SwiftSize vs NATE ResLoad
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
SwiftSize
This HVAC tool quickly calculates residential heating and cooling loads on-site. It streamlines the process for professionals, allowing for faster equipment sizing and more customer consultation time. Generate shareable PDF reports of your calculations.
- Quick heat load calculations
- On-site measurements
- Accurate equipment sizing
- Shareable PDF reports
- Minimizes engineering time
- Equipment changeout focus
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SwiftSize is an HVAC (heating, ventilation, and air conditioning) load calculator for residences. It is designed to very quickly measure off a home's exposures "on the fly" and produce accurate results for sizing heating and air conditioning equipment. Now generates a shareable PDF Report! It is designed to minimize the on-site engineering time required by the HVAC professional. Less time engineering means more one-on-one time with the customer! HVAC heat loads can be a cumbersome and time consuming and tend to distract from time spent consulting. SwiftSize addresses this problem by allowing complete heat loads to be performed in mere minutes. If it takes you more than 10 minutes with SwiftSize you're doing something wrong! SwiftSize is not a comprehensive room-by-room heat loss/heat gain/CFM calculator. If it were it would be SlowSize! It's intended for the equipment changeout market, not the new construction market.
NATE ResLoad
This app performs ACCA-approved residential load calculations for HVAC systems. It allows users to create detailed reports for cooling and heating loads, including room-by-room analysis, and email them as PDFs. It also includes a built-in HVAC Equipment Locator.
- ACCA-approved Manual J8 calculations
- Field-based load calculations
- Emailable PDF reports
- Unlimited project creation
- Global weather database
- HVAC Equipment Locator included
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The NATE ResLoad-J app was developed by Carmel Software for North American Technical Excellence, Inc. (NATE). This is an ACCA-approved Manual J8 residential load calculation app for the Apple iPad. It allows engineers, contractors, and technicians to perform field-based cooling and heating load calculations on residential and small commercial buildings. Users are then able to email PDF reports to customers and local building officials. Reports produced by this app will be acceptable by all municipalities/states (including Florida and Massachusetts which recently passed laws requiring contractors to submit load calcs from ACCA-approved software.) For training webinar schedule, go here: http://bit.ly/SaHmPS For online help and training videos, go here: http://bit.ly/1PhqlDi Bonus: The NATE ResLoad-J app now includes our popular HVAC Equipment Locator app built right in! Click here for details about that app: http://bit.ly/1a2RskH The NATE ResLoad-J app allows users to create unlimited projects and perform both block and room-by-room loads. The app includes weather data for 1000s of cities throughout the world and construction data for 100s of wall, floor, roof, ceiling, and window types. The user is also able to model detailed appliance, duct, infiltration, and ventilation loads. This app was specifically designed for the Apple iPad, taking advantage of the larger screen, rotating user interface, and other functionality unique to the iPad. Other features include: 1. Includes a 1000+ world-wide city weather database 2. Allows you to create and store an unlimited number of projects. You can also re-use existing projects as templates for new projects. 3. Includes data for 100s of construction types for walls, roofs, floors, doors, windows, skylights, and ceilings. 4. Allows you to specify an unlimited # of building envelope types (i.e. – doors, walls, roofs, floors, ceilings), window types, and skylight types for each building. 5. Allows you to input individual home appliance information. 6. Allows you to instantly view total heating and cooling load results as you update input data. 7. Allows you to view comprehensive cooling and heating load breakdown reports including breakdown by envelope load, window load, skylight load, infiltration load, ventilation load and internal load contributions. 8. Also performs room-by-room cooling and heating load calc analysis 9. Includes the ability to display a wide variety of on-screen reports including checksum reports (ie – BTUh/SqFt, SqFt/Ton, etc.), complete heating and cooling load breakdown reports, and even graphically-pleasing pie charts showing cooling and heating load breakdowns. These reports can be converted to PDFs and emailed from right within the app. 10. Includes the ability to display a comprehensive HTML report that you can email to yourself or others, and it also includes a spreadsheet attachment that you can open in Excel to create customized reports. 11. Includes the ability to display units in either English (IP) or Metric (SI). The benefits of using this app are numerous including: 1. Great for use out in the field. Quickly size heating and cooling equipment, show the client, then email the results back to your office for further analysis. 2. Show off your advanced on-screen reports to clients convincing them you are using cutting-edge technology. 3. Save time by inputting information in the field and then returning to your office to perform more in-depth analysis. 4. Submit reports to local municipalities that require ACCA-approved Manual J8 residential load calcs for equipment replacement.
Screenshots
Verdict
The clearest difference is price: SwiftSize at $9.99 against NATE ResLoad's $169.99. SwiftSize also leads on rating (4.0 vs 2.3) and update cadence (every 10 months vs every 31 months). NATE ResLoad's advantage is iOS requirement (13.0 vs 17.0). On review sentiment, ratings volume, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
SwiftSize costs $9.99 and NATE ResLoad $169.99 up front. Neither carries in-app purchases, so what you see is what you pay.
SwiftSize holds the better App Store score, 4.0 against 2.3. Both are backed by a comparable volume of ratings — 3 and 3 respectively. Written reviews split almost evenly too, at 33% and 33% positive.
SwiftSize ships an update every 10 months, NATE ResLoad every 31 months. Both last shipped on October 24, 2026.
| Parameter | SwiftSize | NATE ResLoad |
|---|---|---|
| Price | $9.99 — better | $169.99 |
| Rating | 4.0 (3 ratings) — better | 2.3 (3 ratings) |
| Positive reviews | 33.3% of reviews | 33.3% of reviews |
| Number of ratings | 3 | 3 |
| Update frequency | Every 10 months — better | Every 31 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Best chart rank | #123 — better | — |
| Devices | iPhone, iPad — better | iPad |
| Requires iOS | 17.0 | 13.0 — better |
| Further details — not scored | ||
| Size | 2 MB | 26 MB |
| Age rating | 4+ | 4+ |
| Developer | Design Comfort | Carmel Software Corporation |
Customer experience
SwiftSize
NATE ResLoad
In-app purchases
SwiftSize
No in-app purchases
NATE ResLoad
No in-app purchases
Questions
Is SwiftSize free?
Is NATE ResLoad free?
Which has better reviews, SwiftSize or NATE ResLoad?
Do SwiftSize or NATE ResLoad have ads?
Which is updated more often, SwiftSize or NATE ResLoad?
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