There  are a few ways pool and spa owners can save money on energy of which
two are turning the circulation pump off when the pool or spa isn’t
being used (or at least lowering the speed) and lowering the
temperature of the water when the pool or spa isn’t being used.

Lowering the temperature during the keep out hours can easily save as much as
$200 per month or more. To do this you need a temperature controller
that is set up for the days of the week type of control with the
ability to set the time to lower the temperature at night and the
time to set it back in the morning. It will need to be set back at
least an hour before the opening hour to make sure the temperature is
back to normal. A side benefit of lowering the temperature at night
is that will reduce  usage of the pool or spa  during during those
hours. Imagine sneaking into a spa late at night long after it is
closed only to find the water is 90°F instead of 104°F.

Most commercial pools and spas keep the circulation pump running 24 hours
per day. Most of these pumps are over sized and turn over the water
more than needed but that is the way it is. A variable speed pump can
save a lot of money as you can lower the speed to get the desired
turnover rate which could be every 6 hours. A better approach is to
let the pump run at full speed when the pool or spa is open, and then
lower the speed when it is closed. To do this right would require the
ability to be able to set the open and closed times for each day of
the week.

There are controllers for heaters and even some heaters have it built in
the ability to have two temperature setpoints to realize the savings
in lowering the temperature during the pool or spa closed hours. The
same also goes for the variable speed pumps.

The PoolWarden is a water chemistry controller, meaning that it measures
pH and ORP and controls relays that can feed corrective chemicals to
keep the water chemistry in balance. The PoolWarden also has energy
management built in allowing for control of up to three of any
combination of heaters and variable speed pumps. There are two time
profiles (supporting if you have a pool and spa with different
operating hours) that include a morning time and evening time for
each day of the week. When the time is between these two times the
heater or pump will be running normal, when not between these two
times the heater will be at a lower temperature  and the pump will be
at a lower speed.

A PoolWarden that controls two pools including sensors and flow cells
goes for about $2000. If you save $200 per month lowering the
temperature of the heaters at night that would pay for adding water
chemistry control in a short 10 months, not even counting what can be
saved by using the right amount of chlorine and acid/base. The
PoolWarden also tracks relay on time, you can actually see the hours
that the equipment is in the lower energy usage mode and easily
calculate the savings.

By Scott Lenney

ControlOMatic