Some of the 75-85W 24 hour/day pumps can be shut off for 8 hours
>during the day, to remove usage during the hours of the day when
>energy costs are highest, and temperatures are highest..  Of course,
>these tubs still heat at 4AM, when outside temperatures are low and I
>won't be using the tub.
>
>Why is it so difficult to get good data on energy usage for so many
>items?  Do the manufacturers mislead on purpose?  Or do they not care?
>  
>