llms.txt
+13 −1
https://horizonshield.dev/llms.txt
− - [Guides: reading a contractor quote with public data (hub)](https://horizonshield.dev/guides/): Six guides, one question each, every figure linked to the government record it comes from.+ ## Peer-reviewed research+ - [A Demand-Side Benchmark for Consumer-Facing Construction Cost Questions: Price-Figure Span, Output Consistency, and the Case for a Verifiable Reference Layer](https://doi.org/10.3390/iic2040015): Toshikatsu Oga, Intelligent Infrastructure and Construction 2(4):15, MDPI, October 16, 2026, open access (CC BY 4.0). 40 Japanese renovation price questions put to frontier AI models: the stated going-rate range was a median of 2.5 to 3 times wide; price figures inside one answer spanned a median 10 + - [Guides: reading a contractor quote with public data (hub)](https://horizonshield.dev/guides/): 22 guides, one question each, every figure linked to the government record it comes from.+ - [Is my solar quote fair? Check the price per watt](https://horizonshield.dev/guides/is-my-solar-quote-fair/): Cash price divided by system size in watts DC. Berkeley Lab 2026 Data Update: median prices across the top 100 residential installers in 2025 ranged $2.4 to $6.3/W, roughly 60% below $4/W. IRS: the Residential Clean Energy Credit (25D) is not allowed for expenditures made after December 31, 2025 (made = installation completed). CFPB: solar loan dealer fees typically 10% to 30% of the c+ - [HVAC replacement quote: what each line should say](https://horizonshield.dev/guides/hvac-replacement-quote/): Five kinds of lines (equipment, labor, materials, permit, disposal). IRC 2021 M1401.3: size with ACCA Manual S or another approved method, on loads from ACCA Manual J or another approved method. Verify the matched system with its AHRI Certified Reference Number. BLS May 2025 national wage, HVAC mechanics and installers (49-9021): $29.33 median, $45.78 p90 per hour (pay, not billing ra+ - [How much does it cost to build a house? Read the bid per square foot](https://horizonshield.dev/guides/cost-to-build-a-house/): For contractor-built single-family houses started in 2025, the Census Bureau reports a median contract price of $404,000 and a median of $171.57 per square foot ($198.33 average), with land excluded. Regional medians ran from $157.30 (South) to $194.09 (Midwest). Divide your builder's bid by finished square feet, then check what sits inside it: site work, permits and+ - [Roofing materials on a quote: what each line should say](https://horizonshield.dev/guides/roofing-materials-on-a-quote/): Every materials line on a roofing quote should name a product and a quantity. Shingles and decking have a public floor from the Census import chain: $13.03 to $14.16 per 4 by 8 foot sheet of 7/16 inch OSB before freight and labor. Underlayment, ice barrier, drip edge, flashing and vents have no clean public price, but the 2021 IRC says where they go. Truss work may need a + - [Window repair or replacement: what the quote should say](https://horizonshield.dev/guides/window-repair-or-replacement-quote/): A window quote either repairs parts of a window (glass, sash, hardware, weatherstripping) or replaces it (insert or full-frame), and it has to say which, window by window. Check the product against its NFRC label (U-factor 0.20 to 1.20, lower keeps more heat in). In pre-1978 homes, paid window replacement is never "minor repair" under EPA's lead rule (40 CFR 745.83),+ - [Water heater or boiler replacement quote: what each line should say](https://horizonshield.dev/guides/water-heater-replacement-quote/): A water heater replacement quote is the unit, labor, code items, permit and haul-away. Check the model's UEF in the DOE Compliance Certification Database, labor against BLS plumbers' wages ($30.67 median and $52.13 at the 90th percentile per hour nationally, plain wages, not billing rates), and whether your city requires each add-on. The federal 25C credit en+ - [Electrical panel upgrade quote: what to check before you sign](https://horizonshield.dev/guides/electrical-panel-upgrade-quote/): A panel or service upgrade quote should show a load calculation under National Electrical Code Article 220, the permit, the utility's disconnect, reconnect and meter steps, and each part as its own line. Electricians earn $30.38 median and $52.17 at the 90th percentile per hour, plain wages, not billing rates (BLS, May 2025). The federal 25C panel credit ended for + - [Bathroom exhaust fan install cost: what the quote should show](https://horizonshield.dev/guides/bathroom-exhaust-fan-install-cost/): A bathroom exhaust fan quote is the fan, the duct and cap, the electrical work, the ceiling patch and the permit. The residential code lists 50 cfm intermittent or 20 cfm continuous for a bathroom and says the air goes outdoors, not into the attic. Check the fan's model against ENERGY STAR or HVI listings, the duct against the code's length table, and labor agai+ - [French drain or yard drainage quote: what it should specify](https://horizonshield.dev/guides/yard-drainage-french-drain-quote/): A French drain or yard drainage quote should state the linear feet, trench size, pipe, gravel, fabric and where the water ends up. Divide the price by the feet. Delaware's environmental agency put a contractor-installed 60-foot French drain at $1,000 to $4,000 (2022 dollars). 811 is free. Virginia law requires a locate request before excavation, except hand digging+ - [Home improvement loans: checking the financing that comes with a quote](https://horizonshield.dev/guides/home-improvement-loan-on-a-contractor-quote/): When a contractor offers a loan with the quote, compare the cash price with the amount financed and the total of payments on the Truth in Lending disclosure. The CFPB found solar dealer fees typically run 10 to 30 percent of the cash price, added to the loan. A loan secured by your principal dwelling usually carries a right to rescind until mi