Dear Jim: We are retired, and our interest income from bank CDs is not what it used to be. I thought about replacing our gas furnace to lower our utility bills. What is the most efficient design available?
-- Clare B.
Dear Clare: Many, not just retirees, are experiencing reduced income because of the very low interest rates now. This actually makes it a good time to invest in a new gas or propane furnace. You will save on your utility bills each month, and the lost interest (opportunity cost) from the money you spend to install the new, high-efficiency furnace is not as great.
Most people want to install the highest-efficiency furnace. Depending upon your climate, local fuel rates, the energy efficiency of your house, how long you plan to live in your house, etc., the most efficient and expensive model is not always your best choice. Have your heating contractor do a payback analysis on various models before you make your purchase.
The annual fuel utilization efficiency of some new models is as high as 98 percent. Most older furnaces are in the 60 percent or lower range, so your heating costs may be as much as 40 percent lower than now. The most-efficient models also use special blower motors that require less electricity. This also reduces your electric bills during the summer, because your central air conditioner or heat pump uses the same indoor blower motor.
In addition to reducing your utility bills, comfort is much improved with a new furnace. With the new high-tech smart thermostats and variable heating and blower speeds, indoor air temperatures stay more constant and noise levels are lower.
If you want the most efficient design, most major furnace manufacturers now offer modulating output models. These vary the size of the gas flame from as low as 15 percent of maximum output to 100 percent. In contrast, your existing furnace operates at only zero or 100 percent, no matter what the outdoor temperature or the instantaneous heating needs of your house are.
On a mild winter day, a modulating furnace burner operates at a low flame and the blower runs slower. The furnace runs in longer cycles so the indoor temperature does not spike up and down. Also, since the furnace runs in a more steady-state mode, overall efficiency is higher.
During colder weather, the thermostat tells the furnace to increase the flame because more heat is needed to keep your house warm. These new thermostats include outdoor temperature sensors to accurately determine heating needs. This also helps the thermostat determine when to increase the temperature in the morning so you awake to a warm house.
The next step down from a fully modulating furnace is a two-stage model. This has just a low/high gas valve. This is somewhat less expensive to install and, for most families, provides almost as much savings and excellent comfort.
Another lower-cost option is a single-stage furnace with a variable-speed blower motor. The annual fuel utilization efficiency for many of these is as high as 95 percent.
Dear Jim: We are in the planning process of remodeling our kitchen. We have heard about a "kitchen triangle," but we do not know what it is.
What is it, and how can we use this concept to redesign the kitchen?
-- Scott M.
Dear Scott: A kitchen triangle refers to the relative positioning of the sink, refrigerator and range. These are the three areas most commonly used in a kitchen, and properly locating them makes a kitchen more functional.
These three items should create as much of an equilateral triangle as possible. From an efficiency standpoint, never place the hot range next to the refrigerator or in breezes from open windows.