Installing a solar water heater in your home is a great way to lower your utility bills, and can make your home a lot more eco-friendly. However, figuring out which type of solar water heater is most suitable for your home can be challenging, especially if you aren’t familiar with solar system jargon.

You may have noticed that some solar water heater models are active models, while others are passive heaters. This is an important distinction to make, as active and passive solar water heaters function in very different ways.

What’s the Difference Between Passive and Active Solar Water Heaters?

The key difference between passive and active solar water heaters is the method they use to distribute hot water to different parts of your home. Active solar heaters are fitted with electric pumps, which rapidly distribute hot water or heat-transfer fluids to where they are needed.

Passive heaters do not possess pumps and do not require any power source to move water around your home. Instead, they rely on a natural phenomenon known as convection, which causes hot water to rise through cold water when the two are mixed. A properly designed passive system uses this rising effect to distribute hot water to bathrooms and kitchens, without the need for powered pumps.

Should You Choose an Active Solar Water Heater?

Active solar water heaters are generally more expensive than passive systems. They are also more mechanically complex due to their integrated pumps, so maintaining and repairing an active system can be more challenging.

However, this extra investment can be well worth it. Because active solar water heaters can move hot water around your home more quickly, they tend to lose less heat as waste heat and are consequently more energy efficient. If you live in a larger home with substantial hot water requirements, lower energy bills can help your active system pay for itself over time.

Some active water heaters also work at freezing temperatures. These systems are indirect circulation systems. Instead of pumping hot water around your home, these active systems transport heat to a centralized water storage tank using heat-transfer fluid. The heated water is then pumped from the tank to your faucets and showers.

The Sacramento area enjoys comparatively mild winters, but cold snaps still occur during the winter months. Standard active solar water heaters can freeze up and become useless during sub-zero temperatures, so an indirect circulation system may be a wise investment if you intend to use your solar system year-round.

Should You Choose a Passive Solar Water Heater?

Passive solar water heaters are more suitable for homes with moderately hot water needs, or homes that intend to use their solar system as a complement to an existing electric or gas-fired water heater. They cannot retain heat as well as active systems, so prolonged periods of cloudy weather can leave you with insufficient hot water supplies without a backup heater.

Passive solar water heaters also require large water storage tanks, which must be installed above the heater itself to allow water to flow through the system. This can present structural problems if you live in an older home that cannot support the weight of a large water tank. Your local HOA may also frown upon a large, visible water tank bolted to your home’s roof.

To make up for these drawbacks, passive solar water heaters are a lot cheaper than their active counterparts and require much less maintenance. If you want to reduce your home’s water heating bills without installing a complex system that requires constant oversight, a passive water heater can be a great addition to your home.

If you have any more questions about different types of solar water heaters, or you want more advice on which system is best for you, contact the solar experts at ACR Solar today.

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