When you’re in the market for a new gas furnace, you are going to come across the terms, single stage, 2 stage and modulating. These terms refer to the type of gas valves the furnaces have. Let’s take a quick look at each to provide a better understanding and how this will affect you.
Let’s use a 60,000 btu furnace as the example and look at the ways the difference gas valves would operate
A single-stage gas valve has been the most common furnace for many years, however, is slowly fading away as new technology hits the market. This gas valve simply turns on and off, so your 60,000btus of heat are either 100% on or 100% off, even if you only need to bring the temperature in your home up 1*. This can cause noticeable temperature swings in your home, if you’ve ever had an older furnace, you know what this feels like. The house starts cooling down and then “click” there’s a blast of heat for 5 minutes and then it shuts down again, until next time the house starts cooling down. The benefits of a single stage furnace is that they are the lowest cost furnaces available, they are simple and compatible with most existing setups.
The 2-stage gas valve is now the most commonly purchased furnace in our market today. This operates much like the single stage, however, instead of 100% on and off, you have 2 stages, 70% and 100%. If you home only needs to go up 1* the furnace will only run at 70% of it’s capacity or 42,000btus and only kick up to the full 60,000btus if required. This results in the system running in a quieter, lower speed for a longer period, increasing air circulation and reducing the temperature swings.
The last option is a modulating gas valve. This gas valve has a full range between 40% and 100%. Using the same example as before, if the temperature needs to increase by 1* the furnace will only turn on at 40% of its capacity or 24,000btus and increase in 0.5% increments. This allows the system to run for longer periods, at lower temperatures and lower speeds, improving the comfort, air quality and efficiency of your home.
Let’s look at the temperature swing graph together and compare the 3 different types for a better understanding.
The peaks and valleys on the single stage unit are extreme, the 2 stage gas valve less extreme and more consistent and the modulating gas valve has almost no temperature swings in comparison.
Some key benefits of having longer run times are better air quality – since the fan is running longer it’s able to filter the air more often and control humidifier better more even temperature – longer run times mean the air has more time to circulate throughout the house in between cycles and creating an overall more even temperature
more efficient –the more a system cycles on and off the more energy it’s using and the more wear and tear that is placed on all the components, resulting in higher energy bills, more furnace repairs and lower life expectancy.
Hopefully this short video was able to help you with understanding the difference between the 3 common type of high efficiency gas furnaces and please let us know if you need any help finding the right solution for your home and we are always happy to help. We look forward to working with you soon, take care.
