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Taxes 14 min read

The Complete Tax Deduction Guide for HVAC, Plumbing & Electrical Contractors

The 30+ deductions trades businesses leave on the table every year. With dollar examples, IRS rules, and the documentation you need to keep.

Kellen Boulter, CPA
Founder, Northbound Financial · Texas-licensed CPA

Why trades businesses overpay on taxes

Two reasons.

First, most generic tax preparers — the seasonal H&R Block office, the storefront tax shop — don't actually know what a trades business does. They've never sized an HVAC system. They don't know what a service truck costs. They don't know the difference between a service call and a new install. So they miss things. Lots of things.

Second, even when business owners know a deduction exists, they don't have the documentation to prove it. The IRS standard is "ordinary and necessary" — which is generous — but you have to be able to show the expense was for business if asked.

This guide covers every major category of deduction available to HVAC, plumbing, electrical, and other trades businesses in 2026. Use it as a checklist.

The ground rule: "ordinary and necessary"

Before specifics, understand the standard from IRS Publication 535:

Ordinary = common and accepted in your trade

Necessary = helpful and appropriate for your business

You don't have to prove the expense was essential. You just have to show it was reasonable for your industry.

Category 1: Vehicles (usually the biggest deduction)

Mileage method vs. actual expenses

For 2026, the IRS standard mileage rate is 70¢ per mile for business use. You track your miles in an app (MileIQ, Everlance, Driversnote) and multiply.

Alternatively, you can deduct actual expenses: fuel, insurance, maintenance, repairs, depreciation, registration, financing interest. Multiply by your business-use percentage.

Which is better? Run both. Generally:

Section 179 + Bonus Depreciation (the big one)

For 2026, Section 179 lets you deduct up to $2,560,000 in qualifying equipment and vehicles placed in service during the year.

For most trades businesses, the question is simpler: can I deduct the full cost of my new work truck in year one?

For heavy trucks/vans (F-250, Silverado 2500, Ram 2500, Transit, ProMaster) used 50%+ for business — yes, full Section 179 plus 100% bonus depreciation reinstated under OBBBA. A $72,000 F-250 used 100% for business = $72,000 year-one deduction.

Full breakdown: Section 179 & The Trades Truck Deduction

Other vehicle-related deductions

Category 2: Tools and equipment

Under $2,500 — expense immediately

The de minimis safe harbor lets you expense any individual item under $2,500 in the year you buy it. No depreciation, no Section 179 paperwork. Just a regular business expense.

This covers most hand tools, smaller power tools, diagnostic equipment, and supplies.

Over $2,500 — Section 179 or depreciate

Larger items (drain machines, jet machines, recovery units, plasma cutters, generators) either get Section 179'd or depreciated over 5–7 years.

Specific examples by trade

HVAC:

Plumbing:

Electrical:

Safety equipment

Hard hats, safety glasses, work boots (if required and unsuitable for everyday wear), gloves, hearing protection, respirators, harnesses, fall protection. All deductible.

Category 3: Home office (yes, even for trades)

The home office deduction is one of the most under-claimed deductions in trades businesses. People assume "I work in the field, I don't have a home office." But if you have a dedicated space at home where you:

You probably qualify.

Two methods:

Simplified method: $5 per square foot, up to 300 sq ft (max $1,500/year). Easy, no recordkeeping needed.

Actual expenses method: Calculate the business-use percentage of your home (square footage of office ÷ total square footage), then deduct that percentage of mortgage interest, property taxes, utilities, insurance, repairs, and depreciation.

Critical rules:

Category 4: Insurance and professional costs

Category 5: Licensing, education, and dues

One important limit: Education that qualifies you for a new trade isn't deductible. An electrician's continuing ed is deductible; an electrician's tuition to become a general contractor isn't.

Category 6: Marketing and advertising

Category 7: Software and subscriptions

Category 8: Phone and internet

The business portion of your cell phone bill and home internet is deductible. There's no required formula — but you should pick a reasonable business-use percentage and stick with it.

If you have a dedicated business phone line, 100% is deductible. If you use your personal phone for business, 60–80% is typical for trades owners who answer service calls, coordinate jobs, and run the business from their phone.

Category 9: Subcontractor payments and contract labor

Payments to legitimate subcontractors are fully deductible. The catches:

You must file 1099-NEC for each subcontractor paid $2,000 or more during the year (this threshold rose from $600 starting in 2026 under OBBBA).

You must collect a W-9 from every sub before paying them. If they refuse, you're required to withhold 24% for backup withholding.

They must actually be subcontractors, not misclassified employees. This is the #1 IRS audit issue in trades. Detailed guide: 1099 vs. W-2: Are Your Subs Actually Subs?

Category 10: Other commonly missed deductions

Category 11: Retirement (huge tax savings)

This isn't a "deduction" in the traditional sense, but contributions to a SEP-IRA or Solo 401(k) reduce your taxable income.

SEP-IRA:

Solo 401(k):

For a trades business owner pulling $200K in profit, maxing one of these shelters $50K–$70K from federal income tax.

The Section 199A / QBI deduction

This deserves its own callout. The Qualified Business Income (QBI) deduction allows eligible owners of pass-through entities (sole prop, partnership, LLC, S-Corp) to deduct up to 20% of qualified business income from taxable income.

For 2026, full deduction available when taxable income is under approximately:

Above those thresholds, limitations based on W-2 wages paid and qualified property kick in.

Real impact: On $150,000 of qualified business income, the QBI deduction can shave another $30,000 off your taxable income — and you don't even have to spend anything to get it. It's just there if you structure correctly.

S-Corp election can sometimes optimize QBI by balancing your reasonable salary against distributions. This is part of why the S-Corp conversation matters above certain income levels — see Sole Prop vs. LLC vs. S-Corp for Trades Businesses.

What's NOT deductible (the disappointing list)

The documentation that makes deductions stick

Every deduction in this guide is real and IRS-allowed. None of them matter if you can't prove them in an audit.

The minimum documentation:

The single most important thing you can do for deduction documentation: a separate business bank account and credit card. Everything else falls into place once that's in.

Putting it all together

The owners who pay the least tax legally aren't doing anything aggressive. They're doing the basics consistently:

  1. Clean books that capture every legitimate expense in the right category
  2. A separate business account and credit card (no mixing)
  3. A mileage log kept consistently
  4. Section 179 timing for vehicle and equipment purchases
  5. Home office taken when they qualify
  6. Retirement contributions maxed out
  7. S-Corp election when their profit justifies it
  8. Quarterly tax planning so they make these moves before December 31, not in April

If that sounds like more than you want to manage on your own, Northbound's plans are built around exactly this rhythm — Foundation handles the bookkeeping, Growth adds the tax return and quarterly CPA review reports that catch these opportunities while there's still time to act on them.

Book a free 30-minute call →

Related reading

Tax figures cited are based on 2026 federal tax law including OBBBA-effective changes as of publication. Specific limits and rules can change; always verify with current IRS guidance or a qualified CPA. Nothing in this article constitutes legal, tax, or financial advice for your specific situation.

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