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Commercial HVAC Installation and Replacement
Serving Modesto, Manteca and Riverbank in the Central Valley
Your Next Rooftop Unit May Be a Heat Pump
Commercial HVAC installation in Modesto now starts with a code question. Since California's 2025 energy code took effect in January 2026, many buildings have to look at a commercial heat pump first when a rooftop unit wears out. That one rule shapes which unit you get and what the job costs.
Dycus Heating and Air Conditioning plans around that rule from the first visit, so the unit you pick fits the building, the budget and the code.
365Days Availability
100%Local Technicians
25Years of Experience
15 yearsTypical life of a single-zone rooftop unit, based on ASHRAE equipment data.
65,000 Btu/hSize line under which California's 2025 energy code steers many office, shop and school swaps to heat pumps.
2021Year the state began requiring a certified tester to check new commercial systems before sign-off.
700Top climate score allowed for refrigerant in most new cooling units since 2025, under EPA rules.
What a Replacement Quote Should List
A quote for commercial HVAC installation in Modesto should read like a plan, not a price tag. If any line below is missing from a quote you hold, ask before you sign, since each one changes the cost.
Load Calculation for the Space
Size comes from floor space, how many people use it, the windows and the hours the building runs. Copying the old unit's size can repeat a mistake made twenty years ago, and the business pays for it on every summer power bill.
Your Building's Code Path
Offices, shops and schools usually need a heat pump rooftop unit under 65,000 Btu/h. A gas unit can still qualify with extra energy-saving features, and the quote should say which path you're on.
Electrical Service and Breaker Size
A heat pump can need a bigger circuit than the gas unit it replaces. The quote should show whether your panel can carry it, or what the upgrade adds.
Curb, Crane and Roof Work
In a rooftop unit replacement, the new unit often isn't the same shape as the old one. Look for the curb adapter, the crane and the roof sealing. Those costs tend to show up late when a quote leaves them out.
Permit and Acceptance Testing
A complete quote names the permit fee and the acceptance testing the state requires, so the job doesn't stall at the finish.
Startup and Staff Walkthrough
The last line should cover startup, a full test run and a short lesson on the controls for whoever runs the building.
If the current unit still has good years left, a commercial HVAC repair may be the better spend this season. Buildings with many rooms on different schedules are often a better match for commercial VRF systems, which serve many rooms from one outdoor unit.
Pricing a New Commercial System
Will the new code raise your price? Sometimes. The answer depends on how your building is used and how much work the roof needs, so it gets settled at the site visit.
If the old unit has already failed, a $169 commercial diagnostic confirms it can't be saved before anyone prices a new one. After that, unit size, the code path, crane access and duct changes shape the quote.
Each Modesto install gets its own quote, built around your roof, panel and hours. Equipment gets ordered only after you sign off on the full number.
Heat Pump or Gas Rooftop Unit
We Lay Out Both Before You Choose
The code sets the starting point, not the whole answer. Some buildings still qualify for a gas unit, while some owners would rather go all-electric anyway. Dycus Heating and Air Conditioning prices every option the code allows, side by side, and your team makes the call with every cost in view.
| Heat Pump Rooftop Unit | Gas Rooftop Unit | |
|---|---|---|
| How it heats | Moves heat with refrigerant, all on electricity | Burns natural gas in a heat exchanger |
| Code status today | The standard pick for most small rooftop replacements | Allowed with added efficiency measures or a performance calculation |
| Electrical needs | May need a larger circuit or breaker | Usually fits the existing circuit |
| Winter heating here | Mild Central Valley winters suit heat pump heating | Steady heat no matter the outdoor temperature |
Why Owners Trust Us With Replacements
Installed by People Who Plan First
Bosch and York Equipment Installed
We install both Bosch and York equipment. Bosch bought York's residential and light commercial maker in 2025.
NATE-Certified Installers
Before the crane leaves, someone has to set the refrigerant charge, airflow and controls right. On our crews, that's a NATE-certified technician, tested by North American Technician Excellence, an outside group.
We Handle Breakers and Panels
When a heat pump needs more power, we don't send you to find an electrician. We replace breakers and panels ourselves. So the code upgrade and the new unit stay on one schedule and one invoice.
How a Commercial Replacement Comes Together
Every install Dycus Heating and Air Conditioning takes on moves through the same four stages.
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Site visit and measurements
Our installation manager measures the space, checks roof access and notes how the building is used.
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Your options and the price
You get a separate quote for each code-compliant unit, along with the work it involves, and decide on your own schedule.
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Install day
The crane lifts the old unit off and sets the new one on its curb. We connect power, gas or refrigerant lines and controls, then seal the roof around the curb.
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Testing and final inspection
We start the system, arrange the acceptance tests the code requires, and stay with the job through final inspection.
Plan Your Next Rooftop Unit Now
Replacing in Spring Beats Replacing in July
A planned replacement gives you time to compare options, book the crane and schedule around your business. Our office opens at 7 AM on weekdays. Call then, and we'll set up a site visit before the unit forces the decision.
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Read the Unit's Data Plate
The data plate on the side of the unit lists a serial number, and many brands build the year into it. Read it to us, and we'll tell you how it compares with that 15-year typical life.
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Note Rooms That Run Warm
Tell us which rooms run warm or chilly during the workday. Those notes help us size the new unit and plan any duct changes before the crane arrives.
Where We Install Commercial Systems
Our installers work in every town below. Each city or county runs its own building department, and your permit goes through whichever one covers the address. Sites more than about 20 miles out add an out-of-area fee, listed in your quote.
Reviews From Finished Installs
Customers left these comments on Google after their installs and service visits.
"Doug went above and beyond to make sure everything was done perfectly. He was professional, knowledgeable, and incredibly friendly throughout the whole process."
Desiree B., Google review
"The front office people and the techs are very professional and know their stuff."
Paul G., Google review
Commercial System Reading From Our Blog
Weighing a new system after a long summer? Our post on commercial HVAC maintenance after summer in Modesto covers what to check on the roof before you decide. Browse the blog →
Owners Ask About Commercial HVAC Installation
How long does a commercial HVAC installation take in Modesto?
A straight rooftop unit swap on an existing curb is often a one-day job once the crane is booked. Adding a new curb, ductwork changes or an electrical upgrade can stretch it to several days, and permits add time before work starts.
Can I replace one rooftop unit at a time?
Yes. On buildings with several units, each one is usually replaced as it wears out, which spreads the cost across a few budget years. Matching the new unit's controls to the others keeps the building running as one system, so ask for that in the quote.
Is a new commercial HVAC system tax deductible?
Often, yes, though the rules change. Under Section 179, many businesses can write off HVAC upgrades to an existing commercial building in the year they go in, rather than depreciating them over time. IRS Publication 946 explains the details. Ask your accountant how your project is treated before you sign.
Can a new rooftop unit use my existing ductwork?
In many cases, yes. If the ducts are sound, sealed and sized for the airflow the new unit moves, they can stay. We check them at the site visit. Leaky joints or undersized runs are worth fixing during the swap, while the roof is already open.
Do I need to be closed during a commercial HVAC replacement?
Usually not. Most of the work happens on the roof, and the building loses heating or cooling only while the old unit is swapped and the new one starts up. Planning the swap for a mild day keeps that window comfortable.