New Heat Pumps Cut Utility Bills 30% to 40%
QUESTION: Does it make sense to replace my old heat pump, even though it still works, with a new super-efficient model. I would like one that is less noisy and provides better warmth. How much will I save?
ANSWER: Replacing your old heat pump with a new quiet model can lower your heating and air-conditioning costs by 30% to 40%.
If you now have a gas furnace, installing a new heat pump in place of an old central air conditioner can lower year-round utility bills. In mild weather, an electric heat pump can heat cheaper than an old gas furnace.
For highest efficiency and best comfort, install a two- or three-level heat pump. A two-level heat pump uses a two-speed compressor to vary the heat output. It runs in the efficient and quiet low-speed mode most of the time.
This not only saves electricity, but it makes each run cycle longer to produce constant room temperatures. During severely cold or hot weather, it automatically switches to the high-speed mode for maximum output.
Three-level heat pumps use two compressors--one small and one medium-size. In mild weather, only the small compressor runs. In moderate weather, the medium-size one runs. In very cold (or hot) weather, both compressors run. If the house still is too cool, backup resistant heaters come on.
Two- and three-level heat pumps use special variable-speed blower motors, just like in the new gas furnaces. These efficient blower motors improve comfort and can save an additional $300 of electricity each year.
The most efficient single-level heat pumps use a scroll compressor. Scroll compressors have few moving parts. Without the pistons and hardware of standard compressors, scroll compressors are much quieter.
To compare heat pump efficiencies, use the Heating Season Performance Factor (HSPF) for heating, and Seasonal Energy Efficiency Ratio (SEER) for cooling. Also consider the compressor type and number of heat output levels.
If natural gas is available, consider a new gas heat pump. It is the most efficient heating (more than 100%) and cooling unit available and provides the greatest comfort. It blows out air that actually feels hot.
These use a one-cylinder natural gas engine, instead of an electric motor, to spin the compressor. Since it is simple to vary the speed of a gas engine, the heating and cooling output is constantly fine-tuned to the varying heating needs of your house. Natural gas engines are very reliable.
Write for Update Bulletin No. 515 showing a buyer’s guide of 15 super-efficient electric and gas heat pumps listing HSPF and SEER, heat and cooling output capacities, compressor types, levels and speeds and an annual savings payback chart. Please include $2 and a business-size SASE; mail to James Dulley, Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, OH 45244.
It’s Best to Seal, Shade Shrinking Wood Doors
Q: I try to control the humidity level in my home for the best comfort at a lower thermostat setting. Even so, my interior wood doors shrink in the winter and expose unfinished panel edges. What can I do?
A: This problem is caused either from the door not being sealed or by the low winter sun shining in a window onto the door. Don’t increase the indoor humidity level too much or it may cause mold or condensation.
Next spring, when the door size has stabilized, carefully seal all the sides and edges of the door with polyurethane, varnish or paint. If the sun is shining in on the door (heating and drying it), close the window shades.
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Letters and questions to Dulley, a Cincinnati-based engineering consultant, may be sent to James Dulley, Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, OH 45244.
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Super-efficient heat pump
Electronic indoor blower, fan and heat controller
Outdoor condensor coils
Two-speed condensor fan motor
Variable speed indoor blower
Pipes to indoor blower
Reversing valve switches form heat to cool
Single-speed scroll or two-speed compressor
Optional double low/high output compressors
