Dear Jim: I have noticed my old gas furnace seems noisier and the room temperatures are not steady. I want a new super-efficient model, but comfort is my primary concern. What is new among the 2002 models? — Mic R.
Dear Mic: You are in luck because the most efficient models do provide the ultimate comfort available. If you plan to install the most efficient central-air conditioner now, or in the future, you will need the super-efficient air handler (blower) that comes with the top-of-the-line furnaces.
The AFUE (annual fuel utilization efficiency) of the new furnaces is typically in the 92 to 95 percent range. When you compare this to your old furnace, you should expect to save 30 to 40 percent on your heating bills. It may make economic sense to replace an old furnace even if it is still working.
Some of the newer models for 2002 are smaller and quieter with extra insulation and other sound-deadening features in the cabinet. Much of the noise you hear now also comes from the air blowing through the ductwork and the furnace cycling on and off. Some new models greatly reduce this noise, too.
Installing a furnace with a smart, variable-speed blower motor will have a great impact on your comfort. When it starts, it slowly ramps up to speed. This reduces the noise level and the initial gust of cold air from the registers. Also, it uses 75 percent less electricity than a standard motor.
These motors are called "smart" because they sense pressure variations in the air flow and automatically adjust their speed to compensate. If you close off a register to an unused room or move a sofa against a wall register, the motor will speed up to maintain a constant overall air flow.
A furnace with two heating levels provides the best overall comfort. These models use a two-stage gas valve that fires at a low-heat-output level the majority of the time. In this super-efficient mode, the furnace runs more continuously and room temperatures stay steady. Most models use a smart blower motor.
When the outdoor temperature drops and the low level will not keep your house warm, the gas valve automatically switches to the high-heat output. The smart blower motor simultaneously switches to a higher speed.
For many homes, a less expensive, single-level model often provides a faster payback. Some manufacturers offer optional smart motors in these models, too.
It is wise to select a furnace with sealed combustion. This reduces drafts and wasted energy because the combustion air is drawn from outdoors, not from inside your house. Sealed combustion models are often quieter, and the induced draft blower minimizes the possibility of dangerous backdrafting.
Write for (instantly download — www.dulley.com) Update Bulletin No. 925 — buyer's guide of 16 super-efficient gas (and propane) furnaces listing efficiencies, blower speeds, heating stages, warranties, comfort features and sizing/payback charts. Please include $3.00 and a business-size SASE. James Dulley, Deseret News, 6906 Royalgreen Dr., Cincinnati, OH 45244
Dear Jim: I would like to install a programmable thermostat to save money, but I am technically challenged. I really only need two settings. Are there any simple thermostats like this I can buy? — Mike G.
Dear Mike: Programmable thermostats typically have four setback periods. They really are very easy to program. For people like yourself, most models are preprogrammed with a typical schedule so you can use it immediately.
If you need only two different periods throughout the day, many four-period models allow you to bypass various periods. You can also just set two consecutive periods to the same temperature.