Air Conditioner Guide

Since 1935, Peninsula has been keeping families and businesses comfortable with expert air conditioner services designed to keep your system running smoothly all summer long.

We’ve created this guide to help you make choices when it comes to air conditioner repair, replacement, and maintenance. It includes:

  • Signs Your Air Conditioner is About to Break Down
  • How to Make Sure Your AC Lasts Through the Summer
  • How to Keep Your Cooling Costs Down
  • My Air Conditioner Is Frozen!
  • Tips for Buying a New Air Conditioner
  • Choosing an Air Conditioning System
  • Things to Consider Before Replacing Your Air Conditioner
  • Is Your Air Conditioner Small Enough?
  • Why You Need to Have a Properly Sized Air Conditioner


Few things are as frustrating as having your air conditioner break down unexpectedly during the summer, especially given how hot and humid it can get around the Delmarva. And while you can’t always prevent a breakdown, you can at least prepare for it by looking out for certain signs that your air conditioner may give out!

Airflow is weaker than normal – if you feel like your air conditioner isn’t blowing air as hard as it used to, the first thing you should do is check the filter—a heavily clogged air filter can compromise your airflow and put unnecessary strain on your system. If the filter is not the problem, it’s time to call a professional HVAC company. Weak airflow could be caused by a variety of things, from a damaged blower fan to any number of problems that you might not be able to determine.

The AC is noisier than usual – air conditioners are designed to run quietly and efficiently (noise level is actually a key selling point for air conditioners!). So if your air conditioner is making more noise than usual, this is a sure sign that something is up—a problem with your fan belt, perhaps, which could compromise the efficiency of your unit. Have a local air conditioning company find the source of the noise and fix the problem to prevent anything worse from happening down the road.

Your air conditioner takes a long time to cool – everyone’s used to having to wait a few minutes for the house to cool down once the AC turns on. But taking an unusually long time to cool is one of the surest signs that your air conditioner is about to break down! There are a number of problems associated with a slowly cooling air conditioner—it could be something relatively simple like a refrigerant leak or a totally worn out and corroded system. A member of the Peninsula team will be able to diagnose your air conditioner and determine some next steps to take care of the problem.

Your system is getting older – air conditioners, unfortunately, have a limited lifespan – 10 to 15 years is usually as long as they’ll last. If you’ve been experiencing any of the above issues AND your air conditioner is starting to get up there in age, there’s a good chance that you may need to replace it in the near future.

You can’t always save your air conditioner from a breakdown, but if you know what to look for, you can at least prepare yourself. At Peninsula Oil, we have nearly 80 years’ experience providing families all along the Maryland and Delaware Peninsula with the friendliest, highest quality air conditioner service around. If you’re having air conditioner troubles this summer, or if you think they’re about to start, don’t wait—give us a call today!


  • Get Your Unit Checked Out– The first thing you will want to do is have your AC unit inspected and maintained. This will ensure that everything is working correctly and  will allow you to fix anything that may stop your AC from working to its full potential.
  • Change Out Your Air Filters– Changing your filter on a regular basis will take the pressure of your AC system and allow your airflow to be stronger. If you have pets or allergies you may want to switch out your filter once a month otherwise you will want to change your filter out every 6-8 weeks.
  • Turn Your Thermostat Up– If you have your thermostat turned down really low  your AC will be constantly pumping. This will put a lot of extra use and pressure onto your system. Turning your thermostat up so that you are still comfortable but your system gets a break can help a lot.
  • Replace Your Old AC– If you have an old AC unit, replacing it before summer hits can really help. If you had issues last year, your AC unit is older than 10 years and your energy costs were too high last year, installing a new system before summer will give you peace of mind.
  • Call for Help– If you find your system is making weird noises, smells funny or isn’t keeping your home cool, call for help straight away. Don’t wait until it stops working altogether, call the experts to sort the smaller issue out before it turns into a major issue.


One of the more unfortunate things about our hot summers on the Delmarva is that as the thermostats rise, your energy bills tend to go with them. Cooling costs make up a huge portion of your utility costs during the summer, but with a little effort you can keep them at a manageable level.

Install a Programmable Thermostat

One of the best ways to save money on your energy bills is to set your thermostat higher during the day when no one is home. Unfortunately, it’s not always easy to remember to change the temperature before you walk out the door. That’s where a programmable thermostat comes in handy! A programmable thermostat will automatically adjust the temperature in your home to your setting depending on the time of day.

Each degree you set your thermostat up during the summer can save you about 3 – 5 percent on your energy bills, and a programmable thermostat can help you save without even thinking about it.

Be Mindful of Your Appliances

Your air conditioner is by far the biggest energy consumer in your home during the summer. But that doesn’t mean you shouldn’t keep an eye on your other appliances too! Set your refrigerator temperature somewhere between 38 and 42 degrees, and keep the freezer around zero to five degrees. If your fridge has a power-saver switch, make sure you keep it turned on. Finally, make sure the door seals properly. To test this, close the door on a piece of paper and try to slide the paper out. If it comes out easily, you should think about replacing the gaskets on the doors.

Grilling out is another great way to keep energy costs down—not only does not using the oven keep those costs out, but you’re also not adding additional heat into your home. If grilling every day (or at all) isn’t an option, the next best thing to do is take care to not preheat for longer than necessary and avoid opening the oven more often than necessary. Try to use cold water in the dishwasher and washing machine when possible, and air dry clothes and dishes. Finally, use fans to improve the efficiency of your air conditioner.

Unplug Your Electronics

Did you know? A lot of times, turning off your electronics doesn’t stop them from using power. This is especially true with batteries that charge—if they’re plugged in, they’re drawing power! It’s called “vampire power” and it can cost you a bunch of money. Next time you unplug your phone, make sure you pull the cord out of the wall.

Note: most modern appliances have made big strides in preventing vampire power, but it still happens—try to remember to unplug your bigger electronics when not in use to prevent it.

Keep Your Equipment in Good Shape

Did you know that the biggest cause of air conditioner inefficiency is dirt? If your compressor gets dirty, it stops working as well—hose it off every now and then to keep it spry! While you’re at it, change your air filters monthly, especially now that you’re probably running your AC all day. Finally, have at least one air conditioner inspection to make sure your unit is operating in top condition!


It’s around the summer time that many people start to notice something strange: their air conditioners aren’t blowing air as well as usual, and their evaporator coils are covered with a thick sheet of ice!

What is going on?

Incongruous as it may seem, a frozen air conditioner during the summer is actually a common occurrence. There are a number of things that can cause your AC to freeze:

Weak airflow – the most common, and usually easiest to fix, cause of frozen air conditioners is weak airflow. As warm air passes over the evaporator coil, moisture in the air condenses on the coil and is blown into a condensate drain. Weak airflow will not push the moisture off fast enough, giving it enough time to freeze.

A frozen air conditioner coil can cause refrigerant leaks, so if you notice it you should take steps to fix it immediately. Start by changing the air filters, waiting a few hours, and then checking back again. If the ice is going away or completely gone, your problem is solved.

If your filters aren’t dirty and a freezing air conditioner has always been a problem for you, your ducts may be undersized. If this is the case, have an HVAC contractor come out and take a look at them as soon as possible. You may end up needing new ductwork installation, or you may need to replace your air conditioner with a smaller model.

Refrigerant leaks – the level of refrigerant in your air conditioner has to be maintained carefully to ensure that your air conditioner runs smoothly. Too much or too little refrigerant could cause the air conditioner to freeze.

Low outdoor temperature – sometimes the cause of your frozen air conditioner has nothing to do with the AC unit itself—instead, it’s just too cold outside! Air conditioners don’t fare too well when temperatures are below 60 F. Fortunately, when temperatures are this low you don’t really even need to use your AC at all—you can just throw open the windows and let the breeze in! You’ll save your air conditioner from freezing and save some money at the same time!


If you find that you have a frozen air conditioner, the first thing you should do is figure out what caused it to freeze up in the first place.

No matter what, the first thing you should do before you start is turn off your air conditioner. This will give it time to defrost and prevent the freezing from causing serious damage to your unit.

Once you’ve shut off your air conditioner, check your filters—dirty air filters are the number one cause of frozen air conditioners! Replace the old ones with new, clean filters, turn the AC back on, then check again in 24 hours—if the compressor has thawed out, changing the filters worked.

If changing the air filters DIDN’T work, your problem may require the help of an HVAC contractor. For instance, your air conditioner could be frozen as a result of problems with the level of refrigerant, your ductwork could be inadequate, or your defrost timer could be malfunctioning—all problems a Peninsula technician can fix!


Buying a new or replacement air conditioner is a big investment. And as much as we wish we could say “buy from us, we’re the best!” we also want our customers to know what they’re getting into! The following is a list of some of the best air conditioner purchasing tips we’ve come across over the years. If you’re getting ready to buy a new air conditioner, make sure you read these first!


  • Size is everything when it comes to your air conditioner. Some contractors will attempt to size your system based on the square footage of your home. There’s a lot more that goes into it than that! At Peninsula, we follow the guidelines set forth in the Manual J of the Air Conditioner Contractors of America. Our technicians will spend about an hour looking around your house, taking measurements of the floors, ceilings, walls, and windows while simultaneously checking for insulation in the attic, walls, and crawl spaces. Some other factors that go into the cooling load formula include indoor and outdoor temperatures, the number of people in your home, the amount of shade you get, even the color of your roof!
  • Insist on getting a copy or computer printout of the cooling load calculations. You don’t need to be able to read it, but it will be very useful if you’re comparing bids from a number of contractors. If you don’t see calculations for the items we mentioned above, or you see something you don’t understand, ask!
  • At the same time, don’t be tempted by the lowest bid. Remember—some contractors will only base your air conditioner’s size on the total square footage of your home. A poorly sized air conditioner can cause a number of problems and will end up costing you a bunch of money in the long run. Be willing to pay for the time the contractor must spend to do the job right, and you’ll reap the benefits later!
  • Make sure your duct work is as efficient as your new air conditioner.We can’t tell you how many times we’ve gone in to install a new air conditioner and seen duct work with holes and gaps throughout, or ducts that are the wrong size for your system. Leaky duct work can waste up to 30 percent of your cooling, and poorly sized duct work can make proper airflow impossible. Ideally, your air conditioner installer should use diagnostic equipment to locate leaks and use quality duct sealants to fix them, not duct tape! Remember—you bought your air conditioner to cool your HOME, not the attic!
  • If you can afford it, buy a high-efficiency unit.Air conditioner regulations state that new air conditioners are required to have a SEER of 13 or higher. If possible, it’s usually worth it to buy  a unit with an even higher efficiency level. In most cases, you can think of it like this: higher efficiency = lower bills. If you pay more on the front end for your new system, it will pay you back in lower costs over time! Look for an ENERGY STAR label when you shop. If you are replacing an existing air conditioner, you must replace the whole unit, including the inside coil and often the blower fan, to achieve the rated efficiency. [Information in this paragraph updated by LBNL to reflect new standards of January 2006]
  • Install your system in a way that will make it easy to maintain. This is more on the contractor, but it helps to keep it in mind. You want the inside coil to be reachable for cleaning. The contractor may have to install an access panel, depending on the model. The coil should be cleaned every two years. The air filter should be located where it is easy to remove. Check it every month during the summer, and clean it or change it whenever it is dirty.
  • Place the outside unit (compressor) on the north or east side of the house, out of direct sunlight, and don’t try to add shading for it.Leave plenty of room for free airflow on all sides, and leave at least 4 feet of clearance at the top. Keep the area free of debris and shrubbery. The air conditioner draws a lot of air through it. It’s more important for the unit to have a lot of space than for it to be well shaded.


Choosing the perfect air conditioning system for your home is no easy task—between sizing the system, choosing the right balance of cost vs efficiency, etc., there are a lot of decisions to make when installing a new cooling system. At Peninsula, we pay attention to a number of factors to help you choose an air conditioner that’s right for you.

Home Design and Location

First, your Peninsula technician will look at things like the direction your home faces, the number, size, location of windows, and more. If you don’t already have ductwork installed in your home, we will also look to see if ducts can be installed or if we’ll have to consider ductless heating and cooling.

Location also comes into play, specifically:

  • Site conditions
  • Peak summer cooling conditions
  • Summer humidity
  • Peak winter heating conditions
  • Wind speeds
  • Sunshine hours
  • Typical snow accumulation depths

Finally, local building, fire, and energy codes need to be considered when choosing an air conditioner.

Indoor Cooling Requirements

Calculating cooling loads (the amount of cooling required to keep your home comfortable) should be done by looking at location effects and indoor requirements, and should include things like:

Indoor thermal and humidity levels – we will measure heat generated by your home by things such as lights and appliances, along with general humidity levels.

Ventilation levels – all homes should be ventilated to allow fresh air in and to push stale air out. The number of people in your home and the presence of pollution sources (which can include things like cooking areas, chemical storage, etc.) all determine the amount of ventilation required.

Zoning – if you want to set up different air conditioner zones throughout your home, this will change your air conditioner requirements.

Personal Factors

Do you like your home to be warmer than average during the winter or cooler than average during the summer? Would you rather pay more upfront for a system that will cost less in the future or are you happy to pay more later for a cheaper system? These factors are important to consider when installing a new air conditioner.


1. How Old Is Your Unit?

An air conditioning system is designed to last about 15 years with proper maintenance. When your system gets to be around 10 years old, you will want to start thinking about replacement. Planning at the 10-year mark will help you save for when you actually need to replace it, and will also give you some time to decide what new features and technologies you need.

2. How Efficient Is the System?

Over time, air conditioners start to lose efficiency. Also, technology is constantly changing, and with it comes increasingly efficient air conditioners. This combination means that you could have inflated energy bills simply because your air conditioner is old. If the unit has a SEER rating of 13 or below, you can benefit significantly by upgrading to a more efficient model.

3. Have You Had to Call for Multiple Repairs?

If you’re facing an expensive pending air conditioner repair, or if you’re finding that repair is becoming a routine part of your life, and your system is a decade or more old, then it’s time to consider replacement. There comes a point when continuing to pour money into an old, outdated machine just doesn’t make sense. The Peninsula team can help with both repairs and replacement, and we can help you weigh the pros and cons of both options.

4. Is Your Home Uncomfortable?

If your home feels hot and stuffy, it may be because your air conditioner is just too old or is improperly sized for your home. Replacing the unit with a newer and properly sized one will ensure a cool and comfortable home. Let the Peninsula team help you weigh your options to find one that will keep your home more comfortable.

5. Does Your Unit Use R22 Freon?

Finally, if your unit is using R22 Freon, you need to consider replacement. This refrigerant is being phased out in favor of a new option,R410A. This is a more environmentally-friendly coolant, and eventually the R22 Freon is going to be difficult to get. Switching to a new unit, especially if yours is starting to have Freon leaks, is a wise choice.


Are you thinking of buying or installing a new air conditioner this year? The most important thing to consider, even more than the energy efficiency, is how big your unit is—or in some cases, how small it is! Some people try to cut corners by installing an air conditioner they think is big enough, but making sure your air conditioner is sized properly for your home is one of the major factors that affects how your system will run for its entire life. The cooling capacity required to keep your home and family comfortable is called the load of your home.

Calculating the load of your home goes beyond just calculating your home’s square footage. At Peninsula, we take many factors into consideration, including:

  • Your home’s construction
  • Orientation to the sun
  • “R” value of the insulation
  • Number, size, and placement of rooms
  • Number, size, and placement of windows and doors
  • Types of windows and doors (thermal efficiency)
  • Number and arrangement of floors
  • The local climate

Residential load calculations use mathematical formulas, including one called Manual J. These days, calculations are made with computers, making them much less time consuming and more accurate than ever. Estimating load calculations almost always leads to installing an oversized HVAC system, which will increase your costs across the board, from installation and monthly costs to increased maintenance and shortened equipment life.


Your cooling load consists of two separate components:

  • Air temperature, also called sensible load
  • Moisture or humidity in the air, called the latent load

Have you ever heard someone say “It’s not the heat, it’s the humidity.”? In addition to cooling the air, air conditioners take up excess humidity and make the whole house more comfortable—if they’re the right size.

An oversized air conditioner will cool the air too quickly, and won’t run long enough to remove the humidity from the air, making your home feel cool but clammy. To run the AC longer, many people turn the thermostat down, which increases their utility bills. In extreme cases, moisture and humidity left in the air can lead to mold growth and other moisture related damage.

A correctly sized cooling system runs long enough to pull excess moisture out of the air, keeping you comfortable even at slightly higher thermostat settings.

Air conditioning systems are sized in “tons,” which is a measure of the rate at which they deliver cooling, not how much they weigh. One ton of cooling is equal to 12,000 Btu/h (British Thermal Units per hour), the rate of cooling required to freeze one ton of ice at 32 F in one day.

It’s better to have a system that supplies a little less than the required tonnage of cooling, rather than a system that supplies more than the required tonnage of cooling.


While some regular air conditioner maintenance can be done by the homeowner—such as changing the filter regularly—a full inspection and tune up should be done by a qualified professional. A trained AC tech can get inside the machine and look for problems while cleaning and lubricating the parts.

If you or members of your family suffer from seasonal allergies, having your home’s air conditioner properly cleaned and tuned up can help keep the air they breathe free of some of the most irritating allergens, like dust mites, pet dander, mold, and more.


  • Lower monthly utility bills– Simple procedures such as changing an air filter or cleaning a coil allows the unit to run much more smoothly. When your air conditioner runs smoothly, it uses less energy.
  • Fewer breakdowns– Nearly half of all air conditioning breakdowns are caused because of lack of maintenance. Once dirt gets into the system, parts are more likely to rust and get ruined. By having your entire AC system inspected, problems can be caught before they require expensive repairs or replacements.
  • Warranties– Most companies won’t accept an air conditioner repair warranty claim if your air conditioner has issues due to lack of maintenance.

The Full Peninsula Air Conditioner Tune Up

Our annual air conditioner maintenance service includes:

  • Checking thermostat calibration
  • Monitoring refrigerant pressure
  • Testing AC starting capabilities
  • Testing air conditioner safety controls
  • Cleaning and/or replacement of standard air filters
  • Cleaning and adjustment of blower components
  • Measuring for correct air flow
  • Tightening electrical connections
  • Measuring volts and amps
  • Lubrication of all moving parts
  • Cleaning condensate drain
  • Measuring temperature difference between supply air and return air
  • Application of protective coating
  • Monitoring cooling cycle
  • Inspection of evaporator coil
  • Examination of installation quality
  • Examination of equipment condition area, and clearances
  • Cleaning condenser coil


The Delmarva Peninsula is known for two things: crabs and hot, sticky summers. And while we can’t exactly bring you a fresh bushel of steamed crabs, we can at least make sure your air conditioner is there to keep you comfortable!

If you need air conditioner services in Delaware or Maryland, call Peninsula today at 302-262-8254 or click here to contact us online!


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