Powering your air conditioning with solar energy makes an enormous amount of sense when you think about it. During the hottest months of the year when 87% of households in the US use air conditioning systems, solar energy potential is also at its highest, with extended daylight hours of direct summer sun.
Grid-powered air conditioners use up about 6% of all of the electricity consumed in the United States, costing homeowners about $9 billion annually, and adding roughly 17 million metric tons of carbon dioxide into the atmosphere.
So to cut costs and reduce carbon emissions, why isn’t there a solar air conditioner in every American home?
Well, the truth is, solar-powered air conditioning systems are actually much more common than you may think.
What Is Solar Air Conditioning?
Before we go any further, it is critical to establish that there are two main types of solar air conditioners.
While you may be imagining an all-in-one solar-powered air conditioning appliance, any home that is generating electricity with a solar panel installation can also directly cut utility costs and carbon emissions while running the AC.
Essentially, solar air conditioners can be divided into two main categories:
- Whole-home solar power & air conditioning systems
- Independent solar thermal air conditioning units
In a whole-home system, an array of photovoltaic (PV) solar panels will generate the electricity that is used as a power source to run both the air conditioning and other appliances on a property. Separately, solar thermal air conditioners utilize built-in solar heat collectors and refrigeration systems to cool a space in one seamless process.
Solar thermal AC units are typically built into a property or placed strategically to cool a specific area of an interior. However, whole-home solar set-ups can seamlessly replace the utility electricity traditionally used to power HVAC systems or portable AC appliances.
How Do Solar Air Conditioners Work?
Although they are all technically fueled by the sun, solar-powered air conditioners can be operated in one of three capacities:
- Solar Thermal: In a thermal solar air conditioner, built-in solar collectors capture the heat of the sun to activate a cooling system within a home.
- Direct Current (DC): A DC air conditioner can run off the direct current that is generated by your solar panels, without having to pass through a solar inverter.
- Alternating Current (AC): Like a lot of home appliances, most modern air conditioning systems run on alternating current. Here, a solar inverter is required to modify the DC solar energy into usable home solar electricity.
Solar Thermal Air Conditioners
Using technology similar to solar water heating, solar thermal air conditioners collect energy from the sun and transfer it in a thermodynamic process. Often used to evaporate a refrigerant fluid, solar thermal air conditioners typically need the assistance of an electric-powered fan to distribute the cool air throughout a space.
Solar thermal air conditioners are not very common for residential use, but products do come in many different forms and capacities. In a closed energy loop, solar thermal air conditioners are usually “all-in-one,” but many come as “mini-split systems” with detached parts for the heat capture and cooling processes.
DC and AC Air Conditioners
Today, the majority of both central air conditioners and individual cooling appliances run on alternating current (AC). While solar power is generated as direct current (DC), every grid-tied solar energy system uses either a single DC inverter or a group of microinverters to modify the electricity into the usable AC power that runs a home’s electrical systems.
When going off the grid using a battery backup, solar energy systems generate and store electricity as DC power. Without losing any of the energy necessary to invert the electricity, battery-backed solar systems can be used to directly run a DC-powered air conditioner for maximum energy efficiency.
Knowing this, a DC air conditioner is the best-case scenario for instances in which power generation is limited and efficiency must be maximized, such as on an RV or small property. However, with AC air conditioners, it is much easier to generate the amount of electricity necessary to keep a property cool with rooftop solar panels and operate home appliances as normal.
How Many Solar Panels Do I Need for Solar Air Conditioning?
The number of solar panels you need to run your solar air conditioning system depends on a few key factors:
- Your home’s overall energy consumption
- Your solar panels' output and efficiency
- The amount of annual sunlight your home receives
At a minimum, your rooftop solar panel system should generate enough energy to offset the power consumption of your air conditioner. For instance, if your air conditioner requires 900 watts of power, you would need three solar panels rated at 300 watts each.
If you want to power your entire home (including the air conditioner) with renewable energy, you must install enough solar panels to cover the entire property’s electrical load. To calculate this, take a look at your utility bills to see the amount of electricity your home consumes annually (in kWh).
As an example, let's say you use an average of 1,000 kWh per month. This means that your solar energy system would have to generate approximately 33 kWh daily (1000 kWh divided by 30) or 1,390 watts per hour (33kWh divided by 24 hours x 1000).
In areas with 6 hours of peak sunlight, you would then have to generate approximately 8,340 watt-hours daily (6 x 1,390) to cover the entire electrical load. With 400W modules, this means you should install approximately 21 solar panels (8,340Wh divided by 400W) to power your entire home and air conditioning system.
The Benefits of Solar Panel Air Conditioning
Whether you use a solar thermal appliance or photovoltaic (PV) solar panels, cooling your home with solar power can offer both environmental and financial benefits.
Save on Utility Bills
Solar energy systems use the most abundant natural resource on the planet: free sunlight. When installing a solar system on your home, you can instantly reduce the amount of electricity you consume from the utility grid, which in turn can lower your monthly bills and help you avoid time-of-use and higher-tiered electricity rates.
For even more savings, a hybrid air conditioner that combines a furnace with a heat pump system for heating and cooling can further reduce your energy needs, as they typically run more efficiently than a traditional air conditioner.
For both solar thermal air conditioners and full-home systems, using emission-free electricity can help reduce your home’s carbon footprint. While electricity grid power is generated with a variety of resources, utilizing solar energy can help both home and business owners meet their environmental goals.
Green Energy Tax Incentives
Whether thermal or electric, the purchase of a solar air conditioning system may qualify for certain tax incentives. Depending on the certifications of your system, as well as your tax liability, you may be able to further reduce the upfront costs of your solar air conditioner with the federal solar tax credit or any available state tax exemptions.
Whenever there is a grid blackout or rate hike, independent thermal solar air conditioners are unaffected by utility power and will continue to operate. Likewise, battery-backed off-grid or hybrid solar energy systems can continue running air conditioners when utility power is unavailable or too expensive.
Guide To Solar Air Conditioning
If you are looking for ways to reduce utility bills and minimize your environmental impact, investing in a solar air conditioning system is a great way to cool your home and feel good while doing so. When picking the most suitable type of solar-powered air conditioner for your home, it is up to you to decide between a self-contained thermal solar AC unit or a whole-home solar power system to run new or existing air conditioning appliances.
Before taking the next step, we recommended speaking with a professional about your energy consumption, location details, and climate factors to see if a solar-powered air conditioner would work on your property. To explore whether or not solar energy can help reduce your air conditioning bills, feel free to use our free Solar Design and Savings Estimate tool to see how much you can save by going solar.