What Size PTAC Do I Need?

What Size PTAC Do I Need?

PTAC Sizing Calculator

Dale, the Power Equipment Expert
By 
Power Equipment Expert

Packaged terminal air conditioners (PTAC) are perfect additions to homes, offices, high-rises, or anywhere it's difficult to keep a comfortable temperature. Properly sizing your PTAC is a vital step in the buying process. Lucky for you, our online PTAC sizing calculator will walk you through questions about your space and provide the best sizing estimate you'll find from any online tool.

Step 1. Basic Info
Step 2. Room Info
Step 3. Construction
Step 4. Results
Total Load Calculations
Cooling Load:
Heating Load:
Basic Room & Home Information
Room Size:
Zip Code:
Room Type:
Building Age:
Download As PDF
Print
* For more accurate load calculations, you can edit the detailed information below.
Skip To Results
Tell Us About Your Home
Fill out all of the fields provided to calculate your heating and cooling loads. We'll use that information to help you find the right mini split system for your home.
Select the approximate age range of your home. We will use this to make an estimate of the quality of insulation of your home.
Because different types of rooms are used differently, they have different heating and cooling needs.
Calculate Load Estimates
Temperature Information
High: 90°F | Low: 10°F
Outdoor Design Temp. determined by ZIP Code.
Next: To Wall Details
Wall Details
Select 'Yes' if this wall separates the space being conditioned from the outdoors or an unconditioned space like a garage. Otherwise, if this wall is adjacent to another conditioned space, select 'No'.
Enter the width of the wall. If only a portion of the wall is "Exposed", enter this width.
Select 'Yes' if this wall separates the space being conditioned from the outdoors or an unconditioned space like a garage. Otherwise, if this wall is adjacent to another conditioned space, select 'No'.
Enter the width of the wall. If only a portion of the wall is "Exposed", enter this width.
Select 'Yes' if this wall separates the space being conditioned from the outdoors or an unconditioned space like a garage. Otherwise, if this wall is adjacent to another conditioned space, select 'No'.
Enter the width of the wall. If only a portion of the wall is "Exposed", enter this width.
Select 'Yes' if this wall separates the space being conditioned from the outdoors or an unconditioned space like a garage. Otherwise, if this wall is adjacent to another conditioned space, select 'No'.
Enter the width of the wall. If only a portion of the wall is "Exposed", enter this width.
Window Details
North
We assume Windows are 3'x4'. If your windows are larger or smaller, please adjust accordingly.
We assume French Doors are 3'x7'. Each half of a double door should be counted separately.
We assume Sliding Doors are 6'x7'. If your doors are larger or smaller, please adjust accordingly.
East
We assume Windows are 3'x4'. If your windows are larger or smaller, please adjust accordingly.
We assume French Doors are 3'x7'. Each half of a double door should be counted separately.
We assume Sliding Doors are 6'x7'. If your doors are larger or smaller, please adjust accordingly.
South
We assume Windows are 3'x4'. If your windows are larger or smaller, please adjust accordingly.
We assume French Doors are 3'x7'. Each half of a double door should be counted separately.
We assume Sliding Doors are 6'x7'. If your doors are larger or smaller, please adjust accordingly.
West
We assume Windows are 3'x4'. If your windows are larger or smaller, please adjust accordingly.
We assume French Doors are 3'x7'. Each half of a double door should be counted separately.
We assume Sliding Doors are 6'x7'. If your doors are larger or smaller, please adjust accordingly.
Garage Door Details
Each single garage door should be counted as 1 and each double garage door should be counted as 2.
Next: To Ceiling Details
Ceiling Details
Select 'Yes' if the ceiling separates your space from the outdoors, an attic, or any other unconditioned space. Otherwise, if there is another conditioned room above your space, select 'No'.
Enter the height of your ceiling. If you have a sloped, vaulted, or any other type of non-flat ceiling, enter the approximate average ceiling height.
Next: To Floor Details
Floor Details
Select 'Yes' if the floor separates your space from the outdoors, an unconditioned crawlspace or basment, or is a slab on grade. Otherwise, if your space is over a conditioned room, select 'No'.
Continue to Construction
Wall & Window Details
Garage Door Details
Ceiling Details
Floor Details
Previous
Submit & View Results
Basic Room & Home
Room Type
Room Size
ZIP Code
Building Age
Temperature
Edit
Avg. Outdoor Temp. High
°F
Avg. Outdoor Temp. Low
°F
Desired Indoor Cooling
°F
Desired Indoor Heating
°F
Walls
Edit
Wall Type
Wall Insulation Quality
North Wall Exposed Area
East Wall Exposed Area
South Wall Exposed Area
West Wall Exposed Area
Garage Door
Edit
# of Garage Doors
Garage Door Insulation Quality
Windows
Edit
Window Type
North Wall
East Wall
South Wall
West Wall
Ceiling
Edit
Ceiling Exposed
Ceiling Insulation Quality
Ceiling Type
Floor
Edit
Floor Exposed
Floor Insulation Quality
Floor Type
Load Results (BTU/hr)
Cooling load
Wall
Window
Ceiling
Floor
Bay
Infiltration
Internal
MRA ?
Moisture Removal Allowance: It is typical for roughly 30% of your air conditioner's capacity to be used to reduce the humidity in your home.
Total
Heating load
Wall
Window
Ceiling
Floor
Bay
Infiltration
Total
Print
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Disclaimer: This sizing tool, although based on a version of the ACCA Manual J, is for informational use and is intended only as a guide to assist with finding the best product for your needs. Since the calculations are based on the information provided, Power Equipment Direct, Inc. assumes no responsibility for inaccuracies resulting from improperly sized equipment. For a complete, professional sizing estimate, please call us at 866-554-HEAT (4328).
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How to Use the PTAC Sizing Calculator

Our proprietary PTAC sizing calculator will ask you several structural questions about your home to determine how many BTUs you need. Many of the questions are designed to determine how much energy your home loses. For example, the more windows and exposed walls you have, the more energy you're losing to the outdoors, and the more BTUs you will need.

Once you answer these questions to the best of your knowledge, our calculator will give a rough estimate of the amount of BTUs you need for heating and cooling. You can then download, print, or email that information to yourself and use it when shopping our site. Keep in mind, the results are meant as a guide and do not replace a full ACCA Manual J calculation.

What if My PTAC is Sized Wrong?

If your PTAC it is too small, you'll find your unit running and running, all the while never reaching that temperature you desire. Beyond just negatively impacting your comfort, your PTAC may suffer physically from the extra wear and tear it experiences while running non-stop.


If it is sized too big, you'll likely experience temperature swings and decreased energy efficiency as your unit cycles on and off too frequently. Just like the constant running of your PTAC, frequent starting and stopping, known as short-cycling, could damage your system over time. Short-cycling is also very inefficient, costing you more money than necessary over the long term.

It's easy to be lured into using simple, rule-of-thumb sizing methods, such as square footage, to size your PTAC. Unfortunately, many other factors can come into play and significantly impact your BTU requirements, such as climate, building materials, and more. Get on the right track with our sizing calculator!

 

 

NEXT: How To Pick The Perfect PTAC

Dale, the Power Equipment Expert
By 
Power Equipment Expert
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