Day & Night®

How to determine the date of production/manufacture or age of Day & Night® HVAC Systems.

The date of production/manufacture or age of Day & Night® HVAC equipment can be determined from the serial number located on the data plate.

Parent Company:  International Combort Products (ICP). part of UTC Building & Industrial Systems,  a subsidiary company of United Technologies Corp.
Sister or similar Brands Include: Airquest® | Arcoaire® | Day & Night® | Dettson® | Heil® | ICP Commercial® | Keeprite® | Lincoln® | Tempstar®

Example serial number styles/formats found:

  • Style 1:    4006A17330
  • Style 2:    50304091

Style 1:   4006A17330

Description: Nine (9) character Serial number begins with four (4) numerical digits follow by a single letter and ends with five (5) numerical digits.
Week of manufacture is 1st-2nd characters.
Year of manufacture is 3rd-4th characters.

Style 2:   850304091

Description: Nine (9) digit all numerical Serial number.
Year of manufacture is 1st – 2nd characters.
Month of manufacture is 3rd – 4th characters.

Page last updated: 29 March 2016

650 Heil-Quaker Ave
Lewisburg, TN 37091
(934) 270-4100

ICP – Canada
6060 Burnside Court, Unit 1
Mississauga, Ontario L5T 2T5
(905) 795-8113

Any of the trademarks, service marks, collective marks, design rights or similar rights that are mentioned, used or cited in the articles of the Building Intelligence Center ( are the property of their respective owners. Their use here does not imply that you may use them for any purpose other than for the same or a similar informational use as contemplated by the original authors of these articles under the CC-BY-SA and GFDL licensing schemes. Unless otherwise stated Building Intelligence Center ( sites are neither endorsed by nor affiliated with any of the holders of any such rights and as such Building Intelligence Center ( cannot grant any rights to use any otherwise protected materials. Your use of any such or similar incorporeal property is at your own risk. This guide is intended to assist Commercial/Residential Building Inspectors, HVAC professionals, Facilities Managers, HOA’s, etc.., in determining the date of manufacture and/or age of HVAC equipment to determine the expected useful life (EUL). This web site should not be relied upon for commercial use or interpretations. Accuracy and reliability of the information provided is believed accurate but is not guaranteed. The burden for fitness of information provided relies solely and completely with the user. In no event will Building Intelligence Center or its representatives be liable for any loss or damages whatsoever for consequential, incidental, indirect, special, or tort damages of any kind, including but not limited to loss of data, lost profits, business interruption, loss of business information, or other pecuniary loss that might arise from the use of or reliance on the information provided within.