If you are installing a central air conditioner for the first time in your old house for the first time, you may have some questions. The truth is that installing AC can be a big project, especially if your home doesn’t already have a duct system in place, or the existing duct system needs to be replaced.

Here are some common questions about AC installation in older homes:

What Size Unit do I Need?

It is important to know that not all AC units are created equal. You need to make sure that any new unit you install is the right size for your home to avoid unnecessarily high energy bills and premature damage to the unit itself.

If you choose a unit that is too small for your house, your unit will be constantly running, trying to keep the house a consistent temperature. If the unit is too big, it will short cycle, constantly turning on and off, and put undue strain on the system.

Both of these situations will cause your monthly energy bill to go up. You can figure out the appropriate AC unit size for your home by using this formula:
Sq ft of house x 30 / 12,000 + 1
Keep in mind that residential units only go up to 5-ton units. If you need more tonnage than that, you’ll need to install two smaller units.

Do I Really Need to Install Air Ducts?

The answer to this question, believe it or not, is no! You actually don’t need air ducts to have central AC anymore if you install a ductless split-system. Mini-split systems, as they are often called, involve multiple smaller units that can be distributed around the house, connected by refrigerant lines to a larger outside unit.

This allows the zoning flexibility of individual wall units, while also offering the convenience of central AC. It also eliminates what is known as duct losses, or the loss of cool air into crawl spaces and attics, through poorly insulated ducts.

There are energy efficient models of this system available, some with SEER ratings of 18 or above! The US Government even offers tax breaks for homeowners that employ split-system cooling with a SEER rating of 16 or above.

How Much Should I Expect to Pay?

The cost of central AC installation should range somewhere between $3,000 and $4,500. Of course, the actual cost for your home will depend on various factors, including where you live and what kind of unit you decide to install. For example, the initial cost to install a ductless mini-split system is about 30% higher than that of a traditional AC unit, but it can bring you more savings down the line.

One thing you want to be absolutely sure of is that you are not compromising quality to cut down on installation cost. Make sure that any unit you do purchase is appropriately sized, that it has decent airflow and sufficient refrigerant, and that your ductwork is in good shape. And make sure that you hire only trustworthy and experienced technicians to perform the installation.

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