Solar-Powered HVAC Systems: What You Need to Know

As solar energy continues to break installation records with each passing year, the sun becomes a more integral part of home cooling. That’s where solar-powered HVAC systems come in. Whether you’re interested in installing this type of system with the help of a pro AC installer or want to leverage your existing solar panels for even more good, here’s what you need to know about solar-powered air conditioners.

What Is a Solar-Powered HVAC System?

A solar-powered air conditioner—also called a solar air conditioner or solar AC for short—uses solar energy to power your air conditioner and cool your home. They run like your typical split AC unit, but instead of sourcing energy from the electrical grid, solar air conditioners use solar panels or solar water heaters to capture the sun’s heat and create energy. 

You can purchase independent units for smaller spaces like your RV or large solar-ready systems for your whole house. Before making the jump to solar power, consult a local AC installer to determine whether this type of system is the right fit for your home. 

How Does a Solar-Powered Air Conditioner Work?

There are two different ways that solar units collect energy: through solar photovoltaic (PV) systems and solar thermal systems. Here’s how each one works to provide your home with cool air.

Solar PV Air Conditioners

Solar PV air conditioners use one to three solar panels to generate electricity. A ductless mini-split system with an outdoor compressor and indoor unit affixes to the wall of your choice, making this option best for smaller, one-level residences and offices. 

During the day, solar power provides 90% of the system’s electricity. At night, hybrid systems switch to regular grid power, while off-grid units use a battery to store energy created during the day. 

Solar Thermal Air Conditioners

Thermal air conditioners are a type of solar water heater. This type of air conditioner uses the sun’s energy to heat water, which converts a refrigerant into a heat-absorbing gas that both cools the air and provides hot water for your home. Since water requires less energy to heat than solar panels, this system doesn’t need as many panels as a solar PV air conditioner. 

The only downside to thermal air conditioners is that thermal energy can’t use batteries and the electrical grid at night.

Benefits of Solar-Powered Air Conditioners

Solar-powered air conditioners come with many benefits that make them worth your while. The only main downside is the upfront cost, but even then, you’ll save more money in the long run by switching to solar energy (more on this below).

With that said, here are the benefits of solar air conditioners:

• They’re better for the environment. The U.S. Department of Energy states that 117 million metric tons of CO2 enter our air per year from traditional air conditioners.

• They save on energy bills. You could save 40% or more on your energy bills, depending on whether you need to use the grid at night.

• They help conserve energy. From a snowpocalypse to other power outages, solar energy helps take the load off the grid, preventing blackouts and needless energy consumption.

• They’re easy to maintain. Once installed, you don’t have to do much to maintain your solar panels. Even in the snow, solar panels are designed to let snow slide off within a day or two.

There’s a bit of a problem when connecting solar-powered air conditioners with solar panels. The solar energy captured by PV panels turns into direct current (DC) electricity, but most air conditioners use alternating current (AC) power. This process requires an inverter to convert the electricity from DC into AC.

For your air conditioner to use the energy collected from solar heat, you need to choose between three different types of solar-powered air conditioners.

1. DC Solar-Powered Air Conditioners

You can avoid needing an inverter altogether by choosing a DC-powered solar air conditioner. This air conditioner can run on the DC electricity generated by your solar panels through direct wiring to the panels. You can also run this type of solar air conditioner through an off-grid battery.

Pros:

• Directly wired to solar panels

• Ideal for off-grid living

• Easy to add batteries

Cons:

• Needs large battery storage capacity to run at night

• More costly than AC-powered units

• Can’t run at night

2. AC Solar-Powered Air Conditioners

An AC solar air conditioner, also called an inverter air conditioner, needs an inverter to convert the solar panel’s DC electricity into AC electricity. Once the stored energy in the battery goes through the inverter, the air conditioner can use the electricity to cool your home.

Pros:

• More affordable than DC systems

• Connects easily to the grid, where you can even receive credit back for giving energy to the grid

• Connects to solar panels to generate electricity in the daytime

Cons:

• Not suitable for off-grid living

3. Hybrid Solar-Powered Air Conditioners

As the name suggests, hybrid solar air conditioners can run on DC and AC. They can also connect to solar panels and the grid simultaneously to give you the best power source management.

Pros:

• No need for an inverter

• Easy transition between solar and grid power

• Could be a heat pump that heats your home

• Operates in the day or at night

Cons:

• Few models are compatible with batteries

• You’ll need to use the grid at night if the batteries are incompatible

• If you’re off-grid, it won’t work during the night

Solar-Powered Central Air vs Mini Splits

While there are some solar-powered central air conditioners available, the majority of solar AC units are mini split systems. The key difference between mini split systems and central ACs is that mini split systems operate without the need for ductwork. Mini splits tend to be more energy-efficient compared to central air conditioners, plus they’re more cost-effective and easier to install.

Traditional central ACs consist of an outdoor compressor that pushes air through the evaporator and condenser coils for cooling. This cooled air is then distributed throughout the home via ductwork and vents, all controlled by a thermostat managing the entire system. In contrast, mini splits include an outdoor compressor and one or more indoor evaporator connected by electrical and refrigerant lines. Each evaporator has its own thermostat, working independently to cool a specific zone within your home.

Factors to Consider When Shifting to Solar-Powered AC 

Although there are only three types of solar-powered air conditioners, there are many brands, sizes, battery options, solar panels, and more. How you choose your new solar-powered air conditioner unit will depend on several factors. 

Size of Your Home 

Larger homes require more AC capacity to keep cool, meaning you’ll need more wattage to power your home (or solar panels that generate enough electricity). Solar panels cost between $0.70 and $1.50 per watt on average. The average AC solar system needs around 3,000 to 6,000 watts, or $2,100 to $3,000 on the low end and $4,200 to $6,000 on the high end. 

Battery Options

Wanna go “off-grid?” You’ll need batteries to store energy for the night and for days when the weather doesn’t yield enough solar energy. It’s also a good idea to have batteries if you live in a hot climate that doesn’t get cool enough at night without the help of the AC.

Climate

Some climates receive ample sunlight and can get away with fewer solar panels, while other climate zones have less ideal weather for solar energy. In this case, you might need a larger battery backup to store energy on days the sun is shining or additional solar panels to capture as much energy as possible. 

Is Solar Air Conditioning Effective?

Yes, solar air conditioning is typically very effective. In many cases, it’s even on par with grid power. Various factors can impact the effectiveness, such as the availability of sunlight, the system’s efficiency, and the size and design of the installation. Hybrid systems can be toggled back and forth to receive grid power when there’s not enough solar energy to power them.

Solar-Powered Air Conditioner Cost

A solar-powered air conditioner costs anywhere from $1,600 to $13,000, but the average homeowner spends around $3,400 on a solar air conditioner. Keep in mind, you may be eligible to receive a federal tax credit for investing in this renewable energy source for your home. 

Solar Air Saving Programs

While solar AC systems typically cost more upfront, the energy savings over time can make them well worth the investment. In general, a solar-powered air conditioner pays for itself within 10 years of installation.

In addition to saving on energy costs, there are other savings to take advantage of when installing a solar-powered air conditioner. The U.S. Department Energy offers a tax credit of 30% of an energy-efficient AC’s costs, for a savings of up to $600.

Solar-Powered Air Conditioner Cost Breakdown

You can calculate how much you’ll spend on your new solar air conditioner depends by looking at the cost breakdown of each part of the system, including the following:

• Solar air conditioner unit: $1,000–$2,700 on average

• Photovoltaic panels: $250–$350 per panel

• Wiring: $50–$200

• Cost of solar batteries: $2,000–$3,500

• Inverter: $750–$1,700

• Charge controller: $50–$400 

• Installation: $1,500–$3,500

How Many Solar Panels Do You Need to Run Air Conditioning?

Determining how many solar panels you need to power a solar air conditioner depends on the type of solar AC and how much you use it. If you have an HVAC zoning system with a solar-powered mini split AC, these usually use 500 to 700 watts of energy per hour per zone. Most home solar panels make 250 to 400 watts of energy per hour. So, to power most solar air conditioners, you'd need at least two solar panels.

For central air conditioning, power is measured in tons. You need about one ton for every 600 square feet of space to keep it cool. For every ton, you'd want roughly 1,200 watts of solar panels. So, if you have a 2,500-square-foot home, you might need 14 to 22 solar panels to run your AC smoothly.

DIY vs. Hiring a Pro 

Given the number of parts, the wiring, and the dangers of climbing on the roof for the PV installation, you shouldn’t attempt to install a solar-powered air conditioner by yourself. Instead, opt for working with a local solar installation company or a local AC installer who specializes in solar-powered systems.

A solar professional will:

• Accurately calculate how much energy your family uses to determine battery power and the number of solar panels you’ll need

• Be familiar with your local climate and can advise you on which type of solar AC system will work best 

• Know which AC size you’ll need to keep your house cool, and

• Recommend system set-ups depending on your home’s configuration