What are you getting out of your HVAC contract?

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Many companies with data centers outsource the maintenance of cooling systems to an HVAC contractor. Makes a lot of sense. Maintaining cooling units requires a specific skill set and years of experience.  

What services does your HVAC contractor provide?

In a broad sense, their role is to keep the cooling units running and avoid downtime due to failure or lack of cooling. Typically, the HVAC contractor will do maintenance based on the contract schedule, twice, three times a year, or maybe quarterly. They check out the cooling system to make sure everything is operating the way it should. At different times of the year, they may do added maintenance to remove pollen build up on condensers; much like your mechanic looks after your car. 

There is a lot more to ensuring data center cooling is optimized and providing the right amount of cooling needed versus excess cooling and higher than necessary energy costs.   

Unfortunately, data center cooling doesn’t get the respect it deserves. As long as the cooling units keep running and the data center feels cold, the conclusion is all is good in the cooling world. Meanwhile, significant dollars are being wasted in excess energy to operate the cooling systems. 

But what’s missing in these maintenance contracts?

  1. It’s not the HVAC contractor’s role to assess thermal or airflow conditions in the data center or determine how to eliminate hot spots. As long as cooling units are operating to specification and there are no cooling unit failures, all is good. 
  2. It’s not their responsibility to determine whether the operating cooling capacity is in line with the IT load. In most cases, there is much more operating cooling than is really needed – in an effort to make sure there is no site downtime due to lack of cooling.
  3. They don’t provide recommendations on how to reduce or optimize cooling energy costs. For example, modifying airflow to increase return air temperatures or sequencing operation of cooling units to match the cooling being supplied to the requirements of the IT load. 

What does all this mean?

For one, operating cooling capacity will generally be greatly in excess of what is required. Industry research has shown the average cooling utilization is 38% – that means there is 62% excess cooling capacity. 

If there are issues with hot spots in certain areas the recommendation will typically be to install additional cooling capacity – a major capital expense that in most cases is not required and will not resolve the hot spot issue. 

There are ways to optimize cooling and reduce energy costs

Optimizing cooling will make it more effective and more energy-efficient. In order to do this, the entire data center has to be reviewed, and this requires a unique skill set. To make the right decisions to improve cooling effectiveness and efficiency, the following basic information is required to get started: 

  • information on rack inlet temperatures  
  • actual airflow passing through the perforated tiles (versus making its way into the room through other openings)  
  • supply and return air temperatures to the cooling units  
  • age and condition of cooling units  
  • the overall heat load in the space  

This data needs to be analyzed to see where improvements can be made.  

That’s where we can help

 SCTi has created its energy conservation measure (ECM) toolkit that sections the data center operation into 8 individual areas, all of which impact cooling and energy efficiency.   


As each data center is unique, not all 8 ECM’s are applied – in some cases maybe 5 ECM’s are used and in others only 2-3 ECM’s are necessary. It all depends on where improvements need to be made. If the PUE (power utilization effectiveness) is close to 2.0 then likely more ECM’s will be needed than if the current PUE is 1.5.   

One ECM that we do apply quite often is the Floating Head Retrofit for CRAC units.

Using the earlier example of a mechanic working on your car. Let’s compare a 1980 car to the newest model. We upgrade several older components to make the cooling operate more energy efficiently. The chassis is still from the 1980s but with the upgraded components the CRAC unit will have many more years of service and be upwards of 45% more energy-efficient. Perhaps not as energy-efficient as new units, but the cost is less than 15% of a new cooling unit with payback typically less than 2 years. 

Additionally, these retrofits are eligible for SaveonEnergincentives which further reduces the payback period. 

Let’s look at ROI

How does the payback of the retrofit compare to the purchase and installation of a new energy-efficient cooling unit? 

A new energy-efficient cooling unit will typically have a power draw of 6 kW and cost in the range of $150,000 for purchase and installation (including removal of the old unit). A retrofitted unit will see an improvement of 40% in energy reduction bringing its power draw into the 10 kW or less range. Looking at the energy savings of the two approaches, the energy-efficient unit would have an annual energy cost saving of about $7,500 compared to the retrofitted unit. To payback the difference in cost to go with the energy-efficient cooling unit would take over 15 years.  

If you still think the purchase of a new cooling unit is a good choice, ask yourself

  • Will my current data center still be operational for the next 10 -15 years? The life of a cooling unit would be in the 15-year range and the cost to relocate cooling units is high. 
  • Will existing IT services be moved to the cloud – less IT load means less cooling required? 
  • Will IT applications be virtualized – less heat load so is more cooling needed?
  • Do I want the disruption of removing an old cooling unit and installing a new one? 
  • Is the plan to go with the same cooling capacity or more than the old unit – do I actually need additional capacity? 
  • Do I want to invest the capital at this point not knowing what the future of the data center may be? 

Keep in mind

Having older cooling units doesn’t mean they need to be replaced as there is a lot that can be done to improve the energy efficiency of the unit. 

Retrofitting older cooling units is done with very little disruption to the site. 

We’ve successfully retrofitted over 225 cooling units. The floating head retrofit takes one week per unit and either during or at the end of the retrofit we train your HVAC contractor on changes that were made. From an ongoing maintenance perspective, the floating head retrofit will have no impact on the contractual agreement you have with the HVAC contractor.   

In actual fact, most HVAC technicians prefer working on the retrofitted units as part of the retrofit includes updated displays which provide them with better information on the operation of the CRAC unit. 

Read our brochure to learn more about the floating head retrofit, including FAQs. 

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