You got the call. A private equity firm — or their intermediary — has expressed serious interest in your HVAC business. An LOI is on the table or coming soon.
Congratulations. And now: get to work.
The moment a Letter of Intent is signed, due diligence begins. This is the 60-to-90-day stretch where a buyer's team of lawyers, accountants, and operational consultants systematically disassembles your business to verify every number, inspect every contract, and surface every risk. They are spending $500,000 to $1 million or more in advisor fees to do this. They will find things.
The question is whether the things they find are things you already knew about — or surprises.
This checklist is your preparation guide. Five categories. Twenty-plus items. And for each one, the reason a PE buyer actually cares — not just what it is, but what a problem signals to them and what “good” looks like from their seat.
If you want the condensed version, download the free PE Due Diligence Checklist at /resources. But if you want to understand the why behind every item — so you can walk into diligence with confidence — read on.
What Due Diligence Actually Is
Due diligence is not a formality. It is a professional adversarial review of your business by people whose job it is to find reasons to reprice.
PE buyers hire quality of earnings (QofE) accountants — typically from Big 4 or regional advisory firms — to audit your EBITDA claims line by line. They hire legal counsel to review every contract, license, and liability. They hire operational consultants to assess your team and systems. All of this happens simultaneously, with tight deadlines, and with your cooperation required throughout.
The QofE report alone, which reconciles your stated EBITDA to what the accountants can verify, is the single most consequential document in the process. If your EBITDA drops in the QofE — because add-backs couldn't be supported, or because revenue was overstated — the purchase price adjusts accordingly, usually dollar-for-dollar on the EBITDA delta times your multiple.
The Math That Makes Preparation Non-Optional
On a 7x deal, a $100,000 EBITDA haircut is a $700,000 purchase price reduction.
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Calculate My Valuation →The 5 Due Diligence Categories
1. Financial
This is where most deals get repriced. Financial due diligence is the most intensive category, and it's the one where underprepared sellers give back the most money.
Three years of reviewed or audited financials
PE buyers want three full years of financial statements — income statement, balance sheet, and cash flow statement — prepared by a CPA. Compiled financials (where the CPA simply arranges numbers you provide) are often insufficient; reviewed or audited financials signal that someone independent has actually tested the numbers. If you've been operating on compiled statements, get your CPA engaged 12+ months out to upgrade them.
Trailing 12-Month (T12) P&L
Your most recent fiscal year end may be 6–9 months old. The T12 gives buyers the most current picture of your business. Pull it monthly — they'll want to see the trend, not just the total. Strong seasonal businesses need to present T12 alongside the monthly breakdown so buyers can model cash flow correctly.
EBITDA reconciliation from net income
Don't make buyers reverse-engineer your EBITDA. Build a clean, explicit reconciliation: start with net income, add back interest, taxes, depreciation, and amortization, then list every add-back with its dollar amount and a one-line explanation. This document is your first impression in the QofE process. Present it like a deposition exhibit: sourced, organized, and defensible.
Add-backs with full documentation
This is where most sellers leak money. Add-backs are legitimate — owner compensation above market rate, personal vehicle, personal cell, one-time legal fees, non-recurring events — but every single one needs receipts, bank statements, or invoices to support it. Add-backs presented without documentation are haircutted 50–100% by PE advisors. That personal vehicle worth $30,000 in add-backs becomes $0 if you can't show the expense in your books with a matching document.
Revenue concentration analysis
List your top 10 customers by revenue for each of the last three years. Calculate each one as a percentage of total revenue. If any single customer represents more than 15% of your revenue, you have a concentration risk that PE buyers will either price into their offer or use to walk. Over 20% is a red flag that can restructure a deal entirely.
For more context on how EBITDA and multiples interact, see what your EBITDA multiple looks like in the current market.
2. Operations
PE buyers aren't just buying your revenue — they're buying a business they can operate and scale without you. Operations diligence is how they assess whether that's actually possible.
Standard operating procedures (SOPs) for key processes:
How does your dispatch work? How does a technician handle a callback? What's the install sign-off checklist? If the answers to these questions live only in the heads of your best people, that's a risk buyers will quantify. Documented SOPs signal operational maturity and make training scalable post-acquisition.
Fleet inventory with ownership status:
Provide a complete list of every vehicle and major piece of equipment: year, make, model, owned vs. leased, lease terms if applicable, current mileage or condition notes, and estimated fair market value. Buyers need to know what's included in the transaction and what the near-term capex exposure looks like.
Equipment maintenance records:
Service histories on your vans and major equipment are often overlooked and always asked for. Gaps suggest deferred maintenance, which creates capex exposure. A clean maintenance log is a minor point, but minor points add up — buyers form impressions from the quality of your documentation across dozens of small items.
Vendor contracts and key supplier relationships:
Who do you buy equipment from? What are your terms? Do you have preferred pricing or rebate arrangements? Are there exclusivity clauses or auto-renewal terms? Buyers want to know what supply relationships they're stepping into and whether any of them are tied to you personally.
Customer satisfaction data:
Google reviews, Net Promoter Scores, callback rates, warranty claim rates — any data that speaks to service quality and customer satisfaction. PE buyers building a platform want to grow through acquisitions and organic retention. Evidence of a satisfied customer base is a competitive moat. No data is worse than mixed data; start collecting it now if you haven't been.
3. Sales & Revenue
Revenue quality matters as much as revenue quantity. PE buyers underwrite recurring, diversified, and growing revenue streams at higher multiples than lumpy, owner-driven, concentrated ones.
Recurring revenue percentage and contract copies:
What share of your annual revenue comes from maintenance agreements, service plans, or long-term commercial contracts? Even 20–30% recurring revenue significantly improves your valuation multiple — it's predictable, it's defensible, and it reduces buyer risk. Produce every active maintenance agreement and commercial contract, organized by customer and annotated with annual contract value and remaining term.
Customer list with tenure and lifetime value:
Your top 50–100 customers, sorted by revenue, with the year they first became a customer and total lifetime spend. This document shows buyer churn rate (or lack thereof), the depth of your relationships, and whether your customer base is growing or gradually concentrating.
Pricing model documentation:
Are you pricing by flat rate, time and materials, or a hybrid? Is your pricing book written down and consistently applied across your technicians? Inconsistent pricing is a margin leak and a management risk. A documented pricing model signals operational discipline and makes post-acquisition margin management simpler.
Monthly revenue breakdown by service line (3 years):
Segment revenue by service type — maintenance, repair, replacement, new installation, commercial service — and show it monthly for three years. This lets buyers understand seasonality, service mix trends, and growth trajectory by line. It also surfaces if growth is coming from one segment that may not be sustainable.
4. Legal & Compliance
Legal and compliance issues discovered in diligence carry disproportionate deal risk, because they're often hard to quantify. Unknown liability is worse than known liability.
Current business licenses and contractor certifications:
Every state contractor license, EPA 608 certification, refrigerant handling certification, and any specialty certifications your team holds. Confirm they're current, confirm they're in the company's name (not your personal license), and confirm they can be transferred in an acquisition. A license that can't transfer — or expires at close — creates a regulatory gap that buyers have to price or solve.
Insurance certificates:
Current certificates of insurance for general liability, workers' compensation, commercial auto, and any umbrella or excess coverage. Buyers want to see adequate limits, no significant lapses in coverage, and any open claims noted. They'll also use this to model insurance costs under their platform structure.
Litigation disclosure — past and pending:
Disclose everything: active lawsuits, settled claims in the last five years, EEOC complaints, subcontractor disputes, customer injuries, workers' comp claims. Small things included. Surprises in due diligence are trust-destroying events regardless of the dollar amount. Buyers interpret late disclosure as a signal about how you run the business. Disclose proactively, with context, and you preserve the relationship.
Equipment liens and UCC filings:
Run a UCC search on your business before you go to market. Any financing arrangements — equipment loans, floor-plan financing for inventory, working capital lines secured by receivables — will show up. Buyers need a clean title picture at close. Undisclosed liens complicate the transaction and can delay closing by weeks.
Non-compete agreements with key employees:
Do your service managers, lead technicians, estimators, or key salespeople have non-compete or non-solicitation agreements? If not, a buyer acquiring your business needs to know that their key people could walk the next day and start a competing operation. Employment agreements with reasonable non-solicitation provisions for your top five to ten employees are a standard part of a clean deal package.
5. Management & Team
PE buyers are acquiring a business that needs to operate without you from day one. Management and team diligence is where they assess whether that's realistic — and how much it'll cost to make it work.
Org chart with actual responsibilities:
A one-page visual: owner, general manager, service manager, install lead, office manager, technicians. Beside each role, list what that person actually owns — not just their title. Who handles dispatch? Who approves estimates? Who manages vendor relationships? Who handles customer escalations? This document reveals the management depth (or lack thereof) that a buyer is stepping into.
Key employee retention plan:
Which employees are essential to a successful transition? Do they know a sale is coming? Do you have any retention agreements or bonus structures tied to staying through close? PE buyers lose sleep over key people walking when news of the acquisition breaks. A documented retention plan — even informal — is a meaningful risk mitigant.
Technician tenure and training records:
List your technicians by years of service. Calculate your 12-month turnover rate. Show any certifications, training programs, or manufacturer credentials. Experienced, stable technician teams are a genuine competitive advantage in a tight labor market. High turnover is a cost center and a service quality risk that buyers model explicitly.
Owner role documentation: what you do and what happens without you:
This is the hardest document to write and the most important one in the package. List every function you currently perform: customer relationships you own personally, sales you close, estimates you write, operational decisions that go through you. Then describe what happens to each function post-close: who takes over, what the transition plan looks like, what training is needed.
The 3 Items That Kill Deals
Across hundreds of HVAC transactions, three categories of issues come up repeatedly as deal-killers — not just repricing events, but actual walk-aways.
Missing add-back documentation
You've been running owner expenses through the business for 15 years. That's normal. But when you can't produce the receipts, bank statements, or invoices that tie each add-back to a line item, PE advisors exclude them. A $400,000 EBITDA claim that becomes $280,000 after the QofE isn't just a price reduction — it often moves a deal out of the buyer's return threshold entirely. At 7x, that's $840,000 gone. Fix this before you get an LOI: reconstruct documentation for every add-back going back three years.
Owner dependency with no succession plan
If you hold the three most important customer relationships, close 80% of commercial deals personally, and make every significant operational decision — you are the business. PE is buying a business, not hiring a CEO. When buyers model a scenario where you're out in six months (because you will be), and the model falls apart, they either reprice dramatically or walk. The fix isn't hiring a GM the week before the LOI; it's a documented transition plan, ideally supported by a GM who's been in role for 12+ months.
Environmental liability
Refrigerant handling violations, improper disposal records, EPA audit history — these create open-ended liability that PE buyers generally won't absorb. Environmental issues discovered in diligence often don't get repriced; they get walked away from, because the exposure is hard to cap and indemnification escrows don't fully protect buyers. If you have any history here, get ahead of it with legal counsel before going to market. Voluntary disclosure and documented remediation is far better than a buyer's environmental consultant finding it in week four of diligence.
For the owner dependency deal killer specifically, read the full 12-month sale preparation timeline to understand how to address this before it becomes a diligence problem.
How to Use This Checklist
Start now. Not when the LOI lands.
The most common mistake HVAC owners make is treating this checklist as a post-LOI scramble. By then, you're operating under exclusivity with a ticking clock, your attention is split between running the business and responding to data requests, and every gap you find is visible to the buyer in real time.
The owners who come out of diligence with clean closes and full deal value started working this list 6–12 months before they expected to be in a process. They fixed the add-back documentation. They hired the GM. They got the financials reviewed. They cleaned up the UCC filings. When the PE firm's advisors arrived, there was nothing to find.
Set up a virtual data room before the process starts
A virtual data room is simply an organized cloud folder structure — Dropbox, Google Drive, or a dedicated platform like Datasite or Box — where you pre-load every document a buyer will request. For a complete step-by-step guide to building your data room — including the 7 document categories, what QoE pulls in the first 48 hours, and a 90-day build plan — read how to build an HVAC business data room for PE buyers. Here's the folder structure to start with:
When an LOI comes in and the buyer sends their diligence request list, you should be able to share 80% of it within the first week. That signal — a seller who is organized and responsive — sets the tone for the entire process.
For a deeper look at how the full PE acquisition process works from first contact through closing, read how a PE sale actually works.
Before Diligence Starts, Know Your Number
Due diligence preparation starts with understanding your EBITDA, your add-backs, and what multiple the market is paying for businesses like yours right now. Those three variables — and the interaction between them — determine your walk-away number and your negotiating position when the PE firm's QofE comes back different from what you expected.
Before you get to market, run the free OffRamp calculator to see your estimated EBITDA multiple and PE Readiness Score. It takes about four minutes and gives you the number you need before any advisor conversation, any LOI negotiation, or any due diligence process.
Sellers who know their number walk into diligence with confidence. Sellers who don't give it back.
Before You Talk to PE
Run the Free Valuation Calculator
Get your estimated EBITDA-based valuation range and PE Readiness Score in under 5 minutes. Know your number before any advisor conversation or LOI negotiation.
See Your EBITDA Multiple & PE Readiness ScoreOffRamp is a free valuation tool for HVAC business owners. We don't sell your information, represent buyers, or work on commission. The calculator and reports are educational tools — always consult a licensed M&A advisor before entering a sale process.