Phoenix presents a set of HVAC design challenges that a lot of the country never has to think about. Summer highs in Phoenix are regularly pushing past 110°F, with more than 100 days a year above 100°F. Plus, they have an energy code that requires permit-ready HVAC load calculations on new installations.
HVAC Essentials handles Manual J, S, & D calculations for contractors and homeowners throughout Arizona and the Phoenix metro. Our ACCA-certified team works from plans you submit online and delivers completed reports in less than 2 business days.
Manual J is the ACCA-standard method for calculating a building’s true heating and cooling load. It accounts for everything that affects how much energy a home gains or loses. The result is a room-by-room picture of what the HVAC system actually needs to deliver, not a rough estimate based on floor plan square footage.
In Phoenix, Manual J is required by code when installing a new system. It’s essentially the foundation for every other design decision. Here’s why it matters.
Phoenix homeowners run their AC systems for the better part of the year. A system that’s even one ton oversized will short-cycle constantly. That means the system keeps turning on and off again, rather than running consistently. When short-cycling happens, it burns more electricity, puts more wear and tear on the compressor, and will definitely show up on your utility bills from May to October.
A short-cycling system cools the air quickly but doesn’t run long enough to remove moisture from it. During Phoenix’s monsoon season (July through September), that can leave a home feeling muggy even when the thermostat reads 76°F. Having it properly sized means you’ll have a system that runs longer, so it can get the job done.
While staying comfortable is important, so is keeping your air clean. Phoenix air carries fine particulates, dust, and allergens year-round. A correctly sized system running full cycles filters the air better than one that’s constantly cycling on and off. Constant humidity from an oversized system creates the perfect conditions for mold growth, which is a huge concern for bathrooms, laundry rooms, and kitchens, and anywhere airflow is limited.
Once Manual J tells you what the load is, Manual S tells you the actual equipment you need. Again, this matters more in Phoenix than in other places, since AC units and furnaces perform a lot differently based on outdoor temperature (think of Phoenix’s 110°F days), indoor humidity, and airflow through ducts. Manual S selects equipment based on real-world performance at Phoenix’s actual design conditions.
Running Manual S as part of your design process has these benefits:
Manual D calculates the size and layout of your duct system. It’s so the air moves and reaches the right rooms at the right volume.
Once again, Phoenix makes these requirements non-negotiable. Attic temperatures can hit 150°F in summer. That means every foot of leaky or undersized duct is dumping conditioned air into unconditioned space. Phoenix also follows the 2018 International Energy Conservation Code (IECC), which requires HVAC load calculations for many new construction and replacement projects.
A solid Manual D gives you the best shot at passing. Skipping it leaves you exposed to:
When you need Manual J, S, or D calculations in Phoenix, AZ, HVAC Essentials is ready to help! Submit your plans to us online (hand-drawn sketches accepted), and receive your completed report in less than 2 business days. We also perform Blower Door and duct blast leakage testing for projects that need third-party verification under Phoenix’s energy code.