Buying A New Furnace: Understand AFUE Ratings Before You Choose

If your heating equipment was on the fritz at the end of last heating season, the time is now to upgrade your furnace. Amongst other things, it is imperative that you know how to read and understand the annual fuel utilization efficiency, or AFUE ratings that are displayed on all new furnace models. Here's why:What AFUE isAFUE ratings are a measurement of how well a furnace is able to change the energy within its fuel into usable heat throughout the course of a year. To be more specific, AFUE serves as the ratio of the furnace's annual output of heat versus the total amount of energy that is consumed by the boiler. All new heating equipment including both furnaces and boilers is required to display AFUE ratings so that consumers are able to easily make comparisons between the efficiency of various models.What the numbers meanWhen it comes to AFUE, the larger the number you see, the more efficient the furnace is. As an example, if a furnace has been assigned an AFUE rating of 85 percent, you will know that 85 percent of the energy from its fuel will be efficiently converted into heat from your home. The remaining 15 percent will be lost through your flue pipe, pilot light, or other means of losing efficiency.Other considerations when looking at AFUE ratingsFirst, it is important to keep in mind that AFUE does not take the losses of heat within your duct system or piping into consideration. If your home's ducts are located in your attic, you can expect that as much as 35 percent of your furnace's energy output could be lost. Your HVAC contractor can advise you on the best heating systems for a home with such a duct system. In addition, you should know that bigger is not always better with AFUE. Electric furnaces tend to have AFUE ratings between 95 - 100 percent, for example, but the higher costs of electricity over gas make these an uneconomical decision.For more advice on understanding furnace efficiency ratings, contact the professionals at Air Assurance. We proudly serve residents of the Tulsa and Broken Arrow areas.Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems). Image courtesy of Shutterstock

Forced-Air Furnaces: Understand How They Work Before You Buy

Forced-air furnaces are one of the most common and popular choices for heating your home, and with good reason. Forced-air furnaces are the most energy-efficient and comprehensive choice for keeping your home toasty in winter. Learning how these furnaces work can help you choose the right model for your home.

A forced-air furnace works by burning gas in the heat exchanger. A fan blows air across this exchanger, heating the air and then sending it through the air ducts into your home. When the gas is completely combusted, the flue gases move through the heat exchanger and are vented outside the home.

Efficiency levels

Forced-air furnaces come in two main types, an 80 percent efficiency model and a 90-plus efficiency model. The difference between the two lies in the way that they process and vent combustion air. An 80 percent furnace has one heat exchanger, and connects to your existing flue pipe or chimney to vent 20 percent of the air outside the house, keeping 80 percent of the heated air indoors. A 90-plus furnace has two heat exchangers, using outside air for combustion and venting less than 10 percent outside the home.

Burner settings

Of these two  efficiency models, there are single-stage, two-stage, and modulating furnaces available. "Single-stage" means that the burner uses only one level of heat, "on" or "off." "Two-stage" furnaces have a microprocessor that controls a burner using two levels of heat, high and low. A modulating gas furnace does not come in 80 percent or 90-plus models, but operates at 95 percent or above. These furnaces use a microprocessor to regulate the burner at variable levels, adjusting accordingly to use the least energy possible for the optimum output of heat.

Blower speeds

Furnaces also have two blower speeds. A standard blower blows at a fixed speed and regularity, while a variable-speed will save you money on your electricity bill by adjusting to the heating needs of the house, often improving air circulation and maintaining steadier indoor temperatures.

For more information on furnaces and other home comfort needs, contact Air Assurance, serving the Tulsa area since 1985.Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems). Image courtesy of Shutterstock

Furnace On Its Last Legs? High-Efficiency Furnaces Are More Than Just A New Model

Choosing the right furnace can seem overwhelming.  There are many different types of units and options to choose from.  However, there is one choice that can be easy.  If your furnace has seen better days, replacing it with one of the newer high efficiency furnaces can make a big difference for your energy bills and comfort.High efficiency furnaces help homeowners see significant heating cost savings throughout the life of the furnace.  They are also the best choice for people wishing to be environmentally conscious.  All furnaces now come with an “Annual Fuel Utilization Efficiency” rating or AFUE.  This rating tells the consumer how much of the fuel the furnace turns into heat.Beginning in 1992, new furnaces were required to have an AFUE of at least 78 percent.  This means that all new furnaces must turn 78 percent of the fuel they use into heat.  While most manufacturers list their models as “high efficiency,” the U.S. Department of Energy defines high efficiency furnaces as units that utilize at least 90 percent of energy they consume into heat.  AFUE ratings between 78 percent and 90 percent are classified as “mid-efficiency.”  If you have a furnace that is older than that, furnace AFUE ratings could be as low as 55 percent.The simple math to figure out possible energy savings can come by looking at the difference in your gas bills from summer months (when the furnace is not working) and the winter months (when the furnace is).  If you know the AFUE rating of your furnace and the AFUE of the potential new furnace you are choosing between, you can take the percentage difference from those heating bills.  For example, you currently have a 65% AFUE furnace because it was installed around 20 years ago.  A new furnace with a rating of 95% could save you 30% off your winter heating bills.  This is a conservative way to analyze your potential savings.Replacing an outdated unit with a high efficiency furnace can cost between $2,000 and $3,500, but many homeowners recoup those costs in just a few years.  (A high efficiency furnace costs approximately $500 to $1,500 more than a new mid-efficiency furnace.)  The savings a homeowner will see depends on several factors including the price of the system, energy costs in your area, climate, and the difference in efficiency between your old heater and the new heater.There are also options on heating units that include variable speed blowers.  This allows air to move more freely, and "ramp" up and down based upon need.  This can also allow you to leave the fan on during milder temperatures in order to circulate air (without the noise) for better air filtration, as well as evening out temperatures throughout the home to eliminate hot and cold spots.Other options include 2 stage or modulating heating.  This allows the furnaces to use only the BTU heating that is needed to keep you comfortable.  In other words, if you only need a little heat, it only uses a little bit of gas.  But when temperatures drop, the furnace will automatically go into the higher stage of heat.  These functions create a more even temperature, and better comfort levels throughout the home.In addition to the money savings, more efficient units reduce the negative impact of energy consumption on the environment.  By turning more energy into actual heat, theses furnaces use less total energy.  This means that less pollution is released into the atmosphere.  If you are considering replacing your furnace Air Assurance is happy to offer expert advice or answer any questions you might have.Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).  For more information, click here. Air Assurance services Tulsa, Broken Arrow and the surrounding areas.  To get started, check out our website or see our current promotions.