HVAC Business Taxes in 2026: A Plain-English Guide for Shop Owners

Quarterly estimates, S corp vs LLC, self-employment tax, payroll deposits, 1099s, truck and equipment write-offs, and a tax calendar for HVAC owners in 2026.

Most HVAC owners are good at running calls and bad at taxes. That's normal. You didn't get into this trade to read IRS publications. But taxes are where a lot of profitable shops lose money they already earned: a penalty for skipping estimates, a surprise bill in April, payroll taxes paid late, or a truck deduction that got thrown out because nobody kept a mileage log.

This guide covers the federal basics every HVAC shop owner should know in 2026: quarterly estimated taxes, choosing a business structure, self-employment tax, payroll tax deposits, 1099s for subcontractors, common deductions for trucks, tools, and equipment, the qualified business income deduction, and recordkeeping. There's a tax calendar and a list of questions to bring to your CPA at the end.

This is not tax advice. It's a plain-language summary of IRS rules as published for 2026, so you can have a better conversation with your CPA. Your state has its own rules, your situation has its own details, and tax law changes. Talk to a CPA or enrolled agent before you act on anything here. Where we couldn't confirm a current figure from the IRS, we say so. Any worked example uses made-up round numbers to show the math. They are not industry averages.

Quarterly estimated taxes (Form 1040-ES)

When you work for someone else, taxes come out of every paycheck. When you own the shop, nobody withholds for you. The IRS expects you to pay as you go through estimated tax payments, using Form 1040-ES.

Who has to pay. According to the 2026 Form 1040-ES instructions, you generally must pay estimated tax for 2026 if you expect to owe at least $1,000 in tax for 2026 after subtracting withholding and refundable credits, and your withholding and credits will be less than the smaller of:

• 90% of the tax on your 2026 return, or
• 100% of the tax shown on your 2025 return (the return has to cover all 12 months).

The higher-income rule. If your adjusted gross income (AGI) for 2025 was more than $150,000 ($75,000 if married filing separately for 2026), swap 110% in for 100% in that second test.

Those two tests are what most people call the "safe harbor." If you pay in at least the smaller amount on time, you generally avoid the underpayment penalty, even if you owe more when you file. For a shop whose income jumps around season to season, paying 100% (or 110%) of last year's tax in four equal pieces is often the simplest way to stay safe. Ask your CPA which test works better for you.

2026 due dates (from the 2026 Form 1040-ES):

Two notes from the form: you don't have to make the January 15, 2027 payment if you file your 2026 return by February 1, 2027 and pay the full balance with it. And if a due date falls on a Saturday, Sunday, or legal holiday, the payment is on time if made the next business day.

Notice the periods aren't equal. The second payment covers just two months (April and May). That catches people. Put the dates on the office calendar now.

A simple habit that works: every time you get paid, move a set percentage into a separate savings account you call "taxes" and don't touch. Your CPA can help you pick the percentage. For more on managing cash between big bills, see our HVAC cash flow guide and the cash flow reserve calculator.

Self-employment tax: the one that surprises new owners

If you're a sole proprietor or a single-member LLC (taxed the default way), you pay income tax and self-employment (SE) tax on your profit. SE tax is Social Security and Medicare for people who work for themselves. Per IRS Tax Topic 554:

• The rate is 15.3%: 12.4% for Social Security and 2.9% for Medicare.
• You usually owe it if your net earnings from self-employment are $400 or more.
• It generally applies to 92.35% of your net earnings from self-employment.
• You can deduct one-half of your SE tax when figuring your adjusted gross income.

For 2026, the Social Security part stops at $184,500 of combined wages and self-employment earnings (2026 Form 1040-ES and IRS Publication 15). Medicare has no cap. And an Additional Medicare Tax of 0.9% applies above $200,000 for single filers ($250,000 married filing jointly, $125,000 married filing separately).

Worked example (made-up numbers): your Schedule C shows $100,000 of net profit.

• $100,000 x 92.35% = $92,350 subject to SE tax
• $92,350 x 15.3% = about $14,130 of SE tax
• That's before any federal income tax, and before state tax

That's why a new owner who "made $100K" can end up owing a lot more in April than they expected. If you're thinking about going out on your own, see how to go from HVAC tech to business owner and how to start an HVAC business.

Choosing a business structure: sole prop, LLC, or S corp

This is the most common tax question new shop owners ask. Here are the basics. The right answer depends on your profit, your state, and your plans, so treat this as background for a CPA meeting, not a decision.

Sole proprietorship. No separate entity. Profit goes on Schedule C of your personal return, and you pay SE tax on it. Simple and cheap, but no liability separation between you and the business.

Single-member LLC. A state-law entity. Many owners form one for liability reasons (talk to a lawyer about how much protection it gives in your state). For federal income tax, the IRS treats a single-member LLC as "disregarded" by default, so it's taxed like a sole proprietorship: Schedule C, SE tax on the profit. The IRS also notes that for employment tax, a single-member LLC is still treated as a separate entity, so it uses its own EIN when it runs payroll. An LLC can elect to be taxed as a corporation (Form 8832) or as an S corporation (Form 2553).

S corporation. An S corp is a tax status, not a kind of company. A corporation or an eligible LLC elects it by filing Form 2553, signed by all shareholders. The IRS lists these requirements: a domestic corporation, no more than 100 shareholders, only one class of stock, and only allowable shareholders (individuals, certain trusts and estates). An S corp passes its income through to the owners' personal returns, files Form 1120-S, and issues each owner a Schedule K-1.

For timing, the Form 1120-S instructions say Form 2553 must generally be filed no more than 2 months and 15 days after the start of the tax year the election is to take effect. Form 1120-S itself is due by the 15th day of the 3rd month after the tax year ends (for calendar-year S corps, that's mid-March, moved to the next business day if it lands on a weekend or holiday).

Why owners look at S corps, and the catch: reasonable compensation

The appeal: as an S corp owner who works in the business, you're paid part of the profit as W-2 wages (subject to payroll taxes) and can take the rest as distributions, which aren't subject to employment taxes. That can mean less Social Security and Medicare tax than a sole prop pays on all its profit.

The catch is reasonable compensation. The IRS says S corps must pay reasonable compensation to a shareholder-employee before making non-wage distributions, and it has the authority to reclassify distributions as wages. The IRS lists factors courts have used to decide what's reasonable, including:

• Training and experience
• Duties and responsibilities
• Time and effort devoted to the business
• Dividend history
• Payments to non-shareholder employees
• Timing and manner of paying bonuses to key people
• What comparable businesses pay for similar services
• Compensation agreements
• Use of a formula to determine compensation

In plain terms: if you run calls, sell jobs, and manage the shop full time, paying yourself a tiny salary and taking the rest as distributions is exactly what the IRS looks for. Your salary should hold up next to what you'd have to pay someone else to do your job. Our guide on how much HVAC business owners make has public wage data that can help frame that conversation.

An S corp also adds costs: running payroll for yourself, a separate business return, and often higher bookkeeping and CPA fees. Some states tax S corps differently too. Whether the savings beat the added cost is a math problem your CPA should run with your real numbers.

Payroll taxes when you have employees (Form 941)

Once you hire a tech, a CSR, or pay yourself W-2 wages through an S corp, you're an employer. That means withholding and depositing taxes on a schedule. Publication 15 (Circular E), the IRS Employer's Tax Guide for 2026, is the source for this section.

The taxes. For 2026, Social Security tax is 6.2% each for employer and employee, on wages up to $184,500. Medicare is 1.45% each, with no wage cap. You also withhold federal income tax from employee pay, and withhold an extra 0.9% Additional Medicare Tax on an employee's wages over $200,000 in the calendar year.

FUTA (federal unemployment). For 2026, the FUTA rate is 6.0% on the first $7,000 you pay each employee. You can generally take a credit of up to 5.4% for state unemployment tax you paid in full and on time, which brings the rate down to 0.6%, unless your state is a "credit reduction" state. FUTA is reported yearly on Form 940.

Deposit schedule. Most small shops are monthly schedule depositors. Per Publication 15:

• Your schedule for the year is based on a lookback period. For 2026, it's July 1, 2024 through June 30, 2025.
• If the total taxes reported on Form 941 (line 12) for the lookback period were $50,000 or less, you're a monthly depositor: deposit taxes on the month's payroll by the 15th of the following month.
• If they were more than $50,000, you're a semiweekly depositor: payroll paid Wednesday through Friday is due the following Wednesday; payroll paid Saturday through Tuesday is due the following Friday.
• New employers are monthly depositors for their first calendar year (for Form 941 filers).
• If you ever pile up $100,000 or more in taxes on a single day, it must be deposited by the next business day, no matter your schedule.
• Federal tax deposits must be made by electronic funds transfer (EFT). EFTPS is the IRS's free system for this.

Form 941 is the quarterly return. It's due April 30, July 31, October 31, and January 31. If you made all deposits on time, Publication 15 gives you until May 10, August 10, November 10, or February 10 to file.

Late payroll deposits are one of the most expensive tax mistakes a small shop can make. A payroll service that files and deposits for you is usually worth it. You're still responsible if they get it wrong, so check your EFTPS account now and then to confirm the deposits landed.

To see what an employee really costs once taxes and benefits are added, try the labor burden calculator. For pay rules around nights and weekends, see our HVAC on-call and overtime pay guide.

1099-NEC for subcontractors, and a worker classification warning

What changed for 2026. Under the IRS instructions for Forms 1099-MISC and 1099-NEC for 2026, you file Form 1099-NEC for each person you paid at least $2,000 in the course of your business during the year for nonemployee compensation. That threshold went up from $600 for tax years beginning after 2025, and may be adjusted for inflation starting in 2027. Form 1099-NEC is due to the IRS and to the payee by January 31.

Good habits for subs (duct crews, electricians, crane operators, a helper you pay by the job):

• Get a signed Form W-9 before you pay anyone the first time.
• Track what you pay each sub during the year so January isn't a scramble.
• Keep copies of their license and insurance certificates. See our HVAC contractor insurance guide.

Are they really a contractor? This is where HVAC shops get in trouble. Calling someone a "sub" doesn't make them one. The IRS looks at the whole relationship in three groups:

1. Behavioral control: do you control what they do and how they do it?
2. Financial control: do you control the business side (how they're paid, whether expenses are reimbursed, who provides tools and supplies)?
3. Type of relationship: is there a written contract, are there employee-type benefits, and is the work a key part of your regular business?

The IRS says there's no magic number of factors and no single factor decides it. A "sub" who runs your calls, in your truck, on your schedule, wearing your shirt, using your tools, looks a lot like an employee. If a worker is misclassified without a reasonable basis, the IRS says the business can be held liable for employment taxes for that worker. Either side can ask the IRS for a formal determination with Form SS-8 (the IRS says it takes at least six months), and the IRS has relief programs such as Section 530 relief and the Voluntary Classification Settlement Program for businesses that qualify. States have their own tests too, often stricter ones. If you're unsure, ask your CPA or an employment lawyer before year-end, not after an audit letter.

Common deductions for HVAC shops

Business expenses that are ordinary and necessary for your trade are generally deductible. Here are the ones that matter most to HVAC shops, and the rules that trip people up.

Trucks and vans: standard mileage vs actual expenses

You have two ways to deduct vehicle costs.

Standard mileage rate. Per the IRS standard mileage rates page, the 2026 business rate is 72.5 cents per mile for January 1 through June 30, 2026, and 76 cents per mile for July 1 through December 31, 2026 (the IRS raised it mid-year in IR-2026-29). Parking fees and tolls for business trips can be deducted on top of the rate.

Actual expenses. Publication 463 lists gas, oil, repairs, tires, insurance, registration and license fees, lease payments, garage rent, tolls, parking, and depreciation. If a vehicle is used for both business and personal driving, you split the costs by business-use percentage.

Rules from IRS Publication 463 that matter for HVAC shops:

• You can't use the standard mileage rate if you use five or more vehicles at the same time (the IRS calls this fleet operations). Many shops cross that line at their fifth truck.
• You also can't use it on a vehicle you've already claimed a Section 179 deduction, bonus (special) depreciation, or MACRS depreciation on.
• Either way, you need records: a mileage log or app showing date, miles, and business purpose. No log is the most common reason vehicle deductions get cut.

For a work van with shelving, a heavy truck, and a lot of miles, actual expenses plus depreciation often beats the mileage rate, but run it both ways with your CPA. The service truck cost calculator can help you see what each truck really costs per month.

Section 179 and bonus depreciation for trucks and equipment

Normally you deduct the cost of a truck, a recovery machine, or a vacuum pump rig over several years (depreciation). Two rules let you deduct much more of it up front.

Section 179. For tax years beginning in 2026, IRS Revenue Procedure 2025-32 sets the maximum Section 179 deduction at $2,560,000, reduced dollar for dollar once the Section 179 property you place in service during the year tops $4,090,000. Few small shops come near those limits.

Heavy SUVs. Rev. Proc. 2025-32 also caps Section 179 on a sport utility vehicle placed in service in 2026 at $32,000. Per IRS Publication 946, this cap covers passenger-type vehicles rated over 6,000 and up to 14,000 pounds gross vehicle weight, but it doesn't apply to vehicles that, among other exceptions, have a cargo area at least 6 feet long inside that isn't easy to reach from the passenger compartment, or that have no seating behind the driver and no body section sticking out more than 30 inches ahead of the windshield. Many cargo vans and pickups with long beds may fall outside the SUV cap. Have your CPA confirm for your specific vehicle.

Bonus (special) depreciation. Per Publication 946, P.L. 119-21 (commonly called the One Big Beautiful Bill Act) brought back a 100% special depreciation allowance for qualified property acquired and placed in service after January 19, 2025.

Two cautions. First, a big write-off in a good year means less depreciation in later years, and if you sell the truck later, some of that deduction can come back as taxable income. Second, don't buy a truck you don't need just to save tax. Spending $60,000 to save a fraction of that in tax still leaves you with less cash. Buy equipment because the shop needs it, then use the rules to deduct it well.

Small purchases. Per IRS Publication 334, if you elect the de minimis safe harbor and don't have an applicable financial statement (most small shops don't), you can deduct tangible property costing up to $2,500 per item or invoice instead of depreciating it. That covers a lot of meters, gauges, and power tools.

Tools, uniforms, licenses, and training

• Tools and supplies. Hand tools, meters, recovery equipment, and shop supplies are business costs. Cheaper items often fall under the de minimis rule above; bigger ones may need to be depreciated or expensed under Section 179.
• Uniforms and safety gear. Company shirts with your logo that you provide to techs, and protective gear such as safety glasses, gloves, and boots, are generally treated as business costs. Clothes that are fine for everyday wear usually aren't. Ask your CPA where the line is.
• Licenses and regulatory fees. Publication 334 lists licenses and regulatory fees as deductible business expenses. That includes your contractor license and permit fees. See our license requirements by state guide.
• Education. Publication 334 also lists education expenses. Continuing education to keep your license, certification classes, and manufacturer training for your techs generally fit here. Check with your CPA for your own situation.

For how to set these up in your books so they're easy to find at tax time, see our HVAC P&L and chart of accounts guide.

The QBI deduction (Section 199A) after P.L. 119-21

The qualified business income (QBI) deduction lets many owners of sole proprietorships, partnerships, and S corporations deduct up to 20% of their qualified business income.

It was originally set to expire after 2025. The 2026 Form 1040-ES instructions say recent legislation made the QBI deduction permanent. The current text of 26 U.S.C. 199A, as amended by P.L. 119-21, no longer has the end-of-2025 sunset.

What's new for 2026:

• Minimum deduction. If you have at least $1,000 of total qualified business income from an active trade or business, you may be able to claim a minimum QBI deduction of $400 (both amounts adjust for inflation after 2026).
• Income thresholds. Above certain income levels, limits based on the W-2 wages your business pays and the property it owns can shrink the deduction. For 2026, Rev. Proc. 2025-32 puts the threshold at $403,500 for married filing jointly (limits fully apply at $553,500) and $201,750 for most other filers (fully applying at $276,750). The phase-in range is wider than before: $150,000 for joint filers and $75,000 for others.

One S corp note from the IRS: reasonable compensation you receive as W-2 wages from your S corp isn't QBI. That's one more reason the salary-vs-distribution split is a CPA conversation, not a guess.

Sales tax on materials and equipment

Sales tax is a state and local tax, and how it applies to HVAC work varies a lot by state. In some places the contractor pays sales tax when buying equipment and materials and doesn't charge tax to the customer. In others, the contractor charges sales tax on materials, or on the whole job. Some treat repair work differently from new installs. We're not listing states here because the rules change and have fine print. Check with your state's revenue department and your CPA.

The federal side, from IRS Publication 334: sales tax you pay on things you buy for the business is treated as part of the cost of that item (deducted with it, or added to the depreciable basis of equipment). Sales tax you collect from customers and hand over to the state generally isn't your income. It helps to keep it in its own liability account so it doesn't look like revenue.

Recordkeeping: what to keep and for how long

Per the IRS "How long should I keep records?" guidance:

• 3 years is the general rule for records supporting your return.
• 6 years if you underreported income by more than 25% of the gross income on the return.
• 7 years if you claim a loss from worthless securities or a bad debt deduction.
• At least 4 years for employment tax records.
• Indefinitely if you didn't file a return or filed a fraudulent one.
• Property records (trucks, equipment, buildings): keep them until the limitations period runs out for the year you sell or dispose of the property.

Practical habits for an HVAC shop:

• Keep a separate business bank account and card. Never pay personal costs from them.
• Snap receipts into your accounting software or a receipt app the day you buy.
• Keep a mileage log for every vehicle, or use GPS/telematics reports.
• Save W-9s, 1099s, payroll reports, and EFTPS confirmations by year.
• Close your books every month. Taxes are much easier (and cheaper to prepare) when the books are current.

If you ever plan to sell the shop, clean records matter even more. See how to sell an HVAC business.

Federal tax calendar for a small HVAC shop

For a calendar-year business. If a date falls on a weekend or legal holiday, it generally moves to the next business day. Always confirm current dates on IRS.gov.

State income tax, state unemployment, and sales tax returns have their own due dates. Add them to this list for your state.

Questions to ask your CPA

Bring these to your next meeting. A good CPA will be glad you asked.

1. Based on my numbers, should I stay a sole prop / LLC, or elect S corp status? At what profit level does it make sense for me, after the extra costs?
2. If I'm an S corp, what salary can we defend as reasonable compensation, and how did you get that number?
3. Which safe-harbor test should I use for my estimated payments this year, and how much should I pay each quarter?
4. What percentage of each deposit should I set aside for taxes, including state tax?
5. Should I use the standard mileage rate or actual expenses for each truck? Have I already locked myself out of the mileage rate on any vehicle?
6. For the truck or equipment I'm thinking about buying, should we use Section 179, bonus depreciation, or regular depreciation? What happens if I sell it in three years?
7. Does my shop qualify for the QBI deduction, and do the income limits affect me?
8. Are any of my subcontractors at risk of being treated as employees under IRS or state rules?
9. How does sales tax work on equipment and materials in my state, and am I collecting and paying it correctly?
10. Am I a monthly or semiweekly payroll depositor, and is my payroll service depositing on time?
11. Should my books be on cash or accrual for taxes, and does that differ from how I should read them for managing the business?
12. What records do you wish I kept better?

Taxes, talked about openly

Owners rarely discuss entity choice, payroll services, or how they work with their CPA, which is exactly why those questions are welcome in the Growth Room Discord.

Reminder: this guide is general information, not tax advice. Talk to a CPA or enrolled agent about your situation.

Sources

• IRS, 2026 Form 1040-ES, Estimated Tax for Individuals: https://www.irs.gov/pub/irs-pdf/f1040es.pdf
• IRS, Estimated taxes: https://www.irs.gov/businesses/small-businesses-self-employed/estimated-taxes
• IRS, Topic 554, Self-employment tax: https://www.irs.gov/taxtopics/tc554
• IRS, Publication 15 (Circular E), Employer's Tax Guide (2026): https://www.irs.gov/pub/irs-pdf/p15.pdf
• IRS, 2026 Instructions for Forms 1099-MISC and 1099-NEC: https://www.irs.gov/instructions/i1099mec
• IRS, Independent contractor (self-employed) or employee?: https://www.irs.gov/businesses/small-businesses-self-employed/independent-contractor-self-employed-or-employee
• IRS, S corporations: https://www.irs.gov/businesses/small-businesses-self-employed/s-corporations
• IRS, S corporation compensation and medical insurance issues: https://www.irs.gov/businesses/small-businesses-self-employed/s-corporation-compensation-and-medical-insurance-issues
• IRS, Single member limited liability companies: https://www.irs.gov/businesses/small-businesses-self-employed/single-member-limited-liability-companies
• IRS, Instructions for Form 1120-S (2025): https://www.irs.gov/pub/irs-pdf/i1120s.pdf
• IRS, Standard mileage rates: https://www.irs.gov/tax-professionals/standard-mileage-rates
• IRS, Publication 463, Travel, Gift, and Car Expenses (2025): https://www.irs.gov/pub/irs-pdf/p463.pdf
• IRS, Publication 946, How To Depreciate Property (2025): https://www.irs.gov/pub/irs-pdf/p946.pdf
• IRS, Rev. Proc. 2025-32 (2026 inflation adjustments): https://www.irs.gov/pub/irs-drop/rp-25-32.pdf
• IRS, Publication 334, Tax Guide for Small Business (2025): https://www.irs.gov/pub/irs-pdf/p334.pdf
• IRS, Qualified business income deduction: https://www.irs.gov/newsroom/qualified-business-income-deduction
• 26 U.S. Code 199A: https://www.law.cornell.edu/uscode/text/26/199A
• IRS, How long should I keep records?: https://www.irs.gov/businesses/small-businesses-self-employed/how-long-should-i-keep-records