The idea behind solar water heaters is pretty simple: Sunshine that hits water in black tubes or surfaces gets hot.
Now, imagine all the hot water you use around the house, from the hot morning shower to that cup of coffee. What if you could have all the hot water your family needs without the accompanying utility bills? With solar water heating, you can.
In this article, we explore solar water heating. What is it? How does it work? How does it save you money? What must you consider before installing a water heating system? Stick around; we’re about to shave off some bucks from your monthly budget.
Also check out our guide to getting started with solar water heating.
Table of Contents
What is solar water heating?
A solar water heater uses the sun’s energy to heat water for domestic or commercial purposes. This technology uses a clean and sustainable energy source, which reduces your overall carbon footprint.
Most people associate solar energy with solar panels – a popular form of power generation that converts the sun’s energy into electricity. However, solar technology is not limited to electricity generation. You can also use it to heat water.
How does solar water heating work?
Solar water heating systems use solar collectors to collect heat from the sun. These collectors are fitted to the roof, ideally, where they receive the most sunshine. Alternatively, you can mount your solar collectors on the ground or a South-facing wall. The collectors then transmit the sun’s heat to the water.
Solar thermal collectors come in two types:
- Flat plate collectors
- Pitched or evacuated tubes
Their primary difference lies in the aesthetics, but they operate the same way.
For instance, flat plate thermal solar collectors consist of flat-glazed hot water solar panels mounted on the roof. In contrast, evacuated tubes consist of several dark “vacuum-tubes,” fixed into a manifold and mounted on the top.
Additionally, you can use an immersion heater or boiler alongside your solar water heating system to increase the water’s temperature when necessary.
The Benefits: How to save money with solar water heaters
The beauty of renewable energy is that you can always have more of it whenever you need it. Like with most solar systems, once you go past the initial installation hurdle, the system starts paying for itself from day one.
According to a report by the U.S. Department of Energy, solar water heaters can slash your utility bills by 50 percent to 80 percent. The savings depend on your setup and hot water usage. For example, a family of seven will enjoy more savings than a family of two.
Given such significant savings, solar water heating systems pay for themselves pretty quickly – usually within a period of 5 to 10 years.
It gets even better. Current payback models are tied to the current utility rates. Therefore, as energy prices rise over time, the payback for your solar water heater becomes even shorter because the heater protects you from rising utility prices.
Unlike other sources of energy, the sun is free, forever.
Furthermore, if you are in the process of purchasing a new home or refinancing your current home, you can include the cost of the new solar water heating system in the mortgage. Properties with energy efficiency upgrades improve the resale value.
According to estimates by the National Renewable Energy Laboratory (NREL), for every dollar, you save in your annual utility bill, your home’s value increases by $20.
Beyond free hot water for life, solar water heaters come with other benefits, including:
- Reducing your carbon footprint – According to a Pacific Gas and Electric (PG&E) report, a solar water heating system can prevent 4,000 pounds, or between 30kg-510kg of carbon dioxide from entering into the environment every year. Here’s your perfect way to slash your bills while protecting the planet.
- Low maintenance costs – Unlike other solar solutions, solar water heaters incur lower maintenance costs. With fewer moving parts, the installations last longer, proven by the extended warranties of between five and ten years.
- Lower operating costs – Once you get past the initial installation costs, there are very few other additional costs. The water system utilizes the sun’s energy, which will always remain free.
- Interoperability with existing water heating systems – Solar water heaters work well with other systems such as boilers, heat pumps, and biomass heating systems.
- Renewable Heat Incentive – Solar water heating is eligible for regular incentive earnings for producing energy from renewable resources in the U.K. That essentially means that you get paid for generating your heat regardless of whether you use it all.
- Cheaper to install than P.V. panels – You need fewer solar water heating panels per household compared to the number of P.V. panels
- Energy efficiency and space – Solar thermal panels are very efficient, converting 80% of solar radiation into heating energy. Additionally, they require less space on your roof compared to solar P.V. panels. For instance, while you may need a P.V. solar array with between 10-16 panels, you only need about 2-3 solar thermal panels for your home’s hot water needs.
What to consider when choosing a solar water heating system
Before you make the switch to solar thermal heating, evaluate your current water heating expenditure to determine potential savings. How much you stand to save depends on:
- Your location and the amount of sunshine you get each day
- How much hot water you use daily at home
- The cost of energy and other fuels in your area
- Available financing and other incentives.
You should also consider local building codes, regulations, and any restrictions on installations where you live.
For the best results with your solar water heating installation:
- Ensure your roof faces the south, or consider buying a thermodynamic panel installed on any side of the house for maximum solar collector efficiency.
- You need approximately one square meter of solar collectors per person living in the building when using flat plate collectors. That’s enough to heat between 30-60 liters of water.
- Conduct an energy performance survey to determine your energy use and efficiency. Make the necessary changes before installing the solar thermal heating system.
Renewable energy tends to be cheaper over the long run. With a solar water heating system, you’re guaranteed hot water throughout the year, while cutting down your utility bills. That you are also doing your part in protecting the planet makes the investment all the more worthwhile.
Do you have a solar water heating system at home? What do you like about it, and what do you wish you’d known before the installation? Let us know in the comment section below.