Picture this: an HVAC owner walks into a PE conversation with $2M in EBITDA and a business that looks clean on paper. Strong revenue, good margins, a healthy service book. The buyer's first diligence question is simple: “What percentage of revenue comes from your top 3 customers?”
The owner answers honestly. One commercial property management firm accounts for 35% of annual revenue. The call goes quiet for a moment. By the time the term sheet arrives, the EBITDA multiple has dropped from the 5x the owner expected to 4x — a $2M difference on the exact same business. Customer concentration risk had done its work.
This scenario plays out in HVAC deals regularly. PE buyers are trained to look for concentration risk because it directly threatens the cash flow thesis they're underwriting. Understanding how buyers think about it — and what the thresholds actually are — is the difference between a clean exit and a re-traded deal.
What Customer Concentration Actually Means
Customer concentration refers to the degree to which your revenue depends on a small number of accounts. In the context of a PE transaction, concentration gets flagged at specific thresholds that have become standard across middle-market M&A. These thresholds are not subjective — they are built into most PE underwriting models as automatic risk flags.
PE concentration thresholds
- Any single customer >10% of revenue — flagged during diligence. Buyers will ask for contract details, renewal history, and relationship documentation.
- >20% (one customer) — meaningful discount. Expect 0.5x–1.0x off the multiple at this level.
- >30% (one customer) — deal risk. Many buyers will walk, or require earnout protections tied directly to that account's retention post-close.
- Top 5 customers >50% of revenue — structural concern. Buyers treat this as a different risk profile entirely, with heavy discounts or deal structure changes required.
| Concentration Level | Typical Impact | PE Buyer Response |
|---|---|---|
| <10% per customer | None | Standard multiple applies |
| 10–20% (one customer) | Moderate flag | 0.25x–0.5x discount, more diligence |
| 20–30% (one customer) | Significant flag | 0.5x–1.0x discount, earnout likely |
| >30% (one customer) | Deal risk | Buyer may walk or require reps/warranties |
| Top 5 > 50% | Structural concern | Heavy discount or deal structure changes |
Why PE Buyers Care So Much
PE firms buy HVAC businesses based on a thesis: they underwrite a predictable cash flow stream, apply leverage, and grow the business toward a higher-multiple exit in 3–5 years. Customer concentration threatens that thesis at the foundation. If a single large account walks after the deal closes — because the relationship was personal to the owner, because the contract came up for renewal, or because the customer found a cheaper alternative — the PE firm's model falls apart.
But it's not just about one customer leaving. PE buyers are also focused on:
Contract renewal risk. Even if the customer stays, does the contract auto-renew on favorable terms, or does pricing get renegotiated every year? A concentrated customer who knows your dependency has leverage.
Customer leverage on pricing. When one account represents 30% of revenue, that customer can push back on rate increases. Your margins are hostage to their approval. PE buyers model this as a structural constraint on future profitability.
What happens when the owner exits. In most HVAC businesses with high concentration, the key relationship is personal — the owner knows the property manager or facilities director by first name. When the owner leaves, that relationship doesn't automatically transfer. Buyers price that uncertainty into the offer.
The combination of these factors makes concentration a compounding risk, not a simple one. It's not just “what if this customer leaves” — it's “what if this customer renegotiates, and the owner who kept them happy is gone.”
The Two Types of Concentration PE Buyers Flag
When HVAC owners hear “concentration risk,” they usually think of customer concentration — a single large account driving too much of the revenue. That's the most common form, but PE buyers flag a second type that catches many owners off guard.
Type 1
Customer Concentration
One or a few clients representing a disproportionate share of revenue. Common in commercial HVAC businesses that serve large property management firms, municipalities, or anchor commercial accounts. The flag is triggered at 10% per customer; the discount becomes significant at 20–30%.
Type 2
Revenue Concentration
One service line or one geography driving the majority of revenue. If 80% of your business is new construction and that market softens, or if 90% of revenue comes from a single metro that hits an economic downturn, the business is fragile in a different way. PE buyers model both types and apply discounts to either.
The two types can compound each other. An HVAC business that does 80% commercial work in one city and has three clients representing 60% of revenue faces two independent concentration problems. Addressing one without addressing the other doesn't fully resolve the risk in a buyer's model.
How It Actually Affects Your Multiple
The math on concentration risk is concrete. Consider two HVAC businesses with identical financials — $2M EBITDA, same margins, same service geography:
Business A
Diversified base
Business B
Concentrated base
The difference is $2,000,000 — on the exact same EBITDA, in the same market, from the same service type. The only variable is customer concentration. Business B's owner didn't do anything wrong operationally. The business runs well. But the structural risk of that commercial property management firm representing 35% of revenue is worth a full turn of multiple to a PE buyer.
Why this matters
Concentration risk is one of the few valuation factors you can actually fix before going to market. Unlike your location, your service history, or your historical revenue trend, the customer mix is something you can actively change with 12–24 months of deliberate effort.
What You Can Do About It Before Selling
The earlier you start, the more options you have. Here is a concrete action sequence for HVAC owners who know concentration is an issue and have time to address it before going to market.
- 1
Audit your revenue concentration now
Run a customer concentration report for the last 3 years. Buyers will ask for trailing 36-month data during quality of earnings review — you need to know your exposure before they surface it. Know your top 10 customers by revenue, their percentage of your total, and how that has trended year over year.
- 2
Start diversifying 12–24 months out
Add residential service agreements to reduce dependence on large commercial accounts. Target new commercial verticals you are not currently serving — a school district, a hospitality group, a healthcare facility. The goal is to bring your top customer below 15% before you engage a buyer.
- 3
Sign multi-year contracts with your top accounts
Locked recurring revenue is far less scary to a buyer than at-will relationships. If you can convert a major commercial client from a handshake arrangement to a 3-year service agreement with auto-renewal, you have reduced the post-close retention risk that drives the discount. An active letter of intent conversation is much stronger when your contracts are already locked.
- 4
Document the relationship as a business asset
Show buyers that the account relationship belongs to the business, not to you personally. This means the client is invoiced under the business name, communications go through business channels, and there is a documented service history in your field service software. Personal relationships are not transferable — documented business relationships are.
- 5
Hire an account manager for key commercial accounts
One of the most effective structural fixes is putting an account manager between you and your largest clients. This removes the “what happens when the owner leaves?” question entirely. If a dedicated person on your team already owns the day-to-day relationship, buyers can model the retention with much more confidence.
- 6
Consider growing through acquisition
If the timeline allows, bolt-on a smaller HVAC company in a different customer segment. A residential-heavy tuck-in acquisition immediately diversifies your revenue mix and can bring your top commercial customer below the 20% threshold on a combined-company basis. It also adds to your EBITDA, which compounds the multiple improvement.
What If You Can't Fix It in Time?
Not every seller has 18 months to restructure their customer base before a sale. If you are already in a process, or the timeline is compressed, concentration risk does not automatically kill your deal — but it will shape the deal structure.
PE buyers manage concentration risk through the mechanics of the transaction itself. The most common approaches:
Earnout provisions tied to customer retention. A portion of the purchase price is held back and paid out only if the concentrated customer remains after close and meets revenue thresholds. The earnout structure shifts the risk from the buyer to the seller.
Seller representations that key contracts will transfer. Reps and warranties in the purchase agreement that the concentrated customer has agreed to continue the relationship post-close, or that the contract is freely assignable without customer consent. Breach of these reps can trigger indemnification claims.
Escrow holdbacks. A percentage of proceeds held in escrow for 12–24 months post-close, released only if the concentrated customer remains active and revenue targets are met. This is a direct pricing mechanism that reduces the effective upfront payment to the seller.
If your concentration is real and you are in a deal today, the job of your M&A advisor is to negotiate the structure, not just the headline price. A well-negotiated earnout with a high probability of payout can be a reasonable compromise between what you think the business is worth and what the buyer is willing to pay on a risk-adjusted basis. An advisor who understands HVAC deal mechanics will know which levers are negotiable and which are not.
The bottom line
PE buyers do not always walk on concentration. They price it. The question is whether the price they arrive at is acceptable to you — and whether you have an advisor who can negotiate the structure to close the gap.
See how concentration is affecting your valuation now
OffRamp's HVAC calculator factors in recurring contract coverage — one of the biggest PE readiness signals buyers use when evaluating concentration risk. Run yours in 3 minutes and see where your business stands before you start any conversations with buyers.
Run the Free CalculatorFrequently Asked Questions
What counts as "customer concentration" in an HVAC business?
Any single customer exceeding 10% of annual revenue. PE buyers typically flag this during diligence — the threshold is common across middle-market M&A. The higher the concentration, the deeper the discount and the more complex the deal structure.
Will PE buyers walk over customer concentration?
Not automatically. Buyers use earnouts, holdbacks, and reps/warranties to manage it. But expect a lower multiple and more complex deal structure if concentration is significant. Concentration above 30% from a single customer is where many buyers require deal-structure protections or walk entirely.
How long does it take to fix customer concentration before a sale?
12–24 months is realistic. The key steps are diversifying the customer base, signing longer contracts with top accounts, and documenting that relationships belong to the business, not the owner. Starting the process early gives you the most leverage heading into a sale.
OffRamp 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.