Some things you should know before Replacing Your Central AC System

Maybe your old central air conditioner has quit working, and you think you need a replacement. Maybe you want to upgrade to a more energy-efficient or environmentally-friendly system. Maybe you’re not sure what to do.

Whatever the reason you’re considering a new air conditioner, you’ll want to go through this handy checklist to make sure you are shopping for the right equipment and asking contractors the right questions.

1.   How much time do I really have to replace my system?

At the end of the day, this is a decision you make based on your preferences, immediate needs and purchase ability. If health and safety are an immediate concern you might consider purchasing one or more window air conditioning units to buy some time until you get your central AC replaced. We discuss the long-term disadvantages with these units such as energy costs and noise, in other articles throughout the site. It is best if you have a few weeks to investigate the right equipment for your situation and find a good HVAC contractor who can install it for you. Because the average person will only have to replace an entire system once or twice in their lifetime they aren’t always as knowledgeable about what to expect in terms of cost and maintenance. 

2.    Do I really need to replace my entire system or can it be repaired?

Ultimately this question is best answered by a qualified contractor, but there are some general rules that can help guide your conversation. Depending on the age, how often your system runs and where you live you could be better off replacing rather than repairing it. If the problem is something simple and inexpensive like a failed part you are much better off repairing it. However, if a contractor tells you there is a refrigerant leak or the compressor needs to be replaced you should weigh the cost-benefit options of replacing the whole system versus paying for costly repairs. You will also need to consider what type of refrigerant your old system has (likely R-22) since it is being phased out in favor of a more efficient and environmentally friendly refrigerant, R410A or even R134a. It could be more costly in the long term to continue servicing a system with out-of-date refrigerant.

3.   How much space am I trying to cool (and has it changed since the old AC was installed)?

If you have to replace a system the first thing most people think is, “give me the same thing I had.” In most cases whatever size you had before will work for the replacement system, but there are circumstances where it will not. For example, if you added windows or doors, added new rooms, zoned off unused rooms, or added insulation you may have affected the amount of cooling that is required. Some people want to install a larger system “just to be safe,” but in reality this can cause problems down the road. If your system is too big for your space your electric bill will be higher and you could negatively affect the system’s ability to control humidity, which can lead to several other problems. When it comes to replacing a system, if you’ve made any of the changes above it’s worth having a contractor perform a load analysis of your home to properly size the unit for your needs. If you don’t feel comfortable with the way your contractor is analyzing your space, call another and get a second opinion. They should walk through the home and ask you about comfort and usage, not just ask about square footage.

4.   Do I want something more than “just cold air”?

Just about every basic central air conditioner on the market will produce cold air throughout your home if it’s installed and sized correctly. However, there are some features of high efficiency systems that are often worth the additional price when you take more than just the initial purchase cost into consideration. For example, because higher efficiency systems use less energy, they can reduce your monthly electric bill, and over the life of a system it can easily pay for the upfront cost difference. Because your AC and heating system accounts for roughly 60% of your overall home energy costs each year, those numbers quickly add up to real savings. This is even more important if you live in an area where the electricity rates are high. Comfort is another important factor to consider. Some of the higher efficiency systems available today provide an added benefit from both maintaining the temperature within a more precise range to controlling humidity – both significant factors of overall comfort. While it’s relatively easy to get cold air, consider the long-term financial and comfort factors before making a purchase decision.

5.   Do I really need to cool the whole house all the time?

There are inherent benefits to cooling the whole house including better air circulation, filtration and the elimination of cold or hot spots. However, there are times when cooling the upstairs bedrooms don’t make sense if no one is sleeping in them. There are two real options to successfully zoning your cooling space. The first is to invest in a second air conditioner and have one cool the most active space and the second be on ‘standby’ for the lesser used space. This requires the rerouting of your duct work but can provide additional controls for times when both spaces are used. The second option is to use a high efficiency system which can provide cooling modulation to adapt its power output based on which zones need to be cooled. Because the high efficiency systems are able to throttle up or down they are able to maintain humidity control and air flow and thus, overall air quality and comfort won’t be negatively affected. If you try to shut off rooms with a single, lower efficiency, fixed capacity system it can lead to moisture/humidity problems as well as spikes in temperature to make you uncomfortable. You could also severely damage the system if you shut off too many vents. Zoning is an excellent way to save on energy costs, but your contractor should help you select the right equipment to support that approach.

6.    Is there really anything new in air conditioning?

Because air conditioning systems tend to last for more than a decade most people don’t have a need to keep up with the latest trends. But today’s available systems may be more sophisticated and efficient than the one currently in your home if it is more than 6-8 years old. If you’re looking at a replacement you should consider the following options that have grown in popularity over the last few years.  Geothermal systems use the consistently cool temperature underground to cool your home instead of the normally hot air outside. Geothermal systems are some of the most energy efficient available. Another system that is catching on across the country is a heat pump which can work as an air conditioner in the summer and can the run in reverse and act as a heater in the winter. These systems are also popular in areas where electricity costs and availability provide better economics than burning gas, propane or fuel oil.  Ductless mini-split air conditioners are also gaining in popularity for certain applications. Rather than moving cool air around your house as part of a central system they condition one room at a time. These are usually mounted on a wall or ceiling and are ideal for a room addition or to add cooling to a garage. As you can see there are many more options than just buying cold air. It’s worth the time to explore your options and if you have questions, ask a contractor!

7.   Should I invest in a programmable thermostat?

One of the quickest and simplest ways to reduce energy costs is to use a programmable thermostat. There are many varieties of thermostats available today with a host of features, but the one that provides the bulk of the energy savings is the programmable feature. This allows you to dial back the heating and cooling automatically for times when you know you will not need it – while you are at work, away from home, etc. There are more advanced models that can regulate the cooling based on other factors like humidity and changes in outdoor ambient temperatures which can improve comfort as well as energy savings without you having to lift a finger. You might actually have a programmable thermostat now and not know it. Our research has shown that a surprising percentage of people actually own these programmable thermostats but don’t use the programmable feature.  So check your thermostat and if you decide to buy one of the programmable models be sure to use it and see the savings add up!