An air source heat pump (ASHP) draws heat from the exterior environment and moves it into the house to cool the rooms. It is being used extensively in the United States as it can deliver almost three times more energy compared to what it consumes. This is because it works by moving heat to the building from a source rather than by com busting fuels to generate heat. The only flip side of air source heat pump is that it cannot serve enough heat in times of sub-zero temperature because the pump cannot source enough heat from the surrounding. However, in recent years, air source heat pump technology has improved to hold an important position as a legitimate space heating alternative in colder regions. The efficiency of air source heat pumps is measured by the Coefficient of Performance. This says how many units of useful energy were provided by the pump for each unit of electricity consumed. Air source heat pumps are great energy saver. They can save you a couple of hundred dollars when compared to electric resistance heaters or to oil systems. Here we will take a look various types of air source heat pumps.

Types-

Ductless

As evident from the name the units do not have ducts. The systems have an outdoor unit and indoor unit. Installing them is quite easy. All you need is just a three-inch hole in the wall to connect the outdoor unit to the indoor one.

Ducted

Mechanically they are similar to ductless system. The only difference is that they circulate air through ducts. These are suitable to houses with ventilation duct or newer constructions where new ducts will be installed.

Short-run

Short-run ducted as evident from the name only runs through a small section of the house. They work with ductless units to cool or warm the whole house.

Split

This classification is generally seen for air conditioners. But ASHP can also be classified as split and packaged units. The split has one coil outside and the other inside. Supply and return ducts run from the indoor unit.

Packaged system

They have the coils and the fan outdoors in one cabinet outside the house. Heated or cooled air come into the house through ducts that start from the packaged unit and meander throughout the house.

Multi-zone and single-zone ASHP

A single-zone system ASHP is meant for a single room with one outdoor condenser that has capacity to heat or cool a single room. The multi-zone installations can have two or more indoor units all of which connected to a single outdoor unit.

Air-to-water ASHP

These draw heat from the air outside and transfer this to water that can be used for radiant heating or to produce hot water for the house. However air source heat pumps cannot produce water at a very high temperature. Unlike boilers that can provide water at 85 degrees, an ASHP can go up to 55 degrees. If you try to wrench out a higher temperature it will make the unit work harder. This will have an impact on the utility bill and also influence its efficiency and coefficient.

Air-to-air heat pumps

These draw heat from the air and transfer it to the forced air system in the house.

Modern AHSP are quite advanced than the past models. These units are integrated with thermostatic expansion valves for a better control of the refrigerant flow to the indoor coil. They have variable speed blowers that can push air aptly through gunk filled ducts and dirty filters and coils. The design of the coil, motor and compressor has been streamlined to increase its efficiency. The copper tubing is grooved inside to increase surface area.

Tax benefits:

If you buy an Energy Star certified ASHP, you will get a Federal tax credit of $300. This is to encourage people to increase their dependency on renewable sources of energy. But the units should met following requirements-

For split systems:

• HSPF >= 8.5
• EER >= 12.5
• SEER >= 15

For package systems:

• HSPF >= 8
• EER >= 12
• SEER >= 14