Wednesday, December 17, 2008

Air Source Heat Pumps (ASHP's) Answer to Heating Bills

Air Source Heat Pumps (ASHP's) Work Incredibly Well in Cold Climates

Air Source Heat Pumps used to be of limited use in colder regions because their condensors had to be placed outside. Now, we are in a new era of high-efficiency, year-round ASHP's. Condensors can now go inside, allowing them to operate at peak efficiencies year round. HVAC experts can place the condensor in your basement or unused part of your home. The heat that is extracted may be offset by an electric baseboard heater. Even when condensors must be placed outside, they are able to extract heat even at temperatures below freezing. Individuals have reported hearing the ASHP kick in at -10 below temperatures. Of course, they operate at peak efficiencies when the inside and outside temperatures are closer to one another.

Inside Condensors Eliminate Need for Backup Furnaces

When condensors can be placed inside, there is no need for backup fuel furnaces. These backups kick in to supplement or produce heat when the ASHP cannot provide what you need. Condensors that go inside eliminate the need for backup fuel furnaces -- and obviously the need for fossil fuels. Your one utility expense after installation is electricity, and these units draw less amperage than the normal furnace does.

ASHP's also eliminate the need for flues, most ductwork, and dampers. This will save you space, while eliminating a lot of building code issues (fire barriers and alarms). You are simply transporting hot air from the condensor to your living areas.

How ASHPs Work

Refrigerants are evaporating and condensing fluids used by heat pumps to produce heat. A compressor is used to pressurize and circulate refrigerants, in its gaseous state, through the system. This compressor has a condensor (heat exchanger) on its discharge side that condenses the resulting hot and pressurized gas into a high pressure, moderate temperature liquid. This condensed refrigerant is then passed through a pressure-lowering device (expansion valve, capillary tube, etc.) to produce a low pressure, almost liquid refrigerant. It is moved to another heat exchanger (evaporator) where the refrigerant evaporates into a gas via heat absorption. The refrigerant is then returned to the compressor and the cycle repeats.

The heat pump is basically a vapor-compression refrigeration device that includes a reversing valve and heat exchangers so that the direction of heat may may be reversed. This means you may also use these ASHP's as air conditioners.


Engineers at Foehringer Engineering Inc has stated the efficiency of ASHPs are as high as 160%. High efficiency fossil fuel furnaces, at their best, operate around 98%.


  1. Additionally, an electric heat pump does not have an open flame and reduces the possibility of fuel leaks or carbon monoxide poisoning.

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  2. When the cooling water injection point is less than 15 cm above the waterline, the cooling system can siphon water through the intake when the engine is turned off.