Hot Water
Table of Contents
Introduction
Since replacing an old system with new equipment produces pollution and emissions, we suggest selecting eco-friendly heaters when a building is first furbished, and waiting for old appliances to age out of usefulness before being replaced.
This practice is generally more money and resource efficient than simply buying eco-friendly items for the sake of being eco-friendly. Regular maintenance and servicing can keep old equipment, clothing, etc. going for decades, which reduces water use, mining, and emissions associated with production.
Click the link to the left to learn about the signs that your old water heater is ready to be replaced with an eco-friendly model.
Heating water is often the second or third biggest use of home energy, and absorb about 14-18% of of the average US household's utility bills.
By switching to more efficient heaters we can help reduce our emissions while cutting our own energy bills.
Types of Water Heaters
This section explores the different types of water heaters, their approximate life expectancy, pros, cons, and solutions for the listed cons.
These are listed from most to least energy efficient.
Click the link to the right to see the infographic we used to source much of this information.
Heat Pump / Hybrid Electric Water Heaters
Life Expectancy: 10-15 years
Pro: 2-3 times more efficient than storage water heater, and lower energy costs. An Energy Star heat pump water heater can save homeowners almost $300 a year on electric bills.
Con: Performance is dependent on the installation location, and heat pump heaters exhaust cold air, meaning higher heating costs during cold months.
Solution: Switching the heat pump water heater to regular resistance mode will stop cold air exhaust but also reduce the appliance's efficiency.
Fuel Types: Geothermal, Electricity, Natural Gas
- https://www.energy.gov/energysaver/articles/new-infographic-and-projects-keep-your-energy-bills-out-hot-water
Solar Heaters
Life Expectancy: 20 years
Pro: 50% more efficient than gas or electric water heaters.
Con: Solar water heaters may require a backup system for cloudy days and times of high demand.
Solution: Buy a solar water heater that uses a backup storage water heater as part of the system package.
Fuel Types: Solar Energy
- https://www.energy.gov/energysaver/articles/new-infographic-and-projects-keep-your-energy-bills-out-hot-water
These can be bought or made, and requires sunlight to heat water. Because of water's thermal properties, the water should stay relatively hot then warm after sunset, though this will vary depending on how hot or cold your weather is. Cold areas may benefit less from this option.
"... In Israel, 85% of households get hot water from a dud shemesh, or “sun boiler.” But in the U.S., despite decades of advocacy by Murray and others, the number of households that have a solar water heater is less than 1%. In California, many people don’t even know the technology exists."
- https://ensia.com/features/solar-water-heaters-israel-renewable-energy-thermal-photovoltaic/
Tankless/On-Demand Heaters
Life Expectancy: 20+ years
Pro: Provides a constant supply of hot water, and is 8-34% more energy efficient than storage water heaters. Depending on the amount of hot water your home uses each day, you may save at least $300 a year on electric bills.
Con: Limited flow rate of hot water means simultaneous, multiple uses of hot water can stretch a tankless water heater to it's limit, and sometimes the energy savings don't pay for the cost of purchase and installation.
Solution: Install two or more tankless water heaters connected in parallel or separate ones for appliances that use a lot of hot water.
Fuel Types: Electricity, Natural Gas, Propane
- https://www.energy.gov/energysaver/articles/new-infographic-and-projects-keep-your-energy-bills-out-hot-water
Storage
Life Expectancy: 10-15 years
Pro: Lower purchase cost
Con: Standby heat loss - energy can be wasted to keep the water in the tank heated to the set temperature.
Solution: Look for an insulated tank to reduce heat losses and lower operating costs.
Fuel Types: Electricity, Natural Gas, Propane, Fuel Oil
- https://www.energy.gov/energysaver/articles/new-infographic-and-projects-keep-your-energy-bills-out-hot-water
Tankless Coil & Indirect
Life Expectancy: 10-11 years
Pro: Lower installation and maintenance costs.
Con: Inefficient choice for many homes, especially for those in warmer climates.
Fuel Types: Electricity, Natural Gas, Propane, Fuel Oil
- https://www.energy.gov/energysaver/articles/new-infographic-and-projects-keep-your-energy-bills-out-hot-water
Fireless Cooker / Warming Baskets
These go by many names but most of the information we have found on these suggests that they save between 70-80% on cooking fuel (such as wood or gas), since the food only needs to be brought to a boil before being taken off the heat and placed inside the device where it cooks via retained heat for 30 minutes or a certain number of hours depending on the food being cooked.
In the old days, people also made these out of wood or metal. The main principal being that heat from warmed food or water would remain inside, continuing the cooking process even without applied heat. Modern examples are woven baskets or other insulative items, lined with newspaper, then insulated with a fiber such as cotton or wool, then re-lined with a black material. This material is sewn down to create a space for a cooking pot. An insulated, cloth lid it created to help keep warmth inside.
These don't heat water, but they can keep water that was heated in the evening warm until it is needed the next morning.
Community-Scale Water Heating
District Heating
District heating is increasingly being adopted around Europe in response to climate change and communities wanting to divest from Russian fossil fuels.
Renewables & Thermal Storage
One way to maximize the efficiency of renewable energies, is to find ways to store the additional energy long enough to use it when production is low. Solar and wind fluctuate, but battery technology often relies on toxic chemicals and destructive mining. One solution has been to convert the excess energy into heat, then store it large-scale thermal towers, or in one case, an abandoned cave which was once used for oil storage.
Additional Tips to Reduce Energy Use & Costs
Use Less Hot Water: Most laundry can and should be washed on the cold setting to reduce the chances of stains setting, and to help textiles last much longer. Click the Laundry button to lean eco-friendly ways to keep your laundry in good condition, and save money doing so.
Install Low-Flow Faucets and Shower Heads: These fixtures can cost $10-20 USD per piece, but can help create household water savings of 25-60%.
Buy a More Efficient Model: This is a good idea if your old one needs replacing. Look for models with good energy efficiency ratings then make sure to follow the manufacturer's recommendations for installation.
Turn Down the Water Heater's Thermostat
Fix Leaks: A leak of one drip per second can cost $1 USD per month.
- https://www.energy.gov/energysaver/articles/new-infographic-and-projects-keep-your-energy-bills-out-hot-water
Tools & Calculators
North America
USA
Rewiring America: Track Your Local Pace of Progress "These projections from Rewiring America worked backwards from the emissions targets for 2050, and forward from current sales of machines for cooking, water heating, space heating, transportation, and rooftop solar to set a number of new clean electric machines that must be sold each year to reduce emissions from fossil-fueled machines. Type your city, county, or state into the search bar to get those numbers broken down for your area, by each machine category.
While creating this tool, one of things we found is that some individual communities and states are leading the way: their goals are bolder than the rest of the country and so don’t match the path laid out in our data. That’s a great problem to have. So our tool should not be considered the only source of its kind -- but one that reflects only one of the possible paths to decarbonization."
Tax Rebates
Grants & Funding
Asia
Livable Cities: Financing Partnership Facility "The urban operations of ADB benefits from the support of notable trust funds, which are collectively referred to as the Urban Financing Partnership Facility. Under this umbrella, strategic, long-term, multi-partner investments on innovative urban solutions are implemented. These investments help to achieve the vision of livable cities." These include:
Urban Climate Change Resilience Trust Fund (UCCRTF) eligible countries include Bangladesh, India, Indonesia, Myanmar, Nepal, Pakistan, Philippines, and Vietnam.
North America
USA
Power Forward Communities "is a coalition of some of the country’s most trusted housing, climate, and community investment groups dedicated to decarbonizing and transforming American housing. We’re saving homeowners and renters money, reinvesting in communities, and tackling the climate crisis."