Can You Pour Hot Water On Frozen Heat Pump?

Basic chemistry tells us that pouring hot water on ice initiates or accelerates melting. It works even faster if you use hot water.

So, can you pour hot water on a frozen heat pump to thaw the condenser coils? Does it work? More importantly, is it safe? Read on to find out. We also answer common heat pump defrosting questions, including preventing freezing in the first place.

Can you pour hot Water on a Frozen Heat Pump?

Yes, you can pour hot water (or cold water) over your heat pump to melt the snow and ice that accumulates during the cold weather. Pouring hot water on frozen heat pump raises the temperature of ice, thus accelerating the melting process. However, you must be extremely cautious when pouring hot water on frozen heat pump, lest you get burned in the process and never pick the ice off with a sharp object. This could cause severe damage and personal injury. 

Causes of Frozen Heat Pumps

Heat pumps are a great heating and air conditioning option for your home. A heat pump is like an air conditioner but it is capable of cooling and heating.

Heat pumps are more efficient than air conditioners because they both heat and cool your home so you don’t have to separate heating and cooling system.

A two-stage unit may seem to run longer than a traditional single-stage unit, but this part-capacity operation offers energy-saving benefits that you will feel throughout your home. Heat pumps can freeze during winter for many reasons.

Generally, anything that negatively impacts heat exchange within the appliance will likely cause freezing.

Therefore, common causes include;

  1. Clogged air filters: When air filters are left too long without cleaning (or changing) them, they can gather dust and other solid particles and become blocked, consequently blocking outdoor air from entering the unit. When there’s no air from which to extract heat, freezing becomes inevitable. Replace inside filters regularly and clean the evaporator coils to prevent dust collection. If your unit is constantly on auxiliary heat , then you’re long overdue for a filter replacement. To prevent freezing outside, replace your filters every 30 to 60 days
  2. Low or empty refrigerant: Heat pumps rely on refrigerant, typically freon, to absorb and transfer heat into your home. Therefore, the refrigerant plays a starring role in keeping the condenser coils warm and non-frosted. Low refrigerant levels can, therefore, easily cause freezing.
  3. Dirty evaporator coil: Heat exchange occurs across the surface area of the condenser coil. Now, suppose the condenser coil is covered in a thick layer of the duct. It would negatively impact heat transfer. This can result in significant drops in temperature in the air immediately surrounding the coils, leading to frost formation.
  4. Faulty blow fan system: The main purpose of the blower fan is to draw “warm” air into the unit and maintain the airflow to force cold air out of the unit. Now, imagine that the blower fan is damaged or dead! First, you’d not have enough warm air entering the heating pump. Additionally, you may experience cold air accumulation. These two factors can easily cause freezing.
  5. Heat mode vs cooling mode: If, for example, you have your air conditioner in heat mode in the wintertime, the shift in the unit’s purpose may cause the coils to come into contact with cold air at a higher rate than they would if you were cooling your home.

Signs of a Frozen Heat Pump

Fortunately, it’s not too difficult to tell when your unit is frozen. The following are five telltale signs to look out for;

  • Visible frost over the heat pump: You never want to get here. Anyway, if you notice significant ice buildup over your heating pump, there’s likely even more ice inside.
  • Visible frost over the outdoor coil: Sometimes, you’ll only find ice over the outdoor evaporator coil. You can easily check the outdoor coil by removing the front panel.When the airflow is compromised, your air conditioning unit will not be able to keep the warmth around the evaporator coils long enough to prevent freezing
  • You’re not getting hot air from the heat pump: Place the back of your hand over the indoor air handler – about a few away to avoid burns. Do you feel a gush of warm/hot air? If the air is cold, lukewarm, or there’s no air, the condenser coils may freeze.
  • Condensation around the appliance: Check around the outdoor condenser. Do you see signs of condensation? Do you see ponds of water around the unit? If so, the unit is likely frozen inside.

Dangers of a Frozen Heat Pump

A frozen unit is often a sign of pending trouble. Although it’s relatively harmless at the initial stages, freezing of the heating pump if not addressed promptly, poses the following challenges;

  • Lack of indoor heating: One of the first signs of a frozen pump is poor heating or the lack of heating. This can leave you and your loved ones in the cold.
  • Inefficient heating: However, before it stops working altogether, it will work harder to maintain the thermostat setting. Working properly means drawing more electricity. This can result in an increased energy bill.
  • Blower fan damage: Forcing the unit to run even while frozen can easily damage the blower fan. Broken fan blades are a common problem.
  • The condenser coils can burst: When the copper or aluminum outdoor coil freezes, it expands. Unfortunately, the materials aren’t infinitely elastic. Sustained expansion can eventually lead to burst pipes. This is very bad as refrigerant is dangerous to humans.
  • Total compressor damage: In worst-case scenarios, freezing can cause damage to several other parts of the heat pump, including the wiring and sensors, ultimately totaling the appliance. So, you’d need to replace the entire unit.

3 Tips to Fix Frozen Heat Pumps

Heat pumps are equipped with defrost features that automatically engage to thaw the appliances. You can switch to EM heat and simultaneously run the outdoor fan to thaw your unit.

Here’s how each process works;

1. Run the Defrost Cycle

The defrosting process is built into nearly all modern HVAC systems to protect the appliances from the dangers of freezing. Better still, defrost cycles engage automatically.

Most heat pumps go into defrost mode every 35 minutes as long as outdoor temperatures are below 32°F.

Whenever the two conditions are met, the reversing valve changes the direction of the hot refrigerant, switching from heat mode to air conditioning mode.

The defrost cycle works by reversing the valve to air conditioning mode, which switches the outdoor fan off and turns the outdoor evaporator into a condenser.

Instead of flowing indoors, the high-pressure refrigerant becomes warmer as a result of this, thawing the ice as it passes through. The average defrost cycle lasts several seconds or a maximum of ten minutes. If your heat pump keeps going to defrost mode then there is a problem.

2. Shut it Down and Use EM Heat

Another way to thaw a frozen unit is to shut down the outdoor unit, switch to emergency heat, and wait. The unit will thaw naturally. It might several hours or even a full day (24 hours). However, in the end, all the ice will be gone.

The explanation is that the ice gradually absorbs heat from the surrounding hot air, which causes melting. Natural air movement, i.e., convection, around the ice helps this process by replacing colder air with warmer air in cycles.

3. Run the Fan 

Alternatively, you can run the fan to thaw the system. On the thermostat, switch the setting from “Heat” to “Fan.” Then wait for the fan to do its magic. How does fanning thaw ice? It’s easy. Ice is coldest at its core.

This means that the air surrounding ice is slightly warmer. It’s why frozen ice melts naturally when exposed to the open air even if you do nothing about it.

Fans merely replace the extremely colder air immediately over the ice with warmer air from outside the appliance.

Since this happens at a very high speed, the ice will melt a lot faster than if you let it melt on its own. For freeze-ups lasting longer than 4 hours, call in a service technician to take a look or follow the alternative suggestions listed above

Can you Pour Tap Water on an Iced-Up Heat Pump?

Strangely, yes. You can pour warm water on a frozen heat pump. It’s one of the easiest ways to thaw a heating system. If you’re wondering what kind of water you can use, the answer is – any clean water.

For instance, you can pour tap water on your unit and it’ll do the job very well. You can also use warm or lukewarm water.

Tap water may seem impractical for this application. However, it’s still way warmer than frozen ice. So, the ice will eventually melt away after some time. Of course, pouring hot water on the unit works faster due to greater heat displacement.

However, keep in mind that hot water is also dangerous for the user. For instance, the risk is scalding is high, depending on how you pour the water.

Can you Pour Hot Water on a Frozen Air conditioner

You rely on these HVAC units to keep your home comfortable to live in all year round. In the summer, air conditioning helps you combat humidity and heat, and in the winter, you can keep your home from turning into an icebox.

The answer is “Yes”. Pouring warm water into the air conditioner is faster and easier than waiting for it to cool down or defrost naturally. In fact, the water doesn’t even have to be piping hot, just a little warm water will do wonders

Tips When Pouring Water on a Frozen Air Conditioner

Although generally considered safe to pour hot water on a frozen air conditioner unit to de-freeze frozen coils. You can’t just pour hot water on your frozen air conditioner.

An air conditioner is a piece of electrical equipment that might short circuit if you pour hot or cold water without a care. In adverse cases, it may even cause an electrical fire.

Most of the information here applies to both air conditioners and heat pumps. But read carefully, some of the information is for one or the other. If you follow any of these tips make sure you know if you have a heat pump or an air conditioner or damage could result.

The following are a few important tips to observe to avoid creating new problems when pouring water on a frozen air conditioner or other HVAC system.

  • Disconnect the heat pump from the power supply: There’s a grave risk of electrocution whenever you mix electrical appliances with water. To avoid any accidents, begin by unplugging your unit from the power source. You may even want to switch it off at the circuit breaker.
  • Consider using tap water over hot water: Although hot water works faster, the risk of scaling is a scary thought. Tap water is safer and easier to use without exposing yourself to preventable risk.
  • Be extra cautious when pouring hot water: For instance, don’t splash or throw the water. The splash back can burn you. Instead, pour the water gently in a steady stream. Ideally, you want to only pour the water over the frozen coilsof your air conditioning unit.
  • Ensure the water drains easily and dry the area immediately: Don’t let the water flow everywhere as this presents a new risk of electrocution once you plug back the unit. So, consider directing the flow outside and use a mop with a wooden or plastic handle to dry up the area when you’re done.

Can A Hair Dryer Defrost An AC?

A hairdryer too would hasten the process of melting the ice. Ensure that you run it on the lowest possible setting as high heat can cause further damage to the AC unit. 

How Hot should the Water Be?

This is completely up to you. A few prefer to use boiling water to melt the ice in the shortest possible time. Meanwhile, others prefer warm water. The most important thing if you decide to pour hot water on your heat pump is your safety. The hotter the water, the riskier the operation. So, you must be extremely cautious.

Can you Prevent Heat Pump from Freezing?

Yes, you can prevent heat pump freezing. The following are four quick tips to delay or prevent your unit from freezing;

  • Ensure sufficient clearance: Proper airflow is critical. Freezing isn’t very common when you keep hot air moving throughout the heat pump.
  • Watch out for leaks: Leaks cause low refrigerant levels which, in turn, accelerate freezing inside the heat pump. So, fixing leaks early can help prevent freezing.
  • Replace the air filters: This takes us back to airflow issues. Replacing your heat pump filters regularly ensures smooth airflow, thus reducing the risk of freezing.
  • Ensure regular maintenance: Keep your heat pump clean at all times. Wipe it down regularly with a soft cloth, wipe the condenser coils every week or so, replenish the refrigerant, and keep the filters clean.With an efficient HVAC system, you can keep your spaces comfortable.

The Reason Heat Pump is Stuck in Cooling Mode

In the heating mode, try not to set the thermostat below 65 degrees or above 75 degrees. Below 65 degrees, a heat pump just won’t put out enough heat, and above 75 degrees, it’s using too much energy.

In the cooling mode, try not to set the thermostat below 70 degrees. Besides higher utility costs, this can cause the indoor coil to freeze and cause condensation in the house

How to Unfreeze AC Unit Fast?

Turning your AC’s fan on is a great way to force your AC to cycle more regularly which helps the ice inside of your coils melt faster.

Tip: Make sure you don’t set up your fan to run constantly with this cooling system because it simply forces the compressor to keep operating even when it’s not being used.

When to Call the Pros

Rarely do you need to call the pros for a frozen heat pump as running the defrost mode, running the fan, and shutting the outdoor unit are often enough to thaw the unit.

However, if you go outside and see your unit frozen in a cube of ice like a cartoon, you may have a serious problem.

If you’ve given your heat pump at least 4 hours to defrost itself, and it is still not operating normally, then the heat pump defrost cycle is not working and your best bet is to give us a call and schedule service from one of our HVAC technicians.

After you call the service tech, go ahead and turn your unit to emergency heat, this will turn on your inside gas or electric furnace and keep your outside unit from freezing anymore and also keep your house warm.

What shouldn’t I Do?

You should never try and break the ice formed on your AC with a sharp object. If you do so, you may land up breaking or causing severe damage to some part of the air conditioning unit. This may prove to be a costly mistake. 

Pouring Hot Water on Frozen Heat Pump FAQs

How much Frost on a Heat Pump is Normal? 

An iced-up heat pump is a normal occurrence as long as the ice isn’t blocking airflow into the unit. So, you have a problem if the entire unit is covered in frost.

How Often should Heat Pump Defrost? 

Heat pumps defrost every 35 minutes whenever outdoor temperatures are below 32°F. A defrost cycle lasts several seconds to a maximum of ten minutes.

How can I Know that my Heat Pump is in Defrost Mode? 

You’ll know that your heat pump is in defrost mode if it stops heating and the fan shuts off. You’ll also hear a humming sound from the outdoor unit and probably see an indicator light.

What Happens if a Keep Running a Heat Pump with a Frozen Fan? 

If you keep heating running a heat pump with a broken fan, there’s a high risk of fan damage. The fan blades are usually the first to break.


Now you know how heat pumps work and why they sometimes freeze up. More importantly, you know the signs of a frozen heat pump, how to unfreeze a frozen unit, and how to safely pour hot water on a frozen unit.