How the estimates are built.
Home Project Cost provides planning ranges, not contractor bids. Each model combines current U.S. cost benchmarks with project details that commonly affect labor, materials, and installation difficulty.
How source data is used
Published project-cost guides can differ because they use different datasets, contractor networks, material assumptions, and geographic coverage. Rather than treating one published average as the answer, the calculators use broad national cost ranges and adjust them for the project inputs shown on each page.
Current models use national benchmarks rather than ZIP-level pricing. Local labor rates, material availability, permits, contractor demand, taxes, and site conditions can move an actual quote above or below the planning range.
Roofing model v2026.09
The roofing calculator estimates roof surface area from finished home square footage, story count, and roof pitch, then includes a waste allowance. It applies an installed per-square-foot range based on material and adjusts for pitch, stories, roof complexity, and tear-off.
The model is calibrated against current U.S. roofing cost guides. Published ranges vary substantially by material, labor, roof design, and market, so the calculator preserves a broad planning band instead of relying on a single city-specific or national average.
What the roofing model cannot know in advance
- Hidden roof-deck damage before tear-off
- Project-specific permit and inspection fees
- Short-term contractor demand and local labor conditions
- Specialty flashing, structural repair, or solar removal
- Exact local material and contractor pricing
How to compare roofing quotes
Compare quotes on the same scope. Verify the roofing product, underlayment, flashing, ventilation, tear-off, disposal, cleanup, permit responsibility, decking replacement price, workmanship warranty, and manufacturer warranty. A low bid that omits major scope is not directly comparable to a complete bid.
HVAC model v2026.09
The HVAC calculator starts with broad installed-cost ranges by system type, then adjusts for home size, efficiency tier, ductwork scope, and installation difficulty. The current model is intended for replacement planning, not equipment sizing.
The model is calibrated against current U.S. HVAC cost guides from multiple published sources. Because those sources report different ranges by system, efficiency, home size, and installation conditions, the calculator returns a planning band rather than a single national average.
How to compare HVAC quotes
Compare exact equipment model numbers, efficiency ratings, labor scope, ductwork changes, thermostat and controls, electrical work, permit responsibility, startup/testing, and equipment and labor warranties. System sizing should come from a proper load calculation rather than square footage alone.
Siding model v2026.09
The siding calculator estimates exterior wall area from finished home square footage and story count using a simplified footprint. It subtracts an allowance for doors and windows, adds a waste allowance, then applies broad installed-cost ranges by siding material. Height, exterior complexity, trim detail, and tear-off adjust the final range.
The model is calibrated against current U.S. siding cost guides from multiple published sources. Material type, house design, trim, tear-off, local labor, and hidden wall conditions can produce wide differences in actual quotes, so no single published average is treated as a universal price.
How to compare siding quotes
Compare the exact siding product, tear-off and disposal, weather barrier, flashing, trim, soffit/fascia scope, sheathing-repair pricing, permits, cleanup, and both workmanship and manufacturer warranties. Hidden moisture or rot discovered after removal should be priced separately.
Estimate independence
The cost models are calculated independently from any referral relationships. If an optional connection to a service provider is offered, its availability does not change the planning estimate.