An energy-efficient A/C can help you shave a good chunk off your electricity bill or save on inverter and battery capacity if you’re running solar.

For most people, we recommend using a mini-split if the budget allows because it’s the most cost-efficient solution for the long term. But not all mini-splits are created equal. Plus, you should consider some specific aspects if you use solar to power your A/Cs.

Here’s what the glossy marketing brochures and fancy websites don’t tell ya.

Beware of dated content

Mini-split design and technology have evolved quite a bit over the last few years. While you should research the products and read customer reviews, take content that's over a year old with a grain of salt.

Consider long-term serviceability

Refrigerants for mini-splits have changed from CFC (which destroys the ozone) to hydrocarbons. While you can still buy older units with CFC, you may have trouble getting the refrigerant in the future.

Check the energy efficiency ratings

The higher the SEER/CEER score, the more energy-efficient an A/C unit is. If you’re on solar, using one with a high SEER rating at night helps you save on battery capacity (=$$$). However, because the condition in Caliente gets extreme (heat, low humidity, thinner air), an A/C’s performance may deviate from the rating.

Save battery cost with two units

Let’s say you have a 1,000 sq. ft. house. You could buy one 12k BTU mini-split. But in reality, you rarely have to cool every room 24/7. For example, you don’t need to frost up your kitchen window at night to keep your bedroom cool—especially if you’re on solar because you’ll need more battery capacity to power a big unit at night.

You may buy two units—a smaller (say, 9k BTU) with a high SEER rating (e.g., ~25) for the bedroom to use at night and a larger, cheaper one (i.e., lower SEER rating) for the rest of the house to run during the day when the sun is out since solar power is abundant.

Prepare for the “sh!t breaks” moments

Redundancy is good for resiliency. Having two units gives you redundancy, but we can take it a step further for solar folks. If you daisy-chain two 110V inverters to handle 220V appliances instead of having a split phase inverter (i.e., it can handle 110V and 220V), you should at least buy one 110V unit to avoid having no A/C if one inverter breaks.

Consider a reversible unit

Since we have abundant solar on most winter days, these units can use the excess solar capacity to produce heat to lower your heating costs substantially, making your solar system work harder so that you can make your money back sooner!

Bonus Tip: How to save thousands of dollars on battery capacity

Appliances that move heat (e.g., A/C, heater, boiler, kettle, oven) typically use more power. We recommend our off-grid solar clients make small shifts and use these appliances mostly during the day.

Why? During the day, solar is abundant and goes directly into powering appliances without requiring battery storage capacity. On the other hand, you’ll need to buy more batteries to store power and run them at night.

All it takes to save a pretty penny on batteries is installing a low-cost widget or flipping a few switches. Here are some examples:

Use a timer so the boiler only turns on during the day. The hot water will stay warm for nighttime use.
Put Starlink (which costs up to $50 in electricity per month!) to sleep at night with a couple of taps on the app.
Blast the A/C during the day in your bedroom, and it will stay cool during the night with a fan or two without running the A/C all night.
Set a timer to turn on your well pump during the day to fill a gravity-fed water tank.

What To Consider When Choosing a Mini-Split Air Conditioner