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What is the Right Size for My Central Air Conditioner?


When your air conditioner dies and can’t be fixed, the team
at Happy Home Heating & Cooling can help you replace it in a jiffy.
However, we’ll need to determine the right size of AC replacement to install,
so you can enjoy the ideal comfort level in your home. There are several
factors we take into account when determining the right size of Central AC for
your home. Our skilled AC repair and installation technicians even rely on
advanced computing technology for part of the calculations.

If you are planning on replacing your air conditioner soon,
you’ll probably want to know what is involved in choosing the size of a new AC
unit. Well, it all starts with location, location, location!

Climate Zones Count

The most important consideration when first deciding on your
central AC unit is the location of your home. Different climates are divided
into Zones that indicate how hot and humid the weather gets and what
kind of seasons pass in these areas. North Carolina is divided in half by Zones
3 and 4, with Durham being firmly set in the latter zone.

This is a good thing because Zone 4 residents can still
enjoy mild winters without the excessive heat and humidity of Zones 1-3.
However, you may still experience summer heat waves that make your home

Look at Cooling Capacity

You’ll want to know your zones when picking an AC
replacement, as the air conditioner will need to work harder in warmer climates
to keep the house cool. On average, an AC unit will need to remove between 12
and 22 British Thermal Units (BTUs) of heat energy per square foot to
keep a house in Zone 4 cool.

The BTU needed per Zone is multiplied by the square footage
of your home to get the total BTUs required to cool the entire house. In the
United States, most air conditioner replacement units are measured in Tons,
which means you’ll then need to convert BTUs into Tons. The conversion rate is
12,000 BTUs per 1 Ton!

Building Design Affects Effectiveness

The air conditioner installation expert must also take into
account your home’s architecture and design when picking out an AC unit. As you
already know, the total square footage of the house is relevant to the cooling
capacity of a central air conditioner.

  • Your AC installation contractor will also need to look at
  • Position of the home; North- or South-facing
  • Number of windows and what side they are on
  • Roof shape and color
  • Material used on the roof and siding
  • R-rating of the home and building materials

All this information is usually entered into a software
program called the Manual J Load system. The protocol, created by the
Air Conditioning Contractors of America, calculates the required tonnage to
cool your home based on the above factors.

Air Ducts Can Make or Break the System

Last, but not least, you’ll need to assess the condition and
placement of your HVAC ductwork. If you don’t have enough vents in a large
room, it will never cool properly, no matter how long the AC unit runs.
Conversely, too many vents can make a room seem excessively cool. Plus, a lot
of heated and cooled air can be lost in the ductwork if it isn’t properly
insulated or is leaky.

Any problems with the ventilation will need to be repaired
before the AC replacement is installed to ensure it works as intended.

When you are ready to replace your old Central AC unit in
Durham, we can set up a complimentary consultation with one of our experts.
You’ll get to see firsthand how we determine the right AC replacement tonnage
using the above steps. Give Happy Home Heating & Cooling a call or fill out
our online contact form to get started right away.

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