Using Dr. PTACs on your next hotel?  Don’t overlook this potential costly mistake!

Lately, I’ve been asked a lot of questions about the Islandaire Dr. PTAC and Amana’s comparable, DigiAIR PTAC.  These are both fairly new products in the hotel market and we are finding more and more owners that are implementing this equipment into their hotel guestrooms.  This is typically done to reduce costs on their overall HVAC budgets compared to the alternative, a dedicated outdoor air system. (DOAS)  While the upfront cost savings may seem straightforward, there is one major item that is often overlooked. 

With a traditional DOAS design (No Dr. PTACs or Amana DigiAIR) the fresh air is directly ducted to all the guestrooms.   The DOAS units are placed on the roof, run gas heat and supply all the guestrooms with conditioned, neutral air.   When switching to Islandaire Dr. PTACs or Amana DigiAir PTACs, the guestroom must utilize electric heat.  These PTACs pull in outside air directly through the PTAC unit and use a rather inefficient electric coil to heat the air.   Depending on the utility rates in your area and the amount of time a unit will be calling for heat, this could add up to a significant monthly bill.  This is especially true in colder climates where a unit may be in heating mode for many months straight. 

I’ve seen several situations recently where a dedicated outside air system was designed properly in the original design.  This was later value-engineered out by a mechanical subcontractor who promised to save significant costs on the HVAC design by making this change.  As an owner, it’s important you not only look at this upfront savings, but also the impact on your operational costs of having all guestroom heat switched to electric.  In many jurisdictions, this could drive your electrical costs through the roof and very quickly eliminate any savings in removing the dedicated outdoor air system from the original design. 

Bottom line… both the Islandaire Dr. PTAC and Amana DigiAir are great products when applied in the right application.  Make sure you do your research to fully understand both the benefits and trade-offs of going with this type of system.

 

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