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Does Solar Air-Conditioning Make Sense?

May 15, 2017

Sunlight is a free and limitless source of energy. Solar energy produces no air pollution or hazardous waste. Solar-powered air-conditioning makes sense since it’s typically hottest when the sun is shining… and that’s when air-conditioning use is most in demand! Switching to solar could reduce your heating and cooling costs by half.

Solar air conditioning refers to any cooling system that uses solar power, which is typically supplied by photo-voltaic (PV) cells, engineered into solar panels. Solar has been around a long time, and many products are now in the 4th (or later) generation.  They are available for both residential and commercial applications. Here are just a few of the types of solar air-conditioners to choose from:


Off-Grid: Units that run 100% on solar power run on DC power. These are referred to as “off-grid” because they do not require power from the utility company, e.g., they don’t have to be plugged in. An example of this type are solar-powered window air-conditioning units. They operate on DC power only (from solar panels), and use external battery backup (usually good for about 8 hours operation). The battery is so that the unit will continue to function even when the sun is not shining, like at night. A window unit is expensive – $2-3,000 – but it can be used totally “off-grid” which means there are no energy costs during operation.

Hybrid Systems: Hybrid systems use solar power when available and supplement that with regular electricity (AC power) as needed, and do not require batteries. During the day, solar power provides 90% of the system’s electricity. At night, it switches over to regular grid power. Examples of this type include room-sized/area-sized units, like a mini-split, or whole-house units, like a hybrid heat pump. One advantage of hybrid systems is that they can also provide heat during the winter.  [Check out our previous posts on mini-splits: What You Need to Know About Mini-Splits, Cooling an Add-on Space, Saving Energy and Improving Comfort] .

Solar-Ready Systems: These are systems made like “traditional” central air-conditioning units, in that they use 220V AC power, but some of the electricity feeding it can be obtained from solar panels. The Lennox SunSource Home System is one such system. The more solar panels you add (from 1 to 16) the more money you can save in energy costs. You can start small and expand over time, adding other appliances, such as the home’s water heater, making a total home energy system.


There are many misconceptions when it comes to solar. For example:

  • Solar panels do not have to be in full sun to operate. They also operate in partial sun or shade.
  • Solar panels do not have to go on the roof. They can go just beside the outdoor unit.
  • Hybrid solar units are not bigger than normal air conditioners. In fact, because of their more efficient design, the compressor can actually be smaller than in a traditional unit. And a smaller compressor consumes less electricity!
  • Solar units are actually more efficient the hotter it gets outside, because more energy is collected in the thermal hybrid collector.
  • Installation costs are comparable to that of conventional units, and prices of solar units have come way down.
  • Using solar does not compromise comfort in any way, and the units do not look awkward or obtrusive. In fact, according to the U.S. Department of Energy, National Renewable Energy Laboratory, a solar-powered unit will increase your home’s value substantially and can help your home sell faster!

Advantages are Environmental, Economic, and Comfort

There are numerous advantages to solar.

  • Solar air-conditioners are quieter than traditional units. The ones that run on DC power – such as the hybrid mini-splits – are so quiet that you can walk right up to it and not even know it’s on.
  • Solar units last a long time. Most have at least a 10-year warranty (with some parts having more), and some manufacturers have performance warranties of up to 25 years.
  • Most hybrid or solar-ready units offer seasonal energy efficiency ratios or SEER values in the 21-26 range, as compared with traditional HVAC units which have SEER values around 14.  [See our post: What’s your SEER? Does it Matter?]
  • Solar units are typically Energy Star certified, very efficient, and prevent greenhouse gas emissions.  Plus, they use the new R-410A refrigerant, which is more environmentally friendly.

ROI: Fast Payback

The payback period for a complete system (solar-powered heat and air) is about 2-5 years. With tax credits, the cost of installation can be paid for within the first 6 months of operation! Plus, many vendors offer interest-free financing. The federal solar tax credit, also known as the investment tax credit (ITC), allows you to deduct 30% of the cost of installing a solar energy system from your federal taxes. The ITC applies to both residential and commercial systems, and there is no cap on its value. The 30% tax cut was extended through 2019, and then gradually decreases each year from 2020 through 2022, where it levels off at 10%. What’s more, a solar-powered home can actually earn money: if your house is not using all the power it is generating, you may be able to sell excess power generated back to the utility company!

It is easy to see that if you get tax breaks for installation, the system saves you half on your energy bills and you can sell energy back (making money from the system throughout its lifetime), that a 2-5 year payback can actually be quite realistic.

**Interstate AC Service is not a reseller or installer of solar panels.

Count on Interstate AC Service to help keep you up-to-date on the latest technologies. If you live in the Nashville & surrounding area, know you can rely on us for all your heating and air-conditioning needs.