Resources
Guides for people who pull permits.
Plain-English answers to the questions we hear every week.
Guides
Pick your guide.
Homeowners
Most HVAC quotes are sized by square footage. Here is why bigger usually means worse, and how to know the right size before you sign.
Home builders
You would never ask a framer to price a house before the plans exist. HVAC deserves the same order of operations.
HVAC professionals
Rules of thumb built a lot of businesses. Real designs build reputations. Here is how contractors use an outside design partner without adding payroll.
Permit requirements
What building departments in KY, TN, the DC region and Florida ask for, with sources.
Tools and articles
Everything else.
HVAC load calculator
Estimate BTUs and tonnage, compare with the rule of thumb, and download a one-page PDF.
Why you need a Manual J calculation
Rule-of-thumb sizing is fast and usually wrong. Here is what the Manual J does instead, and why building departments ask for it.
HVAC load calculation requirements by state
There is no single national rule. Here is how the requirement flows from the model codes to your county, and the quickest way to confirm what your permit needs.
Fast load calcs for permit deadlines
Most delays are missing information, not design time. Here is what to send the first time so your calculations come back fast.
Same-day quotes
Drop the plans. Get a quote today.
Drop in the plan set and pick your services. A designer replies with price and turnaround, usually within 30 minutes during business hours.