new heat Pumps
New heat pumps are a direct alternative to both air conditioners and furnaces. Heat pumps are a tested technology, with many millions of units installed worldwide.
Heat pumps aren't just heating units as their name may suggest. They are also cooling units, and can also be used for water heating (and floor radiant heating and swimming pool heating).
New Heat pumps technological advances
Two or three decades ago heat pumps were noisy and failed to provide the required warmth to our homes on very cold days. But recent technological advances have created a new generation of reliable and energy-efficient heat pumps. Anyway new heat pumps still lose their efficiency in freezing temperatures, at least the main type of heat pumps, the air-source type. They are mostly a solution for moderate climates.
The efficiency of new heat pumps is two times greater than those available some decades ago.
For more information, see: New Heat Pumps Technology
What are heat pumps? How do they work?
New heat pumps technology is basically that of air conditioners and refrigerators. In summer they pull the heat out of our homes, releasing it outside; in cold weather, they simply reverse the process (they take the outside heat from the air or ground, and that's the big difference between air-source heat pumps and geothermal or ground-source heat pumps).
Heat pumps are electrical systems, but since they consume a fraction of the power of other HAVC systems (often half or more), they can compete with gas or oil systems.
See: Heat Pump Parts and Heat Pumps Solutions
Types of heat pumps
There are several types of heat pumps, mainly the so called air-source heat pumps and geothermal or ground and water heat pumps.
Air-source heat pumps interacts with the outside air and are capable of extracting heat even from cold temperatures, while ground and water source heat pumps have an underground loop and extracts heat from the soil or ground water (see image). 
The air-source heat pumps can be central ducted systems or ductless mini split heat pumps. If your home doesn’t have ducts, the ductless version of air-source new heat pumps may suit your needs. They are also excellent for cooling and heating parts of the house, or rooms.
Other less known types of new heat pumps include gas heat pumps and heat pump water heaters.
See:
Heat Pump Designs
Ground heat pump loop installation
Heat pump Solutions
To know if a heat pump is the right solution for your home you must take into account your home's needs and consumption, and also your climate and some economic assessments involving the power and natural gas costs...
Air source heat pumps require supplemental heating in freezing temperatures (new heat pump units come with a back-up burner, sharing the same ductwork, to overcome that limitation, but you have to assess the pros and cons).
See, for details:
Heat Pumps Solutions
Heat Pumps vs. Furnaces
Heat Pumps vs. Air Conditioners
New Heat Pump Technology
Efficiency & Performance of New heat pumps
When buying a new heat pump pay look for Energy Star and other certified units. Heat pumps with a high SEER (cooling rating) and HSPF (heating rating) or a high COP (coefficient of performance of ground heat pumps) will provide higher energy savings and typically deserve their higher prices.
See:
Heat Pump Selection and Buying
Heat Pumps Performance and Rating
Heat Pump Tax Credits and Incentives
Heat Pumps Manufacturers and Associations
Heat Pumps Costs, Prices and Paybacks
The Heat Pump Best
Heat pump Problems
Heat Pump Designs
Heat Pumps Cooling
Heat Pump Benefits and Environment