What is a Mini-Split or Ductless Unit?
Mini-Splits, commonly referred to as ductless units, are standalone heating and cooling devices that can be used to cover several different situations and scenarios. Most mini-split units will have an outdoor unit, which will appear to be slimmer in its nature, with refrigeration lines installed to an indoor “head” unit. Most mini splits are going to heat pumps, granting them the ability to create heating or cooling to a designated indoor space, or zone, within a building. These little boogers, albeit small in nature, are very intelligent and efficient devices that can pack a punch when needed for larger spaces to cover with conditioned air.
How does a mini-split work?
Mini-splits, more or less, kickstarted the variable-speed compressor/inverter-driven technology conversation. We now see all the main-line manufacturers of heating and cooling starting to introduce this level of tech into their equipment. These units have very low amperage draws to be able to turn on the compressor or even run the fan on the indoor side. They have the ability for the compressor to ramp up, so when there is a requirement for more conditioned air in a space, the unit is able to match that requirement. They are designed, like all variable-speed compressors, to never overconsume electricity granting homeowners very, very efficient values (SEER and HSPF).
Single-Zone vs. Multi-Zone
Mini-split applications can be vast due to their flexibility in their installation. Your most typical setup will be called a “single-zone,” – and all that means is that there will be one single outdoor unit and one single indoor unit. You will only be able to condition a single zone inside of the home or building in the case of commercial. This is by far going to be the most typical setup installed in all markets across the United States. Where we find ourselves installing it the most is going to be in for that suborn bedroom that we just don’t have the ability to manipulate the central HVAC system or its ductwork, when people have undergone some kind of expansion of their home. We cannot get the ductwork to cover the new square footage, for accessory buildings off someone’s home, three season rooms, and the homeowner wants FOUR seasons of coverage, and finally – the garage because no one wants to get in a cold car even when it’s been inside your home all night or that is your family’s primary gathering area.
The other option would be going with a multi-zone setup. Now we have the ability to do more than just that one space! We can do up to 9 different zones inside a single building. Now, we could cover the entirety of the actual third story (like we see in south Kansas City), attack an entire back half of a home that just gets beat down by the summer sun, condition the sunroom and the garage – I mean the list is pretty endless on what could be possible. If you have several suborn areas, a multi-zone mini split setup will be an option that can be explored when conventional methods aren’t going to be possible.
Heating Capability – Ultra/Hyper Heat vs. Standard Heat
Ok, now you want a mini split to ensure you are comfortable in that home office versus wiping beads of sweat off your face during Zoom meetings. But how is that same space during the wintertime? Frigid cold, or does the existing central HVAC system do a much better job at heating that upstairs bedroom? If you also want the unit to be able to heat the space, even during the most extreme circumstances, make sure you get a unit designed for an ultra or hyper heating capabilities, as referred to. These ultra heat units have the capacity to give you still 100% of their designed heating capability even when the temperatures are -15F ambient outdoor temperatures. Sure, these units typically are a little more costly, but, they are going also to have higher SEER and HSPF values associated with them thus, their operating costs are going to be lower – compared to a standard heating mini split system. Standard mini split systems, for the ones we install, are all rated down to at least -4F, where you will have 80% of its rated BTU output at that below-freezing temperature. A lot of times, we can use standard units as the solution to your issues of comfort, but, in the case this will be the primary heat source for the zone, we will want to investigate an ultra heating unit. Hence, you are completely satisfied with your purchase of equipment.
Is my only option that ugly box high up on the wall?
We know, someone in the home doesn’t like the look of that white box that pushes the conditioned air out of it in that particular space. Well, the beauty is you are not confined to one “look”. There are several different head options, or indoor looks, that a homeowner can choose from. We have some that are small but sit on the floor, we can put them directly on the ceiling, or we can punch through a ceiling and put in a whole ceiling cassette, they have some that can be adapted to ductwork (in the case we can put it in the attic and get ductwork to a few locations), etc. All of the different indoor head units can be utilized for one-to-one, single-zone setups or they can be mixed and matched all over the place when we are exploring a multi-zone setup.
Advanced Set Ups
We think it’s important to mention that mini-splits are still seemingly advancing well beyond their years. We now have products on the market that can have a mini split outdoor unit with multiple ports on the unit. These advanced systems can be tied to your existing central HVAC system, granting you the benefits of a very advanced variable capacity heat pump system, AND have several areas that can have zonal coverage of conditioned air – all from ONE OUTDOOR UNIT! So it’s the best of both worlds – one outdoor unit that can cover most of the home’s needs and still really crush those comfort issues you are having in other spots of the home.
Other things to consider when shopping for mini splits
Ok, we know mini splits sound awesome, but there are still a lot of things that need to be discussed outside of which type of system is going to make the most sense for your project to meet your goals.
All of these units are going to need high-voltage wires ran to them, and the complexity of the situation is going to influence the final installed price. Some of them will require a very high gauge of wire, and some of them not so much. Sometimes conduit will need to run all the way around the house to the location where the electrical disconnect will be added. Sometimes the service panel is 5’ Ft from the outdoor unit location. Once again, it’s just case by case and it takes a professional to be able to get it all right and done by code guidelines.
All of these units will create water, and that water has to be handled appropriately – this is why we were prefer to install these units on an exterior wall of a building so the water can be drained directly out the back of the unit and channeled to an appropriate location outside. In the case we don’t have the ability to use an exterior wall for the indoor head unit, now we have to introduce a condensation pump so the water can be pumped to an exterior location. These pumps are going to require annual maintenance as they are very finicky due to the amount of dirt and debris that will build up inside the pump and associated condensation lines.
A lot of times, where the refrigeration lines are going to travel to get to the indoor head is going to be the same exact route the condensation drain would follow. But refrigeration lines are not as forgiving for getting into tight spaces or for making it really long distances. Additionally, most homeowners are going to elect for line hide (more or less a guttering-like a system that encompasses the refrigeration lines that can be painted to match the home), which is going to carry its own complexity to influence the final price.
If you are an individual that wants this unit to be a primary heat source for you, make sure you are working with a contractor that has the capability to size the units appropriately for heating. Your cooling load, typically, is going to be less than your heating load, so a larger unit may be required. Also, when looking at multizone applications, the contractor should be able to refer to engineering submittal data to know how much each indoor head unit is going to produce. An example would be the case of a 24K BTU outdoor unit. If the contractor knows he/she can put two (2) 12K BTU heads, neither head will be able to achieve exactly 12K BTUs – both their maximum outputs will be diminished. Not to say for that example, it wouldn’t cover the needs, but you need to be sure that the professional knows it will work and has the supplied proof.
What warranties are available with mini splits?
For us, we are able to offer the homeowner that purchases an installed mini split from us a 10-year parts warranty to further protect their investment. For mini splits, we cannot stress this enough, get the unit professionally cleaned once a year. These devices are very susceptible to becoming very dirty on the indoor side, and it’s not an easy process, even for those that are the most talented, to be able to clean them well to ensure they get their designed life expectancy out of the system.