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(707) 539-4533 |  Sonoma Napa and Marin Counties

updated 7/22/22


Air Conditioner Buying Guide

Buying any new appliance can be tricky, and air conditioners are no exception. There’s a lot you have to take into account, even if you’ve already decided on the type of HVAC system you’d like to buy. Between all the different brands and models, it can be difficult to figure out which is best for you. Of course, you can always ask your HVAC contractor for a little help, but sometimes it can be nice to figure these things out for ourselves. That’s why we put together this guide to show you some of the things you should be looking for next time you’re shopping for a new air conditioner.


Of course, your first step is always going to be figuring out which type of air conditioner you want. You’ll have to decide if you want to cool down your whole house or just a single room and look at all the different kinds before making a decision. Choosing between the types of air conditioners deserves a whole guide of its own – don’t worry, we have one of those too – so for now we’re going to focus on the steps to take after that. For the most part, all the advice in this guide should apply pretty equally to all kinds of air conditioners, from portable or window units up to industrial split-system AC.


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Air Conditioner Size

Whether you’re buying a window-mounted AC unit for a single room or a new split-system air conditioner to cool down the entire house, you must make sure it’s sized appropriately. An air conditioner that’s too small will struggle to fill the whole space with cold air, forcing it to work harder and wear down more quickly. On the other hand, bigger isn’t always better. An oversized air conditioner can be incredibly wasteful, driving your power bills up without any extra comfort to go with it. Oversized AC units can also end up short-cycling, which wears down the parts inside and leaves you with more frequent repair bills.


When we talk about the “size” of a specific air conditioner, we’re not talking about the physical size of the unit, but rather its output. Essentially, a “bigger” air conditioner is one that can blow out more cold air to fill a room faster and more effectively. The output of any AC is measured in British Thermal Units, or BTUs. You might have heard this measurement before since it’s used for all kinds of appliances, from propane grills to refrigerators. One BTU represents the amount of heat transfer required to raise or lower the temperature of one pound of water by one degree. It’s a little bit abstract, but you can just think of it as measuring the amount of heat that an appliance can create or remove from any given space.


You also might see an air conditioner’s output measured in tons. In refrigeration and AC terminology, one ton originally measured the amount of heat transfer required to freeze one ton of water into a solid block of ice in 24 hours. Of course, that’s kind of an obscure and confusing measurement, so today one refrigeration ton is equal to exactly 12,000 BTUs. If you’re just buying a window unit or other small air conditioner, the output will be measured in BTUs, but larger central air ACs are usually measured in tons.


Before buying a new air conditioner, you’ll have to do some calculations to figure out how many BTUs are required to keep your house cool. You can figure out a rough estimate using the square footage of the space, but there are a few other variables to consider as well. Spaces with higher ceilings require more powerful air conditioners, and so do spaces with a ton of windows. The number of residents is also relevant since having multiple people in the same space will raise the air temperature. If you’re calculating for a window unit, you have to consider the room you’re in as well. Some rooms, like kitchens, generally run hotter than others. Finally, the climate where you live is also relevant and should be taken into account.


Because these calculations can get pretty complex, we recommend having an HVAC contractor take a look at your home before you try to size your own central air AC. They’ll be able to give you much more precise and accurate figures. However, if you’re buying a small air conditioner for a single room, you shouldn’t have a problem just doing some rough calculations by yourself.


Energy Efficiency

As enormous gas-guzzling cars have gone by the wayside in the United States, so too have power-sucking air conditioners. These days people are more cognizant than ever about the energy efficiency of their appliances, and for good reason. Not only do more efficient appliances help reduce the strain on the environment, but they also save you money every month on your electricity bill. Even with today’s technology, air conditioners are still notorious for being the biggest energy hogs in the average home, so it’s especially important to find one that won’t break the bank every month.


In the United States, air conditioners are all given a SEER number, which stands for Seasonal Energy Efficiency Rating. SEER ratings are found by measuring the cooling output of the unit for a certain period of time and dividing that number by the electricity usage during the same period, so it represents the overall energy efficiency of the unit. Essentially, you can think of it as analogous to MPG ratings for cars. The higher the SEER, the more efficient the air conditioner.


You might also see air conditioners listed with an EER rating instead of SEER. The two ratings are very similar, but SEER is broader. EER numbers are devised by measuring the efficiency of the AC at a single temperature point – when the outside temperature is 95 degrees. SEER measures the efficiency of the unit throughout the entirety of the cooling season, with outside temperatures ranging between 65 and 104 degrees. This makes SEER the more useful and all-encompassing rating.


SEER ratings start at 1 and are theoretically limited only by the laws of thermodynamics, but for now, they rarely go much higher than 25 or 26. Starting in 2023, the US Department of Energy will be enforcing new mandates that require all newly manufactured air conditioners to have a minimum SEER of 14 in the northern part of the country or 15 for the southern part, including California.


When looking for a new air conditioner, you should aim for a high SEER if you can. Units with SEER ratings of 20 or higher tend to be more expensive, but it’s worth spending a little extra if it still fits in your budget. If energy efficiency is important to you but you’re not sure where to start, the US Environmental Protection Agency’s Energy Star program extends to air conditioners as well, so you can start by looking through the lists provided by the EPA. In fact, we recommend looking for Energy Star certifications for every appliance you buy.


Once you’ve installed your new air conditioner, the energy efficiency will be dependent on the condition and cleanliness of the unit. If you allow dust or dirt to build up in the vents or inside the unit itself, the efficiency of the whole system can be cut down by a significant amount. By cleaning the air conditioner regularly, swapping out or washing the air filters as directed, and sticking to yearly maintenance appointments with your HVAC contractor, you can keep your air conditioner running smoothly and efficiently for a decade or longer. However, if the unit is allowed to fall into disrepair, you could find your energy bills creeping higher and higher every month even if you bought an air conditioner with a high SEER.


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Compressor Technology

Modern air conditioning technology works by cycling a working fluid called refrigerant back and forth between two coils, called the evaporator and the condenser. Without getting too technical, the condenser allows for a chemical reaction that causes the refrigerant to release heat, and the evaporator allows the refrigerant to absorb heat from the air. A blower fan next to the evaporator coil then pushes all the newly-cooled air out into your house. We could get into all kinds of details about pressure and chemistry, but the important thing to remember is the refrigerant cycling back and forth between the two coils.


This obviously makes the coils extremely important, but arguably the MVP of the whole system is the compressor. You can think of the compressor as the heart or the engine driving the air conditioner. When your thermostat detects that the temperature in your home has gotten too warm, it sends a signal to the compressor, which switches on and starts to push the refrigerant back and forth between the two coils. Once the house is back down to your desired temperature, the thermostat sends another signal to the compressor, which switches off.


Because compressors are so vital to the way the system works, there’s been a ton of research into improving this specific part of the machine. Modern-day compressors are much more efficient than they used to be, but there’s still plenty of variety when you’re comparing between models. If you ask around or do any online research about the different brands and models available, keep an eye out for any mention of improved compressors. A solid compressor is a great foundation for any air conditioner.


In the last few decades, new compressor technology has made its way to the United States. For a long time, air conditioners were notorious electricity hogs because the compressors only ever had two power settings: on and off. However, in the 1980s, a Japanese company tried adding a DC power inverter to a compressor, allowing them much greater control over the speed of the motor. The resulting technology is referred to as variable refrigerant flow, or VRF. The DC inverter is able to control exactly how much juice is flowing into the compressor at any one time, which in turn allows the system to more precisely control the speed at which the refrigerant passes between the coils.


That might sound a little bit too technical and complicated, but the upshot of all this is a new kind of compressor that uses only as much electricity as it needs. When you turn a VRF air conditioner on in the morning, it can run at full blast until your house reaches the desired temperature. Throughout the rest of the day, it can just use a little bit of electricity here and there to gently nudge the temperature down every time it starts getting higher. Because of the greater control, VRF air conditioners use about half as much power as units with traditional compressors, saving their owners a whole lot of money every month.


While VRF technology was immediately adopted all across Asia, it’s only in the past decade or two that it’s been embraced here in the US. If your budget allows for it, we highly recommend VRF air conditioners to all our customers moving forward.


Additional Features

Once you have all the nuts and bolts sorted out, then you can start digging into the fun stuff. Today’s high-end air conditioners come with all kinds of special features that make them appealing to shoppers.


One thing we always recommend is an HVAC setup that allows for what we call zoning. In HVAC terms, zoning refers to the ability to split your house into different sections and set the temperature in each one independently. That means you can have one temperature for the living room, one for your bedroom, and another one for the kids’ room. With a central air system, you can set up zoning capabilities with multiple thermostats and automatic dampers that open and close different vents leading to the ductwork. The thermostats will control both the dampers and the air conditioner to redirect the cold air to each zone independently. You can also use alternative AC units like mini-split air handlers to put together your own zoned system.


If you’ve zoned your house and you want to take the next step, many new air conditioners and thermostats have smartphone connectivity. Not only can you control these air conditioners with your phone, but you can also set scheduled temperatures for different parts of the day or even have the system set up so it only turns on when it detects that you’re home. That particular feature is already being used by hotels so they don’t waste energy controlling the temperature in every room at once. They use sensors placed in each room that can detect when somebody enters and signal the thermostat to start checking that room.


In lieu of a traditional air conditioner, you can also give heat pumps a try. In most ways, heat pumps are identical to regular air conditioners, but there’s one major difference. Heat pumps come with reversing valves that allow them to switch the flow of refrigerant in the opposite direction. After the switch, the heat pump will absorb heat energy from the air outside, even when it’s cold, and transfer it to the air inside your home. If you live in a climate with both summers and winters, installing a heat pump is a great alternative to having to buy both an air conditioner and a furnace.


If indoor air quality is a concern, you can also find plenty of air conditioners with extra add-ons that filter out contaminants from the air. Whether it’s electromagnetic charges or UV radiation, there are a wide variety of filters and purifiers on the market today. However, we do recommend doing some research before buying any of these, since there are also a lot of pseudoscientific devices out there that don’t really do anything.


Air conditioner technology is constantly advancing, and in a few years, this post is sure to already be out of date. You can get in touch with your HVAC contractor to find out what new features are available in the current models and track down the AC that’s right for you.


Factory Authorized

When you’re looking around for the best place to buy a new air conditioner, you might find some businesses that advertise as “factory authorized” in specific brands. These certifications are given out by HVAC manufacturers to businesses that they have close relationships with. HVAC stores and contracting companies have to follow certain requirements to be factory authorized by manufacturers, and they tend to advertise it prominently when they meet those requirements.


Does this imply an extra level of credibility? Not necessarily, since these certifications aren’t handed out by any actual regulatory board and they don’t mean the company is more experienced or skilled. However, they do mean that the contractors or salespeople at that company have more knowledge and experience with that specific brand. It’s a little bit like how a salesperson at a Ford dealership might not be especially knowledgeable about cars in general, but they’ll definitely know a ton about everything Ford manufactures. Factory certifications also tend to require a certain level of customer satisfaction, as measured by surveys and ratings. After all, manufacturers don’t want their name involved with second-rate dealers.


The upshot of all this is that you should consider your options when looking at factory-authorized HVAC companies. While they’re sure to be fairly reputable and very knowledgeable in their brand of choice, they’re also more likely to push that brand over the others that are available. For that reason, you may want to do a little of your own research first and then find a company or contractor that has been certified in the brand you’ve already decided on.


Factory authorization becomes especially relevant after your purchase has already been made. If you go to a factory-authorized HVAC contractor for installation, maintenance, or repairs, you’ll likely find that they have a lot more experience and knowledge in that specific brand than anyone else would.


Finding a Contractor

Once you’ve decided on an air conditioner, you’ll need to find someone to install it for you. There are a ton of different HVAC contracting companies out there, so your best bet is to start by asking your friends and family for recommendations. Trade businesses like these tend to live and die based on their reputations, so hearing from actual customers is the best way to know how good they’ll be. You can also take a look at Google and Facebook reviews to hear from other customers, although we’d suggest skipping Yelp, which has been known to cheat their numbers.


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You’ll also want to make sure that any contractor you hire is fully certified, insured, and bonded. While there’s technically nothing stopping you from hiring an uncertified HVAC contractor, you’d be setting yourself up to take on a lot of risks. In California, contractors have to be certified in order to hold contractor insurance, which means if an uncertified contractor makes a mistake, you’re going to end up having to pay to fix the damages yourself. Besides that, certification is just an assurance that these people know what they’re doing and have been fully trained.

If you live in Napa, Sonoma, or Marin Counties and you’re thinking about installing a new air conditioner, or you’re looking for someone to service the one you already have, feel free to get in touch with Valley Comfort Heating & Air Today. You can contact us through our website here, give us a call at (707) 539-4533, or stop by our location in Santa Rosa for a chat. We’re more than happy to give you some advice on picking an air conditioner, making sure it’s sized properly, or anything else you might need.