Heat Pumps

Heat pumps are the most efficient systems when the outside winter temperature is on the average 32 degrees or more. For areas of the country such as Southern Virginia and below to North Carolina into Florida heat pumps are used extensively. In moderate winter climates heat pumps are more economical to operate than natural gas. We do however caution the use of heat pumps in California where electric utility rates are 7 to 10 times that of the rest of the country. Heat pumps are also being applied today in northern regions and as far north as Canada.

Why would a heat pump be applied in Northern Climates? Remember that in the winter in the northern climates there are still many times when the temperature is 32 degrees or above. Also heat pumps are used when alternatives are not practical. Where natural gas or fuel oil are not readily available, a heat pump can be a better alternative than electric resistance or propane gas. To install fuel oil requires an outside tank. The cost of propane gas at $1.30 a gallon is more than the cost of pure electric resistance heat. If natural gas or fuel oil are not possible alternatives and almost always never propane gas, the best alternative is a heat pump. Another benefit to heat pumps is air conditioning. A heat pump both heats and cols the house. Air conditioners only cool and furnaces only provide heat but a heat pump does both with the same unit. As efficiencies and durability have increased and prices have decreased the use of heat pumps continues to grow every year. Today more and more new homes being built are having heat pumps installed throughout the country. As early as 15 years ago heat pumps were only used in moderate climates and were rarely considered for use in Northern parts of the country. Today heat pumps have achieved incredible efficiencies and are a proven reliable source of heat for any area of the country where alternative sources of heat are not available.  Heat pumps are clean and safe and now are available with efficiencies as high as 15 Seer and 8.7 HSPF.

How does a heat pump work?

All of us have walked by a window air conditioner during the summer and felt the blast of hot air coming off the outside of the unit. The window air conditioner removes heat from the inside air and compresses the heat to the outside air. A heat pump in simplistic view is simply an air conditioner that reverses the flow of the system. In winter the heat pump reverses flow of the refrigerant with a reversing valve and takes heat from the outside air and put it into the inside of the house. In the summer time the heat pump works like a standard air conditioner. Where is the heat in the outside air when it’s only 40 degrees outside? There is still heat in the air but it has to be compressed out. In fact there’s heat in everything until the matter is at absolute zero which is approximately -360 degrees fahrenheit. The compressor in the heat pump compresses the heat out of the outside air and puts it into the house. What happens however is when the outside air temperature falls below 32 to 25 degrees the efficiency of the heat pump decreases substantially and the heat that is produced drops significantly. As well the discharge temperature of the air decreases from the indoor air handler. Heat pumps generally require a back up heat source. That heat source is generally electric resistance heat. The amount of electric heat required is measured in kw or thousands of watts referring to kilowatts of electric energy that is translated into the amount of heat that can be produced by the electric heat. This back up heat has to be sized according to the heat. The electric resistance heat is sized according to the needs of the house at the average lowest winter outside design temperature.

When we size your heating and air conditioning system at DESCO we also size the correct amount of heat required for the heat pump based on the winter design temperature of your location and type of construction and insulation values of the house. The heat pump is sized according to the air conditioning requirements of the house. Heat pump systems should never be sized according to the heating requirements of the house, only the air conditioning requirements. If the heat pump were sized according to the heating needs of the house it would be too large to provide effective air conditioning. It is the electric back up heat that is sized according to the heating requirements of the house.

Another back up heat alternative could also be a natural gas furnace or an oil furnace. This combination called a dual fuel or all fuel system provides the economical operation of the heat pump efficiency combined with the economical operation of a fossil fuel when the outside temperature is too low for the heat pump to operate effectively. An all fuel system is the most energy efficient system today.

The benefits to using a heat pump in climates where there are moderate winter temperatures are low operating expenses and air conditioning at no extra cost. No other system operates less expensively than a heat pump between 35-70 degrees outside temperature, even natural gas. The disadvantage is low heating discharge temperatures when the outdoor temperature decreases and lower capacity as the outdoor temperature falls. To help alleviate this problem we recommend the installation of a humidifier in all heat pump installations. A humidifier will reduce the so called chill effect on the skin of the lower discharge air temperatures of a heat pump. Further a humidifier will allow you to lower the temperature setting of the inside temperature several degrees and fell as comfortable. Other benefits of a humidifier include reducing respiratory infections, alleviating dry sinus and skin problems, reduction of drying of furniture and wood and elimination of static electricity. In fact a humidifier is the single item that can be added to any forced air heating system to provide the most benefits. A humidifier is an inexpensive investment with the greatest amount of benefits.

Geothermal Heat Pumps

Geothermal heat pumps are heat pumps that use well or pond water or tubing that is laid in the earth at predetermined lengths and depths to take advantage of the constant temperature of the earth’s sub surface temperature to provide very efficient heating and air conditioning. A geothermal heat pump is the most economical system to operate. However a geothermal heat pump is the most expensive system to purchase and install. Unless you have a large enough house with well water readily available from two sources or a pond that is big enough, a geothermal heat pump’s costs make it impractical as a financially sound investment.

There are many advantages to a geothermal heat pump that are significant in comparison to a standard air to air heat pump. For example the operating costs are extremely minimal. In many areas of the country utilities provide rebates and reduced all electric rates that make the purchase of a heat pump more attractive. Further the problem of lower discharge air during heating that is problematic to an air to air heat pump is not a problem with the geothermal heat pump. There is a constant temperature because the well water or earth’s sub surface is always at a constant temperature eliminating varying discharge air temperatures.

The main problems that plague the use of geothermal heat pumps are high purchase and installation costs. Another problem has been the poor design and installation by many contractors in this field further compounding the payback. The typical payback for a geothermal heat pump is 15 years or more. By that time the equipment is worn out and is need of replacement. So before you consider a geothermal heat pump consider the payback. Many payback figures are manipulated by the contractors and the manufacturers to promote their products and deception can lead to making a very bad investment.

DESCO does stock and sell geothermal heat pumps but we do not recommend their application unless the payback is sufficient to warrant the purchase.

What Special considerations should be made in the application of a heat pump?

Heat pumps have come a long way from when they were first introduced in the 1970’s. When heat pumps were first introduced there were many dismal failures due to poor engineering, manufacturing and installations. In fact the problem got so bad that many manufacturers got out of the business. Manufacturers would go in and out of the heat pump business several times during their introduction. Compressors were failing at astronomical rates and the life expectancy of the average system was only five years. Compressor manufacturers soon realized that heat pump compressors needed to be more rugged and durable and the valves and motors needed to be heavier. Contractors were installing heat pumps like the typical gas furnace without serious regard for the extra sizing of the duct system that was so critical to the heat pump’s survival and proper performance.

Only one manufacturer stayed in the heat pump business and emerged to be the most trusted and reliable system which was General Electric. General Electric made changes as quickly as possible to this new industry and focused heavily on dealer and installer education. As a result General Electric was the most successful heat pump manufacturer and was solely responsible for the continued success of heat pumps that are available today. Unfortunately General electric had a policy when they could not dominate any market and have over 50% of the business they sold their interests. So 15 years ago General electric sold their HVAC business to Trane.

Today’s heat pumps are very well built and much easier to diagnose and service. You can easily expect 15 years or more lifetime on a heat pump system with today’s improved technology and manufacturing.

But one thing hasn’t changed and it has become epidemically worse. Contractors installing heat pumps are not designing or installing heat pump duct systems correctly resulting in the heat pump starving for air. As we mentioned previously a large part of heat pump failures were due to improper installations when they were first introduced. Duct systems that carry and distribute the air were too small and didn’t have enough air outlets or diffusers. Further the return air duct systems were too small resulting in the heat pump starving for air.

Today’s contractor installers living in a very competitive market are paying little if any attention to the proper design or installation of the duct systems and the heat pump failures are increasing. Manufacturers can only do so much to make a compressor rugged and durable. When the air distribution system is too small and there aren’t enough air outlets the result is compressor failure. Plus a major result is high energy costs as well. This will occur more frequently on a heat pump than an air conditioning system because the compressor is in operation all year long. When the air distribution system is too small the refrigeration cycle fails to perform correctly resulting in liquid refrigerant returning to the compressor and causing the compressor to fail within a short period of time. The new Copeland Scroll compressors being more efficient with tighter tolerances will not take this abuse compared to the older piston compressors of yesterday. An air conditioning or heat pump compressor is designed to pump gas, not liquid. So when liquid refrigerant returns to the compressor it expands at an incredible rate and further washes the oil lubrication in the compressor out of it and the end result is a dead compressor.

Needless to say when replacing a heat pump or installing a new system careful attention must be paid to the design and installation of the system for proper air flow and distribution. If your heat pump has failed prematurely or the present system didn’t provide proper comfort levels, there needs to be an investigation as to what caused the problem or guaranteed the new system will fail as well. A replacement system will never correct improper air flow or distribution.

At DESCO we will design your new duct system as well as review your existing duct design to be certain that the new equipment will provide many years of trouble free service.

What options and types of heat pumps are available?

If you are considering the purchase of a heat pump system try to purchase the highest efficiency system available that your budget permits. Remember you’ll be feeding this new system out of your wallet every day of every year. The less you have to feed it the better your budget will be. The higher the efficiency the less you have to feed it.

Seer is the efficiency of an air conditioning system. The higher the Seer the less energy the system consumes to produce the capacity rating. The minimum Seer rating of any unit manufactured today is 10. Air Conditioning systems that are 15 years or older will generally have a Seer rating of 6 or less. The higher the Seer rating the larger the unit including the indoor coil and the outdoor unit. Seer is the similar equivalent of miles per gallon of a car. However the biggest difference is the smaller the car the higher the fuel economy. In air conditioning the higher the Seer the larger the equipment. Many customers get Seer confused with capacity. A higher Seer or efficiency unit will not produce more capacity. It will only use less energy to produce the rated capacity. Advantages to higher Seer equipment such as 13, 14 or 15 Seer are the equipment energy consumption decreases, the warranty coverage is greater, and the system runs quieter. 10 Seer systems are generally what is defined as the builder's grade models. In two years from now the standard Seer or efficiency will be 12. Try to purchase the highest Seer system you can possibly afford. Example comparisons of energy savings on the higher Seer units are as follows: If you have an older system and the rated Seer is 6, further consider wear and tear on the system can actually cause the actual performance to be 5 Seer or less. For our example let's say it costs $200 a month to operate an existing 6 Seer air conditioning system. By replacing that same system with a 10 Seer system your energy costs will decrease to $120 per month or a net savings of $80 per month. Replacing that same 6 Seer system with a 12 Seer system will result in energy costs that will decrease to $100 a month or a net savings of $100 per month. You have just cut your energy costs in half while making no sacrifice in comfort or performance. As you can see by this example it soon becomes very clear why you want to purchase the highest efficiency Seer system possible.

Heat pump efficiencies have two different ratings. The first rating is for the air conditioning part of the system. Again referring to the information above regarding Seer is how a heat pump systems air conditioning is rated. For heating the heat pump is rated in HSPF or Heating Seasonal Performance Factor. Somewhat similar to Seer the higher the HSPF factor the more efficient, larger in physical size, quieter, longer warranty and of course the higher cost as well. The heat pump that has a higher Seer rating is also going to have a higher HSPF rating. Unlike Seer where the rating increases are in whole numbers such as 12, 13, 14 or 15 Seer, you will see HSPF factors increase in tenths of a point from 7.7, 7.8, 8.0, 8.2 etc. So a tenth of a point increase in HSPF is more significant. Don't expect to see HSPF factors at the same levels as Seer. The calculation for HSPF is entirely different than Seer but as a comparison you will note that HSPF is a measurement of energy consumed in comparison to heat produced at predetermined outside temperatures and inside temperatures over a seasonal range of varied conditions. As the outside temperature decrease the heat pump heating output capacity decreases. Additional electric heat is added to the system that should have the capacity to provide sufficient heat at the design winter temperature without the need for the heat pump operation. This electric heat has several different names called back-up heat, emergency heat, strip heat, auxiliary heat and it is all one in the same thing. Heat back up comes in kilowatt ratings in 2.5 to 20kw or kilowatts. Electric heat as well as the heat pump should be sized by DESCO for the correct size.

In two years the standard air conditioning or minimum efficiency system that any manufacturer will be able to produce is a 12 SEER air conditioning system. Today that minimum is 10 SEER. A heat pump or air conditioning system that is 15 years or older will have about a 6 SEER performance. Due to age, thermal losses and inefficiencies that actual SEER will be 5 or less. So by replacing that old energy hog will reduce your energy consumption by at least 50%! With today’s incredible rising energy costs you really can’t afford not to replace that old energy monster.

The highest SEER system we have available is a 15 SEER heat pump with a two stage Copeland compressor. This is a Tappan system and uses the new refrigerant R410 or sometimes referred to as Puron. This ultra system has all the latest technology including variable speed drive blower on the indoor air handler and compressor electronic monitoring and Smart start. Variable speed drive air handlers are the latest technology and a must for all heat pumps.

Second down on the list is the Goodman, Gibson, Kelvinator or Tappan systems that have 14 Seer performance with the single stage Copeland Scroll compressor and variable speed drive blower motor.

Third on the list is the 13 Seer performance with the single stage Copeland Scroll compressor and variable speed drive system.

Fourth on the list is the 12 Seer single stage Copeland Scroll compressor and multi speed drive blower.

Last on the list is a Goodman single stage Copeland Scroll compressor and multi speed drive blower.

The fourth and last systems above should only be considered as builder grade systems and only be used as a last resort.

Variable Speed Drive and Multi Speed

Standard versus Variable Speed Blower Systems

An air handler and a furnace all have a blower and motor to circulate the air in the house. An air handler has a blower, blower motor and air conditioning coil in one casing. A standard air handler of furnace has a blower motor which when it comes on, immediately goes to full speed. This creates a tremendous amount of noise and is also very hard on the motor when this occurs frequently in the course of one day's operation. A similar example is having a car that has no throttle and when you turn the car on it immediately goes to full speed. When you reach the correct speed you would shut the car engine off to slow down and then restart the car again at full speed to again resume the desired speed. Imagine how hard this would be on your car if you operated the engine in this condition. That's exactly what happens when you operate a standard air handler. This is also how the blower motor operates in a standard furnace. Most of us have become accustomed to the click, bang and whoosh sound of an air handler or furnace starting and the loud noise the motor creates. Then the dead silence that occurs after the unit shuts off. 

What a variable speed motor does is give us a throttle. Instead of the fan motor coming on at full speed, the motor will start silently and then gradually and slowly within several minutes go to 30% of the air capacity and hold that position for several minutes. This allows the duct system to become full of pressure so there are no shocks to the duct system or noise. After the duct system becomes pressurized then the blower motor will continue to increase slowly up to 100% of the full air speed. The net result of all this technology means you will not hear the air handler motor come on and you won't hear the motor as it goes through the pressurization of the duct system and finally achieves full speed. All you'll hear is air movement if you hear anything. Add the variable speed blower motor to a premium duct system such as our fiberglass duct system, you will most likely never hear anything. On shut down of the air handler the blower motor will gradually decrease to 30% of the air speed and then after a short period of time will then shut off. Imagine an HVAC system that is totally quiet, energy efficient and performs so well with long life expectancy. That's what you can achieve with the variable speed blower system. Variable speed blower systems are available for our gas furnaces, heat pumps and air conditioning air handlers. Because of the variable speed design the blower will also take advantage of residual heat or cooling left on the indoor coil removing every drop of energy used so as to eliminate waste. Variable speed blower systems also have a unique feature for air conditioning called the dehumidification cycle. Unfortunately many installing contractors who sell and install HVAC systems never tell the homeowner this feature exists on the variable speed drive motors or set it up for the homeowner to use. The dehumidification cycle does this: The air conditioner and the blower motor come on during their normal start up cycles but the blower motor only goes to 30% of the regular air speed and stays there allowing the air to move slowly across the coil to remove as much moisture as possible. When the coil becomes saturated with moisture or ice the blower motor senses this change and automatically increases the air speed so as to prevent damage tot he air conditioning compressor unit. This dehumidification cycle is perfect for those 80 degree high humidity days when the air conditioning system doesn't run long enough to properly dehumidify the air because there ;s not enough heat outside. When  running the system in the dehumidification cycle you can remove the moisture from he air without affecting the inside temperature as much as the normal cycle. This is a tremendous feature tot he variable speed system when it's employed into operation. Unfortunately most contractors never advise their customers of this feature in the variable system units and so the homeowner never knows it exists. Again these are just a few of the benefits you receive by dealing with the professionals at DESCO who are engineering certified in the industry You can expect the high efficiency equipment to operate for longer periods of time than a standard system. Not to worry though because this motor consumes the equivalent of a 75 watt light bulb in comparison to a standard blower motor which consumes as much as 7 or 8 large 100 watt light bulbs. All variable speed blower systems are manufactured by General Electric, a name which has become synonymous with quality, reliability and performance.

Remember however that if your Heating or Air Conditioning system is oversized, you just threw away any and all energy savings.

What are the advantages and the differences?

General Electric is the manufacturer of all the variable speed electronically controlled blower motors for over 90% of all manufacturers.

Variable speed compared to a multi speed blower is the difference between day and night in performance, comfort, silent operation and technology.

A multi speed blower motor is a blower motor that simply has several speeds available. Those speeds are low, medium and high and sometimes more selections. Used in blower motors for furnaces and heat pumps the blower speed is selected during installation usually providing a lower speed for heating and a higher speed for cooling. The higher speed for cooling is because cold air is heavier than heated air and need more force to distribute the air throughout the duct system. The blower motor comes on when there’s a call for heating or cooling at full blast of the speed selected and simply shuts off when no longer needed. The motor also consumes high electrical usage and a high inrush of power when starting. You can almost hear a multi speed blower start on a furnace or heat pump and you also know the dead silence after the motor shuts off. There’s no high technology to the multi speed blower and they’ve been around forever. A furnace or heat pump with a multi speed blower single stage is similar to having a car and starting it at full speed and when you’ve achieved the speed you want, you would simply turn the car off and wait for the car to coast to a lower speed and again restart the car at full speed and again attempt to reach the desired speed. Sounds fairly primitive doesn’t it? That’s why a standard heat pump with a multi speed blower will have wide temperature variations. Just the same as the car would have wide speed variations.

As author of this article I can tell you my own personal experience with multi speed blower operation and variable speed on a heat pump application. I had a second house at the ocean that was built in 1976. There was one heat pump system I the house when I purchased it in 1994 and it served the first and second floor of a 1400 square foot Spanish style house. Unfortunately not having a history of the house the heat pump didn’t work and needed to be replaced. So a 3 ton single heat pump was installed with a multi speed blower. The air handler was located in a closet in the master bedroom. The replacement heat pump was a disaster. The air handler woke me up every time it started up during the night with the clicks, loud bang, whoosh of air with start up of the motor. Then it was preceded by dead silence when it stopped. During the air handler blower motor start up the noise could be heard no matter where you were in the house. The only way to sleep was to turn the fan to the on position at night to avoid the loud start up of the blower motor or shut it off altogether. This noise is not at all uncommon for a multi speed blower and most of us have come to accept this normal.

To add more aggravation the duct system feeding the second floor was 1/3 the size necessary resulting in a second floor temperature that was 15 degrees warmer than the first floor. This condition was further aggravated by an open stair case and the wrong placement of the return air. The return air was located in a chase that was part of the chimney of the fireplace and the diffuser was at the top of the second floor staircase. The duct system was installed in the crawl space and the air handler was positioned as a downflow application. This was a heat pump system that was a failure as a result of very poor duct design. To correct the duct problem would have required ripping out the walls on the first and second floor to access the ducts. A variable speed drive system would not have corrected these problems. In fact if a variable speed drive air handler is installed with a duct system that is not large enough there will be even more problems. When a variable speed drive air handler is installed on an air distribution system that is too small or without sufficient outlets the result will be a surging of the blower motor as it tries to maintain a specific volume of air and surges fast and then slow. This surging will continue in cycles and will not stop until the duct system is corrected. Remember that increasing air flow or installing a larger than required system will never solve the problem of inadequate air distribution. There is no quick fix to a poor duct design especially on a heat pump. There is never a week that passes when our sales technicians don’t receive a phone call from a customer that wants to overcome the problem of poor air distribution by replacing the equipment with a larger system.

In 2003 I wanted to add an addition to the house and the plans called for completely gutting the house. The demolition was extensive because the plans were to have a perfect heating and air conditioning system. The only way to achieve this was to remove all the interior wall board. I had an opportunity to install a system that would be efficient, quiet and most of all comfortable. First I needed to decide what system would be the most economical for energy costs. After all I was going to have to feed this system every day of every year. Propane was available underground in the Eastern shore but the cost was $1.79 a gallon. I made a cost comparison at the propane web site: http://glows.usepropane.com/calculator/. When I compared this to the cost of pure electric resistance heat the cost to heat the house with Propane gas was 32% more. After more research of electric utility rates through various parts of the country propane is not a bargain anywhere with the exception of certain pockets in Illinois and Colorado where propane was still selling at .99 a gallon or less or in California where electric utility rates are astronomical. As a general rule it is safe to assume that propane is not an economical source of heat. Further propane prices are not regulated and the price can change drastically form one day to the next. Taking into account there are also chimney or stack losses on any propane gas furnace from 7 to 20% puts propane gas as the worst choice to heat any house. I also considered oil heat but being at the shore required an oil tank that was extremely expensive due to the containment requirements to prevent pollution of the ground should the tank leak. In addition the insurance was too much if in fact any insurance company wanted to provide coverage. A heat pump was definitely the best choice for the most efficient and least costly system to operate. As you can see by this example there are many circumstances where a heat  can be the best choice even in the Northeast part of the country.

I wanted a heating and air conditioning system that was going to have perfect or as close to perfect temperature control as possible. And I also wanted a system that was going to be quiet with no loud blower noise.

The house was going to be 2200 square feet with the addition with 1100 square feet on the first and 100 square feet on the second floor. Keeping the open stair case as before I knew there would be stratification as before and I wanted to have the same temperature on the first floor as on the second floor. I was now placing the master bedroom on the second floor and I knew that 15 degrees hotter was not going to make life very comfortable. I designed the house for two separate systems with a 2 ton high Seer heat pump on the first floor and a 2 ton high Seer heat pump for the second floor. I also used variable speed blowers because I located them in very noise conscious areas of the house. On the second floor I located the air handler in a closet with louvered door in the master bedroom. I located the first floor air handler in a similar closet with louvered door in the living room. If the air handlers were multi speed there is no way I would have attempted to do this due to the high noise levels produced by multi speed blowers. Also I wanted to have perfect temperature and humidity control. I knew I couldn’t achieve these conditions with a multi speed blower.

Now the systems are so quiet I don’t hear them start or stop. The difference in temperature between the first floor and second floor are non existent. They are both equal. However there certain times of the year when the first floor may actually call for heat and the second floor needs some air conditioning at the same time.

Variable speed drive provides totally silent start and stop. Here’s what happens when the system comes on. The air handler starts up slowly to 30% of the required air speed. The air handler continues at this speed for about 5 minutes and then slowly goes up to 100% of the required air speed. So when the air conditioning comes on during the first five minutes the system is primarily focused towards removing moisture from the air or dehumidification. So during those days when the air conditioning requirements are minimal the system continues to provide proper dehumidification. During those exceptional days when there isn’t any air conditioning requirement but the house is very humid, the Honeywell T8300 thermostat turns on the dehumidification cycle and removes the moisture from the air. When the system calls for heating there are no more cold blasts of air like I had before with the multi speed blower.

This house now has an air conditioning and heating system that maintains temperature and humidity at the same precision as what I would typically design for a hospital or operating room air handler. When I want to simply add humidity to the air in the winter the air handler comes on at 30% of the regular air speed and adds moisture to the air from the humidifiers.

In summary the advantages to variable speed are quietness, perfect humidification and dehumidification as well as temperature control. We have had variable speed systems in our offices and training rooms and our technicians have installed these systems for many customers. But I never realized how great they are until my own personal experience. In fact I was so impressed that I put two temperature and humidity recorders in the house on the first and second floor. Incredibly the recorders showed what I had suspected. There was less than ½ of one degree in the temperature variation and 5% variation in the humidity levels.

I have been designing HVAC systems for over 30 years for commercial and industrial applications and for very critical environments such as large data processing centers, hospitals, hi tech manufacturing facilities and food manufacturing where temperature and humidity are very critical. I never thought or even envisioned I could achieve that same level of perfection in a house environment due to the exorbitant costs of the controls and motor requirements. But today I have personally been able to achieve that same level of comfort and control at a minimal cost with the new General Electric Variable Speed Electronic control system. So can you!

During the complete renovation of the house I also had insulation changed to higher levels and installed where there was no insulation previously. The existing leaking double insulated windows were replaced with new double insulated low E and Argon Gas filled windows. There were also more windows added to existing parts of the house as well as to the addition. As mentioned previously there is an outside temperature where a heat pump is no longer efficient and the electric back up heat becomes the primary source of heat. This temperature is referred to as the balance point. What affects the balance point is the insulation values of the house and windows and the size of the heat pump and size of the house. Previously the house had a balance point of 30 degrees. At 30 degrees or less the electric back up heat was necessary to maintain temperature. With the house being renovated and windows changed to more efficient windows and the insulation values increased the balance point is now at 23 degrees. That means the house now does not require the use of electric heat until the outside temperatures falls to 23 degrees or less. Even more incredible is the new 2200 square foot house uses less electricity for heating and air conditioning than the original 1400 square foot house. In fact the house now uses 5% less energy for heating and air conditioning on an equivalent cooling and heating degree day comparison than the original house. Taking this analysis even further the house has increased in size by 57% and uses less energy. In real energy consumption per square foot the savings or reduction in energy consumption was more than 60%. To achieve these energy savings there was a duct system that was leaking and poorly designed with insufficient outlets that was changed to two systems with a fiberglass duct system with an R6 insulation value and no leaks. There was no longer wasted heat going to the second floor. There was no insulation in the crawl space and now there is an R19 insulation barrier. The older insulation in the roof area had lost it’s effectiveness due to previous roof leaks. Fiberglass when exposed to water losses insulation value because it compresses. The second floor walls had R11 in the walls and were replaced with R19. The original windows had lost their thermal barrier between the panes and were no more effective than single pane windows. Also note that the window area of the house has now increased by 25% and three additional sliding glass doors were added. But the new windows are low E Argon double insulated providing maximum energy efficiency. As an example you can see that these types of improvements can produce significant energy savings and increase comfort levels as well. As you are thinking about replacing or installing a new heat pump system consider the results of making the whole house energy efficient.

What components are necessary to make a complete heat pump system?

There are two basic types of heat pumps, packaged units and split systems. A packaged unit is a heat pump system where the total system is in one wrapper. All that is necessary to hook up the packaged heat pump is the duct system, power and thermostat wiring. A packaged heat pump is the easiest to install but does not provide such options such as variable speed or ultra efficiencies and requires long duct runs often resulting in insufficient air flow. A split system is a system where there is an air handler and an outdoor unit called the condensing unit.

Split systems are the most common systems and provide versatility, variable speed drive, ultra efficiencies and maximum comfort control.

For a split system the components are as follows:

The indoor air handler that contains the refrigeration coil and blower: 

The electric back up heat:  This heater inserts into the air handler.

The outdoor condensing unit:

The outdoor electrical disconnect for the condensing unit:

The outdoor electrical whip:

Risers for the outdoor condensing unit:

Condenser pad base to place below the condensing unit:

Refrigeration lineset to connect from the outdoor unit to the indoor coil:  Available in 30 and 50 foot lengths.

House thimble for decorative outlet for the above lineset:

Thermostat to control the system:

Thermostat wire to connect to the thermostat to the air handler and to the outdoor condensing unit:  

Humidifier for the air handler:

High Media filter for the air handler:

Auxiliary drain pan for the air handler in the horizontal position:

Condensate pump:

Vibration Isolator pads for the indoor air handler to reduce noise transmission:

Duct materials to provide the air distribution system:

DESCO will select and assist you in the selection of all components to put together a complete heat pump system including the duct system. For more information visit www.descoenergy.com