Cold is the New Hot: How to Save Energy by Washing Clothes in Cold Water
Heating water consumes about 90% of the energy to wash clothes, according to ENERGY STAR.
Washing clothes in cold water saves energy and can be more effective with the use of detergents specifically formulated for cold water. The active ingredient in cold-water laundry detergents are enzymes that are designed to catalyze chemical reactions at lower temperatures than enzymes designed to work in warm or hot water. Using cold water with cold-water enzymes in an efficient machine saves even more resources because fewer gallons of water are required per load of laundry. One thing to know about high-efficiency washing machines is that some do not trap lint, so to prevent microfiber pollution, you can install a filter on your drain pipe or use a greywater system to handle your effluent.
Two That Matter Most
To know how well you are meeting your need for clean clothes without wasting energy or creating microfiber pollution, these two indicators matter most:
How much energy you use.
How much lint you trap after each load of laundry.
Sustainable Practice: Cleaning 103
Washing Clothes in Cold Water
Clean clothes in cold water, using an efficient machine, with detergents containing cold-water enzymes to remove stains and odors. Install a filter or use a greywater system to trap microfibers that break off clothing during the wash.
Equipment and Materials
Efficient washing machine
Microfiber filter or grey-water system
Washing detergent formulated with cold-water enzymes
Steps
Install an efficient washing machine.
Check whether your washing machine has a lint trap that you can clean after every wash.
If your washing machine does not have a lint trap, install a filter to trap microfibers in drain water or use a greywater system.
Buy washing detergent formulated with cold-water enzymes.
Set your washing machine to wash and rinse using cold water.
Discussion
Washing clothes in cold water using an efficient machine saves water and energy. Washing detergents formulated with cold-water enzymes get clothes cleaner in cold water than detergents without enzymes. A lint trap in your machine, a microfiber filter on your drain hose, or a greywater system prevents microfibers that break off clothing during the wash from polluting our environment.
You can use cold water to clean your clothes effectively, preventing the waste of energy to heat water unnecessarily. The key to making cold water more effective at removing stains and odors is to use detergents with cold-water enzymes. An enzyme is a biodegradable protein that catalyzes a chemical reaction that breaks apart chemical bonds in the substances that soil clothes (“grime”). When enzymes have broken apart large molecules, surfactants in detergent can more easily link the smaller molecules to water molecules that wash grime away.
High-efficiency washing machines use less water than older designs to achieve comparable cleaning results. Unlike older washing machines, which sometimes have a lint trap that could keep microfibers from being released into our environment, high-efficiency washing machines typically do not have a lint trap. Instead, they have a “self-cleaning” drain pump filter. In operation, drain pumps on high-efficiency machines force most microfiber debris down the drain so it doesn’t clog the pump filter.
The operating manual for your washing machine will describe the cleaning procedure for the lint trap or drain pump filter. If your instructions do not advise cleaning a filter after every wash, you can safely assume that your machine is forcing most microfiber pollution down your drain. Otherwise, your filter would soon clog.
If your drain is connected to a sewer or septic system, many of the microfibers you discharge in your wastewater will end up in surface water or municipal sludge, the solid material left over from wastewater treatment. You can prevent this by installing a filter on your drain pipe to catch lint, which is chiefly composed of microfibers. You can then dispose of this lint in your garbage, where it will be buried in a sanitary landfill or burned in a waste-to-energy incinerator.
Wastewater from washing machines is called “greywater” because it is less dangerous than wastewater from toilets. Some jurisdictions allow you to create greywater systems that are separate from sewers or septic systems. A greywater system cannot handle large amounts of feces (from toilets) or food waste (from kitchen sink garbage disposals) but can very effectively handle water from hand-washing sinks, showers, tubs, and washing machines. If your washing machine drains to a greywater system, there is no need for a microfiber filter. Your greywater system will safely trap microfibers and replenish local aquifers with naturally filtered water.
Definitions
Biodegradable: material that biological systems can naturally break down into safe and inert components
Detergent: a surfactant that is effective in dilute solution, often synthetic
Enzyme: a catalyst, usually a protein, that speeds up chemical reactions
Greywater: domestic wastewater that does not contain large amounts of feces or food waste
Hydrolase: an enzyme that uses water to break chemical bonds
Hydrophobic: molecules that are insoluble in water
Lipids: organic compounds with at least one hydrophobic part, including fats and waxes
Microfiber: generally, a piece of fiber less than 5 mm long; in industry terms, a synthetic filament measuring less than 10 microns in diameter and weighing less than 0.7 grams per 9,000 meters of length.
Proteins: large molecules usually produced by living cells
Surface-active agent (surfactant): a chemical compound, such as a soap or detergent, that has a water-repelling and water-attracting part
Troubleshooting
You’re washing in cold water, and your clothes are not getting clean.
Change your detergent.
Pre-treat stubborn stains with concentrated enzymes and let soak before washing.
Wash in hot water occasionally.
Your detergent recommends washing in cool, warm, or hot water.
Change your detergent; it is not formulated for cold water.
Your washing machine starts smelling bad.
Read and follow the manufacturer’s instructions for self-cleaning.
Clean and dry the recommended areas of your machine, such as around gaskets, after every wash.
Replace your washing machine with a better design that does not trap water where mold can grow.
You don’t know whether your washing machine has a lint trap.
Read the owner’s manual.
Search online among message boards for appliance repair technicians for the make and model of your washing machine.
You aren’t sure if you can build a greywater system in your area.
Ask your local code enforcement officer.
Strategies and Goals
Community
Educate
Become a green cleaning expert
Demonstrate best practices
Inspire people in your community to clean green
Water
Increase water efficiency
Use less water to clean your clothes
Protect water quality
Keep microfibers out of rivers, lakes, and oceans
Energy
Increase energy efficiency
Use less energy to clean your clothes
Goods
Buy green
Buy biodegradable detergent with cold-water enzymes
Milestones
Increase environmental knowledge
Measure: Knowledge relevant to washing clothes in cold water
Method: Quiz
Time Period: Season
Increase people in a community who wash clothes in cold water
Measure: Community members cleaning clothes in cold water
Method: Logbook
Time Period: Year
Decrease water used to wash clothes
Measure: Water use
Method: Utility bills or water pump operating hours
Time Period: Month
Reduce microfibers released into the environment
Measure: Lint collected from washing machine (and not washed down drain)
Method: Logbook
Time Period: Month
Decrease energy used to heat water
Measure: Energy use
Method: Utility bills and logbook
Time Period: Month
Increase purchases of sustainable cleaning supplies
Measure: Purchased amount of washing detergent with cold-water enzymes
Method: Logbook
Time Period: Month
Decrease purchases of unsustainable cleaning supplies
Measure: Purchased amount of washing detergent without cold-water enzymes
Method: Logbook
Time Period: Month
Limitations
Some types of soiled clothing require washing in warm or hot water.
Installing an efficient washing machine, a microfiber filter, or a greywater system requires time and money.
Opportunities
Cleaning 101 - Using Safer Solutions
Use washing detergent formulations without dyes and scents.
Buy dry detergents in bulk to reduce packaging waste.
Plastic 102 - Buying Natural Fibers
Buy clothing and fabric made from natural fibers instead of plastic (synthetic fibers).
Reduce the amount of microplastic you create from washing your clothes.
References
Articles
Washing detergents with cold-water enzymes
Microfiber filters
Greywater design resources
Keywords
cleaning, cold water enzymes, washing clothes, detergent, efficiency, greywater systems, wastewater