What are the key differences between different HVAC systems?
Almost everyone knows what an air conditioner is. “AC” has been around for decades, and—for many of us—it’s hard to imagine getting through Albuquerque’s summers without it. Yet, terms like “heat pump,” “ductless,” and “mini-split” are probably a little less familiar to you.
In this article, we’ll break down the key differences between air conditioners and heat pumps, and then get into the differences between heat pumps and ductless HVAC. By the time you’re done reading, you’ll have a much better understanding about what each of these systems is and why we might recommend one over the other for your home.
What are the differences between air conditioners and heat pumps?
Just from the names alone, you might be inclined to think that these two things are opposites—after all, air conditioners cool and the word “heat” seems to imply something very different. In actuality, air conditioners and heat pumps have a lot in common, with one key difference between the two.
Here’s a simple way to think about it. Air conditioners can only run one direction: using a process known as refrigeration, they transport heat energy found inside your home and release it outside, lowering the temperature inside. As you might have guessed from the name, your refrigerator uses this same basic process, just on a much different scale. Heat pumps also use that same refrigeration process, but they can switch gears and run in two directions. This allows them to heat the home in the winter in addition to cooling it during the summer.
To do this, heat pumps draw heat energy from outside air, just like the air conditioner pulls heat energy from indoor air. Even on relatively cold winter nights, there’s ambient heat energy in the air. The heat pump absorbs this energy and then releases it inside the home, raising the indoor temperature. Thanks to this ability to switch-hit, heat pumps serve as a year-round HVAC system.
From the outside, a heat pump looks a lot like an air conditioner. Both require an outdoor condenser unit, which is typically located outside the home or on the roof. Both force cooled air through ductwork in the home and out of vents and registers, cooling down temperatures inside. And both are controlled through the thermostat. Both systems look nearly identical, and it’s for this reason that many homeowners casually refer to their heat pump as an “air conditioner.”
In another way, it could be said that the true difference between a heat pump and an AC unit is that owning a heat pump means you don’t need a furnace or other heater in your home.
What are the differences between heat pumps and ductless mini-splits?
It’s understandable that many people get these two types of systems confused—after all, they’re both alternatives to traditional air conditioners and have both become increasingly popular over the past decade or so. Yet, the two terms are not synonymous. The easiest way to think about them is this: all ductless mini-splits are heat pumps, but not all heat pumps are ductless mini-splits.
How do ductless mini-split systems work?
At a fundamental level, both systems use the same heat exchange process, as we described in the section above, to cool your home in the summer and heat it in the winter. It’s this ability to “pump” heat energy from one area to another that allows these systems to make your home comfortable. Yet, their setup is remarkably different. Traditional heat pumps make use of ducts and registers, just like an air conditioner or furnace. Ductless mini-splits—as their name probably gives away—don’t need ducts to operate efficiently.
Instead, ductless setups feature individual units in the major rooms of your home. These wall-mounted blower systems are all connected to an outdoor condenser—that’s where the “mini-split” part of the name comes from, since the condenser is “splitting” out to multiple indoor units. Just like a heat pump, this setup is capable of reversing direction in the winter, so that your home can be heated to just the right temperature.
If you hear someone talking about a “heat pump,” you’re probably right to assume that they’re referring to a forced-air, duct-based system. Heat pumps are an increasingly popular replacement for air conditioners in relatively mild winter climates, since they’re capable of both cooling and heating homes.
Watch: Installing a ductless mini-split
To get a better idea of what a ductless mini-split is and how it works, check out this video from the team at This Old House:
Other types of AC
If you search online for “air conditioners,” you’re bound to see both portable (sometimes called “standalone”) and window air conditioners. Most people in the HVAC industry don’t consider these to be true air conditioners, since they’re not whole-home systems and therefore serve a much different purpose than a forced-air air conditioner, heat pump, or ductless mini-split.
Both portable and window-mounted systems are relatively inexpensive, but have their limits and drawbacks. First, they’re not nearly as effective as a whole-home system. At best, they can cool a small room of your home—not nearly enough to make your home as a whole feel comfortable. Because the compressor is right in the system, they’re often noisy and—in the case of window-mounted systems—require one of your windows to be open at all times, compromising both your privacy and your home’s energy-efficiency.
A portable or window-mounted AC unit is better than nothing. In a pinch, either type of system can provide some relief. But, they’re never a true alternative for a whole-home air conditioner or heat pump, in the same way that an electric scooter cannot fully serve as the replacement for a family minivan.
Find the right type of cooling system for your home
Here at Wagner, we install all three types of cooling systems: forced-air air conditioners, heat pumps and ductless mini-splits. Our focus is on finding the right system for your home, based on its unique needs. There are some homes—such as historic properties, mother-in-law suites, and more—where a ductless mini-split fits perfectly. There are others that will get more mileage out of a traditional heat pump. Either way, our technicians will help you work through which AC unit is right for your home.