Should I drain my pool in the winter?

Once the summer season is over, no-one is swimming in the pool anymore and the water temperature dips below 12/15°C, the pool can be put into wintering mode. This is the perfect time to tackle annual equipment maintenance: filter cleaning and descaling.

Active wintering, passive wintering, what is the difference? Here is a list of all the right questions you need to be asking yourself when selecting the best wintering solution for you and your pool.

Passive wintering: the alternative option... to be selected with caution

Passive wintering is one of the most popular methods to use, but its advantages and disadvantages, environmental impact and special characteristics must be properly understood. 

How does passive wintering work?

Passive wintering, as indicated by its name, involves leaving your pool to rest with the filtration and water circulation systems switched off. On the contrary to active wintering, this method consists in partially draining the pool water (to approximately 10cm below the skimmers), which is problematic from an environmental point of view, and then adding chemicals when spring rolls around again.

With this type of wintering, all equipment in the plant room must be purged (including the pipework). Also, don't forget your heat pump if you have one!

You must also add wintering chemicals, place floats diagonally across the pool, a gizmo in each skimmer, plugs in the outlets nozzles and vacuum fittings, and lastly, cover the pool with a wintering cover.

In what context is passive wintering the best option? 

Passive wintering is generally best in regions where the winters are hard, with temperature below 0°C. Under these conditions, leaving the water in the pool can result in considerable ice damage.

Advantages of passive wintering

1. Protection against ice damage: by partially emptying the water from the pool, you reduce the risk of ice damage.
2. Less maintenance: passive wintering requires less maintenance during the winter season.

Disadvantages of passive wintering

• Environmental impact: partial draining of the pool is detrimental to the environment, because precious water is wasted.
• Topping up the pool in the spring: in the spring, you should fill up the pool again if winter rains are not sufficient, which can be costly in terms of water and energy.
• The tedious option: the pool winterising process is complicated and involves many steps (purging, floats, etc.)
• Water quality: stagnating water in an unfiltered pool can become cloudy and conducive to a proliferation of algae.

Overall, passive wintering is the less eco-friendly option due to the annual waste of water.

Active wintering: the eco-friendly option

Active wintering is becoming more popular because it is simple and eco-friendly. As opposed to passive wintering, which involves partially draining the pool water, with active wintering the water level is maintained. There are several environmental and financial advantages to this.

How does active wintering work?

Under active wintering, filtration and water circulation systems continue to run; for 3 hours a day for single-speed pumps (preferably at dawn, which is the coldest part of the day), and 24/7 at slow speed (between 600 and 800 rpm) for variable speed pumps. These consume much less energy than single-speed pumps, even when operating around the clock*.

You can therefore maintain clean, clear water throughout the winter, without seeing your electricity bill go through the roof.

*A variable speed pump running at 600 rpm consumes around 480 W in 24 hours, compared to approximately 2,250 W consumed by a 1HP single-speed pump operating for 3 hours.

In what context is active wintering the best option? 

Active wintering is particularly recommended in regions where winters are mild or moderate. If there is no dramatic and extended drop in temperatures during the winter, with this method your pool will be ready for use as soon as the first warm spring days come around.

Advantages of active wintering

1. Water savings: by keeping the water in your pool, you avoid having to top up the basin in the spring, which proves to be both a cost-effective and eco-friendly solution.
2. Maintenance of water quality: continuous circulation of water and filtration reduce the formation of algae and deposits, thus maintaining the quality of your water.
3. Energy savings: thanks to variable speed pumps, year-round filtration will not cost you a fortune in electricity.
4. Chemical savings: no expensive chemicals are required for the winterising and re-opening processes.

Important points to consider for active wintering

• Regular maintenance is needed during active wintering to keep everything running smoothly.
• Active wintering is less suitable for very cold climate, where ice can damage the pool equipment.

In conclusion, active wintering is an eco-friendly and cost-effective option for maintaining your pool in perfect condition during the winter. Thanks to variable speed pump technology, you can enjoy crystal-clear water whilst taking care of both the planet and your own wallet.

Passive wintering may well be the most suitable option in regions with hard winters, but its impact on the environment must be taken into account in your choice.

Before making your decisions, go ahead and talk about it with your pool installer, who will be able to advise you on which type of wintering is best for you. To find a Hayward stockist, go to our store locator to find your nearest Totally Hayward dealer.