Despite only running for a few months each year, air conditioners use about 6 percent of all the electricity produced in the US in a year. They also cost homeowners $29 billion in energy bills alone.
It is not surprising then, to find that the government has been looking for ways to reduce energy costs. One of the ways they have been doing that is by supporting solar power innovation.
While solar power as a means of going off-grid is becoming more popular, our focus in this article is Solar Powered Air Conditioner.
We will be exploring what they are, how they cut electricity bills, and why they are a worthwhile investment for many homeowners.
What is a solar-powered AC?
As alluded to earlier, a solar-powered air conditioner is different from a residential solar-powered system, which also supplies electricity to the air conditioners.
A solar-powered AC has its own dedicated solar generating system comprising solar panels and a few other optional accessories. In other words, your house may still obtain electricity from the local grid, while the air conditioner alone runs on solar.
The most common system absorbs solar energy via panels. Each setup comes with between two and six panels.
The power generated is then transmitted to an inverter, which converts the direct current to alternating current. Any excess energy generated from the solar panel can be stored in batteries.
However, not all solar air conditioners work the same way. To understand them better and to know which one suits your lifestyle, you must understand the broad groups and subdivisions of solar air conditioners.
There are two broad groups of solar ACs.
Solar photovoltaic air conditioners
This type of solar air conditioner uses a solar photovoltaic (PV) system. It comes with a solar panel and may also use an inverter and batteries.
Solar PV air conditioners work like regular mini split air conditioners in that the indoor unit looks and operates the same way.
Solar thermal air conditioners
A solar thermal air conditioner does not function like a typical air conditioner. It uses a process of evaporation and condensation to cool the home. Solar collectors heat water or any other cooling liquid, which evaporate as they pass through the system.
Solar PV air conditioners are more effective and are usually what people refer to when speaking about solar ACs.
Different Types of Solar PV Air Conditioners
As solar-powered air conditioners have grown in popularity, their technology is constantly changing to meet different needs. There are three main types of solar-powered ACs in mass production:
DC powered solar air conditioners
Solar panels generate direct current (DC) power. However, typical air conditioners (and every other electrical device in your house) run on alternating current (AC).
As the name implies, DC-powered solar air conditioners can use the DC electricity directly from the solar panel. This is ideal for people who want to live off-grid. To store energy for use when the sun goes down, you would need to buy batteries, an inverter, and a solar charge controller.
This system’s major drawback is that it costs a lot more than AC-powered solar air conditioners when you buy the accessories.
AC-powered solar air conditioners.
Also known as inverter air conditioners, these run on AC power and need to be connected to the grid. This type of solar air conditioner also needs an inverter to convert the DC from the solar panel to AC for the conditioning unit.
You can also use batteries to store excess power to use the units when there is no sunlight. One peculiar advantage of this type is that you can channel some of that stored energy in the batteries to power some of the lights in your home.
As a result, these are cheaper and more efficient for people who don’t want to live off-grid.
AC/DC Hybrid solar powered air conditioners
There’s nothing sweeter than being able to eat your cake and have it, and that’s what you get with the hybrid. Do you want to connect your air conditioners directly to the panel? No problem!
Do you want to use the inverter? No problem! Want to live off-grid? No problem!
As great as this sounds, there is a downside, as there always is. Most of them don’t work with batteries, so you can’t use them at night unless you connect the air conditioner to the grid.
How Much Do Solar Air Conditioners Cost?
While solar panels are energy-saving, they are pretty expensive to set up, and the same is true for solar air conditioners.
The average price for a base unit is roughly $2,000 on its own and up to $5,000, including installation. However, it is possible to get up to a 26% discount on the total cost with the federal tax credit.
While this will not bring the price down to the same level as a regular affordable air conditioner, the reduction in your annual electricity bill can more than make up for the difference.
How Can a Solar-Powered Air Conditioner Cut Electricity Costs?
Air conditioning accounts for about 12% of the total energy costs for the average US household. In hotter regions, this goes up to about 27%. As the climate continues to change, this figure is expected to keep increasing.
Depending on the type of solar-powered air conditioner you use, you could cut your air conditioning electricity consumption down to zero. DC-powered systems can be taken off-grid completely, meaning you won’t spend anything on utility costs.
For an AC or hybrid system connected to the grid, you can still cut energy consumption by as much as 73%. Given that the average US home spends over $260 a year on air conditioning electricity costs, you could expect to save $190 or more each year.
Is a Solar-Powered Air Conditioner Worth It?
It is easy to answer ‘yes’ to this question, which would be very misleading because there are several factors to consider before making this assertion.
Of course, the answer is clear-cut for people who want to live off-grid. For this group of people, making a substantial initial investment is worth it because they don’t want any running electricity costs.
However, for everyone else, there are a few things to consider, the most important one being your location.
Though nearly 90% of American households have at least one air conditioner, their usage varies drastically across the country. As such, how much you would spend will depend on where you live.
In the temperate marine region, the average family spends about $60 a year on air-conditioning electricity costs. In the hot-humid region, however, this jumps up to $525.
Considering how much it costs to buy the system, it is not financially viable if you live in very cold or marine regions. But if you live in the mixed-humid or hot-humid regions, you could potentially get your money back in ten years or less.
The other thing to consider is the size of your home. The higher the British Thermal Units (BTU), the more it costs, and so it will take a lot longer to break even. That’s why some people chose to buy energy-efficient air conditioners to avoid the high purchasing costs.
Other things that will affect the cost are buying batteries, an inverter, or other expensive accessories.
Do I Need to Buy Batteries With a Solar Air Conditioner?
Not every type of solar air conditioner works with a battery, and the ones that can, don’t always require it to work.
The purpose of the battery is to store up extra solar power so that you can use the air conditioner when there is no sunlight. If you only run your air conditioner during the day, then you don’t need batteries.
Not buying batteries will save you anywhere from a couple of hundred dollars to a few thousand dollars, including installation.
However, this also means you won’t be able to connect the batteries to the grid on hot yet cloudy days.
If you are buying a solar air conditioner because you are concerned about the environment, buying batteries will maximize the power generated from your solar unit.
How Many Batteries Do I Need?
The number of batteries you buy depends on several factors, including the type of batteries, how much sunlight you get, and most importantly, how much backup power you want.
Batteries have different volts, with the most efficient and recommended one for solar air conditioners being 48V. However, many people also use 12V without complaint.
To find the number of 48V batteries you need, you would have to know the wattage of the ac, how many hours of daylight you get, and how long you want to use the batteries.
The easiest way would be to, of course, ask the manufacturer. Most solar panels are sold with an adequate number of batteries to power the system for 8 hours per day, which is the average.
A local dealer will also know how many hours of sunlight you get annually. With 211 clear days in a year, Phoenix, Arizona residents won’t need as many batteries as those in Portland, Oregon, who get 75 days max per year.
If you would like to confirm what your dealer is recommending, various sites have solar calculators.
How Many Solar Panels Do I Need?
Unlike batteries, solar panels are compulsory. The number of panels you need also depends on the wattage of the air conditioner and panels themselves.
To power a 1,000-watt air conditioner, for example, you would need four 250W solar panels.
Just like with batteries, the manufacturer will also supply the correct number of panels for your unit. Most solar air conditioners are sold in bundles based on the power you want, which may also include an inverter and a charge controller.
What Size of Solar Air Conditioner Do I Need for My Home?
Solar air conditioners, just like regular air conditioners, are sized according to British Thermal Units (BTU). The BTU is the amount of cooling power they generate, which determines the size of the space it can comfortably handle.
To know the size of the solar air conditioner you require, you first need to measure the space you will use it in. The guide below provides an easy reference.
The most popular solar air conditioner on the market currently sells 12,000 BTU ACs or higher. That is enough to cool a room between 450 sq ft and 550 sq ft.
However, it is worth noting that manufacturers often give different guidelines, and it’s not uncommon to find differences as much as 200 sq ft for the same BTU.
The reason behind this is that there are other factors to consider when calculating the correct size—for example, the number of people occupying the space. The general rule is to add 600 extra BTUs per person.
If the room gets a lot of direct sunlight, you would need to increase the capacity by at least 10 percent. If the room itself generates a lot of heat, like a kitchen, you need to increase the capacity by 4,000 BTU.
Therefore, for a single-occupant 250 sq ft bedroom, all you need is a 6,000 – 7,000 BTU system. A 250 sq ft kitchen, however, would require a 10,000 BTU air conditioner.
The Future of Solar Air Conditioners
As great as solar air conditioners are, the initial installation cost can be discouraging. Hence, one should know how to hire a qualified HVAC technician for quality work. However, the solar tax credit or the investment tax credit (ITC) offers a good discount for purchases made until 2022.
Related article: Homeowners Guide To Hiring An HVAC Technician
After that, the discount for residential units will drop to 22 percent in 2023 and disappear in 2024.
Commercial users, on the other hand, will still enjoy a 10% discount in 2024. The decline in the ITC is intended to coincide with the reduction in the cost of solar panels.
So, while we can continue to expect electricity prices to increase and the strain of climate change to affect annual electricity budgets, the cost of solar air conditioners should continue to decline.
New types of solar air conditioners are also being developed to improve efficiency and longevity. While solar panels used to have a shelf-life of no more than five years, you can now find units that last for up to twenty years.
The lifespan of batteries has also improved significantly.
The development of central solar air conditioners is also in the pipeline. These are currently unrealistic alternatives as the price is unbearable for most. However, with government funding and a ton of research, we can expect a good option in a few years.
Solar air conditioners are currently the best way to drastically cut down on your annual air conditioning electricity bill without compromising your health and comfort. They deliver good long-term value and are perfect for off-grid living.
The downside is their hefty installation cost. While you will save a few hundred dollars a year, it will take a long time to recoup your investment.
Where you live and the number of clear days you have in the year are the major determinants of how cost-effective a solar air conditioning unit is.
However, there is a lot of research going into improving the technology, and we expect that soon enough, the installation cost will no longer be a factor. Until then, you can take advantage of the ITC and start cutting your electric bills now.