Commercial HVAC replacement and installation in Boulder.

Most commercial replacements come down to three choices, and the honest way to compare them is to price all three at once. A like-for-like swap is fastest, because the curb, the gas line, and the electrical feed all stay where they are. A high-efficiency unit costs more up front and pays back through the meter; the federal high-performance specification targeted energy use up to 50% below the older standard, and manufacturers now offer more than twenty models that exceed it. A heat pump rooftop unit adds reverse-cycle heating, which matters if you want to cut gas use or emissions. Heat pump units come in three shapes: all-electric, dual fuel with gas backup, and cold-climate models built to hold capacity at lower outdoor temperatures. Heat pump heating efficiency drops as outdoor air gets colder and trends toward electric resistance, so the heating design temperature at your site decides which of the three fits.

No two roofs price the same, so read a quote line by line instead of comparing bottom numbers. These are the items that separate two bids on the same building, and each one should show up as its own line rather than disappearing into a lump allowance.

The most expensive habit in facility management is replacing on failure. A unit dies in August, one option shows up, and the building buys whatever is on a truck that week. Planned replacement flips that. You pick the timing, you compare equipment, and you have room to chase incentive money that a same-week emergency will never qualify for.

Start with the load, not the nameplate. Twenty years of occupancy changes, added plug load, lighting retrofits, and envelope work usually mean the old tonnage is wrong in one direction or the other. Oversized units short-cycle, dehumidify poorly, and wear out compressors early. Undersized units run flat out and never quite catch up. A load calculation based on how the space is used today costs a fraction of the equipment and decides whether the next fifteen years are comfortable.

Then settle the fuel question once, at the portfolio level if you own more than one building. The inputs are the same every time: heating hours, electricity and gas prices, available electrical capacity, and whether contractors nearby routinely install and service the equipment you are considering. If one of those points the wrong way at a given site, a dual-fuel unit keeps gas heat as backup while still moving most of the operating hours to the heat pump.

Two buildings can buy the same tonnage and still land a month apart on schedule. The difference is almost never the equipment. It is what the roof, the electrical room, and the operating calendar allow.

A quote written from a nameplate photo is a starting point, not a price. It tells a contractor the tonnage and the age. It says nothing about what happens when the old unit comes off the curb.

A real site review walks the roof and the electrical room. On the roof, it confirms curb dimensions, unit weight against the structure, condensate routing, service clearances, and how far a crane has to reach from the nearest place it can legally set up. In the electrical room, it confirms available capacity, spare breaker positions, and whether the feeder can carry a unit with electric heat. If a heat pump is on the table, the review also has to answer what happens to the existing gas line: abandoned, capped, or kept for dual-fuel backup.

Equipment availability belongs in the same conversation. Lead times move with tonnage and configuration, and a unit that is weeks out changes how you sequence the work, whether you need temporary cooling, and how you staff the shutdown. So does contractor familiarity. Newer heat pump rooftop units need people who have started them up before, and that experience is not evenly distributed.

Two questions matter long after the crane leaves. The first is who carries the risk when the unit is down again in year eight: warranty terms, the service agreement, and whether parts for your refrigerant are stocked nearby. The second is what the building is supposed to be in ten years. Replacing on failure quietly answers that for you, one unit at a time, in whatever direction the market happens to be pointed the week a compressor quits. Neither question has a universal answer, but both are cheaper to settle while the roof is open and the crane is already scheduled.

The purchase price is the smallest number in a rooftop decision. A unit stays on the roof for many years after the invoice clears, and the energy it burns over that life usually costs more than the equipment and the install combined. That is why the waste figure on an aging unit matters. An old, inefficient rooftop unit can cost $900 to $3,700 a year more to run than it needs to, and a roof carrying six of them is losing real money every season it waits.

Phasing is how most owners make that math survive a capital budget. Rank the units by age, service history, and how much of the building each one serves. Replace the worst two this year and the next two the year after, sharing mobilization and permit work where the schedule allows. A phased plan also leaves time to look into utility and federal incentive programs before equipment is ordered, since incentive paperwork is the first thing an emergency replacement loses.

Procurement follows the same logic. Order early enough that lead time is not making the decision for you. When equipment gets ordered under pressure, the building takes what is available, and availability has no opinion about your load calculation.

Bids only compare if they describe the same project. Ask each contractor to put these five items on the face of the quote, so you are reading one scope priced several ways instead of several different scopes.