How to Winterize Your Spa? Complete Guide 2025 | Market Spas
Dec 17, 2025
Winter is coming and you’re wondering how to protect your spa from freezing? It’s a crucial question: improper winterizing can cause irreversible damage to your equipment (cracked pipes, damaged pumps, cracked shell).
In this complete guide, discover the different winterizing methods, their pros and cons, and especially our expert recommendation to effectively protect your hot tub during the cold season.
📋 Contents
❄️ Why is winterizing your spa crucial?
Freezing is your spa’s number one enemy in winter. When water freezes, it expands by about 9%, which can cause significant damage to your equipment.
Risks of improper winterizing
Warning: Most spa breakdowns in spring are caused by improper winterizing. Repairs can cost several thousand euros or even require complete replacement of some components.
- Cracked or burst pipes: Frozen water in the pipes expands and causes PVC pipes to burst
- Damaged pumps: Pump housings can crack if water remains trapped inside
- Heater out of order: The heating element can be destroyed by freezing
- Broken jets and nozzles: Small plastic parts are very sensitive to freezing
- Cracked shell: In extreme cases, the acrylic shell can crack
Did you know? A spa usually contains between 10 and 50 meters of piping hidden under the shell. This piping is the most vulnerable to freezing because it is difficult to drain completely.
🔧 The 3 winterizing methods
There are three ways to manage your spa during winter, each with its advantages and risks.
| Method | Active winterizing ⭐ | Passive winterizing | Year-round use |
|---|---|---|---|
| Principle | Water kept at 10-15°C | Complete drainage | Normal use at 35-38°C |
| Filtration | 1-2h/day minimum | Stopped | Normal (4-8h/day) |
| Gel protection | ✓ Excellent | ◐ Well done | ✓ Excellent |
| Risk of damage | Very low | High if done poorly | Very low |
| Electric cost | €20-40/month | €0 | €80-150/month |
| Restart | Immediate | Long (draining, filling) | None |
| Difficulty | Easy | Complex | Easy |
We recommend active winterizing (low temperature water)
After years of experience and customer feedback, we strongly recommend leaving your spa filled with low temperature water (10-15°C) rather than draining it completely.
Why? A complete drain is extremely difficult to do properly. There is ALWAYS water left in pipes, bends, pumps, and the heater. This residual water can freeze and burst your pipes.
- Maximum safety: Moving and slightly heated water never freezes
- No risk of incomplete draining: No unpleasant surprises in spring
- Instant restart: Just raise the temperature
- Controlled cost: €20-40/month electricity vs €2000+ in repairs
✅ Method 1: Active winterizing (RECOMMENDED)
Active winterizing — Low temperature water
⭐ RECOMMENDEDActive winterizing means keeping your spa running at low power during winter. The water is kept at a low temperature (10-15°C), filtration runs a few hours a day, and the water remains treated. This way, the spa is protected from freezing without consuming as much as normal use.
Operating principle
Moving and slightly heated water cannot freeze. As long as the filtration runs regularly and the temperature stays above 10°C, your spa is fully protected, even at -15°C outside.
✅ Benefits
- Full protection against freezing
- No risk of incomplete draining
- Immediate restart
- No risk of burst pipes
- Can use the spa at any time
- Easy to set up
❌ Drawbacks
- Electricity consumption (reduced but present)
- Requires minimal water treatment
- The spa must remain powered
How to perform active winterizing?
Deep clean your spa
Perform a thorough cleaning: waterline, filters, pipe purging with a suitable product. Change the water if it is over 3 months old.
Balance the water
Check and adjust the pH (7.2-7.6), TAC, and hardness. Add disinfectant (bromine or chlorine) to maintain healthy water.
Lower the temperature
Set the thermostat between 10°C and 15°C. This temperature prevents freezing while limiting electricity consumption.
Program the filtration
Set the filtration to run at least 1 to 2 hours per day, ideally during the coldest hours (night/early morning).
Check the cover
Make sure the thermal cover is in good condition and properly positioned. It is essential to retain heat and reduce consumption.
Regular checks
Check your spa every 2 weeks: water level, water condition, filtration operation, cover condition.
🌡️ Recommended temperatures for active winterizing
Market Spas tip: Most modern spas have an "economy mode" or "frost protection mode" that automatically manages temperature and filtration. Check your manual or contact us to activate it.
⚠️ Method 2: Passive winterizing (complete draining)
Passive winterizing — Complete draining
⚠️ RISKYPassive winterizing means completely emptying your spa and shutting it down for the winter. The spa is drained, dried, and all equipment is turned off until spring.
⚠️ Important warning
This method is technically the riskiest. Indeed, it is extremely difficult to drain 100% of the water from a spa. There is always water left in pipe bends, pumps, heater... This residual water can freeze and burst your pipes.
✅ Benefits
- No electricity consumption
- No water treatment to manage
- Suitable for prolonged absence
❌ Drawbacks
- High risk of freezing if done incorrectly
- Complete draining almost impossible
- Requires antifreeze and specific equipment
- Long restart in spring
- Seals that can dry out and crack
- Pump priming required
Warning — Major risk: At Market Spas, every spring we see customers with burst pipes due to poorly done passive winterizing. The repair costs (€2000-5000) far exceed the electricity savings. We do not recommend this method unless you are sure you can drain 100% of the water.
If you still choose passive winterizing...
Here is the procedure to follow at your own risk:
📋 Passive winterizing procedure (only if really necessary)
- Turn off the spa's power supply
- Drain the tank via the drain valve or a submersible pump
- Open ALL drain plugs on pumps, heater, blower
- Use a vacuum/blower to push water out of the pipes through each jet
- Soak up any residual water in the basin
- Pour non-toxic antifreeze into the skimmer, jets, and pipes
- Remove and store the filters in a dry, temperate place
- Protect the pipes with rock wool or insulating sleeves
- Cover the spa with a durable winter cover
- Check regularly during winter (snow, cover condition)
Reminder: Even when following this procedure exactly, some water may remain in certain bends or corners of the plumbing. That’s why we always recommend active winterizing.
🌡️ Method 3: Year-round use
Normal use — Enjoying your spa in winter
👍 MAXIMUM ENJOYMENTThe third option is simply to keep using your spa normally throughout winter! In fact, it’s one of the great pleasures of a spa: relaxing in 38°C water while it’s -5°C outside, possibly under falling snowflakes...
A unique experience
Using your spa in winter is a magical experience. The contrast between hot water and cold air, the rising steam, the stars in a winter sky... For many, it’s the best time to enjoy their jacuzzi!
✅ Benefits
- Enjoy your spa all year round
- Unique winter experience
- Full protection against freezing
- No restart needed
- Health benefits (joints, stress)
❌ Drawbacks
- Higher electricity consumption
- Normal maintenance to keep up
- Winter energy bill
Actual cost: Using your spa in winter costs about €80-150/month in electricity (depending on insulation and outside temperature). It’s more expensive than active winterizing (€20-40/month), but the enjoyment is unmatched, and you avoid any risk of freeze damage.
Tips for using your spa in winter
- Check the cover’s condition: It must be in perfect shape to limit heat loss
- Maintain the water level: Evaporation is higher in winter
- Treat the water regularly: Even occasional use = same maintenance
- Clear the snow off the cover: Don’t let snow accumulate on it
- Keep a clear path: To access the spa safely
- Have robes and towels nearby: Getting out of the spa will be... chilly!
💰 Cost comparison
Here is an estimate of costs for each method over a 4-month winter period (November to February).
Active winterizing
€20-40/month electricity consumption
- Electricity: €80-160
- Maintenance products: €20-40
- Risk of damage: Almost none
- Total: €100-200
Passive winterizing
€0 electricity + equipment
- Electricity: €0
- Antifreeze + equipment: €50-100
- Risk of damage: €2000-5000
- Potential real total: €50-5000
Normal use
€80-150/month electricity consumption
- Electricity: €320-600
- Maintenance products: €60-100
- Risk of damage: Almost none
- Total: €380-700
Passive winterizing: a false economy
Saving €100 on electricity with passive winterizing may seem appealing. But if a pipe bursts due to incomplete draining, repairs will cost between €2000 and €5000.
Conclusion: Active winterizing at €100-200 is by far the most economical and safest long-term solution.
🚫 The 8 mistakes to absolutely avoid
❌ NEVER do this with your spa in winter
- Draining the spa and leaving it empty without antifreeze — Residual water in the pipes will freeze and break everything
- Lowering the temperature below 10°C — Risk of freezing even with water in the spa
- Stopping filtration completely — Stagnant water can freeze inside the pipes
- Neglecting the thermal cover — A damaged cover = huge heat loss and risk of surface freezing
- Forgetting to check the water level — If the level drops too low, the pumps can run dry
- Letting snow accumulate on the cover — The weight can damage the cover and the spa
- Cutting the power "to save money" — Guarantees a frozen and damaged spa
- Thinking "it doesn’t freeze where I live" — One night at -3°C is enough for irreversible damage
Real case: Every year, we receive calls from desperate customers in spring. "I drained my spa in November, and now there is water everywhere when I fill it." Diagnosis: pipes cracked by freezing. Average repair cost: €2500. The cause? A "complete" drain that wasn’t.
🔒 The "freeze protection" function of your spa
Most modern spas are equipped with an automatic freeze protection function. This function is your best ally for active winterizing.
How does freeze protection work?
A temperature sensor continuously monitors the water and/or air temperature in the equipment room. As soon as the temperature approaches the critical point (usually 5-7°C), the system automatically activates:
- The circulation pump to keep the water moving
- The heater if needed to slightly raise the temperature
- Sometimes the blower to agitate the water
Check your spa: Consult your spa’s manual or contact us to find out if your model has this function and how to activate it. It’s often a simple setting in the control panel menu.
Important: The freeze protection function only works if the spa is powered! In case of a prolonged power outage, your spa is no longer protected. Check regularly in winter, especially after storms.
Questions about winterizing your spa?
Our Market Spas experts are available to advise you on the best way to protect your spa this winter. Contact us or visit one of our showrooms!
❓ Frequently asked questions about spa winterizing
What is the minimum temperature I should maintain my spa at during winter?
How much does active winterizing cost in electricity?
Can I drain my spa and leave it empty all winter?
What should I do if I go on vacation for several weeks in winter?
My spa has a frost protection function—is that enough?
Should I treat my spa water in winter?
What to do in case of a power outage in winter?
Can I use my spa when it’s snowing?
Key Takeaways
- Active winterizing = our recommendation — Keep the water between 10-15°C
- Avoid complete draining — Too risky, residual water in the pipes
- Filtration at least 1-2h/day — Moving water doesn’t freeze
- Insulating cover required — Check its condition before winter
- Never cut the power — Your spa must stay powered
- Regular Checks — Check your spa every 2 weeks
