Thompson Mechanical, Inc.
2800 Supreme Street NE, Warren, OH44483
PH 330-372-6400 Fax 330-372-6420
What are your Choices When Looking for a New Furnace?
Energy Efficiency or AFUE rating
The first consideration is the efficiency rating. There are basically two choices, 80% and 90%+. These numbers relate directly to the amount of burned fuel that heats your home versus the amount of burned fuel that is exhausted out the chimney or flue system. Therefore, if you choose an 80% efficient furnace, for every $1.00 you spend to heat your home, 80 cents of that dollar actually heats your home and 20 cents goes out the chimney. In comparison, if you choose the 92% efficient furnace, only 8 cents of each dollar is exhausted out the chimney and you are saving 12 cents on every dollar that you spend to heat your home. Unless you have free gas this can add up substantially over the length of our heating season.
Single Stage, Two Stage, Variable Speed
Your next choice to consider is the variation of the furnace you wish to have installed. Most manufacturers have equipment that falls into one of the following categories, Single Stage, Two Stage or Two Stage with Variable Speed Blower. The following is a synopsis of the differences and benefits of one type over the other.
Single Stage Furnace - This is the base furnace. Single stage operation means that on a call for heat, the burner section comes on and burns at full capacity. If your furnace is rated at 100,000 BTUs for example, when the thermostat calls for heat, the burners are ignited and the furnace burns at full capacity and burns all 100,000 BTUs until the call for heat at the thermostat is satisfied. The disadvantage to this system is that during the mild portions of the heating season (approximately 2/3 of the season) heat is built up in the system that is not required by your home. This is due to the fact that your furnace has to be sized for the coldest days of the winter so that it has enough capacity to heat your home at design conditions. The unrequired heat is blown into your home and the temperature rises above the set point. This temperature swing usually makes the occupants feel cool or cold when the temperature comes back down to the actual set point. The advantage to this system is that it is the least expensive to install.
Two Stage Furnace - This furnace is the next step up from single stage. The burner section has the capability of burning at a lower rate than full capacity, usually somewhere in the range of 70% of full capacity. The advantage of this is that when you need less heat in the mild portions of the heating season, you get less heat. Therefore, you do not overshoot your set point and your home stays the same temperature all of the time. This provides a much more comfortable atmosphere in your home and saves a little more money because you are not using gas that you did not need. When you need full capacity, the furnace will automatically switch to second stage and burn at full capacity.
When comparing dealers and equipment with two stage operation make sure you are getting true two stage operation. Some dealers will “Cheat” by installing a single stage thermostat and jumping out terminals on the furnace so that it runs on a timer. They save approximately $100.00 on the installation cost, however they are robbing you of true two stage operation. True two stage operation allows the unit to go to second stage immediately when needed. This happens whenever the set point of the thermostat is more than five degrees higher than the room temperature or when you actually lose temperature during a heating cycle. When the furnace is jumped out, it runs for 10 minutes on first stage and then bumps up to second stage. This causes the unit to run longer than necessary and causes uncomfortable periods while the furnace is trying to catch up. We do not use this method of installation and every two stage product we install receives a two stage programmable thermostat.
Two Stage Variable Speed Furnace - This furnace has the same two stage burner capabilities as explained above and it also has the variable speed blower package. The advantage of the variable speed blower is that this blower system operates at a slower speed most of the time. The motor ramps up and down based on the needs of your home. This promotes better filter efficiency and better air conditioning efficiency increasing your air conditioning system’s efficiency rating by one SEER point. It is quieter and it is more energy efficient, operating at approximately 30% of the cost of the standard multi tap motor. This is the most efficient product available as it saves on both gas efficiency and electricity efficiency.