It’s very simple. With ducted or ductless mini-split systems, you only pay for and use as much or as little heating and cooling as you need at any given time in any given room?How does it work?
Technically, it has everything to do with something called an inverter-driven scroll compressor that is inside the outdoor unit (a.k.a. condenser, compressor).
Practically, it’s like a pay-as-you-go cell phone. You only pay for the minutes you use every month. Period. No more, no less. Talk as much or as little as you want, wherever and whenever you want, and only pay for that time.
Let’s Break it Down?
The high-tech modulating compressor thing-y (inverter-driven scroll compressor) in the guts of the outdoor equipment adjusts the amount of electricity and refrigerant (the hot and cold liquid that is used to condition the house) to deliver exactly the amount of heating and cooling needed at any given time in any given room. No more, no less. So, when you only need a little bit in your Master Bedroom at 10 pm, it will power up just enough to give you that little bit.
That hot and cold refrigerant is then sent from that compressor to small air handlers (a.k.a. indoor fan coils) that are strategically placed through with HVAC Design inside and throughout the house to deliver exactly the amount of hot and cold air that each room needs. What determines those needs is the dedicated controller (a.k.a. thermostat) in that room that the owner sets to maintain a certain temperature.
So, instead of a central air handler delivering a LOT of air, it’s like a bunch of tiny air handlers delivering small amounts of air wherever and whenever it’s needed. Again, no more, no less.
The air handlers can have ductwork and be concealed in a ceiling, attic or floor cavity to serve up to three or four rooms. OR, they can deliver the air without ducts with wall-mounted or recessed (in wall/ceiling) ductless units. Either way, these air handlers deliver air with a fan that is generally quieter than a human whisper.
They just make sense
Everything about these systems are variable, efficient, quiet, great for good indoor air quality, and extremely effective. What more would you want in an HVAC system?
Contrary to what you might be thinking, or know, these systems can and DO work in all climate zones. They’ve been used in Europe, Asia, Canada, and South America for decades, and have proven themselves to be reliable. HVAC companies rave about how few call backs and/or repairs that there are with these systems.
Generally, they can be as much as 30%-50% more efficient than conventional systems. Though they’re rated efficiency (at full capacity) ranges from 14 to 20 SEER, they rarely ever run at full capacity. This makes their real world efficiency seem higher. In fact, an alternate efficiency rating, called Integrated Energy Efficiency Ratio (IEER), is used to more accurately factor the variability of the equipment in to the rating.
A final technical note: Conventional outdoor units (heat pump or air conditioner) draw about 25-40 amps of electricity when in use.
The maximum amp draw on mostresidential mini-split outdoor units is 18-20 amps. Again, because of the variability, and the fact that the system is never on full capacity, the amp draw is usually much lower…maybe around 10 amps or lower….
To the left is a graph showing just one of the many ways that the mini-split systems are better at minimizing energy use.
If you need more information about these systems, or are considering them for your new or existing home, don’t hesitate to contact us. We have experience with these and many other types of systems, and can design a system that suites your needs…precisely.
written by Chris Laumer-Giddens, Architect, HVAC Designer, HERS Rater, Building Science Professional, LEED AP