Is It Better to Pressure Wash With Hot or Cold Water?
Pressure washing, also known as power washing, is a popular method for cleaning various surfaces, including driveways, decks, sidewalks, and buildings. It uses a high-pressure stream of water to blast away dirt, grime, and other substances, usually more quickly and with less effort, versus manual scrubbing.
While pressure washing is generally an effective method for removing tough dirt and stains, one question that often arises is whether it is better to pressure wash with hot or cold water.
This article will explore the pros and cons of using hot and cold water for pressure washing and some factors to consider when deciding which option is right for you.
Hot water removes dirt and grime, kills bacteria and germs, and removes stains and oil/grease, but it is also more expensive and may only be suitable for some surfaces.
Cold water is safer for most materials and surfaces, but it typically is less effective at removing specific types of dirt and stains.
Most budget pressure washers are rated for use with cold water only, typically up to a maximum of 140°F (60°C), with some premium models being compatible with either hot or cold water. There are also hot water-specific pressure washers available on the market.
Ultimately, the best choice will depend on your particular needs, the task you’re completing, and your pressure washer’s capabilities.
Is It Better to Pressure Wash With Hot or Cold Water?
Is Hot Water Better for Cleaning?
When heated, water molecules move faster due to their high kinetic energy, making hot water a more effective solvent (something that can dissolve other substances, in this case, dirt and grime).
As a result, hot water is better suited to challenging cleaning tasks versus cold water, which is hindered by a more compact molecular structure and less kinetic energy, making it less effective at removing stains.
In addition, water expands when heated, providing more space between the molecules for dissolved dirt. Because of this, hot water can dissolve more material than cold water, making it particularly effective at removing hard-to-wash stains like grease and oil.
A further benefit of hot water is that it transfers heat upon contact, which helps loosen the dirt and hence the pressure washer’s cleaning ability.
It’s possible to increase the benefits of using hot water by combining it with a detergent while pressure washing. When used with detergents, hot water provides a greater solvent content within its molecular structure, allowing more detergent molecules to bond with and remove dirt from surfaces for improved cleaning performance.
Advantages of Using Hot Water for Pressure Washing
In addition to the improved cleaning capabilities of using hot water noted above, other benefits of using hot water for pressure washing include:
- Uses less detergent – The added cleaning power of hot water means that you can typically use less detergent while pressure washing versus cold water cleaning, which is better for the environment.
- Saves time and effort – The added cleaning power of hot water also leads to quicker cleaning times, as it takes less time and effort to remove stubborn stains than cold water.
- Uses less water – Faster cleaning times also mean you can use less water when pressure washing with hot water, further improving its environmental credentials.
- Faster drying times – Using hot water leads to faster drying times versus cold water, allowing cleaned areas to return to use sooner.
- It’s more hygienic – Hot water is more effective at killing bacteria and germs, providing a more thorough and hygienic clean.
Disadvantages of Using Hot Water for Pressure Washing
Some of the downsides of using hot water in your pressure washer include:
- It requires specialist equipment – Not all pressure washers can be used with hot water. Most budget pressure washers are rated for use with cold water only, with a premium model typically needed if you want to use hot water.
- The potential for damage – It’s important to note that not all surfaces will be suitable for hot water pressure washing, and doing so could cause damage to delicate surfaces.
- It can cost more – Not only are hot water-capable pressure washers usually more costly to purchase than cold water alternatives, but they can also cost more to run, given the additional fuel source to power the integral boiler to heat the water.
- More complex maintenance requirements – Adding an integral boiler increases the complexity of hot water pressure washers versus those that use cold water. As a result, there is more to maintain and more to potentially go wrong with these machines.
Advantages of Using Cold Water for Pressure Washing
Despite the additional cleaning benefits that arise from using hot water, there are several advantages to using cold water with your pressure washer:
- It can cost less – Cold water pressure washers are typically cheaper to purchase than hot water alternatives and can also be more cost-effective to run since they do not require a fuel source for an integral boiler to heat the water.
- Less potential for damage – Cold water is also safer for certain surfaces, such as wood, and certain types of paint, which you can damage with hot water.
- Fewer maintenance requirements – Cold water pressure washers are less complex than hot water models, with fewer components to maintain and less potential for issues to arise. The absence of an integral boiler is one such example.
Disadvantages of Using Cold Water for Pressure Washing
The main disadvantages of opting for cold water over hot water for your pressure washing include the following:
- Uses more detergent – Cold water pressure washing typically requires more detergent than hot water cleaning, which can harm the environment due to the increased use of chemicals, given that cold water has reduced cleaning power compared to hot water.
- Requires more time and effort – Because cold water has less cleaning power, it can take longer and require more effort to remove stubborn stains, resulting in increased cleaning times compared to hot water.
- Uses more water – Because cold water pressure washing takes longer, it typically requires more water than hot water cleaning.
- Slower drying times – Compared to hot water, using cold water leads to slower drying times, which can delay the return of cleaned areas to use.
- It’s less hygienic – Cold water is less effective at killing bacteria and germs than hot water.
Frequently Asked Questions
1. What Is the Difference Between a Cold and Hot Water Pressure Washer?
Both hot and colder pressure washers are very similar; however, hot water washers have an integral boiler that heats the water before being emitted from the cleaning lance, whereas cold pressure washers do not.
The boilers of most hot water pressure washers use diesel or kerosene as the fuel source, but it’s also possible to use washers with an electric boiler that prevents the emission of exhaust gases or fumes where this is important, for example, in restaurant kitchens or food processing facilities.
Cold pressure washers can only use cold or warm water (usually up to a maximum of 140°F or 60°C), but you can also use hot pressure washers with cold water by switching off the boiler in situations where improved energy efficiency or cleaning delicate surfaces is required.
2. Can I Use Cold Water for Pressure Washing?
Yes, you can use cold water for pressure washing, with cold water pressure washers being the most common type.
In most cases, cold water pressure washers can use water up to a temperature of 140°F (60°C), but we strongly recommend checking with the manufacturer as the maximum rated temperature can vary.
Cold water isn’t as effective as hot water for cleaning stubborn stains such as oil and grease; however, the high-pressure jet of water makes cold water pressure washers much more effective than a conventional garden hose for removing heavy dirt.
Cold water pressure washers are well suited to cleaning large surface areas, as the time and cost required to heat sufficient water in comparable hot water pressure washers can prove prohibitive when cleaning larger areas.
Additionally, certain surfaces, such as wood and certain paints, may be more sensitive to hot water and can be damaged by its use.
3. Can I Use Hot Water for Pressure Washing?
Yes, you can use hot water for pressure washing, provided your pressure washer is hot water compatible.
Most budget pressure washers are rated for use with cold water only, with some premium models being compatible with either hot or cold water. There are also hot water-specific pressure washers available on the market.
Some hot water pressure washers are capable of raising the water temperature to as much as 311°F (155°C), producing a steam output, although a more common temperature is around 176°F (80°C).
4. Can I Use Warm Water for Pressure Washing?
While we’ve discussed the possibility of using hot water in a pressure washer, the question remains, particularly if you’ve got a cold water pressure washer that is unsuitable for hot water, can you use warm water with your pressure washer?
Even a minor increase in water temperature from cold to warm can assist with pressure washing. It is often possible to use warm water in a cold-rated pressure washer, provided the temperature is at most 140°F (60°C), but we strongly recommend checking with the manufacturer as this will only apply to some pressure washers, and the maximum rated temperature can vary.
A common issue with using warm water is being able to continually monitor the water temperature to ensure it falls below the maximum. For example, if you’re using a tap, it can be difficult to gauge this via touch alone. In contrast, if you rely on a thermometer to test the pressure washer’s output, you risk using water that is too hot before reaching the required temperature, potentially damaging internal seals or other components.
5. Is It Safe to Use Hot Water for Pressure Washing?
Hot water can be safe for pressure washing, but you should take proper precautions, such as wearing suitable protective clothing and equipment.
As mentioned above, some hot water pressure washers can emit water anywhere from 176-311°F (80-155°C), so considerable care should be taken to ensure that the steam or high-temperature water emitted from the pressure washer does not come into contact with yourself or others to avoid injury.
It’s also worth mentioning that you shouldn’t use hot water on certain surfaces or materials, for example, some types of wood and most painted surfaces, as doing so can cause damage. Because of this, we recommend proceeding cautiously, following the manufacturer’s guidelines or best practices for the material or surface, and testing on a small, inconspicuous area first to ensure it is safe to use hot water for pressure washing these areas.
6. Can Hot Water Damage My Pressure Washer?
Hot water will likely damage your pressure washer if it is not rated to handle higher water temperatures.
All pressure washers come with a specific maximum water temperature during operation; exceeding this can sometimes void your warranty.
Using overly hot water can cause damage to your pressure washer’s vital internal components, including seals, hoses, and the pump. In most cases, this leads to an expensive repair bill or the cost of a replacement pressure washer.
In Summary
In conclusion, whether it is better to pressure wash with hot or cold water depends on the specific needs and circumstances of the cleaning task you’re completing.
Hot water can more effectively remove dirt and grime, kill bacteria and germs, and remove stains and oil/grease. It might not be available in sufficient amounts to complete the job, however, and it usually isn’t suitable for use on delicate surfaces that are more susceptible to damage.
Cold water is safer for most materials and surfaces, but it typically is less effective at removing specific types of dirt and stains.
It’s important to note that most budget pressure washers are rated for use with cold water only, typically up to a maximum of 140°F (60°C), with some premium models being compatible with either hot or cold water. There are also hot water-specific pressure washers available on the market.
Ultimately, using hot or cold water for pressure washing will depend on various factors, including the type of surface you’re cleaning, the kind of dirt or grime you’re removing, and whether or not your pressure washer is capable of using hot water.
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