Working Through Janis' Mechanical And Electrical Systems In Buildings
If you're an architect or engineering student trying to actually use this book rather than just buying it for a course requirement, here's how to get value out of it. Richard R. Janis wrote Mechanical And Electrical Systems In Buildings as a practical reference, not a theoretical treatise. The problem is most people approach it like a textbook and get bogged down in chapters that don't apply to their actual work. Don't start with the intro chapters on history or theory. Go straight to the HVAC section if you're doing anything climate-related, or the lighting section if electrical is your focus. I learned this the hard way during a late-stage retrofit project where we spent three weeks fighting with a VAV box layout because I hadn't cross-referenced the duct sizing tables early enough. Janis has those tables spread across multiple chapters in a way that isn't immediately obvious. You need to open the book, flip to the index, and find the specific component you're dealing with before you get trapped in chapter one. The electrical load calculation chapter is genuinely useful if you know how to use it. Most people skip past it because the examples look oversimplified. They aren't. I ran into a situation last year where a municipality was rejecting my lighting power density calculations because I was using outdated fixture counts. Janis' method of breaking it down by space type and occupancy gave me the exact framework I needed to redo the calculations and get the plan approved. It took about ten minutes once I stopped second-guessing the approach.
What The Book Gets Wrong Or Leaves Out
Here's the thing nobody tells you: the book was last updated years ago and doesn't cover modern building automation systems the way current practice requires. The sections on controls are adequate for understanding fundamentals, but if you're specifying a BMS or working with actual EMS commissioning, you'll hit a wall. I've had clients ask me to justify control sequences and I had to pull from other references because Janis simply doesn't go deep enough on the programming side. The plumbing sections are similarly light. If your project involves anything beyond basic domestic water distribution, you need supplemental references. I worked on a high-rise residential project where the stack venting calculations alone required pulling three different codes and cross-referencing them against Janis' coverage, which barely scratches the surface of what actual practice demands.
How To Actually Use This For Real Projects
Treat it as a lookup reference, not a reading book. Keep it open on your desk while you work through schematic design. When you encounter a system you're less familiar with—heat recovery ventilators, say, or arc-fault detection requirements—go to that section and read it with a specific problem in mind. The information lands differently when you're looking for an answer to something you're actually stuck on. I also recommend keeping a separate spreadsheet where you note down the chapter and page number every time Janis gives you a useful figure or method. By the end of a project, you'll have a personalized quick-reference list that's worth more than the book itself. I've done this for every major project over the last decade and it's saved me hours of flipping back and forth through the index. The download question comes up sometimes. The book is published by Wiley and available through standard academic and trade channels. I wouldn't recommend scanning it or finding pirated copies because the diagrams and tables are what make this reference valuable, and low-resolution reproductions render those nearly useless when you're trying to read duct sizes or wire gauge tables. Your time is better spent ordering a used copy from a reliable seller than hunting for a digital shortcut that won't hold up under real use.
Get the Full Details
One more thing: if you're using this for LEED or energy modeling purposes, pair it with the ASHRAE 90.1 standards. Janis references them but doesn't reproduce the full compliance language. I learned this when a client's energy model came back non-compliant and I realized I'd been working from Janis' summary tables instead of the actual standard. Took me an afternoon to reconcile everything and get the documentation right. Not ideal, but a useful lesson.
