HVAC Residential Load Calcs

• Price: $34.99
• HVAC Equipment Locator — $9.99

Last verified 6 Aug 2026

3.0 3 ratings · App Store

1. 3/5Envelopes are confusing

   3 stars because it does the job. What job that is, whether it is accurate… Dunno yet. Envelope categories: Not positive but I think that in Manual J, 16B- refers to a vented attic with insulation at the roof deck, meaning the insulation follows the slope of the roof rather than sitting on the ceiling. Not in this app! It is classified as “Under attic”. The descriptions are not the best. And the categories seem incomplete too. Pretty sure there are many not listed here. But I’m mostly worried they are completely wrong. Another weird thing: when I define, say a floor, in the Block Load Info > Envelope, it asks for length and width (say, 14’ x 10’). Great! Changing the length and width values in this section definitely affects overall heat load. Also great! But then if you go to Room List > Envelope and assign that floor to the room, it asks me for Area… Not great! Why, if it already knows the area from the Block Load info > Envelope section, am I entering Area?But ok… it asks, so I enter: 140 sq ft. Heres the weird thing though. If I change the Area of the envelope when assigning it to a room, it affects the Heat Load for that room. Kind of what you would expect. But if I go to the Block Load Info > Envelope list and change the length and width, it also affects the Heat Load for that room! Since changing either of them has an effect, are both being applied and, if so, why? I am tempted to make the Block Info > Envelope simple 1 square foot (1’x1’) — mostly because the number it is spitting out for my 1660 sq ft house (50k BTUh) seems a bit high. Still hoping these are quirks with the app that have solutions after learning it better. I am probably going to calculate all by hand against manual j and find out.

   smallcitydesign · 6 Aug 2026

2. 5/5Go to load Calc app.

   Used this app many times to perform load calculations with success.

   battson34 · 6 Aug 2026

3. 1/5DW

   Can’t open app customer service will not respond. Don’t waste your money like I just did.

   airoworth · 6 Aug 2026

4. 5/5Good app and great support

   I downloaded this app and, yes, it was a little hard to use at first. Isn't all software? I called Carmel, and they got back to me ASAP and trained our guys for 1/2 hour for FREE. After the training, we knew how to use it much better, and now 3 of my guys use it constantly in the field. It's a great tool and I love the email capabilities so I can review their work later on. Yes, it's not perfect, like I wish the reports were simpler and more appropriate for customers, but they are working on that. As far as I know, this is the only load calc app out there, and it's a great first step in this whole mobile app world. Great app and look forward to more......

   AirConReseller1001 · 6 Aug 2026

5. 5/5Great HVAC load calc app

   I've been using this app for a couple weeks now at the recommendation of Trane. It's been very useful and accurate. I've compared it to my desktop Manual J software, and it is the same heating and cooling loads. I especially like the fact that when I first downloaded it, I called Carmel and asked if they could help me out. In fact, they offered to train me and a couple of my guys on how to use the app for about 1/2 hour. It really made a difference in using it after the training session. I would highly suggest being trained. The negative comments that have been posted may be due to the fact that they do not know how to use the software properly. I would suggest the training. Great app!

   HVAC Reseller · 6 Aug 2026

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