Commercial HVAC replacement and installation in Renton.

Most roofs land on one of three paths, and the split matters because the cheapest install is rarely the cheapest decade. DOE's rooftop unit work frames the core choice as replacing an aging unit with a more efficient one or retrofitting the existing unit with advanced controls, depending on which makes better financial sense for that building.

There is a fourth path, and it picks itself if you wait: replacement on failure. It costs the most in downtime and leaves you no leverage over lead time, equipment selection, or when the crane shows up.

Price at least two of these against each other. One quote tells you what something costs. Two quotes tell you what the choice is worth.

Two quotes for the same tonnage can differ by a wide margin, and the difference is almost never the box. It is the work around the box. For each line below, ask what is included, what is excluded, and what is an allowance the contractor expects to revisit once the old unit comes off.

A heat pump rooftop unit is not an exotic machine. DOE describes them as technologically similar to standard air-conditioning rooftop units, with reverse-cycle heating added. The install looks familiar. The real question is whether your building and your utility rates make the heating side pay.

DOE's guidance walks the checks in a useful order: heating load and geography, the utility bill impact at your electric and gas prices, emissions goals, building type, equipment availability, and infrastructure. Infrastructure is the one that surprises owners. Electrical capacity, physical constraints on the roof, and existing gas lines decide whether an all-electric swap is a clean substitution or a small electrical project bolted onto a mechanical one.

Efficiency behavior matters too. As outdoor temperatures drop, heat pump heating efficiency falls and trends toward parity with electric resistance heat. That is why the equipment comes in three shapes: all-electric, dual fuel, and cold climate. Dual fuel keeps a gas heat source for the coldest hours and runs the heat pump the rest of the time.

So ask for both prices. A gas-heat replacement and a heat pump replacement, same tonnage, same roof, with the electrical work priced honestly on the heat pump side. The gap between them is the actual decision, and it is usually either smaller or larger than owners expect.

The same tonnage can be a straightforward substitution or a three-trip project. What separates them is rarely the equipment. It is the curb, the power, and the parking lot.

A quote written from a nameplate photo is a starting number, not a price. It is genuinely useful for triage when a unit is down and you need options today. It is not what you sign.

The site review exists to close the gaps that later become change orders. Someone gets on the roof and confirms curb dimensions and condition, checks the structure where the load lands, reads the actual electrical service and available capacity at the panel, traces the gas line if one is staying, and looks at the lot the way a crane operator will. Reach, staging, and how many stalls come out of service for how long.

The other half of the review is the building, not the roof. Sizing should come from how the space is used now. Occupancy, plug loads, and the envelope all change over twenty years, and the old nameplate carries forward whatever the last person assumed. If tenants have complained about one zone since before the unit started failing, that is a sizing or distribution problem, and a new box will inherit it.

Get the findings in writing. A site review that produces no document produced no findings.

The install itself is over quickly. The decision keeps paying or costing for the life of the equipment, and two parts of it get much harder to change after the crane leaves. The first is refrigerant, which is now a compliance and service-planning question rather than a spec-sheet footnote. The second is timing, which is the difference between buying equipment and buying whatever is available the week your compressor dies. Neither shows up in the installed price. Both show up in the operating budget. Raise them while you still have two quotes on the table and some leverage to use.

Almost nobody replaces one rooftop unit and stops. If you own a roof with several, the real question is sequencing, and the sequence should follow age and waste rather than whichever unit generated the loudest complaint last summer.

Start with an inventory: age, tonnage, heating type, and service history for every unit. DOE flags fifteen years as the point where rooftop units begin wasting substantial energy and money compared with newer models, and puts the annual waste of an old, inefficient unit at $900 to $3,700. Multiply that by the number of units past fifteen years and you have the cost of the do-nothing plan in numbers a finance team will accept.

Then group the work. Replacing two or three units on one crane day costs less per unit than three separate mobilizations, and it lets you standardize on one equipment platform and one controls approach across the roof. Standardizing pays back every year afterward in parts, in training, and in how fast a technician diagnoses something on a Monday morning.

The scale here is not theoretical. Through DOE's Advanced RTU Campaign, more than 200 organizations upgraded over 43,000 rooftop units and saved a combined $37 million a year on energy bills — recurring savings, from equipment that was going to need replacing anyway.

Quotes are only comparable when they describe the same scope. When two prices are far apart, one of them is usually missing something below. Ask for these in writing before you compare.