Split AC Review: Cheap, Smart, and (Mostly) Reliable

Mini-splits make a compelling climate control solution for a number of reasons.

They are much smaller and easier to install than HVAC systems, they’re far less expensive, and they’re quiet.

Many are sold at big-box stores and online, and enterprising DIYers can certainly install one without professional help, provided they have the required electrical connections.

(Some mini-splits operate on 115 volts, but others require 220-volt wiring, which will likely mean a call to an electrician.) They’re also increasingly outfitted with smart features like mobile app support, tricks that you can’t do on HVAC units without a fancy thermostat.

While the Della Optima costs only $921 (with coupon on Amazon), professional installation will run you considerably more than the hardware.

A local provider here in Austin quoted $3,600 for the work.

On the day of installation, a crew of two spent about five hours removing the old mini-split and installing the new one, a process that was largely unremarkable except for the need to drill a new conduit hole, since the old unit's hole was in a slightly different spot.

By late that afternoon, my Della Optima was blowing appropriately chilled or hot air as requested, and I was able to follow the included instruction manual to quickly set up the Della+ mobile app on my iPhone.

The Optima offers two ways to control it: a remote control and the mobile app.

The remote is surprisingly complex, with 15 different buttons and a busy LCD.

You may not need every one of the dizzying array of operational modes here—including turbo, quiet, and eco modes—along with an on/off timer and a self-cleaning mode.

A vicinity sensor lets you set the unit to use the remote control as a temperature sensor (instead of the one built into the air handler), so you can tune the temperature based on another part of the room rather than where the air handler is installed.

The remote also gives you control over directional air flow features, with both vertical and horizontal vanes oscillating to your specifications.

The horizontal vanes did not, however, seem to move during my testing, but Della assured me they were just difficult to observe.

Note that the remote is infrared: If you enter commands without aiming it at the air handler, the remote’s LCD will update, but the command won’t actually be accepted.

If the handler doesn’t beep after a button is pressed, that means the command has not been received and won’t be executed.

Note that the unit was also quite quiet—at a distance of 3 feet from the air handler, I measured 50 decibels on the highest (turbo) mode and 40 dB on the quietest (night) mode.

Ambient sound was 30 dB.

Nearly all of the remote’s features are available in the app, which is considerably more intuitive thanks to more explanatory icons and a simpler interface.

In addition to changing operational mode on demand, the app has a robust scheduling system that lets you configure cooling or heat based on time and day of the week.

The app also works over Wi-Fi (after bridging the Optima to your 2.4-GHz network), so you can control it from anywhere and without the line-of-sight the remote needs for your commands to go into effect.

The unit also supports Alexa and Google Assistant, and I was able to quickly set it up with Alexa and perform basic functions via voice commands.

Missing, however, is a logging system that keeps a running history of operations, which I felt could be useful.

One of the additional sells with the Optima was a geofencing mode that can turn the unit on or off based on your location.

This isn’t unique to Della, but it’s far from ubiquitous—and you’re more likely to find this feature on HVAC smart thermostats than mini-splits.

The bad news: I could never get it to work, and after 10 solid days of troubleshooting with Della tech support, I still couldn’t get it to function.

Actions set to change modes when leaving or arriving simply didn’t kick in—not even once.

If you want more reliable geofencing features, you might need to look at better-known (and likely more expensive) brands.

Despite a few rough edges, it’s tough to argue with the cost of this unit, which at under $1,000 is offered at a solid price—though bargain-basement import brands can be had for even less.

Della provides a lifetime warranty if installation was performed by a licensed HVAC technician or done with its rental installation kit, but note you’ll need to provide a significant amount of documentation of this during your registration, including a copy of the invoice, your HVAC installer’s license number, and photos of the install, in order to be eligible for the warranty.

Della’s Optima isn’t perfect, but the price is right and the main function of the device—keeping the room properly cooled and heated—is working great, even if I do have to do most of the turning on and turning off manually.