Unless you’ve been under a rock over the last few years, the ductless mini-split system is in full invasion mode. More than likely you’ve installed a few yourself already. These super-efficient and highly practical systems have been heating and cooling spaces internationally for decades, but the U.S. market is finally starting to expand – and somewhat dramatically, in fact. According to leading statistics over 1.5 M units will be installed this year and the number is growing at about 15% a year. As a contractor, that’s thinking about this business, there’s nothing more to wait for. It’s already here.
The system is referred to in many ways. A ductless split, a mini split, a multi-split, duct-free system, ductless or a variable refrigerant flow (VRF) heat pump system. Regardless of the name they all tend to have similar functionality and putpose. Spot cooling without duct work.
Whatever you call it, it’s a lot like a standard air-source heat pump: there’s an outdoor condenser unit and an indoor evaporator/air handler unit. The main difference is that the indoor unit is placed in the single room or zone that it serves; it doesn’t rely on ductwork to deliver conditioned air. Without ductwork (where 30% of a system’s cooling/heating power can be lost) it’s more efficient than a central air system. And because the compressor is distanced from the air handler, operation is far quieter than the PTACs found in motel and dorm rooms.
Ductless mini-splits are ideal for retrofitting older homes with baseboard heating and window air conditioners. They’re great for room additions when it is inefficient or expensive to extend existing ductwork. And they’re godsends for hard-to heat spaces like attics, sunrooms and basements. This basically refers to millions and millions of residences.
Also used in light commercial HVAC applications (typically less than 10 tons), these systems can be installed and operated for substantially less than traditional ducted HVAC systems. But they are essentially the same system with the same physics and therefore very similar maintenance needs.
And therein lies the rub.
Mini-splits should be maintained on a similar calendar as central HVAC systems. Twice yearly service helps maintain system efficiency and indoor air quality. Among other things, here are the basic steps to maintaining a ductless mini-split.
- It goes (almost) without saying, turn the unit off and disconnect power before cleaning.
- Clean or replace filters. Additionally, encourage your customers to inspect their filters monthly or more often and clean or replace them as needed. If you are cleaning, use a HEPA vac or follow directions from the manufacturer for a wet cleaning,.
- Remove and clean the IAQ components. These vary depending on manufacturer and model. For instance, some models use negative ion technology to further purify air.
- Clean the evaporator coils. You’re dealing with a unit in a finished living space, so it’s especially important not to overwhelm the condensate line. The easiest solution we know of is from a company called BBJ Environmental. They offer a ready-to-use cleaning kit. It includes an aerosol called Micro Coil Clean, available this April. It’s an aerosol spray that clings to coils and cleans them without overwhelming the unit’s drainage capacity. Follow with a light rinse, and your coil cleaning is done. Be careful to check that condensate lines are not blocked prior to rinsing.
- For best results, once coils are clean apply a fungistat and bacteriostat to keep dangerous biological growth at bay. Mold Control, an EPA registered mold, mildew and odor inhibitor battles odor-causing organisms for up to one year, and it’s safe for use inhabited areas.
- Inspect and clean the outdoor condensing unit as you would for a central air conditioning system. Inspect the refrigerant lines and insulation wraps.
- Make sure the unit is solidly mounted on its base and that the fan wheel and blower assembly are balanced. Remove excess debris from the outside of the unit, then spray the coils clean. It’s more effective to clean coils from the inside out. Check out our Condenser Needle that turns a standard water hose into a specialized coil cleaning machine.
Mini split, ductless units whatever you call them are here to stay and offer a great way to increase maintenance revenue.
What do you think? Have you installed or serviced mini-splits, and do you see an increase in your area? We’d love to hear from you.