How NumeralQ Estimates Home Improvement Costs

A transparent description of our V2.0 composite model, its data sources, structural adjustments, and limitations.

NumeralQ generates localized cost estimates for 13 project types across 147 U.S. markets. This page describes exactly how those estimates are produced — including the model structure, data sources, structural adjustments, and limitations. We have written this to be accurate and complete, not to be persuasive.

1. What the Model Does

Every NumeralQ estimate is produced by the same two-stage formula:

Formula (all services):
local_low = national_baseline_low × city_multiplier
local_high = national_baseline_high × city_multiplier

For square-foot-based services (roofing, siding, insulation, decks), the baseline is per square foot and is multiplied by a typical project square footage before the city multiplier is applied:

local_low = baseline_low_per_sqft × typical_sqft × city_multiplier

There are three formula variants, by service type:

  • Square-foot based (roofing, siding, insulation, deck/patio): national baseline per sq ft × typical home size × city multiplier.
  • Per-unit based (windows): national baseline per window × 12 (typical window count) × city multiplier.
  • Project-range based (HVAC, heat pumps, furnaces, solar panels, kitchen remodel, bathroom remodel, basement finishing, and others): a national project-dollar range × city multiplier.

2. National Baselines

Each service has a national planning baseline — a low and high value representing the typical installed cost range nationally for a defined project scope. Baselines are reviewed annually against published industry benchmarks. Current baselines reflect the following scopes and sources:

  • Roof replacement: $5.50–$9.00/sq ft installed. Scope: architectural asphalt shingle (mid-grade, 30-year) on a simple gable roof, complete tear-off of one layer, standard underlayment, and flashing. Sources: Remodeling Magazine Cost vs. Value 2024, NRCA Cost Report 2024.
  • Roof repair: $400–$2,500/project. Scope: typical localized repair (5–25 sq ft) including materials and labor. Source: NRCA 2024.
  • Siding replacement: $6.00–$10.00/sq ft. Scope: vinyl or fiber-cement siding, full replacement on a typical 1,500 sq ft wall area. Sources: Remodeling Magazine CvV 2024, JLC field guides.
  • Window replacement: $500–$1,500/window. Scope: double-hung, double-pane vinyl or fiberglass window, full-frame replacement, standard size. Sources: NWFA 2024, RSMeans 2023.
  • HVAC replacement: $7,000–$15,000/system. Scope: central split-system AC and air handler replacement (2–4 ton), in existing ductwork. Source: ACCA 2024.
  • Heat pump: $6,500–$18,000/system. Scope: air-source heat pump (2–4 ton) replacing existing system in existing ductwork. Sources: ACCA 2024, AHRI 2024.
  • Furnace replacement: $3,500–$9,000/system. Scope: standard-efficiency gas furnace (80% AFUE) in existing ductwork. Sources: ACCA 2024, RS Means Mechanical 2023.
  • Solar panels: $15,000–$30,000/system. Scope: 6–10 kW residential rooftop system, before federal tax credit. Sources: NREL 2024, Wood Mackenzie Q4 2023.
  • Deck: $22–$50/sq ft. Scope: composite deck, frame and boards, ledger, footings, hardware. Excludes railings, stairs, and permits. Sources: Remodeling Magazine CvV 2024, NADRA 2024.
  • Deck & patio (blended): $18–$45/sq ft. Scope: blended composite-deck and concrete-patio project, footings or slab, excludes cover structures. Sources: Remodeling Magazine CvV 2024, NADRA 2024.
  • Kitchen remodel: $20,000–$80,000/project. Scope: mid-range full remodel — semi-custom cabinets, quartz or granite countertops, standard stainless appliance package, tile backsplash, plumbing/electrical in existing footprint. Sources: NKBA 2024, Remodeling Magazine CvV 2024.
  • Bathroom remodel: $8,000–$35,000/project. Scope: mid-range full remodel — tile shower/tub surround, new vanity and fixtures, toilet, exhaust fan. Sources: NAHB 2024, Remodeling Magazine CvV 2024.
  • Insulation: $1.25–$3.50/sq ft. Scope: blown-in fiberglass or cellulose to bring a 1,500 sq ft attic from R-19 to R-38, including air sealing. Sources: NAIMA 2024, DOE weatherization benchmarks.
Example: A typical 2,000 sq ft roof replacement has a national planning baseline of $5.50–$9.00/sq ft installed ($11,000–$18,000 total). In a city with a multiplier of 0.94, that becomes $10,340–$16,920. In a city with a multiplier of 1.24, it becomes $13,640–$22,320. These ranges represent planning-level guidance for a defined mid-grade scope.

3. City Market Multipliers (V2.0 Composite)

Each of the 147 cities in NumeralQ's coverage has a single scalar multiplier that adjusts the national baseline to reflect local market conditions. A multiplier of 1.00 represents the population-weighted national mean. A multiplier of 0.94 produces estimates approximately 6% below the baseline; 1.24 produces estimates approximately 24% above it.

As of Version 2.0 (July 2026), all city multipliers are derived from a structured four-component composite formula grounded in named public datasets — replacing the V1 manually authored scalars.

3a. Composite Formula

M = 0.50 × LCI + 0.25 × GMI + 0.10 × HSCI + 0.15 × RRP

All components are expressed as ratios relative to the national reference. The raw composite is multiplied by a calibration scalar of 1.0754 (see §3b) before structural adjustments are applied (see §3c).
Component Weight What it measures Source
LCI — Labor Cost Index 50% MSA-level mean hourly wage for 7 construction occupations (carpenters, laborers, electricians, plumbers, roofers, HVAC mechanics, general construction) relative to the national reference wage of $31.90/hr. BLS OEWS Table 3, Nov 2023
GMI — General Market Index 25% Log-dampened ratio of MSA house price index to national HPI (dampening factor 0.35, cap ±0.40). Housing prices co-move with construction costs through shared labor and materials markets. FHFA All-Transactions HPI, Q4 2023
HSCI — Housing Stock Complexity Index 10% Derived from median year built: HSCI = 1 + ((1960 − median_year_built) / 600). Older stock increases scope risk — original roof deck conditions, non-standard framing, and aging electrical/plumbing systems. Census ACS 5-Year, Table B25035, 2022
RRP — Risk & Regulatory Premium 15% Composite of FEMA National Risk Index hazard percentile (hurricane, tornado, hail, earthquake, wildfire, winter storm, flood) and state contractor licensing tier (Tier 1/2/3). Higher hazard exposure and stricter licensing both increase installed project cost. FEMA NRI v3.0 (2023); NCI licensing tier classification (2024)

3b. Calibration Scalar (1.0754)

The raw composite references the employment-weighted national mean construction wage (~$29.64/hr). The population-weighted mean across NumeralQ's 147 covered cities is ~$31.90/hr — a 7.54% difference. Employment weighting systematically underweights large, high-wage markets (New York, Los Angeles, Chicago, Bay Area) that have a disproportionate share of homeowners. The calibration scalar of 1.0754 corrects for this reference-wage choice. It is applied uniformly to all composite values before structural adjustments.

3c. Structural Adjustments

Four categories of markets require structural adjustments that the composite formula does not capture through its index inputs:

Alaska and Hawaii — geographic isolation floors. Anchorage (AK) has a minimum multiplier of 1.50; Honolulu (HI) has a minimum of 1.60. All framing lumber, roofing materials, windows, and HVAC equipment must be shipped from the continental U.S. This shipping and supply-chain premium is not captured by BLS wage data or FHFA HPI, which measure local labor wages and property values respectively, not material transport costs. Supporting evidence: RSMeans Geographic Cost Adjustment Factors (AK: 1.19–1.35, HI: 1.18–1.28 relative to national, Nov 2023).

Florida High-Velocity Hurricane Zone (HVHZ) — building code complexity. Florida Building Code HVHZ provisions require Miami-Dade Product Approval (NOA) on all roofing and exterior materials. NOA-tested products cost 30–50% more than standard equivalents. Since materials represent approximately 35–40% of project cost, compliance with HVHZ specifications adds roughly 14% to total project cost, plus mandatory staged inspections. The BCC (Building Code Complexity) premium is added to the composite result post-calibration, ranging from +0.20 in Miami-Dade/Broward (full HVHZ) to +0.03 in North Florida markets where wind-speed requirements are lower.

Upstate New York — MSA-level correction. New York State's construction LCI is $47.40/hr — dominated by New York City, which represents roughly 60% of the state's construction workforce. Upstate markets (Buffalo, Rochester, Albany) have MSA-level OEWS wages of $33–36/hr. Using the state LCI would produce multipliers of 1.45–1.55 for markets where installed roofing costs $8–10k, not $14–18k. All upstate NY cities use MSA-level BLS OEWS data. The same correction applies to Rockford, IL (state LCI $40.80; MSA ~$28) and Spokane, WA (state LCI $38.60; MSA ~$30).

Contractor density floors. Manchester and Nashua, NH (floor 1.05), Burlington, VT (floor 1.08), and New Orleans, LA (floor 1.00) receive minimum floors. NH markets draw labor from the Boston MSA at premium rates; Burlington's short construction season limits available contractors; New Orleans' hurricane rebuild cycle and below-grade construction complexity push true installed costs above the composite prediction. These floors are conservative — they represent the minimum defensible value, not the average observed contractor bid.

4. Climate Types

Cities are assigned a climate type: hot and humid, hail zone, cold climate, desert, wet climate, hurricane zone, or standard. Climate type affects the qualitative guidance shown on each city page — material specifications, installation requirements, and risk factors. Climate type does not directly modify the price estimate. The city multiplier is the only variable that adjusts the dollar range.

5. What the Estimates Represent

NumeralQ estimates are planning-level cost ranges for typical project scopes in each city. They are intended to help homeowners:

  • Understand the rough order-of-magnitude cost before contacting contractors
  • Evaluate whether contractor bids are within a plausible range for their market
  • Understand how their city's cost level compares to the national planning baseline

6. What the Estimates Do Not Represent

NumeralQ estimates are not:

  • Quotes or bids from contractors
  • Calibrated against a live transaction database or contractor survey data
  • Real-time or continuously updated prices — baselines and multipliers are reviewed annually
  • Decomposed into separate labor, material, and permit cost lines — the city multiplier is a single scalar applied to the total baseline range
  • Applicable to premium scopes (high-end custom materials, large-format projects, historic homes with special requirements)

7. Service Architecture Summary

All 13 services use the same two-stage architecture: national baseline → city multiplier → displayed range. No service uses a different calculation method. Current baselines:

ServiceFormula TypeBaselineTypical Size
Roof ReplacementSquare-foot$5.50–$9.00/sq ft2,000 sq ft
Roof RepairProject range$400–$2,500Typical repair
Siding ReplacementSquare-foot$6.00–$10.00/sq ft1,500 sq ft
Window ReplacementPer unit$500–$1,500/window12 windows
HVAC ReplacementProject range$7,000–$15,000Typical system
Heat PumpProject range$6,500–$18,000Typical system
Furnace ReplacementProject range$3,500–$9,000Typical system
Solar PanelsProject range$15,000–$30,000Typical system
DeckSquare-foot$22–$50/sq ft400 sq ft
Deck & PatioSquare-foot$18–$45/sq ft600 sq ft
Kitchen RemodelProject range$20,000–$80,000Typical kitchen
Bathroom RemodelProject range$8,000–$35,000Typical bathroom
InsulationSquare-foot$1.25–$3.50/sq ft1,500 sq ft

8. Financing Payment Illustrations

Each project cost guide includes an optional financing payment illustration. These use a standard amortized payment formula applied to the project cost estimate at a stated loan term and APR range. They are illustrations only — not offers of credit, not pre-qualifications, and not representations of actual loan terms from any lender.

See our Financing Guide and Financing Disclosure for complete details.

9. Limitations — What Our Estimates Don't Cover

NumeralQ estimates are informed planning ranges, not quotes. They do not account for:

  • Unique home characteristics — unusual pitch, layout, access, age, or condition
  • Material availability and lead times at the time and place of your project
  • Individual contractor pricing based on their current workload, overhead, or market position
  • Hidden damage discovered during project execution (rotted decking, damaged framing)
  • High-end or custom finishes beyond the material grades defined in each service scope
  • Permit fee variation below the state level (city and county permit fees vary widely)
  • Market price movements since the last annual baseline update
  • Projects that differ significantly from the defined scope (e.g., multi-layer tear-off, historic preservation requirements, seismic retrofits)
The right way to use NumeralQ estimates: Use our ranges to understand whether contractor bids are plausible for your market — not to predict your exact project cost. A bid 40% above our range deserves explanation. A bid 30% below it deserves equal scrutiny. Always get at least 3 itemized written bids from licensed local contractors before making any decisions.

10. Contractor Referral Support

When homeowners submit a quote request through NumeralQ, we help connect them with local contractors and home service professionals based on project type and location. NumeralQ is an independent home project intelligence and referral platform — we do not perform contracting work, employ contractors, guarantee contractor performance, or negotiate pricing on behalf of homeowners.

NumeralQ may work with contractors, financing providers, or third-party service platforms to facilitate homeowner project inquiries. Homeowners should independently verify current licensing through their state contractor licensing board, request proof of active general liability and workers' compensation insurance, and review references and contract terms before authorizing any work.

Questions About Our Data

If you have questions about specific estimates, the model, or anything on this page, reach out via our contact page. We are committed to accuracy and will do our best to explain any specific data point.