Commercial HVAC replacement and installation in Denver.

Start with the business problem, not the model number on the old unit. A repair may make sense when the failure is isolated, the equipment still serves the load, and parts remain practical to obtain. Replacement becomes stronger when service calls repeat, occupied areas cannot hold temperature, or one failure could close a critical space. DOE guidance notes that rooftop units more than 15 years old can waste substantial energy compared with newer models, but age alone does not settle the choice.

A like-for-like replacement may shorten design work when the old arrangement still fits. It can also preserve old problems if loads, schedules, ventilation, or space use have changed. A redesign takes more study but can correct poor zoning, control conflicts, oversized equipment, or an outdated heating approach. Compare the choices by shutdown risk, expected service needs, energy use, comfort, and the building’s future—not by purchase price alone.

There is no supported universal installed price for a Denver commercial system. Ask bidders to separate equipment, enabling work, labor, access, controls, and closeout so the sources of cost are visible.

Packaged rooftop units are common in schools, restaurants, retail buildings, and small offices. They combine major heating and cooling functions in one roof-mounted package. A high-efficiency RTU can be a practical replacement where the roof layout, zones, and ducts still work. Features such as variable-speed fans and better controls can improve part-load operation, but the quote must state what is included.

A heat-pump RTU provides cooling and reverse-cycle heating. DOE guidance says the decision should account for climate, utility bills, emissions goals, building type, equipment availability, electrical capacity, physical limits, and existing gas service. In colder conditions, heat-pump efficiency falls, so the design must show how the selected system handles winter demand. Options may include all-electric, cold-climate, or dual-fuel equipment. A heat-pump conversion deserves a load and utility review rather than a simple fuel swap.

Larger or more complex buildings may use air handlers with boilers, chillers, pumps, and terminal equipment. Replacing one plant component without checking flow, temperatures, controls, and connected loads can leave capacity unused. For that scope, compare a packaged replacement with a coordinated boiler or chiller installation.

Two replacements can use similar equipment yet demand very different design, access, and shutdown work. Classify the site before treating bids as comparable.

The survey should identify every unit in scope, its served area, capacity, heat source, refrigerant, electrical data, controls, curb, duct connections, drainage, and service condition. It should also record roof access, lifting paths, ceiling access, occupied hours, and spaces that cannot lose heating or cooling. Photos help, but field measurements and equipment data are what make the scope usable.

Next, test the reason for replacement. Review service history, comfort complaints, schedules, and any change in tenants, process loads, kitchen equipment, lighting, or occupancy. Confirm whether the old unit is truly undersized or whether failed dampers, dirty coils, poor airflow, or weak control sequences are limiting performance. If distribution is part of the problem, include ductwork inspection and balancing in the plan.

The result should be a basis of design that states required capacity, ventilation, heating strategy, efficiency, filtration, zoning, controls, redundancy, and acceptable outage windows. That document lets bidders price the same result while still proposing equivalent equipment.

Denver’s 2025 Building and Fire Codes became effective December 31, 2025. Drawings for new projects submitted after that date must use those codes. They incorporate the 2024 I-codes, except the Energy Code, which incorporates the 2021 IECC. Denver also publishes local amendments and policies, including current material for A2L refrigerants.

For an August 2026 project, the design team should confirm the submission path and current requirements before equipment is released. The review may affect equipment selection, refrigerant documentation, structural work, energy documentation, service clearances, and the permit set. Roof-mounted work should also account for applicable structural criteria rather than assuming the old curb proves the new load is acceptable.

Colorado’s industry mix includes advanced manufacturing, arts and media, food and agriculture, and transportation and logistics. Each setting creates different HVAC priorities, even when the equipment appears similar.

A lower first price can become expensive when the project leaves unclear controls, hard-to-source components, poor service access, or no plan for occupied work. Review the system as an operating asset. Ask who will maintain it, which parts are stocked, what staff can see through the controls, and how failures will affect tenants or production.

DOE has reported substantial energy waste from older commercial rooftop units and has documented broad savings from high-efficiency replacements. Those national results show the opportunity, not a guaranteed result for one Denver building. A useful financial comparison starts with site utility history, modeled loads, expected schedules, maintenance history, and the actual equipment proposed.

Do not set the shutdown date until equipment availability, approved submittals, permits, crane access, trades, and required accessories are aligned. Long-lead controls, curbs, electrical gear, or specialty components can matter as much as the main unit. The schedule should show design, review, release, delivery, enabling work, removal, setting, connections, startup, testing, and owner training.

Occupied buildings need a written phasing plan. State which zones can be down, for how long, and under what weather limits. Identify temporary conditioning where loss of service could affect people, products, technology, or production. Coordinate roof closures, parking restrictions, delivery paths, noise, dust, and after-hours access with the facility team. If several units are aging, staged replacement can spread capital needs and preserve service, but each phase should fit one long-term controls and equipment plan.

Closeout is part of installation. Require startup records, test results, air-balance reports where applicable, control sequences, setpoints, warranties, equipment schedules, operation manuals, and staff training. Verify alarms and trends before final acceptance. A design-build mechanical approach can help when equipment, controls, electrical work, ductwork, and phasing must be resolved under one coordinated scope.

Use one written basis of design and require the same breakdown from each bidder. A short total with broad exclusions is not enough to compare risk.