Installed cost: the gap that starts this comparison
Vinyl runs $3 to $12 per square foot installed, against $5 to $14 for fiber cement, per Fixr and HomeGuide's own siding cost data. A full house sided in vinyl averages around $12,000 nationally; the same wall area in fiber cement can run from roughly $8,000 at the low end of its range well past $20,000 depending on the profile chosen.[1],[2]
A warranty, not a guess, on how long each one lasts
James Hardie backs its fiber cement boards with a 30-year, non-prorated warranty, and separately says the product is built to hold up to the elements for decades on end. Vinyl's trade group, the Polymeric Exterior Products Association, points to a lifetime warranty for the original owner and a prorated warranty running at least 50 years for whoever owns the house after that.[3],[4]
A long prorated warranty isn't the same promise as a non-prorated one: a prorated claim typically pays out less the further the siding is into its warranty term, while Hardie's 30-year coverage pays the same regardless of when the claim happens inside that window.
Upkeep: a hose versus a repaint
James Hardie recommends a low-pressure spray and a medium-bristle cleaning brush once or twice a year to clear dirt and debris off its boards. Pre-primed boards still need their own topcoat, though its ColorPlus factory-finished line skips that step at install and carries its own 15-year paint-and-labor warranty.[3]
Vinyl's maintenance is lighter still: an occasional rinse, no repainting ever expected, since the color runs through the material rather than sitting on top of it as a separate coat.
Fire resistance, where the two materials really part ways
James Hardie's siding is verified noncombustible under ASTM E136 and carries a Class A flame spread rating under ASTM E84, with a flame spread index of zero. Vinyl siding is a petroleum-based plastic and doesn't carry a noncombustible rating of that kind, which is part of why some wildfire-prone jurisdictions restrict or require upgraded detailing around it.[5]
Impact and moisture: where fiber cement's weight cuts both ways
Fiber cement's density is exactly what gives it an edge against hail and flying debris, but that same density is why it costs more to ship, cut and install than a light vinyl panel. James Hardie markets its boards as resistant to swelling and warping in ways traditional wood and vinyl can struggle with over time, though no siding material is actually waterproof on its own without correctly installed house wrap and flashing underneath it.[3]
Vinyl handles moisture well in its own right, since the material itself can't rot, but a hard impact, a thrown rock, hail, debris in a storm, can crack or punch through a vinyl panel in a way it generally won't dent or crack a fiber cement board of the same thickness.
Putting the tradeoff in plain terms
Vinyl costs less to install and needs almost nothing done to it afterward, but trails on fire rating, impact resistance and how its warranty actually pays out over decades. Fiber cement costs more upfront and needs occasional cleaning, and in Hardie's ColorPlus line, no repainting, in exchange for a noncombustible rating and a flat, non-prorated warranty term. Run both materials through this site's calculator for your own wall area before deciding which gap matters more for your budget.