DALC vs Building Start
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
DALC
This tool helps engineers, architects, designers, and contractors accurately estimate air leakage from ductwork. It simplifies determining pass/fail for duct air leakage tests and allows combining multiple duct sections for total leakage calculations, adhering to industry standards.
- Estimate ductwork air leakage
- Determine DALT pass/fail
- Combine multiple duct sections
- Calculate total allowable leakage
- Provides suggested leakage classes
- Compliant with industry standards
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This simple to use but effective application is provided by the Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA). This tool allows engineers, architects, designers, and contractors to easily and accurately estimate the leakage of air from ductwork. It also allows a quick and easy way to determine the pass/fail mark for properly specified Duct Air Leakage Tests (DALT). Users can combine multiple sections of ductwork that vary by size and shape to calculate a total allowable leakage. The application uses the method outlined in SMACNA’s HVAC Air Duct Leakage Manual, and provides suggested leakage classes from SMACNA’s latest edition of the manual. The method used is compliant with ASHRAE 90.1, IECC, IGCC Version 2, IMC and the UMC.
Building Start
This platform digitizes field testing for construction and engineering projects. It allows for centralized test plan creation and offline execution on field devices, synchronizing data back to the cloud upon completion.
- Centralized test plan authoring
- Push test plans to field devices
- Offline field testing capabilities
- Data synchronization to cloud
- Digital capture of construction projects
- Support for TAB, Building Startup, Commissioning, Energy Audits
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Building Start is a field services platform used in construction and engineering to perform centralized test plan authoring and management and push the test plan from the cloud to field devices to perform on-site field testing digitally. Once a field technician has been assigned a project, they can receive the project on their field device and perform the test plan and responses offline and synchronize them back into the cloud when they complete their work for the day. Building Start is widely used in the construction industry with over 30,000 construction projects digitally captured in such efforts as Test, Adjust & Balance (TAB), Building Startup, Building Commissioning (LEED, Green Building,etc) and Energy Audits.
Screenshots
Verdict
The clearest difference is rating: Building Start at 3.4 against DALC's 2.2. Building Start also leads on review sentiment (50% vs 15%). DALC's advantage is update cadence (every 2 weeks vs monthly) and ratings volume (26 vs 8). On price, ads, in-app purchases and monetization model 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
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Building Start holds the better App Store score, 3.4 against 2.2. Both are backed by a comparable volume of ratings — 26 and 8 respectively. Written reviews point the same way: 15% of DALC's written reviews are positive against 50% of Building Start's.
DALC ships an update every 2 weeks, Building Start monthly. The most recent releases landed on October 8, 2026 and September 24, 2026 respectively.
| Parameter | DALC | Building Start |
|---|---|---|
| Price | Free | Free |
| Rating | 2.2 (26 ratings) | 3.4 (8 ratings) — better |
| Positive reviews | 14.8% of reviews | 50.0% of reviews — better |
| Number of ratings | 26 — better | 8 |
| Update frequency | Every 2 weeks — better | Monthly |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 6.0 — better | 15.0 |
| Further details — not scored | ||
| Size | 10 MB | 12 MB |
| Age rating | 4+ | 4+ |
| Developer | SHEET METAL CONTRACTORS NATIONAL ASSOCIATION, INC. | Building Start |
Customer experience
DALC
Building Start
In-app purchases
DALC
No in-app purchases
Building Start
No in-app purchases







