Pool Pumps, Air-Conditioning and Solar: Timing Big Loads to Your Solar Hours

If you have solar, the cheapest time to run your pool pump and air-conditioning is usually the middle of the day, when your panels produce more than the house needs. Every kilowatt-hour you use from your own solar instead of exporting it saves the gap between the retail price of grid electricity, commonly 30-45 c/kWh, and a feed-in tariff that is often only a few cents. Pool pumps and air-conditioners are large, flexible loads, so shifting them is one of the most effective changes a solar home can make.

Why timing matters more than it used to

When feed-in tariffs were generous, exporting solar and buying power back later made little difference. Feed-in rates in NSW have fallen well below retail prices, and many homes are on time-of-use tariffs where late afternoon and evening power costs the most. That combination rewards using solar directly, and every load you move into daylight is also one less load a battery would need to cover in the evening. To see what your exports are actually earning, try our feed-in tariff comparison tool.

Know your big loads

Start by identifying which appliances draw the most power and which of them can move. Electrical draw varies widely, so check the rating plate or manual, but as a rough guide:

Hot water is the other big flexible load in most homes, and a heat pump or solar diverter timed to your solar hours handles it well. It deserves its own discussion, so this article focuses on pools and air-conditioning.

Pool pumps: run times and settings

Pool pumps are the easiest win, because the water doesn't care what time of day it is filtered. The hours needed depend on pool volume, pump flow, the season and how heavily the pool is used, and your pool professional can confirm what your pool requires. What we change is when those hours happen:

• Move the whole run into roughly 9am to 3pm in summer, when solar output is strongest
• In winter, when the pool needs fewer hours, centre the run around midday
• If the pool needs more hours than solar can cover, split the run so most of it still falls in daylight
• Make sure any salt chlorinator is programmed to operate while the pump runs
• If the pump is old and single-speed, consider a variable-speed replacement, which can run longer at low speed while drawing much less power

Our Pool-Pump Optimisation service, listed in our energy market from $390 for a timer or controller installed (indicative), sets this up for you. A variable-speed pump replacement is quoted separately.

Air-conditioning: pre-cooling and pre-heating

Air-conditioning is less flexible, because you need comfort when you are home. A house can hold its temperature for a few hours, though, especially if it is well insulated and shaded. On hot summer days:

1. Start cooling in the early afternoon while solar output is still strong, rather than waiting until everyone gets home in the evening.
2. Use a moderate set point in the mid-20s rather than a very low setting, which keeps the load manageable for your solar.
3. Close blinds and curtains on west-facing windows before the afternoon sun reaches them.
4. Cool only the rooms or zones you will use in the evening.
5. Run ceiling fans alongside the air-conditioner, which lets many people feel comfortable at a higher set point.

In winter, reverse the approach: warm the living areas in the early afternoon and let the building carry that warmth into the evening. Wi-Fi controllers and the scheduling built into most modern systems make this automatic. Pre-cooling works best in insulated homes. In a poorly insulated house much of the stored cooling escapes, and improving insulation or shading may achieve more than any schedule. If an older air-conditioner is inefficient, our Efficient Air-Conditioning option starts from $2,990 for a split system installed (indicative).

Timers, smart controllers and automation

Good intentions fade, so automation is what makes load shifting stick. The options range from simple to fully coordinated:

• Simple timers: fixed schedules for pool pumps and similar loads, suited to predictable routines
• Smart load controllers: contactors that switch a load on when your solar is exporting, so it runs on genuine surplus rather than by the clock (from $490 per controlled load, installed, indicative)
• Appliance apps and Wi-Fi controllers: schedules for air-conditioners, dishwashers and washing machines
• Home Energy Management System: one system coordinating solar, battery, EV charger, hot water and big appliances (from $990 per home, installed and set up, indicative)

Hardwired controls for pool equipment and air-conditioning must be installed by a licensed electrician, so please don't wire timers or contactors into these circuits yourself.

Where a battery fits

Load shifting and batteries work best together, in that order. Move everything that can move into solar hours first, then look at what remains in the evening. A household that has already shifted its pool pump and pre-cools the house often needs a smaller battery than one that hasn't, and every kWh of storage adds cost. Our solar batteries page explains the options, and when we model a battery for your home we account for the loads you can shift, so the battery isn't oversized. Your monitoring app will show the change as it happens: after load shifting, midday exports should shrink and evening imports should fall.

Next steps

Want to find out how much more of your solar you could be using yourself? Request a quote and tell us about your pool, air-conditioning and daily routine. Our team will look at your system and switchboard and recommend the simplest controls that suit your home. Prices are indicative until confirmed after an assessment.

Frequently asked questions

Is it cheaper to leave the air-conditioner running all day?

It depends on your insulation, the weather and your tariff. In a solar home, running an efficient inverter air-conditioner at a moderate setting through the sunny part of the day often draws little from the grid, and it avoids a heavy pull-down when everyone gets home. On a mild day, or in a draughty house, switching off is usually cheaper. Your monitoring app shows the result clearly.

Can my solar panels heat the pool?

Indirectly, yes. A heat-pump pool heater can be scheduled to run in solar hours, and on sunny days much of its power can come from your panels, although a large heater may draw more than a small system produces. Solar pool heating is a different technology that uses rooftop collectors to warm the water directly. We check any heater's power draw against your system's output when assessing your home.

Do smart plugs work for pool pumps and air-conditioners?

Rarely. Most ducted and many split air-conditioners are hardwired, and many pool pumps draw more current than a typical smart plug is rated to switch continuously. Using an underrated plug is a fire risk. Hardwired loads need a contactor or controller fitted in the switchboard or equipment enclosure by a licensed electrician. Smart plugs remain useful for smaller appliances such as fans and dehumidifiers.