What it is

Your business entity is the legal shell you operate inside. It decides who's on the hook when something goes wrong, how you're taxed, and how legitimate you look to customers, vendors, and lenders. When you go solo you're choosing one of three common forms: stay a sole proprietor (no separate shell at all), form an LLC (a limited liability company), or run an LLC that's taxed as an S-corp once you're making real money. This article walks the differences in language that matters to a tech, not a tax attorney, and shows you how to actually get one set up.

Why it matters

Two reasons: liability and taxes. HVAC is a trade where things can go expensively wrong — a brazing job near combustibles, a miswired unit, a refrigerant mistake, a customer who slips on your drop cloth. If you're a bare sole proprietor and you get sued, your house, your savings, and your truck are all fair game because there's no legal line between you and the business. An LLC draws that line. It's not bulletproof, but it puts a wall between a business problem and your personal life.

The tax piece matters once you're profitable. How your entity is taxed changes how much self-employment tax you pay. Most new shops don't need to optimize this on day one, but it becomes real money the year you start clearing solid profit — so it's worth knowing where the lever is.

How to do it (step by step)

Here's what each option actually means, then how to form the one most shops pick.

Sole proprietor. You do nothing and you are the business. Cheapest and simplest — no filing, no separate entity. The catch is there's zero liability protection: a business debt or lawsuit reaches straight into your personal assets. Fine for a side hustle mowing lawns; risky for a trade that pulls permits and works in people's homes. Most HVAC owners outgrow it fast.

LLC (limited liability company). The sweet spot for the vast majority of one-truck and small HVAC shops. It gives you the liability wall without the heavy paperwork of a corporation. By default a single-owner LLC is taxed just like a sole prop (the profit flows to your personal return — no separate corporate tax), so it's simple, but you get the legal separation. This is why "should I form an LLC" almost always answers itself for a trades business.

S-corp. Not a separate kind of entity so much as a tax election you can make on an LLC. Once your profit gets high enough, an S-corp election lets you pay yourself a reasonable salary and take the rest as a distribution that isn't hit with self-employment tax — which can save real money. The downside is added cost and complexity: payroll, more bookkeeping, a stricter "reasonable salary" rule, and a CPA you'll actually need. The rule of thumb a lot of accountants use is to wait until your net profit is comfortably into the five figures — often around the $40,000–$60,000 range or higher — before the savings outweigh the hassle. Don't elect it on day one; revisit it with your CPA once you're making money.

How to actually form the LLC:

  1. Pick a name that isn't already taken in your state and meets your state's naming rules (usually has to include "LLC"). A quick search on your Secretary of State's website tells you if it's available.
  2. File the formation paperwork (usually called Articles of Organization) with your state, online in most places. Pay the filing fee.
  3. Get an EIN from the IRS. This is your business's federal tax ID — free, online, takes about ten minutes. You need it to open a business bank account and to hire anyone later. Don't pay a third-party site for this; it's free directly from the IRS.
  4. Set up the basics that make the LLC real: a registered agent (you can often be your own, or pay a service), an operating agreement (smart even for a single owner), and a business bank account opened with your EIN and formation docs.
  5. Handle local registrations — some cities and counties want a separate business license or registration on top of the state filing. Check yours.

What it costs

State LLC filing fees vary a lot — anywhere from around $50 to a few hundred dollars to form, depending on your state, plus an annual or biennial report fee in many states. A registered-agent service, if you don't act as your own, typically runs $50–$150 a year. The EIN is free. You can absolutely do the whole formation yourself online for the cost of the state fee; the paid "formation services" mostly charge you for steps you can do directly. An S-corp election adds payroll and bookkeeping costs (often a few hundred to a couple thousand a year for payroll service plus a CPA), which is exactly why you wait until the tax savings cover it.

Common mistakes

  • Staying a bare sole proprietor too long. Saving a small filing fee isn't worth exposing your house to a lawsuit the day you start working in customers' homes.
  • Paying a service for the free EIN. The IRS issues it for free. Anyone charging you for "EIN registration" is charging for nothing.
  • Electing S-corp on day one. Before you're profitable, the payroll and accounting cost of an S-corp usually exceeds anything it saves. It's a "once I'm making money" move.
  • Forming the LLC, then ignoring the formalities. If you commingle funds and never keep the business separate, a court can "pierce the veil" and the protection you paid for evaporates. Keep business money in the business.
  • Forgetting local registration. The state LLC isn't always the whole picture — your city or county may want its own business license.

Tips & gotchas

The LLC only protects you if you treat it like a real, separate thing. Separate bank account, business in the business name, no running personal expenses through it. The single fastest way to lose your liability protection is to act like the LLC and your wallet are the same thing.

You can change your tax treatment later without re-forming. Form the LLC now; make the S-corp election the year your CPA says the math works. You don't have to predict your profit on day one.

Get the operating agreement even as a single owner. It's not legally required everywhere, but it reinforces that the LLC is a distinct entity and it makes banking, partners, and future changes cleaner.

Talk to a CPA before the S-corp jump, not after. The "reasonable salary" rule has teeth, and getting it wrong invites an audit. This is the one spot where paying a professional pays for itself.

Bottom line

For nearly every HVAC tech going solo, the answer is an LLC: it gives you the liability wall that a sole proprietorship doesn't, without the weight of a full corporation, and by default it's taxed simply. Form it yourself through your state, grab the free EIN from the IRS, keep the business money strictly separate so the protection holds, and revisit an S-corp election with your CPA once you're actually clearing solid profit. Don't over-engineer it on day one — get the LLC, get the EIN, and get to work.