You've invested thousands of dollars in a pool heat pump to extend your swimming season, and the last thing you want is to discover it's been damaged by winter weather. We hear from pool owners every year who face the same concern: "Will my heat pump survive the cold?" The good news is that with proper winterization and a few preventive measures, your heat pump can weather even harsh winters and be ready to go when warm weather returns.
Unlike pool cover pumps that need to operate during winter, heat pumps should never run in freezing conditions. They're designed to heat your pool water efficiently during swimming season, not to withstand ice and snow. Let's walk through everything you need to know about protecting your investment through the cold months ahead.
Why Heat Pumps Are Vulnerable to Freeze Damage
Heat pumps contain water throughout their system — in the heat exchanger, the evaporator coil, and connecting pipes. When temperatures drop below 32°F (0°C), any water left inside can freeze and expand, causing catastrophic damage that's often not covered by warranty.
The damage happens faster than you might think. A single night of hard freeze can crack a heat exchanger, split pipes, or damage the titanium coils that make these units so efficient. We're not talking about cosmetic issues here — freeze damage typically means a repair bill of $500-$1,500, or in severe cases, complete unit replacement.
Heat pumps are particularly vulnerable because they're designed with thin-walled components for maximum heat transfer efficiency. That same design that makes them excellent at warming your pool makes them terrible at handling ice expansion. It's the price we pay for efficiency.
The Critical Temperature Threshold
Here's what you need to remember: Most pool heat pumps should not operate when air temperatures drop below 50°F (10°C), and they must be winterized before the first freeze.
Our BLACK + DECKER Pool Heat Pumps and ComforTemp Heat Pumps all come with clear operating temperature ranges in their manuals, but the 50°F threshold is a good general rule. Some models can handle slightly cooler temperatures, but running your heat pump in truly cold weather is never recommended.
Even if you're not running the unit, standing water inside poses a risk once temperatures hit 32°F. This is why proper winterization is non-negotiable in any climate where freezing is possible.
Step-by-Step: How to Winterize Your Pool Heat Pump
Winterizing your heat pump isn't complicated, but it does require attention to detail. Missing even one step can leave water trapped in the system. Here's how we recommend doing it.
1. Turn Off Power to the Unit
Safety first, always. Locate the dedicated circuit breaker for your heat pump and switch it off. If your heat pump has a disconnect box mounted near the unit, turn that off as well.
Double-check that the power is off by attempting to turn on the heat pump — nothing should happen. We can't stress this enough: water and electricity are a dangerous combination, and you'll be working around both.
2. Drain All Water from the System
This is the most critical step in the entire winterization process. Your heat pump has multiple points where water can collect, and you need to drain them all.
Start with the main drain plugs:
-
Locate the drain plugs on your heat pump (typically on the bottom of the unit)
-
Most heat pumps have 2-3 drain plugs — one for the heat exchanger and others for the evaporator and water flow system
-
Remove all drain plugs and let the water drain completely
-
Keep these plugs in a safe place — you'll need them in spring (we recommend storing them in a labeled plastic bag attached to the unit)
Open any pressure relief valves if your unit has them. This allows air to enter the system and helps water drain more completely.
Tilt or angle the unit slightly if possible to encourage any remaining water to flow toward the drain points. Even a few degrees can make a difference in getting that last bit of water out.
Pro tip: Use an air compressor to blow out remaining water from the lines if you have one available. Set it to low pressure (10-15 PSI maximum) and blow air through the system for 30-60 seconds. This isn't required, but it adds an extra layer of protection.
3. Disconnect Water Lines
If your heat pump has flexible water connections or unions, disconnect them and drain any water trapped in the hoses or pipes. Tip them upside down to ensure complete drainage.
For permanently plumbed connections, make sure water can drain back to the pool or completely out of the system. If your plumbing has low spots where water could puddle, you may need to blow these out with an air compressor or add antifreeze (more on that below).
4. Clean the Unit
While you've got everything open and accessible, take a few minutes to clean your heat pump. Remove any debris, leaves, or dirt from around the fan, coils, and cabinet. This prevents corrosion during winter storage and ensures you're starting with a clean unit in spring.
Check the fan blades for damage and clear any obstructions. Inspect the cabinet for signs of rust or wear that might let moisture in during winter.
5. Cover the Heat Pump Properly
A good cover protects your heat pump from snow, ice, and debris accumulation.
What makes a good heat pump cover:
-
Water-resistant material (not completely waterproof — you need some breathability)
-
Secure tie-downs or elastic hems to prevent wind damage
-
Adequate ventilation to prevent condensation
-
UV-resistant material that won't degrade over one winter season
Never use plastic tarps or completely sealed covers. These trap moisture inside, which can lead to corrosion, mold, and — ironically — more freeze damage if that trapped moisture freezes.
Should You Use Antifreeze in Your Heat Pump?
This is a common question, and the answer is: it depends on your specific model and installation.
Most residential pool heat pumps should NOT have antifreeze added to them. If you've properly drained the unit following the manufacturer's instructions, antifreeze is unnecessary and can actually cause problems with seals and components.
However, there are exceptions:
-
Some commercial or larger heat pumps have complex piping where complete drainage is difficult
-
If your installation has unavoidable low spots in the plumbing where water will remain
-
In extreme cold climates where you want absolutely zero risk
If you do need antifreeze:
-
Use only propylene glycol pool antifreeze, never automotive antifreeze (which is toxic)
-
Follow the manufacturer's recommendations for dilution ratios
-
Document how much you added so you can properly dilute it when restarting in spring
For most residential installations with our BLACK + DECKER Heat Pumps (ranging from 53,000 BTU to 137,000 BTU models) and ComforTemp Heat Pumps, proper draining eliminates the need for antifreeze entirely.
Special Considerations for Mild Winter Climates
If you live in an area where hard freezes are rare but possible — think coastal regions or southern states that occasionally dip below freezing — you face a unique challenge. Full winterization might seem like overkill, but one unexpected freeze can cause serious damage.
Our recommendation for mild climates:
Complete the full winterization process as soon as nighttime temperatures regularly fall below 50°F. Yes, you might have a few warm days after that where you'd love to swim, but the risk isn't worth it. One surprise freeze overnight can cause thousands in damage.
Alternatively, monitor weather forecasts religiously and be prepared to drain your heat pump on short notice if a freeze is predicted. This requires discipline and availability — if you travel frequently or aren't home to respond to weather changes, just winterize it and be done.
What About Heat Pumps That Claim "Freeze Protection"?
Some heat pumps advertise built-in freeze protection features. These typically consist of sensors that detect low temperatures and activate the circulation system to prevent water from sitting still and freezing.
Here's the reality: These features are designed to protect against brief cold snaps during shoulder season, not sustained winter freezing. They're a safety net for unexpected temperature drops in fall or spring, not a replacement for proper winterization.
If you live in an area with regular freezing temperatures, don't rely on freeze protection features alone. The system still needs to be winterized. These features can fail (power outages, sensor malfunctions, etc.), and when they do, you're looking at expensive damage.
Troubleshooting: Signs Your Heat Pump Has Freeze Damage
Despite our best efforts, sometimes freeze damage happens. Maybe you didn't winterize early enough, or a surprise cold snap caught you off guard. Here are the warning signs to look for when you start up in spring:
Water leaks: Any water leaking from the unit (other than normal condensation drainage) indicates cracked pipes, split heat exchangers, or damaged seals.
Unusual noises: Grinding, rattling, or scraping sounds often mean ice damage to the compressor or fan components.
Reduced heating capacity: If your heat pump runs but doesn't heat as well as it used to, internal damage may have reduced efficiency.
Error codes: Many modern heat pumps will display error codes indicating refrigerant leaks or sensor failures — common results of freeze damage.
Visible cracks or splits: Inspect all visible piping, the heat exchanger housing, and connections for cracks.
If you notice any of these issues, don't continue running the heat pump. Shut it down and contact a qualified pool equipment technician. Running a damaged heat pump can turn a repairable problem into a complete replacement scenario.
The Spring Startup Checklist
When warm weather returns and you're ready to fire up your heat pump again, don't just flip the breaker and hope for the best. Follow this startup sequence:
-
Inspect the entire unit for any visible damage from winter weather
-
Reinstall all drain plugs with new thread tape or o-rings
-
Reconnect any water lines you disconnected
-
Remove the winter cover and clean any debris from the unit
-
Check the fan — it should spin freely by hand
-
Restore power and let the unit sit for 24 hours before starting (this allows refrigerant to settle)
-
Prime the system by ensuring water is flowing through before starting the heat pump
-
Start the unit and monitor it for the first hour of operation
If anything seems off — unusual sounds, error messages, leaks — shut down immediately and call for service.
Choosing the Right Heat Pump for Your Climate
If you're in the market for a new heat pump and winter weather is a concern, consider models that are designed for easier winterization and greater durability.
Our BLACK + DECKER Heat Pump line ranges from the 53,000 BTU model for 10,000-gallon pools ($1,699.99, save $1,732) up to the massive 137,000 BTU unit for pools up to 45,000 gallons ($3,999.99, save $2,600). All feature straightforward winterization procedures and durable construction.
The ComforTemp Heat Pump series offers similar capabilities with competitive pricing — like the 53,000 BTU model at $1,599.99 (save $1,732) or the 137,000 BTU powerhouse at $3,949.99 (save $3,050).
What to look for:
-
Easily accessible drain plugs
-
Clear winterization instructions in the manual
-
Titanium heat exchangers (more durable than copper)
-
Good warranty coverage (but remember, freeze damage typically isn't covered)
-
Availability of covers designed specifically for your model
The Bottom Line: Winterization Is Non-Negotiable
Here's the truth: every winter, we hear from pool owners who skipped winterization or didn't do it thoroughly enough, and they're now facing expensive repairs. The 30-45 minutes it takes to properly winterize your heat pump is the best investment you'll make in protecting your equipment.
Think of it this way: you wouldn't leave a garden hose full of water outside all winter. Your heat pump contains dozens of garden hoses' worth of water, running through expensive, precision-engineered components. One freeze is all it takes.
Need Help Winterizing or Ready to Upgrade?
Whether you're protecting your current heat pump or considering an upgrade to a more efficient model, we're here to help. Our selection of pool heat pumps includes options for pools from 7,500 to 45,000 gallons, with savings up to $3,050 on select models.
If you have questions about winterization procedures specific to your heat pump model, or if you're not sure which size heat pump is right for your pool, our U.S.-based customer support team is standing by. Give us a call at 1-855-766-5246 or email cs@poolpartstogo.com.
Don't wait for the first freeze warning to start thinking about winterization. Take care of it now, and you'll enjoy peace of mind all winter long — and a perfectly functioning heat pump when swimming season returns.
