Heating Service and Repair
Information About Furnaces
What To Look For
There are three important factors to consider when selecting a new furnace. First is size, which is determined by the amount of heat needed to heat your home or business. The second factor is efficiency, measuring how much of the heat actually gets transferred to the air in your house versus how much gets wasted up the flue or chimney. The third is called single stage, two stage, variable speed, or modulating furnace. The last is the largest change in our industry. With today’s new products we can deliver the absolute best in home comfort.
You’ve probably heard numbers such as 100,000 BTUs, 80,000 BTUs and so forth. Natural gas and propane furnaces are rated in BTUs which stands for British Thermal Units. These numbers rate how large the furnace is and how much gas it will burn. The larger the space is, the larger the furnace needs to be. Manwill’s sales consultants and service personnel have been trained to calculate the proper size furnace for any environment. Undersizing a furnace has it’s obvious disadvantage, it will run constantly but not keep the house warm. On the other hand, an oversized furnace will run very short cycles but burn a large amount of gas in each short cycle. This results in higher heating bills and excessive high and low temperatures in the house, making your home very uncomfortable. A properly sized furnace will save you money on gas, plus assure you of the personal comfort you expect.
Be sure to consider the furnace’s efficiency. You’ll soon become familiar with efficiency ratings such as 80%, 90% and up to 96% fuel efficiency. The best way to describe fuel efficiency is: if you purchase $100.00 worth of gas, with an 80% efficient furnace you would receive $80.00 of the heat generated by the gas into your home and you would loose the remaining $20.00 up the flue or chimney. However, with a 95% efficient furnace you would get $95.00 of heat into your home and only loose $5.00 of heat out the flue. Many older furnaces (built prior to 1990) have an even lower efficiency. Some are as low as 50% efficient although the majority of the older furnaces are 65 to 70% efficient.
When sizing a furnace, we consider how much heat is actually transferred into your home. To do this, you calculate the input rating on the furnace by the efficiency. For example: a 25 year old furnace, 100,000 btu with a fuel efficiency of 65% will put 65,000 btu’s into your home (100,000 x .65 = 65,000 output). In this case, you could replace that furnace with a 70,000 btu (considerably smaller than the previous 100,000 btu furnace) with a fuel efficiency of 95% and actually put more heat into the house. 70,000 x .95 = 66,500 btu. Now you can burn 30% less gas and still provide the same amount of heat to your home – keeping warm and comfortable while preserving our environment and your pocketbook.
Compare a two-stage furnace to the gas pedal on your car. For better economy and comfort, you seldom push the gas pedal all the way to the floor, usually just enough gas for the power you need. Think of this as the first stage. When passing another car, climbing a hill, or whenever you need to push the gas pedal all the way to the floor, this is a second stage. The first stage is for milder temperatures and the second stage for those few times when our outdoor temperature really gets chilly. Two-stage furnaces are available in both 80% and 95% efficient furnaces.
Similar to a two-stage furnace, a modulating furnace will vary the amount of gas burned or heat produced depending on the outdoor temperature. Unlike a two-stage furnace that has only two burner settings (high and low), a modulating furnace can vary the amount of gas going into the furnace from a very low amount of heat to the full BTU rating of the furnace, and everything in between. Just like a gas pedal in a car, it can vary the amount of power or heat that is needed. Available in both 80% and 95% efficient furnaces, This results in the very best in comfort.
When a furnace is termed “Variable speed” it refers to the blower motor. You’ll find both the 2 stage furnaces and modulating furnaces will have this option. Variable speed furnace motors utilize a DC (direct current) voltage motor versus an AC (alternating current) voltage motor. DC motors are much more economical to operate and also quieter. A typical DC motor can run 24 hours a day, 30 days a month for less than $10.00. This is very beneficial to those in need of constant air circulation. An example would be a home where room temperatures vary from one room to another. A constant blower will help mix the cooler air from one room with the warmer air from another room, creating more even temperatures throughout the house. Another example is a condition where the customer needs better air filtration or humidification. The constant blower can work in conjunction with a humidifier or electronic air filter to constantly be cleaning the air and maintain a constant moisture level in the house. Another great feature with Variable speed motors is your air conditioning costs. A variable speed motor will generally increase your air conditioning SEER (efficiency) rating by one full point!
*Humidifiers and air filters are accessories designed for all furnaces, not limited to just variable-speed furnaces.