Are you looking to save money on your electricity bill? Or, maybe you would like to reduce your carbon footprint and reduce your energy usage from conventional sources. Many people are switching their energy sources to renewable energy.
One of the most common and most affordable options is powering your hot water heater with solar power. Even if you live in a northern or cloudy climate, using solar panels can help reduce the amount of conventional energy you heater needs.
But, where do you start to explore the possibility of using solar power? There are a few things to figure out before you jump in. Let’s answer some questions about using solar powers to heat your water heater.
How much Electricity do Water Heaters use?
Water heaters use a lot of electricity to run. In fact, they are the second largest consumer in most homes just behind heating and cooling. That’s why many people are turning to solar power to heat their water heaters.
- Conventional Water Heater
Conventional Water heaters are reservoir tanks of ready to use water. They actively heat water for about 3 hours per day. They typically use about 4000 Watts per day for these 3 hours of active heating.
When you take a shower or wash a load of laundry, you drain from the reservoir. It may take up to an hour to re-heat the water in the tank. Reheating the water is what consumes the most energy.
Conventional water heaters are the most common in American homes. To save electricity, people can choose to install a solar-powered water heater. The two types of solar-powered water heaters are active and passive.
- Active: circulating pumps and controls
There are two types of active solar water heaters: direct circulation and indirect circulation systems.
The direct system has pumps that circulate the water through the collectors into the home. This system works well in climates that don’t often have freezing temperatures. Solar collectors use radiation energy from the sun, convert it into heat and transfer that heat to cold water.
The indirect system pumps non-freezing, heat transfer fluid into the collectors and a heat exchanger (pipe or tube surrounded by a fluid). This heats the water for use throughout the home. This system works well for colder climates.
- Passive: No circulating pumps and controls
Passive water heating doesn’t use pumps or controls to heat the water. Sometimes people choose this method to save money. Passive water heating, however, is usually not as efficient as active water heating.
The two types of passive water heating are integral collector-storage and thermosyphon.
The integral collector-storage system (ICS) heats a large amount of water by combining the tank and collector. There is no need to have pumps or controls because it is heated and stored in one unit. ICS is one of the easier solar water systems to install as it can be put inside any conventional water heater.
Thermosiphon water heaters use gravity to move water between the tank and the collector. The hot and cold water pressure help circulation. This is called the thermosiphon principle. The collector generates the heat and the tank stores the heat.
The collector sits below the tank so hot water can circulate easily. The hot water in the collector has lighter pressure than the cold water in the tank above it. When the hot water rises the cold water falls back into the collector unit.
- How much money can you save with a solar water heater?
Like any budget estimate, you need to take a few things into consideration when estimating your savings with a solar-powered water heater.
Consider:
- How much water you use
- How well your system works
- Your climate and frequency of sunny days
- How much fuel or electricity your conventional system uses
Most estimates state you can save anywhere from 50% to 80% on your regular energy bill. When you attach the cost of a solar water heater to a new 30-year mortgage, the monthly cost falls somewhere between $15 to $20 a month. Federal income tax deductions can bring that even lower to about $5 a month. In the end, you save more than you pay for!
How many Solar Panels do you need?
Today, most PV (photovoltaic system) panels create a high amount of energy rated at five watts with an 18% efficiency rate. Storage tank heaters average 3.6kW. One solar panel can usually cover the electricity needs of a household water heater.
If you want to directly heat water, you would use a solar thermal system. Solar panels produce electricity, whereas solar water heaters simply heat water. This system can cover up to 90% of hot water needs in the summer and 40%-60% in the winter depending on your local climate. It can also increase your water boiler lifespan.
Let’s say you want to go to the solar panel side and use that electricity for your conventional water heater. What panels are the best for this? According to the solar panel experts, these are the top five:
- SunPower
- Very high-quality panels
- Highest efficiency and co-efficiency
- Panasonic
- Very high-quality material
- High efficiency and tied for best temperature co-efficient
- Manufacturing excellence
- LG Solar
- Very high-quality panels
- Reputable corporation and warranty support
- Canadian Solar
- High-quality panels
- Lower price, better value
- Warranty Support
- Trina Solar
- Solid performance
- Low cost for Tier 1 panel
Solar thermal systems may take a bit more research and time to set up. But, they can also be more efficient at heating water than relying on a solar panel and conventional unit. Here are the most popular brands of solar water heaters for 2020:
- Duda Diesel offers systems from 100L to 1000L as well as a variety of solar water heater parts. This company uses biodiesel and a variety of alternative fuels in its manufacturing.
- Sunbank Solar specializes in solar water heaters and makes collectors, pumps, plates, and other system parts.
- SunEarth produces different types of solar energy equipment for homes and businesses, including solar water heating systems and elements.
- Apricus is a popular brand of solar water heaters that provides water heater packages.
- Rheem meets the needs of both residential and commercial solar water heaters.
Should you get a solar panel or a solar water heater?
Solar panel systems have risen in popularity in recent years. The cost of solar panels has gone down within the last few years. You can save even more money by installing panels to cover your home’s energy needs as well as your water heating.
Solar water heaters, however, are more efficient if you are just looking at heating water. Also, solar water heaters use less space compared to solar panels for meeting the needs of a conventional water heater. Many people today are combing both solar panels and solar water heaters to cut down their conventional energy use.
How many Off-Grid Batteries do you need?
When you don’t have access to the grid, you must rely on batteries as back up for your solar system. These batteries should supply enough energy for some overcast days. It also needs to be small enough to be charged on your panels.
Figure out your amp-hour needs to find the number of batteries
To do this you can see the amount of wattage your system uses in hours per day. Then plan for how many days you want to be able to supply with your battery.
Calculate the minimum battery AH capacity. Take the watt-hours per day and multiply it by the number of days. Then multiply that by 3. This will give you a 50% depth of discharge on your batteries. Therefore multiply by 2 and convert the kWh result into amp hours (AH). To get the AH, dived the kWH by the battery voltage.
Example: Your solar needs are 1800 watt-hours per day. You want to have a 3-day backup without recharging. The math is 1800 x 3 x 2 = 10,800 (10.8kWh), which is the energy you would need from the batteries.
To convert to AH, you need to divide 10,800 by the voltage of your system. Often times it will be 12V or 24V or 48V for commercial use. If your system uses 24V, you take 10,800/24 = 450AH.
To figure out the number of batteries you need, you can divide 450AH by the rating of the battery.
Off-Grid Energy Without Batteries
Other than batteries, you can store solar energy as hot water. By using an inverter connected to the water heater heating element, solar energy is taken directly from the panel to heat the water. No battery required.
Some inverters can connect directly to multiple solar panels. This allows a single inverter to supply hot water for a household. Depending on the size of the inverter, it can meet the needs of a two to five-person family.
You don’t necessarily need to invest in batteries to store solar energy when using hot water. This lowers your energy bill and enables you to be off-grid or deal with unpredictable grid issues. This system is suitable for cold climates and is more cost-effective than installing multiple solar panels and solar thermal systems.
Top Solar Energy Storage Products
The solar industry has a wide range of options for solar power energy storage. Here are some of the top products of this year.
- ABB Solar Universal 10/4 is a residential solar system that powers loads on and off-grid with the ABB Universal 10/4 solution. The Universal 10/4 does simultaneous AC and DC coupling. It comes with an ABB solar inverter and accepts charging from multiple AC and DC sources.
- Electriq Power Electriq PowerPod is a home energy storage, management, and monitoring system that includes lithium-ion batteries and a hybrid solar/battery inverter.
- Fortress Power eVault 18.5-kWh uses lithium-iron-phosphate technology, offers a digital display to show battery percentage and power output. More compact and affordable, the eVault powers up to 222 kWh.
- Goal Zero Yeti Tank and Link Expansion System allows users to chain lead-acid and lithium batteries together. Consumers can scale based on the individual power needs for a fraction of the typical cost.
- LG Electronics Energy Storage System is a home energy management system. The LGE ESS boasts a quick installation, a compact design, a scalable LG Chem lithium-ion battery, and a smart energy management system. Offered in both AC-coupled and DC-coupled configurations.
Save Money and the Planet with Solar Power
Solar power not only saves you money, but it is also environmentally friendly. Many conventional energy supplies come from “dirty” energy sources like coal or natural gas. You can reduce your use of fossil fuels by using renewable energy.
Water heaters are the second greatest consumer of electricity in American homes. Conventional systems tend to be inefficient and use a lot of energy to reheat water. Solar water heater, however, is becoming increasingly common and more affordable for modern homes.
With a bit of research and a little investment, you can be on your way to cutting your water heater cost by 50% or more! Statistics have shown that solar paneling and solar water heaters are truly effective in supplying household hot water needs.
Installing solar power by yourself is more than possible by using instructions and videos online. There are many companies that will provide everything you need in a solar power package. Installing a solar power water heater is a great first step towards renewable energy sources in the home.
Switching over to solar power water heating has never been easier or more beneficial. With Federal income tax deductions and affordable prices of solar systems, there’s no reason not to install your new solar power system.