# Show HN: Open-Source M&A Tools > Source: > Published: 2026-10-02 19:21:17+00:00 ### HVAC Rollover-friendly, PE-active. HVAC multiples compound with recurring maintenance plans. Valuation calculators, QoE checklists, deal-structure models, diligence packs, and AI agents. Built for lower middle-market deals in HVAC, plumbing, roofing, pest, landscaping, pool, and electrical. Pairs with the [20 live tools on mainstreetwealth.ai](https://mainstreetwealth.ai/tools). Every category maps to a stage of the deal. Pick your spot and dig in. Calculators and models to size a business and defend a number. Normalize the financials, prove the earnings, and stress the quality. Model earnouts, seller notes, waterfalls, and net-of-everything proceeds. Build the buy-box, run outreach, and manage the pipeline. Request lists, data rooms, red-flag scanners, and operational checks. NDAs, LOIs, disclosure schedules, and state-by-state references. For owners: score the gap, plan the pre-sale year, and plan the proceeds. Open datasets, APIs, and dashboards covering multiples and trade KPIs. Prompt libraries, extraction pipelines, evals, and an MCP server for agents. HVAC, plumbing, roofing, pest, landscaping, pool, and electrical bundles. Quick to adopt, searched often, and the fastest path to a defensible valuation. Reconstruct EBITDA from net income by adding back interest, taxes, depreciation, and amortization. Compute seller's discretionary earnings for owner-operated businesses, including an owner's compensation add-back. Build a defensible add-back schedule with a documentation checklist for each adjustment. Look up typical EBITDA multiples by trade and revenue band, with the sample size and the source. Model rollover equity: cash at close, retained equity, and the second-exit outcome. What the seller actually keeps after taxes, broker fees, legal, and payoffs. Score the business across financials, people, systems, and growth to see how sale-ready it is. Score owner dependence across sales, operations, finance, and relationships. Each trade has its own economics. Jump to the hub toolkit or straight to the advisory page on mainstreetwealth.ai. SBA-financeable at the bottom; family offices and PE roll-ups at the top. Storm cycles and insurance mix drive add-back schedules and multiples. Highest recurring-revenue mix in the trades. Attracts premium multiples. Maintenance vs. design-build mix changes multiple and buyer universe. Seasonal, membership-driven. Route density and geography do the heavy lifting. Open data by trade and size, with sample sizes and sources. Pulled by hand first, then kept honest with community PRs. Cross-checked against the main-site [comparable sales](https://mainstreetwealth.ai/tools/comparable-sales) and [competitor acquisitions](https://mainstreetwealth.ai/tools/competitor-acquisitions) tools. Illustrative figures. Full dataset ships with sample size and source for every row. Every tool here ships with a byline and a review date. Here's who's behind it. This hub is built in the open. Everything from calculators to the AI tooling takes PRs. Each tool page lists what's needed. Start with the ones tagged for new contributors. Learn more One tool, one PR. Keep the scope small. We'll review within a week. Learn more Contributors are credited on the tool page, in the changelog, and in the data license. Learn more Share a few financials and we'll walk you through what a buyer would actually pay today, with context on how we got there. Not legal, tax, or financial advice. For a specific recommendation, talk to a licensed advisor.