The practice of keeping the water temperature consistent is also a more energy-efficient way for them to operate their hot tub in the winter, as opposed to turning the temperature down and then back up again. As a side note, in the event of a power outage, it will take three to five days for a hot tub heated to 40 C (104 F) to completely freeze.
There are several external considerations the customer should be aware of when using their hot tub in frigid temperatures:
- Use a floating thermal hot tub blanket to reduce evaporation.
- Protect the hardcover using a vinyl-cover spray.
- Clear snow off the hot tub cover before lifting it. This will prevent snow from falling into the hot tub and messing up the water chemistry.
- If the hot tub cabinet is made of wood, apply a weatherproof sealer or linseed oil to prevent moisture absorption and freeze-thaw damage.
Preventing the hot tub from freezing
For customers who know they are not going to brave the elements and head outside for a soak should be told to keep their water heated, but a much lower temperature than what they would normally set it for bathing.
Most people enjoy their hot tub water at plus/minus 39 C (102 F); however, for customers who have decided not to use their hot tub, they can save energy by turning the water temperature down to plus/minus 15 C (60 F), while also ensuring the circulation pump is operating.
Before the customer takes their last soak of the season, tell them to adjust (balance) the water’s pH and alkalinity. Since the water will not be used, a concentrated shock treatment, along with a winter algaecide, should also be administered.
To ensure the plumbing remains clear, the hot tub owner should periodically run the jet pumps to circulate the water. The latent heat in the hot tub will also maintain a safe temperature to prevent freezing. If the customer’s hot tub has a freeze protection setting, or can be set to filter the water more often, this will do the trick. In many hot tubs, a ‘standard’ setting or ‘F3’ filtration option should keep the water circulating, while most modern units have a built-in sensor that turns the heater on when temperatures dip below freezing.
Even though the hot tub is not being used, evaporation remains an issue—especially in the cold. If the water level drops below the highest jet, it could cause the hot tub to stop working.
In addition to evaporation, maintaining proper water chemistry should still be stressed. While the homeowner’s regular water maintenance routine should wane a bit, as organics are not being introduced to the water, retailers and service professionals should advise customers to periodically check the water and continue to add a sanitizer (e.g. chlorine)—at the very least.
The goal is to keep the water circulated and oxidized. Using a water conditioner will help prevent spikes in pH, which will allow the water to last longer, while total dissolved solids (TDS) will be kept to a minimum. In the spring, the customer can decide whether to drain and refill their hot tub.