Della Optima TP Series Mini Air Conditioner Review: Cheap, smart, and (mostly) reliable.

Ductless mini split air conditioners Its popularity has risen dramatically in recent years. One study now estimates their domestic market share at more than 40 percent compared to large-scale HVAC units, and smaller systems are more popular in Asia and Europe than in the United States.

Microsplits make a compelling climate control solution for a number of reasons. They are much smaller and easier to install than HVAC systems, they are much less expensive, and they are quiet. Many are sold in department stores and online, and enterprising DIYers can certainly install one without professional help, provided they have the required electrical connections. (Some mini-breaks operate at 115 volts, but others require 220-volt wiring, which probably means calling an electrician.) They’re also increasingly equipped with smart features like mobile app support, tricks you can’t do on HVAC units without a fancy thermostat.

Photo: Chris Noll

Bring the positives

Della invited me to test the Optima 048-TP-12K1V-23S-IN mini, which offers 12,000 BTUs of cooling and 12,400 BTUs of heating capacity. Maximum power draw is 960 watts from a 115 volt circuit, and is estimated to cover 550 square feet, or one small room. The manufacturer offered to cover the cost of professional installation, and I was eager to get professional installation help. A fairly small model splitter was installed in my house when we bought the place, and it was clearly picked up from Costco and set up by the owners themselves. The unit died within two years of us moving in, likely due to installation errors, according to the professionals who removed it.

ScreenshotDella+ app via Chris Null

Like most mini-splits, Della’s product arrived in three boxes, one for each essential component: the indoor air handler (the part you see on the wall inside), the compressor (the larger component that lives outside and circulates the refrigerant), and the duct that connects the two (including the refrigerant lines, drain lines, and electrical wiring). Inside the house, the air handler is mounted on a metal stand that is also included. The template in the box guides installers where to attach the bracket to the wall and where to drill the duct hole.

While the Della Optima costs just $921 (with a coupon on Amazon), a professional installation will save you much more on hardware. A local provider here in Austin offered $3,600 for the work.

On installation day, a two-man crew spent about five hours removing the old mini-split and installing the new one, a process that was pretty standard except for the need to drill a new conduit hole, since the hole for the old unit was in a slightly different location.