Solar Water Heaters: Key Points to Consider

Did you know that there is enough solar energy that comes down on our planet every day to power the entire world’s energy needs for 1 year? (National Geographic)

That’s a lot of energy that we receive which is going to waste. One way that homeowners can begin to harness some of that energy is to upgrade their hot water system to a solar-powered system.

Solar domestic hot water systems, especially when combined with tankless water heater technologies for sale, can be a cost-effective way to get the hot water you need without the costly power bills.

Solar water heaters can be used in any climate. They are connected to a fuel source that doesn’t cost you anything beyond the initial expense and any upkeep costs. With energy prices continuing to rise, especially in the United States, looking at solar water heating systems is something that every household should consider.

What You Need to Know About Solar Water Heaters

Solar water heaters come in two types of systems: active systems and passive systems.

If you’re thinking about the installation of an active solar water heater, then you have two options from which to choose.

  • Direct Circulation. This type of water heating system will pump circulated water through the heating system that is powered by solar energy. Many tankless systems fit into this category. The water is then distributed throughout the home.
  • Indirect Circulation. This water heating system option circulates a heat-transfer fluid through the heat exchanger and collectors that are installed. It is this process which will heat the water, which is then distributed into the home.

Homeowners that live in a geographic area that rarely experiences freezing temperatures will usually benefit from the installation of a direct circulation system. If winter temperatures do tend to drop below freezing, then an indirect circulation system is usually a better choice.

There are also two options available for homeowners who are thinking about using a passive solar water heating system as well.

  • Integral Collector Storage. This type of system works well when there are higher levels of hot water required in during daylight hours, but not during evening hours. This type of system usually works better for homes that are in warmer geographic locations.
  • Thermo-Syphon Systems. This option allows for warm water to rise to the surface for use as colder water sinks. They are a good all-around option for many homes, though the storage tanks for the water are quite heavy and may not be suitable for all homeowners. This option also tends to be the most expensive of the solar systems that are available on the market today.

Solar systems are a great way for rural households, energy-conscious families, and home that are off-the-grid to continue receiving the hot water they need each day. If you’ve decided that one of these solar systems is right for you, then your next choice must involve how you will collect the solar energy that is going to be used.

There are 3 Solar Collection Options from Which to Choose

Unless you’re using a solar tankless system, your solar water heater will require a storage tank of some type. These tanks have an additional inlet/outlet combination built into them to work with the solar collector. If the system is a two-tank design, then the solar water heater will warm the water before it enters into a conventional tank-based system.

In a one-tank system, a backup heater is supplied to the tank to ensure that the water is hot enough for use at all times.

To collect the solar energy that will heat the water or provide power to your water heater, there are three options available to homeowners today.

  1. Flat-plate collectors.
  2. Integral collection storage.
  3. Evacuated-tube solar collectors.

Many homes use the flat-plate collectors because they are very easy to install. Their boxes are weatherproofed, and the absorber plate is quite dark to encourage energy collection. Glazed collectors are generally used for hot water systems, though unglazed options are increasing in popularity.

ICS involves black tubes or tanks within an insulated, glazed box. The cold water will pass through the collector to provide the initial heating. Then the water goes into a conventional system. These pipes tend to be outdoors, which is why climates where freezing is possible typically avoid this type of system.

Evacuated-tube collectors use parallel rows of glass tubes that collects energy and reduces standby losses simultaneously. They are becoming increasingly popular in residential applications, though the cost of this system type has kept it a commercial application in the United States up until now.

Do I Need a Backup System with a Solar Water Heater?

Yes. Most solar water heaters and systems require some type of backup to ensure there is hot water available to the home.

Even if a tankless system is being used, cloudy days or times of high household demand can reduce the effectiveness of the installation. A backup source of power, or a standby traditional hot water system, is almost always necessary.

Many solar water heaters include a conventional method of hot water storage as part of the initial capital cost. If a tankless system is being connected to a power source, an option to connect the system to a breaker on the traditional grid is usually included.

Backup systems for solar water heaters can be part of the solar collection system.

How Much Hot Water Access Do I Have with Solar Water Heaters?

Most solar water heaters will provide the same level of hot water access as a traditional system. The only difference is the power source which is fueling the hot water in the first place.

Rheem is one of the top manufacturers of solar hot water systems operating in North America right now. They currently offer 5 different models that incorporate solar power in some way to reduce energy usage costs for most households.

Their system capacities range from 75 gallons, with their SolPak or Solaraide HE models with gas assist, to 120-gallon capacities in the Universal Solaraide or Solaraide HE without a gas assist.

If you decide to purchase one of the best tankless systems that is available right now that works with solar power, you can have unlimited hot water access. You would just need to stay within the operational guidelines of the unit to ensure there are no gaps in hot water service during use.

When to Use Tankless Water Heaters with Solar Energy

Tankless models are designed to provide homes with enough hot water to operate up to 3 appliances at the same time, for an extended period, without losing access. Every home is unique, which means some homes may benefit from a tankless system and others may not.

If you use about 40 gallons of hot water every day, or less, then you are an excellent candidate to upgrade to a tankless water heater.

Solar energy is a good option with a tankless water heater when you live in a geographic area that receives warm temperatures and high levels of sunshine throughout the year. In these situations, you can work with a digital thermometer to precisely set the temperature levels of your hot water. This provides comfort, while you receive a reduction in your monthly water heating costs.

Tankless systems do not provide any hot water storage, however, so they will not work with all types of solar water heating systems. You would need to connect the tankless system to a solar power source to utilize the heating element for immediate hot water access.

Should I Invest into a Solar Water Heater?

It all depends what your budget can afford. If you can handle the initial capital expense of a solar water heater, then you’ll reduce your environmental impact without reducing your hot water access. Over time, the cost-savings experienced by getting off-the-grid may pay for the system.

Tankless systems will help you save even more money over time as well. They also have a higher initial expense, which means it may not be the correct choice for every homeowner.

Tank-based models, especially when solar energy is preferred, still tends to be the industry standard in the United States.

Solar is not right for everyone. Going tankless may not be suitable for your water usage needs or your family size. If you’re unsure of what hot water system would be right for your home after reviewing the information found here, and on this site, then consult with a local plumber or contractor about your needs or concerns.

Always weigh your options. In doing so, you’ll be able to make an empowered decision about your home’s hot water access now and well into the future. For other energy saving tips, read our article here.

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Greg Mattson

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