Q. My house needs a new heating and cooling system. I thought about installing a geothermal heat pump for its efficiency and the tax credit. How efficient is one and what features should I look for?
A. A geothermal heat pump is very efficient and usually provides the lowest utility bills of any residential heating and cooling system available. In the heating mode, a geothermal heat pump can produce up to five dollars worth of heat to your house for each one dollar on your electric bill. This is called a COP (coefficient of performance) of five.
In the cooling air-conditioning mode during summer, some geothermal heat pumps, such as the WaterFurnace Envision model, produce an EER (energy efficiency ratio) as high as 30. This is significantly higher than the best central air conditioners and about twice that of many new models.
For most families, installing a geothermal heat pump makes economic sense even though its initial cost is significantly more expensive than a standard air-to-air heat pump. The final cost of the installation depends upon the geothermal heat pump capacity, the type of ground loop needed and the topography of your yard.
The Federal income tax credit is significant and there may also be state and local tax credits and rebates from your electric utility company. For 2010, you can receive a tax credit of 30 percent of the cost of your geothermal heat pump with no maximum limit. The tax credit on most other energy efficiency improvements to your home is limited to maximum of $1,500. The efficiency of the system must exceed current Energy Star requirements to qualify.
As a brief background, a geothermal heat pump draws its heat during winter from the ground. This is typically accomplished with an underground loop of piping. Instead of having to try to draw heat from cold winter air, the geothermal heat pump draws air from the loop, which stays at a fairly constant warm temperature.
During summer, the concept is reversed. Instead of having to try to transfer heat from inside your house to hot summer outdoor air, it transfers this heat more efficiently to the much cooler ground loop. If you install a desuperheater feature, this summertime waste heat from cooling your house can be directed to your water heater for free hot water. The heat pump can also heat your hot water efficiently during winter.
Since no outdoor condenser unit is needed with a geothermal heat pump to exchange heat with outdoor air, everything is located indoors in your utility area or basement. It operates quietly, will not bother nearby neighbors and will not be damaged by playing children or debris from storms and trees.
The basic features available on geothermal heat pumps are similar to super-efficient standard air-to-air heat pumps. The most efficient models use multiple-stage compressors to adjust the heating and cooling output to the instantaneous needs of your house. An ECM variable-speed blower motor is a good comfort and efficiency feature. It is also best to install a matching computerized thermostat and central air cleaner.
Q. I have a lighted doorbell button at my front door. Recently the doorbell stopped working, but the button is still lighted. Where should I look for the problem with the doorbell?
A. Since the light is still working on the doorbell outdoor button, the transformer (doorbells operate at a low voltage) is still good. First remove the button and touch the wires together so see if it chimes. Just because the button lights does not mean its switch is working.
If it still does not chime, remove and reattach the wires to the back of the chime to insure a good connection. If that does not work, the chime is probably bad and should be replaced.
• Write to James Dulley at 6906 Royalgreen Drive, Cincinnati, OH 45244 or visit dulley.com.