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30+ Most Frequently Asked Questions About Solar Hot Water Heaters: Everything You Need To Know About Your Residential Solar Powered Water Heater 2022

Most Frequently Asked Questions About Solar Hot Water Heaters: Everything You Need To Know About Your Residential Solar Powered Water Heater

ultimate guide residential solar water heater hot frequently asked questions all you need to know usage, safety, output, efficiency

We get a lot of questions about residential solar hot water heaters. So, whether you are interested in a solar hot water heater for your home or you are doing a homework project for school…here are some of the most frequently asked questions about residential solar hot water heaters.

Here are the top questions…

Does My State Have Enough Sunshine For Solar?

Germany is one of the largest solar markets in the world. Their solar conditions/sun exposure pales in comparison to our conditions here in the United States.

The map in the first link below shows the comparison very well. The darker colors represent more intense sun exposure. So, whether you are installing a solar water heater or a solar electric system, most of the U.S. has terrific sun exposure for solar.

Want more data? Check out this site…

Look at solar power from a pure potential standpoint, it is a no-brainer to understand the better your sun consistency and coverage, the better chance you have of saving money in solar power energy such as solar panels.

You can see from this map what the top solar-producing states could be as well as you could create a list of states benefiting from solar energy.

As you know, I think solar energy in the United States will grow aggressively, and knowing the pure science potential is a great place to get a foundation for that growth.

Will It Work On My House?

Solar hot water heaters will work on most homes. The main thing to watch out for is significant shading caused by trees or other structures. It is also important that you have enough roof space to receive southern sun exposure between the hours of 10 am and 2 pm. Usually 60 to 80s.f. is plenty.

If you do not have enough clear roof space then it is possible to mount the panels on the ground using a special mounting system.

How Do Solar Water Heaters work?

  1. Your solar panels capture free, 100% renewable energy from the sun. The typical solar water heater installation will include 2 or 3 solar panels mounted on your roof.
  2. Your solar station regulates the connection between the solar panels and the hot water storage tank.
  3. Your free, solar-heated water is ready for household use.

How Much Money Will I Save?

Solar hot water heaters are literally money-saving machines. They work while you sleep to save you money every single day, month after month, year after year. While they will not put tens of thousands of dollars in your bank account overnight, they will eliminate significant amounts of energy costs that in turn will save you a boat load.

The average lifespan of a quality solar water heater is 25-30 years. So, this means you are locking in your savings over this period of time.

Here’s an example from one of our clients…

After installing one of our solar hot water heaters…this family of 4 (2 adults, 2 children) is saving $60 per month on their electric bill. This adds up to $720 over 1 year. We all know energy prices are rising, but predicting where they will be 5, 10, 15 years from now is difficult speculation. So, in this example let’s assume a 10% annual energy price increase.

They are saving $60 X 12 months = $720 per year

Figuring a 10% energy price increase each year…
Their savings after 3 years – $2,383.20
Their savings after 5 years – $4,395.67
Their savings after 10 years – $11,474.95
Their savings after 25 years – $70,809.88

The solar hot water heater cost them $2,175 after their Federal and state tax incentives. Their upfront costs were repaid in less than 3 years and they no longer have to worry about unpredictable, skyrocketing energy prices.

Does It Work On Cloudy Days?

One of the most common questions people have about solar hot water heating is “Will I have hot water on cloudy days?” The answer (without question) is…YES!

First, light and heat are both forms of energy. Solar hot water panels convert light energy into heat energy. The sun is over ninety million miles away from the earth.

When the sun shines on the earth it does not shine a direct beam of heat through 93+ million miles of space/vacuum to heat up a solar hot water panel on your roof. It beams radiation through space in the form of light.

When the light reaches the earth’s atmosphere it diffuses. Direct sunshine on the surface of the earth is never direct, even though it may seem that way. The sunlight is simply radiation that is less diffused in cloudless weather and more diffused when the clouds are heavy.

Solar hot water systems use this diffused radiation to heat water. Unusually heavy cloud cover will reduce the amount of radiation reaching your panels but this normally does not affect the temperature of your household water.

Here’s why…

During sunny hours of the day, your solar hot water panels heat water at peak levels. This hot water is stored in a specially insulated water storage tank, and saved for use at a later time/day. A high-quality, properly installed storage tank will keep your water hot for days and days.

On cloudy days (and at night), you will have plenty of hot water in your insulated storage tank (assuming your system was designed properly) for household use. Even if there are heavy clouds for several days in a row, a correctly sized and installed system will provide you with plenty of hot water and no worries.

As a failsafe, most solar hot water heaters have gas or electric backup elements should you use all of your stored hot water. Gas or electricity is only used if absolutely necessary.

Will I Have Hot Water At Night?

The answer is absolutely, positively…YES!

An important issue to consider if you have a large household or use high volumes of hot water is the size of your solar hot water storage tank(s). The more hot water you store, the more you will be able to use and have during extended periods of gloomy days.

Often, we will install (2) large solar hot water storage tanks for our residential clients. These tanks are usually between 80 and 100 gallons each. Determining the right amount of hot water storage for your home is not hard. Usually, this has a lot to do with how much space you have available for the tanks.

How Much CO2 Will I Eliminate?

During a 20-year period, one solar water heater can avoid more than 50 tons of carbon dioxide emissions.
(source: U.S. Dept. of Energy)

What Do They Look Like?

Residential solar hot water installations generally consist of 2 or 3 solar collectors/panels mounted on your roof and a single or double storage tank configuration. 

What Is The Return On Investment? (ROI)

The return on your solar hot water heater investment comes in the form of savings. The money you would have otherwise given to your utility company STAYS IN YOUR POCKET.

Estimating the amount of savings you will accumulate over the lifetime of your solar water heater can be calculated by analyzing your utility bills, hot water usage patterns, and looking at energy price trending.

What Is The Payback Period?

What you pay for a solar hot water system is an investment. It’s like investing in a stock with a guarantee that it will never go down in price.

Over a number of years, your solar water heating system will save you enough money in energy costs to pay for itself. The Payback Period is the number of years that it takes for this to happen.

For example

The installation cost of a solar hot water heater in Maryland typically ranges from $8,000-12,000. Federal and Maryland State solar tax incentive programs frequently cover 60%+ of the initial installation cost.

Add in your energy savings and the income you receive from SRECs here in Maryland…and it’s possible to achieve a payback period of LESS than 2 years.

Solar Hot Water…Solar PV, What’s The Difference?

Solar hot water (solar thermal) uses the sun’s energy to directly heat liquid, (either water or a glycol solution depending on the type solar water heater) while solar PV (solar photovoltaic) coverts solar energy directly into electricity.

For more on the science of how solar energy works…

Which Is Best, Solar Hot Water Or Solar PV?

Solar water heating panels and solar PV (electric) panels are two completely different things. One is designed specifically for heating water and one is designed to generate electricity.

At least on the residential level, solar thermal does not produce electricity very well and solar PV does not heat water efficiently. So, the short answer is…

They are both best at what they are designed to do.

Solar hot water panels are much less sensitive to shading. Often, solar hot water works just fine on a house that has too much shading for solar electric panels (solar PV). A small amount of shading on a solar electric panel can significantly hinder the performance of the entire system, greatly affecting the overall efficiency.

Another big factor is the square footage of roof space available. The typical residential solar water heating systems requires only a fraction of the space needed for a solar electric installation. Typically, solar hot water panels only need 60-80 square feet of space while solar electric panel may cover 3 to 4 times the amount of space or more.

Here are some tips…

  • If you have a limited budget and are looking for the “best bang for your buck”, a solar water heater is the right choice for you.
  • If you are hoping to eliminate more than 30% of your utility costs and your budget allows for a larger investment…a solar electric system may be worth considering.
  • Shading may be a deal-breaker for solar electric panels, but this does not necessarily rule out a solar hot water system.
  • If you are able…install both and really put a dent in your utility bill!

How Long Will It Last?

In the field, we have seen solar hot water systems 35+ years old and still in working order. Most, higher quality systems will last a solid 25-30 years or more. This assumes the system was properly installed and minor, periodic maintenance was performed.

What Maintenance Is Required?

Solar hot water heater maintenance is pretty straight forward. Storage tank maintenance is basically the same as a traditional hot water tank…flush periodically, check anode rods, and perform a visual inspection of all plumbing connections to make sure the are no leaks. If your system is a closed loop style solar hot water heater, the condition of the glycol solution should be inspected every 2 years.

Also, a visual inspection of the solar panels to make sure there are no cracks or other damage that may hurt performance.

Will It Work In The Winter?

A properly sized and installed residential solar hot water heater will work in the winter time.

Can I Heat My House?

You can, but retrofitting a solar thermal heating system generally yields a poor return on investment due to the high renovation costs involved. If you are building a new home or adding an addition the returns may be more favorable.

Will It Replace My Existing Water Heater?

When we install a new solar hot water system, these are the two most common scenarios…

1.) The new solar hot water storage tank is installed next to the existing water heater. They are connected together and the existing water heater acts as a backup. This assumes the existing water heater is in acceptable condition.

2.) A single solar hot water storage tank (with a backup gas or electric element) is installed and the old water heater is removed.

How Long Will It Take To Install?

In the field, we have seen solar hot water systems 35+ years old and still in working order. Most, higher quality systems will last a solid 25-30 years or more. This assumes the system was properly installed and minor, periodic maintenance was performed.

Will It Heat My Pool?

Most pool heating requires a different type of solar panel and different equipment. So, the solar hot water system for heating your household water is not used to heat your pool.

What Quality Standards Exist?

In 1980 the Solar Rating and Certification Corporation (SRCC) was incorporated as a non-profit organization whose primary purpose is the development and implementation of certification programs and national rating standards for solar energy equipment.

The corporation is an independent third-party certification entity. It is unique in that it is the only national certification program established solely for solar energy products. It is also the only national certification organization whose programs are the direct result of combined efforts of state organizations involved in the administration of standards and an industry association.

Will I Have To Change My Hot Water Usage Routines?

Nope. A solar hot water heater allows you to save money and save the environment without sacrificing your quality of living.

Is Saving Money The Only Reason?

“Is saving money the only reason why I am interested in solar?”

This is a good question to ask yourself if you are considering a solar water heater for your home. While the savings benefits are significant over a long period of time a solar water heater corrects one of the least efficient areas of your home. By using the sun’s clean, 100% renewable energy to heat your water you have made a tremendously positive impact in helping the environment. You are reducing tons of CO2 emissions which means less pollution and damage to your world. This is a wonderful benefit!

Making the decision to switch to a solar water heater does make financial sense, but should that be the only reason? There are a lot of things we buy that don’t save us money and don’t help the environment. Maybe it’s time to take a closer look at why we are truly interested in renewable energy investments…like solar water heaters.

Why Energy Companies Suck?

This may sound a bit harsh, but energy companies really do suck. While they do provide you with electricity, energy to power your HVAC system, energy for water heating, etc…They are not doing you any favors. Even programs like this do not change how you consume energy. These types of programs help with how much energy you consume, but you are still purchasing a constant stream of non-renewable energy. Buying into a plan that involves continually rising energy prices that are completely out of your control is not the best idea. But, I guess this is better than nothing.

Honestly, do really believe that it’s in your energy company’s best interest for you to spend less money and consume less of their product? From a business point of view this simply does not make any sense. Your dependency on their product has put you in a losing position…

  • You pay whatever they tell you to pay for energy = you lose.
  • A constant outflow of your hard earn money = you lose.
  • Rising prices cause you to spend more every year = you lose.
  • Burning fossil fuel (their product) trashes your environment = you lose.

How Excessive Energy Consumption Is In The United States?

This interactive map puts into perspective how excessive our energy consumption is in the United States. Hover your cursor over the nation of your choice to see its CO2 emissions, population, birth and death rates. David Bleja collected this data from United States Government statistics, from the CIA World Factbook and the United Nations Statistical Division.

Click here to view the map

What Is Solar Photovoltaic Technology(Solar PV)?

Solar cells, also called photovoltaic (PV) cells by scientists, convert sunlight directly into electricity. PV gets its name from the process of converting light (photons) to electricity (voltage), which is called the PV effect. The PV effect was discovered in 1954, when scientists at Bell Telephone discovered that silicon (an element found in sand) created an electric charge when exposed to sunlight. Soon solar cells were being used to power space satellites and smaller items like calculators and watches. Today, thousands of people power their homes and businesses with individual solar PV systems. Utility companies are also using PV technology for large power stations.

Learn more HERE.

How To Be A Sustainability Hero?

Level 1 Sustainability Heroes know they should be doing more to build a more sustainable life for themselves, their family and future generations. Upon recognizing this they begin to take small, but very important actions like utilizing “10 Ways to Go Green” lists, conserving gasoline, using energy efficient light bulbs and even installing Energy Star rated appliances. Positive results can be generated as a Level 1 Sustainability Hero, but it requires education and consistent action.

In addition to going green in the more common ways like installing energy-efficient appliances and purchasing environmentally friendly products, Level 2 Sustainability Heroes begin to address their energy use in a more dramatic way. By offsetting a portion of their fossil fuel-based energy consumption with solar, geothermal, or wind systems they begin to take more control over their spending and energy use by generating their own power.

Level 3 Sustainability Heroes realize that it is possible to generate nearly all of the energy needed to power their lives without sacrificing comfort or quality and in some cases create a surplus of energy that can actually make them money. Not only do they realize this, but they also create a plan and take massive action ultimately creating the most sustainable life possible for themselves, their family, and generations to come.

Do You Know How Much You Spend On Water Heating?

Water Heating Costs. It’s More Than You Think.

According to government statistics around 24% of your household energy consumption is spent on water heating. If live in Maryland and are heating water with oil it is probably more.

Here is an example that helps to reveal your true water heating costs over a 25-30 year period. We are looking at an estimated amount that you could be spending to heat your household water. We are also assuming a 5% increase in energy prices per year.

This is a lot of money! What’s even worse is this is only showing your monthly energy expenses. There are numerous other costs involve in figuring our total water heating costs. Over a period of 25-30 years, you are certainly going to have repairs, maintenance, and complete water heater replacement costs. Not to mention the tons of CO2 emissions being pumped into the environment from the burning of fossil fuel.

We are a nation of consumers and spenders. As new products, services and conveniences enter the marketplace we find ourselves adding to our list of needs. 15 years ago would you have considered your cell phone a need or an optional convenience? How about e-mail? As optional conveniences slowly shift into our needs column we begin to lose sight of what they are actually costing us. They become needs, have-to-haves, and we choose to ignore or justify the financial side effects.

Most of us would consider hot water a basic need, right? I know I do. The convenience that water heaters provide is of great value. How would you heat your water if you did not have a water heater? Showers, washing dishes, and cleaning your home would become much more difficult. Utility companies fully understand the leverage they hold and are not the least bit hesitant to use it. They know you will pay whatever price they tell you to pay as long as you “need” the convenience that water heaters provide.

Solar water heaters do more than save money and reduce CO2 emissions. They fundamentally change how you consume. More specifically, how you consume energy. Instead of buying the convenience of hot water from your utility company (gas or electricity), you are utilizing the sun’s energy to heat your water. You are no longer at the mercy of your utility company.

What Is Solar Panel Strength And Durability?

I receive a lot of questions about solar water heaters. Most of the questions are about solar payback periods, monthly utility bill savings, CO2 emissions, etc…Recently, I was asked about the durability of the flat plate collectors installed. The question was…

“How strong is the glass covering on your solar panels?…if a tree limb falls on the panels..will they break?”

The short answer to this question is no. Flat plate collector manufacturers conduct special testing to determine the strength and durability of their solar collectors. This testing has helped them create very strong and impact-resistant solar panels.

I suppose if a very large tree came crashing down on your home you might experience some damage, but this would be a very unusual and extreme scenario.

What Is A Solar Ready Water Heater?

Is it time to replace your old or failing hot water heater? Not sure whether to install a high efficiency water heater or go to the next level with a tankless or solar water heater?

With all this talk about massive amounts of CO2 emissions, rising energy prices, and global climate change, you have an opportunity to correct one of the least energy-efficient areas of your home. Old or poorly performing water heaters can increase your monthly energy bills and emit ridiculous amounts of CO2 into the atmosphere.

If you are still on the fence with solar water heaters or just can not make the investment at this time, an option worth considering is the installation of a solar-ready water heater. Solar ready water heaters are simply gas or electric-powered units with integrated connections for a future solar panel installation. The costs to install these units are far less than a complete solar water heater installation and should you decide to add the solar panels at a later date, you have the freedom to do so. Solar-ready water heaters are definitely a great option if you need a new water heater soon but still are not sure about making the complete solar investment.

Can I Apply The Solar Tax Incentives To My Hot Tubs?

Just a quick bit of advice for anyone who wants to heat their hot tub with solar. If you are considering installing a solar water heater to heat water for your house and water for your hot tub you need to know this.

The 30% federal tax credit for the cost of a solar water heater installation does not apply to heating hot tubs.

However, you can install a solar water heater with an additional heat exchanger (hot tub hookup) without connecting it to your hot tub. This would allow you to be eligible for the solar tax credit and give you the ability to connect the hot tub sometime in the future.

How To Invest In Solar Energy?

Many people are making the choice to switch to a solar water heater purely for investment and energy security reasons. The fact that solar water heaters eliminate CO2 emissions is an added bonus for many people, but not the reason they decided to install a solar thermal system.

With the stock market doing poorly and the real estate market in a tailspin opportunities for investing become more uncertain. The days of buying a house and waiting for it to double in value are over and the stock market is incredibly unstable with companies struggling to stay afloat.

Where does this leave you as an investor? Where do you put your money? Stocks, bonds, mutual funds, real estate?

Investing in energy producing assets for your home can make a lot of sense. Energy producing assets help to reduce your cost of living by eliminate fossil fuel based energy consumption. This reduces your bills and your dependence on foreign oil.

High levels of uncertainty and low returns in traditional investment vehicles make the idea of investing in technologies that produce energy very attractive. Something to think about.

How To Move On From Fossil Fuel Addiction?

Today, most households are addicted to fossil fuel consumption. Many of our every day comforts are currently dependent on the consumption of fossil fuel. As energy prices rise, the costs involved in maintaining our lifestyle will increase dramatically, both financially and environmentally. The time will come when the price gets too high and we will be forced to change rather than taking control.

Our children, grandchildren, and beyond are the beneficiaries of not only the environment we leave them but the habits and behaviors we instill in them over time. The world is changing so we must begin adjusting and teaching our beneficiaries more sustainable ways to live today.

If you are a young person reading this you have a tremendous opportunity to educate yourself and begin to adjust in preparation for a very different world.

Don’t wait for the price to get too high and force you to change. Forced change is never pleasant.

Solar Thermal Vs. Solar PV?

If you have completed any research on solar PV (photovoltaic) for the home you probably know it can be pricey. Now, I am a huge fan of solar PV and truly believe if you are able to make the investment you will not be disappointed but, solar thermal systems or solar water heaters will get you the most bang for your buck. If you just can’t bring yourself to make the larger investment in a solar PV system to produce electricity for your home it is definitely worth considering a solar thermal system.

Your existing water heater is likely the least efficient use of energy in your home. Solar water heaters are incredibly efficient and do an amazing job of offsetting this poor use of energy. Even if you install a complete solar PV system it is wise to install solar thermal collectors for the water heating portion of your energy usage. Solar water heaters are so efficient that it does not make sense to heat your water with electricity generated by a solar PV system.

So, if you are considering a complete solar PV system, but are concerned about the cost you really should look into starting with a solar water heater/solar thermal system. You will get the most bang for your buck and it will complement a future solar PV installation.

How Flat Plate Solar Collectors Work?

Here is a very simple overview of how flat plate solar collectors work.

These days most flat plate collectors have a very sleek, low profile design that looks like skylights when installed on your roof. Most solar installations require 2 or 3 of these flat plate collectors.

Flat plat collectors are basically a box lined with an absorber plate and copper tubing. The copper tubing usually runs in a parallel pattern.

When the sun shines on the solar collector it uses the solar energy to heat a special fluid inside the copper tubing. Once heated this fluid is transferred to your hot water storage tank and heats your household water.

What Is The Affordability Of Solar Energy For Home Use?

Many people initially feel they cannot afford a solar water heater or that solar water heaters are too expensive, but when they fully grasp how much they will be saving on their energy bills over the years, they find it to be very affordable considering the alternative. Let’s take a look at a simple example.

Suppose you are spending $65 per month on energy to heat your hot water. Also, suppose energy prices rise at a rate of 10% per year. At this rate, you are certain to spend $32,243 or more in energy costs to heat your water over the next 25 years. In Maryland for example, you will save up to 80% of this figure. With solar water heating your energy costs to heat hot water will be more like $6,449 over the same 25 year period.

Often people realize that the cost of doing nothing is far higher than the cost of installing a solar water heater. So, the big question becomes, “Would you rather continue to pay unpredictable, increasing amounts of money or have a predictable, fixed amount that you can rely on over a long period of time?” The real decision is not about the affordability of solar but deciding whether you want to pay yourself or the utility company.

Cash For Clunkers Vs Cash For Solar

You have probably heard about Cash For Clunkers by now. There are a number of specific rules, but basically, you will get a $3,500-$4,500 credit for trading in your old car and buying a new one. This is a great opportunity if you need a new car, but it is a shame this credit receives more publicity than the renewable energy tax credits and incentives currently in place. For example…you could install a new solar hot water heater on your home and get up to $6,000 in tax incentives depending on the size and cost of your new solar water heater. Plus you will get free hot water for 30+ years. Let’s take a look…

Cash For Clunkers

$4,500 Credits + Having to pay for gas ($3, $4, $5+ per gallon) and maintenance for 30 years (if it lasts that long).


Cash For Solar Water Heaters

$6,000 in Solar Tax Incentives + Increased home value + Free hot water for 30+ years + Reduced CO2 emissions.

It’s up to you.

(Forget cash for clunkers, solar water heaters are cash for water. It’s really a win-win. Homeowners save money, and the average house reduces its C02 emission by 2,000 pounds a year.)


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