Solar Water Heater vs Heat Pump

Hot water comes at a price.

Traditional electricity and gas systems are more expensive, while solar hot water and heat pumps are less expensive.

So, as electricity and gas costs continue to rise, these more efficient options appeal to many homeowners. And for good reason.

However, once you decide to save with a more economical (and environmentally) friendly system, you face another problem:

Which one should you choose?

Fortunately, it didn't take long to find the answer to this question.

Our research shows that while both heat pumps and solar thermal systems can provide you and the planet with domestic hot water at a lower cost, heat pumps are the more convenient and affordable option for most homes.

To understand why a heat pump is often a better fit, let's review how each system works:

Heat Pump Hot Water System

Just like home air conditioners, heat pump hot water systems use refrigerants to collect heat from the surrounding air to provide hot water to the home.

But what if it's really cold outside, I hear you say? Well, 10 degrees in a day would be considered cold for a human, but, for example, if the refrigerant inside the heat is minus 25 degrees, then the surrounding air is actually a quite hot. Since heat is always absorbed by anything cooler, in this case, a heat pump hot water system will draw 35 degrees of heat from the air, providing free thermal energy for your domestic hot water usage. This ingenious energy absorption allows the heat pump water heater to produce an average of 3 kW of heat for every 1 kW of energy consumed. A good heat pump system will efficiently provide hot water at sub-zero temperatures. The average energy efficiency of a heat pump hot water system is 65-70%.

Solar water heating system

Solar water heating systems use the radiant heat of the sun to heat water-filled solar panels or vacuum tubes on the north side of a home's roof. When the sun hits the collector, the water inside heats up, and this free hot water is stored in a storage tank for later use. Since this simple technique relies on radiant heat, if it's nighttime or cloudy, the system will require a gas booster or electronics booster to heat the tank. The average energy efficiency of this solar water heating system is 65-80%.

Advantages of heat pump systems

1. Low cost of heat pump system

The initial cost of a heat pump hot water system is generally less than half that of a solar hot water system. This means paying for the system itself is much faster. In addition, the system is completely above ground, so there is no need to worry about panels or pipes on the roof leaking or taking up too much space for those who wish to use this space for a solar power system.

2. Reduce carbon emissions

Because heat pump systems collect three times as much energy as they use, they are more environmentally friendly than traditional electric hot water systems.

3. Work efficiently in rain, hail or sunlight

Heat pump systems absorb heat from the air and therefore operate efficiently without sunlight. This means the system can operate at cheaper off-peak electricity rates, further reducing your electricity bill.

Disadvantages of heat pump systems

1. Non-silent operation

Heat pump systems utilize an air conditioner compressor to transport refrigerant through the system. This means that the heat pump hot water system can be as noisy as an air conditioner. When deciding where to place your heat pump system, it's important not to get yourself too close to your bedroom window, but also to consider your neighbors.

2. Maintenance costs

Since heat pump systems have more components than traditional electrical or gas hot water systems, the demand for service is higher. Typically, heat pump systems require service every 3-5 years, while other systems require service every 5-8 years

Advantages and disadvantages of solar water heaters

Advantage:

1. More efficient when the collector is placed correctly.

2. Roof installation system is simple and very reliable, with low maintenance cost.

Shortcoming:

1. Very high upfront installation costs

2. Efficiency depends on weather, climate and season

3. Solar technology is still in its infancy and needs further development

4. The maintenance cost of the split solar system is higher.

When to Consider Solar Hot Water

Heat pumps do require tank space in your home. If you don't have that space and don't consider solar panels, a tightly coupled solar hot water system (tank mounted on the roof) will help you enjoy energy efficient hot water.

When to Consider a Heat Pump

The only downside to heat pumps is that they do make some noise. However, many current models are as quiet as a library. Most people's voices are no louder than the moderate traffic in suburban neighborhoods. For most homes, they are a more convenient and cost-effective alternative to solar water heating and electric and gas systems.

There is a way to combine solar energy and heat pumps to maximize energy savings:

Solar + Heat Pump

Of course, the best option is to not have to choose! A complete photovoltaic solar panel array will provide your home and your heat pump with clean, renewable energy from your own roof.

Recently, going solar has become more affordable than you might think - most systems pay for themselves within 3-7 years and will reduce electricity bills by 30-60%.

As for hot water, your solar system will further reduce costs by acting as a "hot water battery" for the heat pump. Here's how:

1. Time your heat pump to turn on around noon, when the sun is at its highest.

2. Your heat pump will store free solar energy in the form of hot water.

3. Even if there is no sunlight, your family can use solar hot water anytime.

4. This time-shift + energy self-consumption combination will reduce your electricity bills compared to just the solar system or the heat pump itself.

No need for expensive EVs or $10,000 batteries to store solar energy - your heat pump system will allow you to store it along with equipment you already own.