Learn About The Pros and Cons Between Hybrid Water Heaters vs Solar Water Heaters

Let’s talk hybrid water heaters vs solar water heaters. Between hybrid water heaters vs solar water heaters, which one is a better investment for your home? Both water heaters require an initial investment. They both tout the benefit of energy savings, but in the valley of the sun, which unit is a better long-term investment? Only you can decide which water heater option is best for your home but let’s go over the pros and cons of each water heater. Admittedly, this information was difficult to come by during my research on solar water heaters. Even the manufacturer was unable to give me clear answers on the energy rating of a solar water heater compared to a hybrid water heater. A lot of information that I found was based on opinion. I believe it is your opinion of the unit that matters since you will be living with your decision. So I’ve presented the facts to the best of my ability with the information available to me from www.energy.gov

A pro for both options is that a solar water heater or a hybrid water heater are now our only choice when it comes to having an electric option that is greater than 50 gallons of water.  If you want a 65 gallon, 80 gallon or larger tank style water heater, a solar water heater is the only option approved by the EPA for manufacturing and installation.   

 Solar water Heaters 

First things first. What is a solar water heater and how does it work? A solar water heater is very much like it sounds, it utilizes the sun to heat your water. In the Phoenix metropolitan area, also known as “The Valley of the Sun”, you’d assume that this is a great idea because something we have in an abundance is sunny days.  

 How does a solar water heater work?  

 To start explaining how a solar water heater works we must break down the different types of solar water heaters. I know what your probably thinking! “ What do you mean types of solar water heaters? Aren’t they all the same?” Well the answer is no. There is actually 3 main types of solar water heaters. 

The open loop solar water heater 

The open loop system is the simplest of the 3 systems. Basically you have a tank that usually is an 80 gallon tank. The tank has a single heating element used as a back up heat source. Next, water starts pumping up to a solar panel on the roof.  The heat is then transferred from the sun to the water heating it up. The water is then sent to the tank to be stored for use. In addition to the tank, pump, and solar panel, the system will also have at least 2 temperature sensors and a control module. The control module controls when the pump runs to maintain the temperature in the tank. This system might be the most common. It is generally a cheaper system due to the simplicity of the storage tank. 

 The closed loop system 

A closed loop system has all the same components as the open loop, however there is a very big difference between the systems. The closed loop system tank is very different and there is additional fluid used for heat transfer. To be more specific there will be inlet and outlet ports for the water and another set to the solar panel. The term closed loop is used because there is a glycerin based fluid that is pumped through the solar panel and then through copper tubing that is wrapped around the tank. Once pumped around the tank, it transfers the heat absorbed from the panel to the tank. This system is very common but there is an additional cost in equipment. There are commonly additional costs from the tank design and manufacturing. The thought process behind this system however, is that the glycerin based fluid is less corrosive. With less corrosive fluid, the panel and pumps should last longer.

The drain back system 

The drain back system is also referred to as a piggy back system. The piggy back system is also a closed loop. However, it can be used with water or a glycerin based fluid. It also has a pump that pumps the fluid up through the panel and to the tank. It also has an additional reservoir that holds the heat transfer fluid when the pump is not running. So it essentially, “drains” back into this reservoir. Ideally, it is meant to lessen the strain on the solar panel because it is not under constant pressure. There are some versions of this system that can be added to a standard water heater. It becomes the main heating source and then the standard tank heating source, be it gas or electric, becomes a secondary source of heating the water. 

Savings? 

To talk savings we have to know what the efficiency is of the solar water heating system. I will be going over how the different efficiency ratings work. I will also try to simplify them for you as much as possible. If you would like to check out the technical data that can be found at https://www.energy.gov/energysaver/estimating-cost-and-energy-efficiency-solar-water-heater  

 

So to determine the energy efficiency of a solar water heater, you factor the amount of energy delivered by the system, divided by the electrical or gas put into the system. This will usually give you a solar energy factor of 2 or 3. Basically this means for every $1 you put into the electricity and/or gas you get 2-3 dollars worth of hot water. Another solar water heater performance metric is the solar fraction. The solar fraction is the portion of the total water heating load. The higher the solar fraction the greater the contribution to the heating of the water from the solar panel. The solar fraction will vary dramatically based on the amount of pure solar energy that can be utilized. 

Energy Efficiency

For simplicity, let’s stick to energy efficiency. Energy efficiency is also known as the UEF, which is more commonly used to rate the energy efficiency. UEF is also used by many companies to rate their water heater efficiency. And we will utilize the calculations provided by the link above. I am going to forgo comparisons to gas water heaters because the only way it may come into account is when the piggy back system is used with a gas water heater and that is not a common situation. The average 50 gallon electric water heater has a UEF of approximately .94 cents and cost the average residential home in 2021 around $460 to operate for the year. Based on the calculations provided you could save an average of $275 a year with a solar water heating system. These savings would bring your average cost for hot water to about $185 in 2021. 

So let’s take into account the up front cost of a solar water heating system. This will vary from system to system and your location. Here in the Phoenix metropolitan area you would be looking at roughly $12,000 to $15,000 for a solar water heating system. Generally, they have a life expectancy of 10 years on the tank and 6-8 years on other components. This cost analysis does not include repairs to the system. In short, with the up front cost of a solar water heater and the average annual savings it provides, you can expect to be making repairs on the system before it starts to pay for itself in savings. If you are lucky the components might last long enough to break even. 

 

Heat pump or Hybrid water heaters 

Hybrid water heaters and heat pump water heaters are the same thing. Often, they are referred to differently depending on the area of the country you reside in. Here in Arizona we refer to them as hybrid water heaters.

How do they work though? 

The Hybrid water heater utilizes a heat pump just like your air conditioner uses just much smaller. The heat pump absorbs the ambient heat. Next, it transfers the ambient heat to the water heater through a copper coil wrapped around the tank. You might recall that the closed loop solar water heater uses the same design. The heat pump works so well at absorbing ambient heat that depending on the manufacturer it will still work down to 34 degrees. The Hybrid also has 2 heating elements to assist in heating based on the setting you are in. A huge plus as well is that the Hybrid unit is an all in one system. No additional components are required on top of what is in the box for it to function. 

Hybrid efficiency  

Once again depending on the manufacturer the Hybrid water heater boast an incredible 3.55-4.00 UEF. Just a reminder that means that for every $1 you put into the Hybrid water heater it will net you $3.55-$4 worth of hot water. The average residential house hold can expect to spend roughly $150 a year for hot water with a hybrid water heater. That’s less than a solar water heater system will average. 

Savings 

The Hybrid water heater, generally, (as of this writing) will cost you somewhere between $4500-6500 depending  on size and installation. It will save you around $4700 in electric cost over its 10 year warranty period. Which means it could pay for itself before the warranty period is up. Also, with proper maintenance, a hybrid water heater will last longer and at that point, you are actually saving more money than the original up front cost. 

To sum things up..

After going over hybrid water heaters vs solar water heaters, a solar system is around twice as much to install as a hybrid water heater. It also requires several independent components to work properly. A solar water heater is also dependent on clear sunny days for the efficiency to kick in where as the hybrid works the same rain or shine. The UEF on the hybrid water heater is more than twice as high which means it saves you twice as much in energy cost. There is no equipment on the roof with the Hybrid risking a roof leak. I don’t know about you but when you start comparing cost of install and savings there really is not a choice. The hybrid beats out any possible advantage the solar water heater might have.

Services in Phoenix & Beyond

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