Hot Gas Reheat vs. Hot Gas Bypass?
Tony Mormino
HVAC Addict, Host of HVAC TV (YouTube @HVAC-TV), and the HVAC TV Podcast. It is brought to you by Air Control Concepts. “HVAC TV is the best YouTube channel in the world.” - Marie Mormino, Tony’s Mom.
In over 20 years in the HVAC industry my experience shows that these two terms are commonly misused and misunderstood. In this article and video below I explain the difference.
HOT GAS REHEAT uses the high pressure, high temperature, compressor discharge gas to reheat the air leaving the evaporator coil. This is achieved by running the gas through a hot gas reheat coil using hot gas reheat valves. Hot gas reheat is typically used in dehumidification modes to meet the desired space sensible temperature set point.
Modulating hot gas reheat, the more advanced form of reheat, allows us to precisely control the HVAC system leaving air temperature. As opposed the the older style electric reheat, which works well but wastes a lot of energy. Advances in HVAC controls and technology in HVAC systems over the years has made hot gas reheat very popular.
HOT GAS BYPASS provides an artificial load on the evaporator by introducing a portion of high pressure, high temperature gas to the evaporator/suction side of the system. Inexpensive and simply way to keep the HVAC system running without freezing the coil but a huge energy waster. The hot gas bypass valve is old technology used on limited basis today quickly being replaces by modulating compressors or variable capacity compressors.
If know anyone else who might be interested in this article please share!
Have a question for me? Please feel free to message me on LinkedIn, call or email...
Call me: 828-712-4769
Email me: [email protected]
Visit my YouTube Channel: https://bit.ly/2W3z8no
Sales Director at MSA Group
1 年Hot gas reheat is a great way to turn a $50k job into a $200k+ job.
President at Entratech Systems
3 年I would like to see more companies other than Lennox offer hot gas reheat for residential applications.
Product Manager , Applied & Unitary
4 年Excellent information .However normally hotgas reheat is required for DOAS units more than normal rooftop units .