Commercial HVAC Retrofits For Dummies

What you need to consider before pulling the trigger on your next commercial HVAC retrofit project

Written by CMI Mechanical CEO – Rick Dassow

Facility Managers - CMI MechanicalLet me start by saying, I love the “Dummies” book series.  What another reading material distills tons of information into easy to read bullet points with cartoon pictures? That’s perfect for me.

I wish they had an “American History for Dummies” when I was in high school.

Sans the cartoon pictures, today’s goal is to replicate the genius of the “Dummies” book series here and provide a condensed version of the main elements of commercial HVAC retrofits so that you can pre-plan and make informed decisions about your next project.

It is completely understandable many people in the commercial real estate industry, depending upon their background, have not had much experience with direct, hands-on capital replacements.  

CMI Mechanical HVAC and Refrigeration often receive calls from prospective clients asking us to upgrade or retrofit their HVAC system.  The nature of these calls can range from a slight sense of urgency to downright panic.

We are always happy to help regardless of the circumstances, however, there is an issue that frequently seems to arise in these situations – the company in need of assistance doesn’t take into consideration advanced planning which can severely disrupt the timeframe and budget involved in the process.

Also, complications can stem from the fact that properties and tenant spaces have changed hands on a frequent basis.  A property or facility manager may have inherited unknown problems from the previous ownership or occupant.

As an example, one of my most interesting calls came from the parent company of a restaurant in Orlando.  It was the beginning of summer, and they wanted to change out their chiller. As it turns out, the interior atmosphere of the restaurant was 90 degrees with high humidity, forcing customers to leave the restaurant.

After some mechanical engineering, we discovered the site was roughly 160 tons short of cooling. This was the result of a recent addition that was put on the building without performing the necessary commercial HVAC mechanical engineering. You can imagine their surprise when they started looking at new budgetary numbers and time frames associated with the processes involved in adding this extra tonnage.

While this is an extreme example of a common theme, it illustrates the need to develop a manner of thinking and preparation when it comes to retrofits.

Fundamental Ideas For Commercial HVAC Retrofits

Know the use of the space when the equipment was originally installed

Commercial HVAC Project ManagementWe see this problem over and over, especially in retail and office spaces. The facility may have been renovated or changed use since the equipment was originally installed.

If this happens to be the case with your facility, the first thing to do is to get a mechanical engineer to examine the new use of the space and determine if the equipment and systems are correctly sized and up to code.

Determine the specifications of the equipment

In other words, what type of equipment are you asking the commercial HVAC contractor to install? In the case of rooftop units, this may include: the SEER rating or efficiency of the unit, whether the unit will have economizers, smoke detectors, EMS controls, humidification, hail guards, new electrical disconnects, coated condensing coils if you are near the ocean, and so on.

Lead time

How long will it take to get the equipment to the site? If you are replacing a common item, it may be in stock. More often than not, the commercial HVAC equipment can take 8-10 weeks to ship from the manufacturer.


Additionally, if you are changing the brand of the equipment, this will likely require custom-built adapta-curbs which also takes time.


You will want to get recommendations on whether or not the project will require structural engineering and reinforcement. This will be determined by the weight of the new compared to the old equipment, as well as any additional weight added from adapta-curbs or other equipment.


Is there enough power to handle the new unit? This piece of information is especially important if you are adding new equipment, but may also come in to play for existing change outs.

Some other electrical issues that you may encounter include fusible disconnects, GFI outlets, wiring, panel upgrades, and in some cases, service upgrades.


How long of a reach is it for the crane? Where can the crane set up and how does it affect your business?  Also, ask if the building needs to be unoccupied when the crane sets the units.

Fire protection

If the unit being installed has a rating of over 2,000 CFM, the unit’s smoke detectors will need to be tied into the main fire panel. This will require involvement by your fire protection company.


Always. Pull. Permits.  Volumes could be written revolving around this subject.  In summary, it takes the liability out of your hands and places it somewhere else.

Additionally, be aware that the City may require upgrades to bring unrelated items up to code. This can add to the cost of the project.

Other considerations

Commercial HVAC Rooftop InstallationOther areas you may want to consider which could affect your commercial HVAC retrofits project include roofing, piping, natural gas, welding, the height of the project, zoning, core drilling, or test and balance.

As an FYI – In the case of zoning, the city may require fencing around the project or other related restrictions.

In summary, there are many challenges you have to examine that can affect your commercial HVAC retrofit project. However, knowing all of the potential hurdles and problems in advance will give you an incredible advantage in delivering your project on time and on budget.

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