A guide to interpreting furnace jargon
AUFE Rating stands for "annual fuel utilization efficiency". It is like km / litre for your furnace: the higher the AUFE rating, the lower your operating cost.
Blower Motors come in single, dual and variable speeds. Single speed motors operate at one speed all the time and are all or nothing. Dual speed offer a low and high setting that creates more efficiency and more accurate temperature control. A variable speed motor is able to fine tune itself more precisely in response to environmental conditions. This improves furnace efficiency and ensures accurate temperature control. Variable speed motors consume 2/3 the amount of electrical energy as well.
The heart of a furnace is the motor. Basic furnaces come with a permanent split capacitor (PSC) motor. These motors run on AC current and offer single speed capacity. The more advanced models incorporate electronically commutated motors (ECM). These motors use AC current but have a built in inverter to conver it to DC and therefore offer variable speed caoability. ECM motors run much more efficiently and quietly than PSC motors.
Burners come in three options: single stage, dual stage and modulating stage. The stages refer to how many heating levels the burner is capable of. A dual stage furnace has two heating levels (low and high) and saves energy and increases temperature accuracy by not having to be in high all the time. A modulating stage burner operates at a low level most of the time, slowly ramping up the heat as temperatures require, making it more efficient and accurate.
The heat exchanger is where cool air gets heated and distributed thorughout your home. Most models come with one heat exchanger with more advanced models have a secondary heat exchanger that draws heat from the exhaust gas as well. Two heat exchangers run more efficiently than one.
Heat exchangers are made of stainless stell or aluminum. Stainless steel is more restant to corrosion and therefore more durable. Due to the difference in raw material costs, stainless steel models are more expensive than aluminum.
Basic furnaces have a standing pilot flame to feed the burner. The more advanced models use electrical ignition, firing up on-demand and allowing the unit to operate more efficiently
More advanced models will include sound reduction features to offer quieter furnaces during operation
Thermostat compatibility is an important consideration when choosing a furnace model. Many people want the ability to digitally control their furnace and use the smart features that allow programming of temperature control. Wifi enabled models can work with thermostat products like the Nest and smart phones.
BTUs are a measure of thermal or heat energy (British Thermal Units). It reflects the thermal energy output of your furnace. If your furnace produces too many BTUs your furnace will turn on and off too frequently and lose efficiency. If it produces too few BTUs it will run for too long and won't adequately heat your home. A general rule of thumb is to provide 40-45 BTUs per square foot of your house. A home that is 1200 sqft will require a furnace that produces about 48,000 to 54,000 BTUs
If compressor, coil or heat exchanger fails due to defect during the applicable No Hassle Replacement limited warranty time period, a one-time replacement with a comparable unit will be provided.
Timely registration required for 10-year parts limited warranty and lifetime limited heat exchanger warranty. Limited warranty period is 5 years for parts and 20 years for heat exchanger if not registered within 90 days of installation. Jurisdictions where warranty benefits cannot be conditioned on registration will receive the registered limited warranty periods. Please see warranty certificate for further details and restrictions.
The heat exchanger is the most important component of the product warranty. It is the central piece of the furnace and operates in a high temperature, cooling cycle and therefore is the most susceptible to failure. If this cracks your furnace needs to be replaced. A lifetime warranty is important.