Choosing and Installing Heat Pump Systems: Air and Ground Source

All you need to know about heat pumps and putting one in your home

Technician repairing heat pump

Technological advancements to improve heating and cooling efficiency are constantly underway, but the advancement of the heat pump as an efficient household heating and cooling appliance has impressed many people lately, and for good reason. Instead of creating new heat, it takes heat from one place and deposits that heat to another place. During warm weather, it takes heat from inside and places it outdoors using a refrigerant in the pump.

Due in part to rising governmental standards, heat pumps are now far more efficient than ever before--by some estimates, up to 100% more efficient--which means that now is a better time than ever to buy these systems. If you're looking into the best heating system, then the money you save from spending on other heat sources will quickly outweigh the cost of installing a heat pump.

First, you must know if you're a good candidate for having a heat pump. What is the climate in your region? Does weather remain pretty temperate, or do temperatures swing violently in either direction during the year? Heat pumps are excellent choices for temperate climates. It is not the best choice in extremely cold and freezing weather, however. For much of the year, it will work like a charm for you, but when the temperatures drop into the deep-freezing dead of winter, you will need a backup-heating source. If you can afford both a heat pump and a gas furnace, then the gas furnace will be most efficient below 30 degrees Fahrenheit, while above that temperature (until around 70 degrees Fahrenheit) the heat pump will work best.

So, how do you find a heat pump to ensure that it works best for you? The first step is to choose a model:

  1. Air-source heat pump. We're all fairly familiar with the function of air conditioners. An air-to-air heat pump works basically the same way, except that it can switch from providing cold to providing heat. (These pumps each have a valve that determines the direction that the refrigerant flows within the device.)

    Air-source heat pumps won't require the contractors to dig into your yard and bury anything, as will the ground-source ones. (Who knows what they might dig up?) However, you'll have to deal with the fact that it extends out into the cold, where frost can build up. Because the frost hampers the ability of it to provide heat, it has to occasionally divert its attention to thawing itself out--just like a refrigerator thawing cycle! This disrupts the flow of heat into your house until the air-source heat pump has satisfactorily thawed itself.

  2. Ground-source heat pump. Ground-source, or geothermal, heat pumps serve the same purpose, but instead of moving heat from the outside air into your home, they move heat from the ground (earth) into your home in cold months, and transfer heat from your house back into the ground in the summer. Because the temperature a few feet below the earth's surface is steady, and warmer in winter months than the outside air, performance can remain closer to the same level year-round.

    Though digging (vertically or horizontally, depending upon available space) will be required to install the piping of the heat pump underground, these pumps will not suffer the defrost cycles that air source heat pumps have to endure; the whole unit, minus the underground piping, is actually indoors. However, installing one in the ground will also cost more than installing air source pumps.

  3. Absorption heat pump. The absorption heat pump is an option for large residences (those that are at least around 4,000 square feet). These types of systems are basically a type of air source heat pump that uses another heat source for energy. These sources could include natural gas, water that’s heated by solar or geothermal electricity, or propane. Models for smaller residences may be available in the future.
  4. Ductless heat pump. This one, also called a mini-split-system pump, is a good choice for older homes or apartments that do not have ducts for heating or cooling. They can also be used in room extensions, where creating new ductwork might be expensive or not an option. With a ductless heat pump, a compressor or condenser is located outside, while an air-handling unit stays inside.

 The main benefit of using a ductless heat pump is that they are small and flexible enough to be used in many different configurations. These systems are also easy to install, as they don’t require hooking up to a duct system. They also don’t lose energy through the ducts like central forced air systems. Although they are flexible, ductless heat pumps can be expensive, and they are noticeable in a room (as a window air conditioner would be).
  5. SEER and HSPF Ratings. Consider these ratings when choosing a heat pump. SEER (Seasonal Energy Efficiency Rating) refers to the efficiency of the heat pump acting as an air conditioner, while HSPF (Heating Seasonal Performance Factor) tells you how efficient the heat pump works as a heating unit. If you can, choose one that is most efficient; the highest SEERs range from 14 to 18, while the highest HSPFs range from 8 to 10.
  6. Size. You could probably get away with heating and cooling exclusively on a heat pump, but you'd be better off relieving it with a different heat source in the coldest parts of the year; they aren't as efficient in extreme cold. Some are portable, allowing you to choose where to place them depending on heating and cooling needs.

There are many review sites online that can give you additional basic information as well as reviews and cost information for different types of heat pumps. Be sure to compare both heat pump models and review sites for complete, unbiased information, as many sites also sell heat pumps. A few of these sites include:

You should definitely rely on professional contractors to properly install a heat pump, be it air-source or ground-source. But that doesn't mean you shouldn't be equipped with some basic installation guidelines to ensure that the job is well done. Once you’ve chosen the right model for your house, use these tips to learn how to install a heat pump:

  1. If installing a ground-source heat pump that draws on well water or a local water source, make sure the water quality is high and that this process is legal in your area. Poor water with lots of particulate matter, or highly acidic water, will hamper the performance of your pump.
  2. The manufacturer's product literature will tell you how loud the heat pump can be. Make sure that this noise level falls within the acceptable bounds of your area. If using an air-source heat pump, the contractor should install it ideally where it won't be near your bedroom or near neighbors.
  3. Be sure the installation is made in the proper location relative to pre-existing furnaces.
  4. The outside portion of the air-source heat pump should be on a platform to promote drainage and ensure that it won't be snowed in. A windy location should be avoided when you install a heat pump.
  5. No matter what type of heat pump you chose, make sure you have chosen a reliable, experienced contractor with a good track record to help with installing the heat pump. The contractor should be able to examine your home and tell you how much work your system will have to do to heat and cool it. Also, the contractor should check to make sure your ductwork and electrical system can handle the addition of a heat pump.

Now you know how a heat pump works, how to choose one, and how to get it installed.

 

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