Central Heating & Cooling: Guide to Installing a Central A/C

This guide has everything you need to know about installing a central air conditioner.

It will walk you through the process and terminology as you plan to have your central A/C installed.

If you want to alleviate the problem of which air conditioning system is right for you, how they work, sizing, installation and what to expect when your technicians get started, you're in the right place.

Let's face it...

When adding to an existing central heating & cooling system, central air for a 2,000 square foot home roughlycosts $3,500 to $4,000. If ducts need to be added the cost will increase.The final cost will depend on the system, additional items added and the technician's installation rates.

And whether or not you've got ductwork, adding central air is more affordable and less disruptive than you might imagine.

But you probably have a bunch of questions before you get started...

1. What actually is a central air conditoner?

The central air conditioning system found in most homes are a "split system". This typically means there is a compressor unit (outside) and an indoor coil, installed on your furnace inside the home.

2. How does a central A/C system work?

Central heating and cooling systems are separate things, but they are matched to work together. Here's what Trane and "How Stuff Works" have to say how central cooling and heating works:

How Does a Central Heating and Cooling System Work

Heating and Cooling System Basics

3. What does the term HVAC stand for?

HVAC (Heating, ventilation and air conditioning) is the technology of indoor and vehicular environmental comfort. It's goal is to provide thermal comfort and acceptable indoor air quality.

4. How often should I replace my filters? And why do I need to change my filter regularly?

Changing your furnace filter is one of the least expensive maintenance items for your home with one of the greatest benefits. They should be changed regularly to improve air quality, increase the efficiency of your furnace and extend the life of your HVAC system.

Never Forget to Replace Your Air Filter Again

How to Replace Furnace & AC Filters

5. How often should I have maintenance done on my unit?

Keeping your AC system running smoothly depends on proper maintenance and service needs.

Air Conditioning Maintenance - The Ultimate Guide

The Importance of Annual HVAC System Maintenance is Greater Than You Think

6. What size central air conditioner should I have?

Too big? It will not be energy efficient. Most will turn on quickly, cool your house, then turn off. Then repeat the same cycle.

Too small? Your A/C will constantly run trying to cool your home. This will increase the wear and tear on the unit.

Just right? a properly sized central A/C will run through the required amount of cycles to keep your house comfortable, but will not run inefficiently.

ASM (All Systems Mechanical), created a short but thorough guide on:

What Size Central Air Conditioner Do I Need for My House?

Simply put, size matters...

Go to Chapter 5 for more on sizing.

7. Should I close the registers and doors to areas of the home that I do not use on a regular basis?

The short answer - closed vents increase pressure.

Here's an excerpt from Energy Vanguard, "When you start closing vents in unused rooms, you make the duct system more restrictive. The pressure increases, and that means an ECM blower will ramp up to keep air flow up whereas a PSC blower will move less air. Most homes don't have sealed ducts either, so the higher pressure in the duct system will mean more duct leakage."

They summarize 9 unintended consequences of closing vents.

8. What is the SEER rating?

SEER stands for Seasonal Energy Efficiency Ratio. It is the ratio of the amount of cooling produced (BTU) divided by the amount of electricity (watts) used.

The ratings measure an A/C unit's energy efficiency. The higher the rating, the most efficient.

The ever-present federal EnergyGuide label can help you determine a unit's SEER rating at a glance.The label helps identify high-efficiency A/C units.

9. Should a thermostat be set to "auto" or "on"?

There are pros and cons of both:

Should I Use My Thermostat's Fan "On" or "Auto" Setting

When Setting Your Thermostat, Should You Use Fan On or Auto?

Why "On" Isn't always the best choice.

What are the Advantages and Disadvantages of the settings?

10. What's the difference between a split and a package unit?

which leads us to the next chapter...

Whether you are a homeowner looking to upgrade your system, a homeowner looking for available options, or a business adding A/C, there are a variety of central air conditioners on the market.

1. Split System

The most common or popular is the split systems.Simply put, the split system has it's cooling parts of the unit inside the home, and it's heatingparts outside of the home. With a split system, the condenser and compressor are housed outside.

An indoor cabinet has the evaporator coil. There is also an air handler that is usually part of the furnace. This handler sends the warm or cool air through the ductwork.The most important aspect of this particular combination is matching both parts for maximum efficiency.

2. Package System

The package system is self contained - not split up - and the entire unit is installed outside at ground level, or on top of the roof.

Here's a recent photo of a "package rooftop unit" we installed for a church.

A package unit is a completelyself contained heating/coolingunit that has the blower, coil and condenser all built into one unit. Fully self-contained air conditioners are ready with refrigerant and can be used on a rooftop like in this case or ground mount.It is imperative that the unit be level for your HVAC system to operate properly and efficiently.

The older system was loud and there was no way to get a new indoor unit into the attic. The access was not big enough.

Sitting on the roof as an option will air condition the space below and fit (unlike the constricted space in the attic). It was the solution for an easy-to-install outdoor unit.

Wefigured out a way ofrouting the ducts from the unit into the attic and connecting to the existing duct system.

3. Mini-Split System

Like a split system, the mini-split system uses anoutdoor compressor/condenser linked tothe indoor air-handling unit.

The advantage of the mini-split system is that the indoor units are small and can be used to cool rooms, or zones. Also, a professional installer can create these "zones" and can hook up multiple units to oneoutdoor unit.

TheFujitsu Mini Split systemis the perfect solution for homeowners who have boiler systems, and requires the minimum amount of disruption to your home.

It offers both acentralheating & cooling systemthat is perfect for seasonal transitions, although you can use it year round.

4. Heat Pump

Installation for this type system typically consists of two parts: an indoor unit called an air handler and an outdoor unit similar to a central air conditioner, but referred to as a heat pump. As part of a central heating and cooling system, it uses the outside air to both heat a home in winter and cool it in summer.

A central air conditioner is really either a split-system or packaged unit. Choosing the right A/C system for your home is a decision you have to live with. You want to guarantee your comfort, cost-savings and optimum performance.

Today's best air conditioners use 30% to 50% less energyto produce the same amount of cooling as air conditioners made in the mid 1970s. Even if your air conditioner is only 10 years old, you may save 20% to 40% of your cooling energy costs by replacing it with a newer, more efficient model. (more on energy efficiency in Chapter 6.)

"If youre thinking about adding central air conditioning to an existing house, statistics show youve got a lot of company. In fact, while air conditioning was installed in just over 60 percent of homes as recently as the early 1990s, today about 87 percent of existing U.S. residences now enjoy some form of A/C."

Griffith Energy Services reiterates ...

What's Involved When Adding Central Air Conditioning to Your Home?

Time agrees central air conditioning will change your life.

"No more sweaty nights tossing and turning because you havent installed the window units yet. For that matter, no more installing the window unitsor bashing your knuckles carrying them up and down the basement stairs each spring and fall."

And it lets you understand the ...

5 Things to Know Before You Add Central Air Conditioning

What if you're on the fence as to whether you should upgrade?

Answer these questions provided by HGTV:

Before spending money on a new HVAC system, it's wise to check for costly air leaks.According to Energy.gov reducing air leakagecan "significantly reduce heating and cooling costs, improve building durability, and create a healthier indoor environment."

Once you decide you're ready to replace your system, the question of cost will be next on your list.

Furnace Compare recently updated their article on central air conditioner pricing. It isn't about the average price of central air conditioners but the result of a series of interviews with contractors and distributors about how they set their prices.

A few of the questions they answered...

Their best advice: "periodically consider the age of your system and ask a technician during regular maintenance how the system looks."

Basically don't get caught in an emergency situation where you are desperate for A/C.

"The fact is that it takes time to do your research to find contractors to request bids from, research their bids and learn all that you need to know about AC system replacements."

75 percent of air conditioning problems can be resolved by the correct method of installation in combination with the right-sized air conditioning unit.

Electrical Requirements to Install Your A/C

Your electrical must be able to handle the additional demand of the A/C unit. An older circuit breaker panel may need to be upgraded to supply higher amperage.

Modern homes may have a panel that has the ability to add additional circuit breakers. Discuss the possible upgrades with your contractor in advance of beginning work. A reputable contractor can recommend a licensed electrician that is familiar with upgrading electric service.

Space Requirements for Your Air Conditioner

The central A/C unit will have a condenser unitoutside that will need space and the blower and connections inside your utility room. An independent electrical outlet hookup may be necessary with wiring to your main panel.

All the required space should be planned out in advance. Your contractor can help to plan the details. Any construction necessary should be figured into the total cost of installation.

Thermostat Replacement - Options to Fit Your Lifestyle

This would be a good time to replace an older dial-type thermostat with a new programmable model. Modern programmable thermostats can save you significantly on monthly utility expenses. Available options are 5 or 7 day modelswith several different settings for each day.

Several are capable of wireless control by your smartphone or other communication device from anywhere the internet is available. You can be notified when a filter change is necessary, time for regular maintenance, or if there is a problem with the system.

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Central Heating & Cooling: Guide to Installing a Central A/C