Heat loss calculator and selection guide for Slant/Fin hydronic heating products. Figure heating loads and select the right hydronic heating equipment with greater speed and accuracy!

What’s New

Version 2.8

Update product information

Ratings and Reviews

1.0 out of 5
2 Ratings

2 Ratings

jamescobalt ,

Imperfect but handy

I’m rating this based on the price of Free. I read Slant/Fin plans to charge for this in the future, which is fine, provided it’s souped up first. For the layman (I’m not an installer; just a homeowner), there are some terms that aren’t clearly explained within the app, and finding help and doing some actions (like deleting objects) are completely unintuitive and require too many steps. Some standardized swipe actions would go a long way. Visually it’s a bit Web 2.0 and behind the times, but what’s important is the calculation, and that’s what it does in a more convenient form factor than a spreadsheet. My plumber did the Slant/Fin calculation prior using the spreadsheet version and, as they often do, left a lot of fields blank. I didn’t trust his calculation so I did it myself in this app, resulting in much more accurate number that was nowhere near his original.

It’d be nice if there was a third party version of this app that included products from lots of manufacturers. The data was useful but when I used the built in ‘find a boiler’ feature, there was nothing that matched my needs.


wasted 2 hrs entering data into the heat loss calculator before crash rendered data inaccessible

Worse than just not working, it has a heat-loss calculator that appears useful, just jumping you through hoops before failing. I would have been much better off had it done nothing at all, instead of luring me in. I measured every wall, window, and door, characterized my attic and wall insulation in every room, on-and-on, entering the data as I went. Just as I finish up the whole house and get ready to look at the bottom line number... bam! the app crashes, never to open again (without immediately closing). So now, not only do I not have the answer, but I must go re-accomplish all of the measurements and data entry into another app to get it.

DMSO84 ,


Detailed tool for estimating heat loss for each room in a house/project. For homeowners, additional help texts (e.g. Definitions and field explanations) would be great. For HVAC techs, fields for heat gain (e.g. Solar exposure, shade, etc.) would make this tool that much more useful.

The summary report is a bit buggy (I.e. Correct BTUs, but wrong convector lengths on several rooms). Would be helpful if it could export a more detailed report (e.g. All numbers per room), or export to an Excel worksheet, and could add comments on the room (as opposed to just the project) level. Usability could be improved, but it's not bad.


Slant/Fin Corp.
13.5 MB

Requires iOS 7.1 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
Frequent/Intense Mature/Suggestive Themes
Frequent/Intense Medical/Treatment Information
Infrequent/Mild Horror/Fear Themes
Infrequent/Mild Alcohol, Tobacco, or Drug Use or References
Infrequent/Mild Simulated Gambling


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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