Pipe Insulation Calculator

Insulation R-value here depends on exactly two things: Insulation thickness and Insulation material -- nothing else. Pipe diameter, Pipe length, Fluid temperature, and Ambient temperature are all completely inert on Insulation R-value, holding steady across their entire declared ranges, because the formula (thickness divided by the material's k-value) never references pipe size or temperature at all. Of the two inputs that do move it, Insulation thickness has the larger effect across the full menu of both selects, since it scales the R-value directly while material choice only shifts it through the material's k-value.

Heat loss (insulated), by contrast, responds to pipe geometry: increasing Pipe diameter always raises it (a bigger pipe has more surface area to lose heat through, even with the same thickness of insulation wrapped around it), and increasing Pipe length always raises it too, scaling in direct proportion since it's simply the per-foot heat loss multiplied by run length. Fluid temperature is the one input that behaves less simply than "higher is worse": heat loss tracks the absolute temperature difference between the fluid and the surrounding air, not the fluid's temperature on its own, so as Fluid temperature climbs from the low end of its range up toward the Ambient temperature default, heat loss actually falls toward zero before climbing again past it -- a chilled-water line running well below ambient can lose about as much heat as a hot-water line the same number of degrees above it. Temp drop per 100 ft, notably, does not change with total Pipe length -- it's already expressed as a per-100-ft rate, so a longer run changes the total heat lost, not that rate.