Window Units Vs. Central Air: Which Is More Efficient?

Window Units vs Central Air

We’re in the midst of a sweltering and humid Chicago summer, which inevitably causes air conditioning to become a major topic of conversation.

Often, the technicians at J. Blanton Plumbing are asked a surprisingly simple question with a surprisingly complicated answer: “Is it better to use a window unit, or to have central air?”

This discussion has gone on in some form or the other for years now, with each side – pro-window and pro-central – claiming that their solution is greener, cheaper, and better overall. The thing is? They’re both sort of right!

When it comes to energy efficiency and cost, it’s tough to declare a clear winner between central air conditioner systems and window units. Much of it comes down to the behaviors of the individuals using the air conditioning – such as the size of their home, or their personal comfort needs.

For proof, let’s break down a few different scenarios, and see how these two different air conditioning methods stack up:

For Conserving Energy

When considering the benefits of one air conditioning system over the other, one of the factors that immediately comes to mind is energy efficiency. It’s hard to overstate how important of an issue this can be – particularly when you consider that nearly 15 percent of the energy use of the average home comes from air conditioning.

It makes sense that smaller, simpler window units would use less power than centralized air systems, but the answer isn’t actually that simple. You see, central air conditioner units and window units are actually standardized and measured in two different ways.

As Slate explains in a handy guide for consumers, both types of units are EER, or energy efficiency ratio, certified. This ratio is a measure of “the unit's energy consumption while cooling a prescribed volume of 95-degree air over the course of an hour;” in order to achieve Energy Star certification for this metric, central A/C units need to score a minimum of 12, while window units need only reach a minimum between 9.4 and 10.7, depending on the size of the model.

So that’s a point for central air. Another check in its favor is that a central A/C needs to be SEER certified, as well, while window units do not; SEER refers to the system’s “seasonal energy efficiency ratio,” which considers energy use given a variety of environmental factors, including temperatures and humidity levels. This is important, particularly when you consider that A/C is not just for lowering temperatures, but also…

For Treating Humidity

Perhaps even more than high temperatures, high levels of humidity in a room can make working, sleeping, or even watching TV feel downright unbearable.

When it comes to fighting back against humidity, central A/C takes the win over window units. Part of the reason why comes down to that SEER rating. You see, window units typically only work at one or two speeds, cooling a small volume of air very effectively; you feel cooler because that air has been chilled to a very cold level. However, when a system can work at variable speeds at a higher volume, it is able process a more significant amount of air, resulting in greater dehumidification.

Ultimately, this helps because you can run your central A/C at a higher temperature but feel just as comfortable as you would with a window unit, thanks to the system’s ability to process humidity more effectively.

It should be noted that there are a few other humidity factors working against window units, too: For one thing, they’re harder to seal up or insulate, causing humid air to enter your home more easily. For another, they tend to sweat themselves, introducing even more moisture into your living area.

For Smaller Living Spaces

With all of this being said, we shouldn’t knock window units too hard. They serve a very useful function – namely, cooling smaller areas very quickly and effectively. If you live in a small apartment or don’t mind only having A/C in one part of your home, window units can offer a lot of power for the right price.

It’s also important to realize that homes and apartment buildings that aren’t equipped for modern HVAC can be costly and time-consuming to update, so some homeowners may have little choice but to use a window unit.

And they certainly offer some advantages which we didn’t touch on earlier. Specifically? Central air systems offer the potential for duct losses as air is forced from place to place; if your ducts have holes or other imperfections, this can end up wasting a ton of energy (and money) every year. It can also be easier to prevent overuse with window units; it’s easy to turn them on and off when you leave the house, but it can be harder to remember to shut off a central air system. And to automate a centralized A/C, you may need to upgrade to a smart thermostat – which takes time and effort in and of itself.

So that’s the low-down on window units and central air! Have any more questions? Looking for HVAC service or a free estimate for your Chicagoland home today? Don’t hesitate to drop J. Blanton Plumbing a line! Our experienced team is always here and ready to help!