Calculators and straight answers about heat, air and moisture in buildings — built by a licensed professional engineer, and checked against the same references the industry designs from.
Dew point, wet-bulb, humidity ratio, enthalpy and specific volume from any two known conditions. Correct over ice as well as water, with true elevation correction.
Pitch, angle, rafter length and roof area — the geometry that drives attic volume, ventilation area and roof-plane load.
Whether a given surface — window, duct, rim joist, wall cavity — will sweat under your indoor and outdoor conditions.
Most free building calculators are built by marketers rather than engineers. They tend to be close enough for a rough estimate and quietly wrong at the edges — below freezing, at altitude, or anywhere the simplifying assumption stops holding.
That is a real problem when the answer decides whether a duct sweats inside a wall, or whether a system is sized correctly for the house it's going into.
Everything here is built to the reference standards the industry actually designs from, and each tool documents its own method so you can check the work rather than trust it. Where a result depends on an assumption, the assumption is stated.