What efficiency values are available?
First and foremost, we like to start to educate people on their air conditioner options by understanding the SEER values associated with air conditioners (and heat pumps, we will get there). SEER stands for Seasonal Energy Efficiency Ratio, and it’s best to understand this much like miles per gallon in a car; the higher the SEER value, the less energy the air conditioner utilizes to create a cooling load for the home. It’s important to remember that SEER values are determined using averages of how the unit performs across a year. Also, building envelope factors need to be considered, such as windows, insulation, size of the home, how the ductwork was designed, the amount of air leakage on the ductwork and overall house, etc. Simply put, the highest efficiency unit can be installed in a home, but if the house leaks conditioned air to a great degree, the savings may never be actualized.
Currently, we are in the middle of a shift in how we describe SEER for newly installed air conditioners. We can still install the 2022 government minimum SEER values of 13 BUT, the manufacturers can no longer produce that unit – so when we are out of those units, they no longer will be in circulation. Now, consumers will start to see SEER values described by their M1 ratings or SEER2 as it is more commonly known. We believe this shift needed to happen because the manufacturers got away with the idea that a unit could be advertised as a specific SEER value but when designed in real-life situations, it was never able to achieve the advertised efficiency value. SEER2 has shown to be more like real-life situations, being tested on ductwork that causes higher static pressure in lab settings (aka your ductwork isn’t perfect, and it causes back pressure on the blower thus, it takes more mechanical work to move air). Now, manufacturers produce the minimum efficiency value of the 14.2 SEER2 air conditioner. However, as expected by any for-profit manufacturer that has had to undergo many engineering changes, they have also increased the cost of air conditioners considerably.
Single Stage, Two-Stage, and Variable Speed/Variable Capacity Compressor Types – What’s the deal here?
Single Stage compressor types
The most popular compressor type installed in the United States is a single-stage compressor. This was the standard for many years and is the most common compressor type; thus, the compressor we service the most. And truth be told, it’s the unit we install the most as well.
A single-stage compressor is an air conditioner that will turn on when the thermostat is set to cooling mode and the temperature rises above the set point on the thermostat. So, if your thermostat is set to 72 degrees and the room temperature goes to 73 degrees, your single-stage compressor will turn on, with your blower motor, until it can cool the home back down to the set point of 72 degrees on the thermostat. However, these units only have one stage, or mode, available. They are either at 100% capacity or off. They run at full blast, consuming the maximum amount of electricity required. These units very commonly will be turning themselves off and on multiple times during the day when the outdoor temperatures are significantly elevated.
Single Stage compressors are more typically going to be found in lower SEER value units as they need the ability to change how they are consuming electricity. Also, these units will have the lowest degree of humidity control.
Two-Stage Compressor Types
A two-stage compressor would be your next step up in overall, advertised efficiency values – but more importantly, operating efficiency values (more to come on operating efficiency values). A two-stage compressor type will grant the home two different stages for it to be able to cool the home; a high stage and a low stage.
A two-stage air conditioner can run at its maximum capacity when the weather and the home’s cooling requirements require it, but it also could use around half of itself for days when the weather is starting to undergo a change of season or times of more mild conditions. Being here in Missouri, we all know we will have a string of rainy days in the middle of the springtime, and then “first summer” comes to give us a taste of the heat. Although the temperatures will not be at the level of the middle of the summer, our homes still become incredibly sticky due to a spike in humidity that is starting to infiltrate our homes, and the temperature will rise to a level most would consider uncomfortable. If you don’t want to turn on your air conditioner during that moment and time due to electrical consumption costs, consider installing a two-stage air conditioner in your home. Another scenario where a two-stage air conditioner can be of value to someone’s overall comfort is in the middle of the summer, when the sun goes down and we have cooler nights. If you’re like a lot of people, even though the sun is down and your AC has seemingly done an excellent job at cooling the home during the day, the house starts to feel sticky again. And with your single-stage compressor, you turn down the thermostat at night. You’re attempting to use a single-stage compressor to be a whole home dehumidifier. But, with a two-stage compressor and communication systems, that air conditioner will be able to recognize the higher humidity levels, turn itself on in its first stage, and start to cool the home slowly and dehumidify the home at higher rates.
Air conditioners consume the most electricity right when they turn on. A single-stage compressor will turn itself on and off all day long, costing the most. A two-stage air conditioner will “run” more but, less “on and off’s” thus, creating higher efficiency values and much better comfort control over humidity in the home.
Variable Speed/Variable Capacity Compressor Types
Are you an individual who likes high-efficiency units? Do you have a larger floor plan with areas that seem not to condition as well as others? Do you want to lower your carbon footprint? Do you want the ultimate level of control over your central air conditioner? Do you want to achieve the highest comfort inside your home by using your air conditioner? Then an air conditioner with a variable speed compressor is what you would need to achieve any of these things.
A variable-speed air conditioner works differently than all the other compressors, as it doesn’t have stages to speak of. It just varies the capacity at which the compressor works ranging from typically 25% all the way up to 100% of its designed capacity. Consumers with these types of air conditioners will notice, especially during peak usage seasons, that their air conditioners never seem to turn off. They will make a steady flow of conditioned air for the home to hold temperature and constantly dehumidify. As described, to achieve control the unit will almost never turn all the way off.
Alright, we know that sounds counterintuitive, and we know what you are thinking – “When it is hot out there, I don’t want an air conditioner that runs all the time and doesn’t cool the house quickly!”
Well, think about it, we know that a compressor coming on is the most expensive portion of the air conditioning process. This compressor can turn on at a very low capacity and modulate how much conditioned air is created. Also, we are constantly having air cycled through the home, and more importantly across a cold evaporator coil (the box on top of your furnace that your copper air conditioner/refrigeration line set goes into). Cold metal inside the evaporator coil and air moving slowly create condensation, which is the water in the air. Thus, less humid air is delivered to the living spaces. Do that long enough, and we can drop that humidity really, really well even when the temperatures/humidity levels are elevated outside. Typically, if we can decrease your humidity levels in the home, then you will be able to raise your thermostat temperature further lowering your costs of operation.
It’s important to reinforce this idea of humidity control – as controlling humidity is the root of being able to achieve comfort inside a home. If you have ever been to Arizona when it’s 100F outside, the temperature doesn’t “seem” to be that high as they have a very, very dry climate all year round. Whereas, if you move that temperature over into the swamps of the southeast, it’ll feel like you’re living in a fat man’s armpit! It’s the “feels like” effect you are noticing and are familiar with as it is described on the news constantly. We experience this situation inside our home as well. With variable speed, we can create climates that are more like Arizona than the humid friend we referenced.
Other things to consider about purchasing an air conditioner.
Properly sizing the air conditioner for the size and construction of the home is essential.
Ok, so now you understand a little bit about how the compressor type can create comfort in the home. But, an oversized air conditioner is the most detrimental to a home’s comfort and will shorten the lifespan of the air conditioner. All air conditioners should be installed per a load calculation – which, is a software that will help a contractor understand the building’s size and construction to ensure the air conditioner is properly sized.
In the case that it is oversized, the air conditioner will give the home TOO MUCH cooling TOO FAST thus, never having the ability to dehumidify the space. And, the compressor will “short cycle” meaning it will kick on and off very often (remember, that would be the most expensive time an air conditioner runs so we want to avoid on/offs as much as possible). Also, short cycling is hard on the compressor affecting the refrigeration cycle and the oil return process to keep everything running smoothly.
Obviously, an undersized air conditioner is not what you want either; you’ll just never have enough air conditioner to be able to achieve the temperature set points you would desire. It’s a fine science, at times, to be able to get it correct for your home.
If indoor air quality is of concern to you, buying the right equipment will help.
Another topic to talk about is how the different compressor types inside of an air conditioner can help with your overall indoor air quality. Opting for a two-stage or variable-speed compressor can help keep the air cleaner since these units utilize the fan on your furnace more often, circulating the stale air in the home. At higher levels of humidity in a home, certain invisible airborne particles will flourish in those environments. Lowering the humidity will also lower the ability for mold spores to be able to grow and spread, prevent a rapid increase of dust mites, and even prevent insects and spiders from living in the home! Yes, that is right – Your air conditioner can also help your pest problem. Insects require a certain level of humidity around them to stay alive. That is why they burrow into the ground during the winter since there is no humidity. Once the humidity comes back, they come looking for new food sources and sometimes that means they cuddle up inside your home. Drop that humidity down low, they become dissatisfied, they leave and now the spiders don’t have a food source either, so they follow them out the door.
Since the fan is running for longer periods of the day as well, your air has a better chance of being filtered using your furnace filter, or if you elect for additional products found with Respicaire’s line, they will perform better under these circumstances.
Local utility rebates, federal tax credits, and the all-mighty AHRI certificate
You may be aware that there are several different ways that you may be able to offset some of the costs associated with having an air conditioner installed in your home. Here in Kansas City, Evergy, Independence Power and Light, and Ameren all have programs where they will award instant rebates to homeowners for the installation of “qualifying air conditioner systems” but what does that even mean? Well, the governing body that determines the efficiency values is the AHRI. All of these units work as systems and their certificate proves the efficiency value, which typically requires a specific air conditioner, a specific furnace, and a specific evaporator coil. It’s very difficult to get just an air conditioner and evaporator to rate appropriately for utility rebates to be applicable, but we aren’t saying it’s impossible! Just very unlikely.
For federal tax credits, please consult with your tax professional to determine if these would be of value to your tax situation. We can ensure the units will hit all the minimum requirements set forth by the CEE.