80% Efficient Gas Furnace 90+% Condensing Gas Furnace Cutaway of 90+ furnace
Most gas furnaces installed today are ultra efficient condensing furnaces. Ultra efficient condensing gas furnaces don't require an expensive chimney or sidewall assisted blower kit. Condensing furnaces save an average 15% more gas than standard gas furnaces. Although standard gas furnaces cost slightly less than condensing gas furnaces, the added requirements of a chimney and additional energy consumption make standard gas furnaces more expensive to install and operate. In addition to ultra efficiency there are other features that increase efficiency, performance and comfort. Two stage heating and variable speed. Additional furnace features increase heating efficiency and provide additional energy and comfort benefits to air conditioning systems.
Gas furnaces can usually burn natural or propane gas. Gas furnaces come equipped from the manufacturer ready for natural gas. To use propane gas there are nozzle changes required for single stage gas furnaces and a complete gas valve change for two stage gas furnaces. When using propane gas the furnace capacity is reduced. Refer to the manufacturer's specifications for the capacity ratings when considering propane gas usage.
Gas furnaces installed beginning in 2006 furnaces with 95%+ efficiencies, two stage and variable speed are eligible for tax credits from the federal government of up to $200. A $200 rebate in addition to the energy savings and comfort gained provide significant motivation to purchase the most efficient furnace possible.
For oil furnace owners there isn't much good news. Today there are fewer oil furnace manufacturers than ever before. There are few oil furnaces available with efficiencies greater than 86%. Unfortunately because of the limited number of homes using fuel oil the demand for oil furnaces has been on a constant decline. Convincing a manufacturer to invest in an efficient oil furnace design in a shrinking market doesn't roust their attention. To manufacturer a cost effective energy efficient oil furnace with limited demand is highly unlikely to occur in the near future. Standard oil furnaces already cost more than an ultra efficient gas furnaces with all the bells and whistles. Unless and until demand for oil heating increases significantly, which is not too likely to occur, high efficiency condensing oil furnaces will be too costly for most homeowners budgets. Condensing oil furnaces require more expensivematerials and a greater engineering challenge in dealing with the more corrosive nature of condensed fuel oil byproducts. There are a few manufacturers producing ultra efficiency condensing oil furnaces but the cost of these furnaces continues to be exorbitant to most homeowners budgets. The payback or return in investment for ultra efficiency oil furnaces is high even in light of the dramatic cost increases for fuel oil. In light of the present energy crises and high energy costs we hope that changes soon . New products continue to be introduced so there may be a more cost effective high efficiency condensing oil furnace in the near future. Until then the most cost effective choice is the standard oil furnace. Homeowners using fuel oil may want to consider other alternatives.
Furnaces and air handlers can be mounted in multiple configurations of vertical or upflow, horizontal or downflow.
Electric furnaces are typically used in heat pump and air conditioning applications. Due to the high cost increases of fossil fuels homeowners are finding electric furnaces a more economical choice in certain areas of the country. In areas where energy choices are limited and the cost of fossil fuels remains volatile and uncertain, electric is becoming a more reliable source of heating. Propane gas costs have risen so much in the past five years making electric heating costs 50% less than propane.
The efficiency of the electric furnace must be considered when making cost comparisons. Electric furnaces are all rated at 100% efficiency since there is no waste or energy lost. A more common feature added to air handlers is variable speed blower motors which reduces motor energy consumption by up to 90% over a standard blower motor. Although an electric furnace with variable speed is rated the same 100% efficiency, variable speed furnaces also have a tax credit rebate available. Variable speed also adds many more comfort benefits plus provides silent operation. Electric heat packages of many various capacities can be installed on electric furnaces. Electric furnaces are also manufactured with air conditioning/heat pump coils installed. The furnace is selected by the air conditioning requirements and then the electric heat kits are selected on the basis of heat required. There are limitations on the size of electric heat kits which can be installed based on total air flow.
Electric furnaces cost slightly less than ultra efficient gas furnaces and significantly less than standard oil furnaces.
Boilers and Radiant Heating
Hot water heating produces the most comfortable heating available. Hot water circulated through radiators, baseboard or in floor radiant heat, produces incomparable comfort levels. This hot water is produced by a boiler. A boiler is a pressure vessel that converts energy from electric or fossil fuels to water to produce hot water or steam.
Older boiler heating systems produced steam and hot water with high comfort levels but wasted lots of energy. The older boilers were large oversized massive hunks of metal. The amount of energy required to heat the massive heat exchangers combined with the drafts of large chimneys caused large amounts of heat to be constantly sucked up and out of the house. Even with the boilers turned off large amounts of heated air from the house continued to draft up the chimney. Operating at peak efficiency these boiler systems were only capable of producing 40 to 50% efficiency. Add to this inefficiency were uninsulated hot water or steam pipes located in floors and walls radiating wasted heat to the exterior. Uninsulated piping on interior walls created hot spots and hot walls which overheated and wasted energy. Piping insulation would deteriorate and become ineffective. Because of high energy costs associated with boilers and hot water/steam heating systems their use was discarded. In the 1970s and 1980s boiler sales were dropping rapidly. Homeowners only purchased boilers on a replacement basis in existing hot water systems. Hot water heating was rarely used in new home construction. In the 1980s in floor radiant heating systems were introduced. Consumer confidence gained and rebounded the growth of a new heating industry - radiant in floor heating systems. Boilers were becoming smaller and efficiencies were increasing as the radiant heating systems gave a breath of new life to boiler manufacturers. In the beginning of this century new boiler technologies and homeowner demand for even smaller, more compact and efficient boilers created the super efficient wall hung boilers. Unlike their cast iron dinosaur counterparts, wall hung boilers gave new meaning to lightweight, compact and efficient. Wall hung boilers were designed for on demand use eliminating cast iron mass and more focused heat to a smaller plate heat exchanger. Since there is no water storage there are no off cycle losses. Efficiencies to 98% are common to the Trinity wall hung boilers. In addition to the lightweight compact efficient design wall hung boilers are also loaded with hi technology previously reserved for large industrial boilers. But sparing no oversight in efficiency the Trinity wall hung boilers provide hot water reset, modulation firing and advanced electronic ignition systems. Hot water reset provides automatic adjustment of the hot water temperature according to outside air temperatures. Modulation allows the boiler to automatically adjust capacity according to the heating requirements at any given demand. One Trinity boiler can replace hundreds of models of competitors models. Modulation adjustment and hot water reset features save an additional 23% of energy use in addition to the rated efficiency. Trinity compact wall hung boilers are perfect for in floor radiant heat, hot water baseboard and radiators.
Boiler efficiencies today range from 78% to 98%. Boilers are single stage, two stage or modulation. With single stage the boiler fires at 100% capacity. With two stage the boiler will fire at 50 to 60% of it's total capacity and 100%. Modulating boilers fire at a minimum rate of 25% and anywhere in between to 100% of it's capacity. Two stage is more efficient than single stage boilers. And modulation is the most efficient allowing heating loads to be matched with the heat required at any given time. Boilers are available in electric, natural and propane gas and oil fired. There are boilers that also fire with wood, wood pellets, coal, paper, and waste oil. In addition there are boilers that can fire with dual fuels using a combination of the fuels mentioned previously. Some areas and states require special ratings and certifications. For more information about boilers and their requirements and selection go to our Product section and click on subtitle Boilers.
The Best when Designing for Comfort
But what was so significant to radiant heat that caused a dying industry to turn around and breathe new life into it? All the problems of comfort associated with the ever popular forced air systems were eliminated. Forced air systems produce stratification which is the natural process of hot air rising and cold air falling creating different layers of temperature within a space. In any typical house with a forced air heating system the temperature measured at floor levels is anywhere from 6 to 15 degrees colder than at ceiling levels. Add to this problem a two story house with open staircase and the stratification increases even more. With floor radiant heating systems there is actually inverse stratification providing a warmer floor temperature than ceiling temperatures. In a floor radiant heating system it is possible to walk around the house all winter in bare feet or get out of a shower and place your feet on tile or marble floors without any feeling of cold or discomfort. As the heat radiates from the floor it warms surrounding objects and finally surrounding air. As the mildly heated air rises it dissipates heat to the surrounding objects and people. By the time the air reaches ceiling levels it has dissipated it's energy and heat. Instead of stratification as typical for forced air systems, reverse stratification occurs where the floor temperature is warmer than the ceiling temperatures. The problem of stratification associated with other types of heating systems is gone forever. Another advantage to in floor radiant heating is the ability to control individual room temperatures. When a room or area isn't in use a lower temperature setting can be maintained without affecting the rest of the house. The energy savings from being able to control and lower room temperatures as required is very high. Because there are no drafts from circulating dry air such as in forced air heating systems lower room temperatures can be easily maintained at greater comfort levels. In addition with no forced air circulation indoor air is cleaner. It is the forced circulation of air that increases respiratory problems associated with allergy and asthmatic sufferers. Quiet is the keyword for radiant heating. Forced air heating systems not only produce annoying drafts but also annoying noise from blowers and air movement. Radiant heating systems are totally silent allowing you to bathe in silence and comfort. Radiant heating is all about Designing for Comfort!
What is involved with designing and installing the best heating system? Pex tubing is placed below subflooring is to supply heat similar to ducts used in a forced air heating system. A high efficiency boiler produces the hot water which is circulated throughout the pex tubing by means of pumps. Loops of pex tubing are joined together to form a zone. Each zone is established per area. An entire floor or a single room can be a zone depending on how much control you desire. The more zones installed the more potential is given for energy savings. Each zone has it's own pump and thermostat providing individual control of that zone to whatever temperature desired. Unlike hot water baseboard heating which is operated at 180+ degree water temperatures, radiant floor heating systems use water temperatures at 1/2 those. Radiant heating systems can vary the temperature of the water according to the outside temperature and the zone heating needs. Hot water temperatures used in the radiant heating is kept to a minimum providing slow motion to dissipate heat in the most effective and efficient manner. Radiant heat supplied in the tubing flows upward through the sub flooring to the floor and then to surrounding objects and then finally to the air. A radiant reflective insulation barrier is installed below the pex tubing to radiate heat upwards. Tubing is stapled to the sub floor with metal plates holding the heated pex tubing in direct contact with the sub flooring. This is one example of several methods of installing floor radiant heating systems. There are many more as each installation can be different. The method for installing pex tubing in an existing house or for a cement garage floor or for outside snow melting all require different installation methods. Radiant heat can be applied to an entire house or only specific rooms or areas. If you like the idea of radiant heating but also want a forced air system in conjunction with radiant heating the radiant system can be applied as floor warming. In a floor warming application radiant heating offsets the cold floor effect eliminating chills and lessens stratification. Some homeowners want and need the forced air heating system in addition to radiant heat for controlling humidity and air exchanges required for today's tight energy efficient homes. To learn more about radiant heating go to our products section under subtitle Radiant Heating. Although radiant heating is used in less than 3% of homes it's use is growing rapidly because of the efficiency and comfort provided.
There is also electric in floor radiant heat. Electric radiant heat shares the same comfort benefits as hot water radiant heat. Electric radiant heat can also be utilized in spot locations such as bathrooms and bedrooms or entire houses. In floor electric radiant heat is also cost effective where electric rates are lower or equivalent to the costs of fossil fuels.
What about the high cost of in floor radiant heating? Radiant heating doesn't have to be costly especially when it's a do it yourself project. Most contractors think homeowners requesting high efficiency systems have fat wallets. Radiant floor heating systems are labor intensive. Installing the pex tubing, interconnecting piping and mounting of all the components accounts for 80% of the labor required. And there are no high skill levels required for this work. You can reduce any contractor quoted price by 60% to 75% by completing these items alone.
If you are designing your house for comfort, the system that achieves the goal of best heating system is in floor radiant heating.
In existing homes the installation of floor radiant heating can be a major project. All floors need to be accessed from below or raised with for the installation of the PEX tubing. The second best heating system is baseboard heating. Baseboard heating is convective rather than radiant heating and does require slight air circulation to achieve ultimate comfort. Baseboard is installed on exterior and sometimes on interior walls. The hot water temperature required is 140 to 180 degrees. Baseboard heating does provide a high level of comfort and can also be zoned to achieve individual room or area control. Baseboard heating systems are labor intensive and require more piping and plumbing skills than pex tubing. Although interconnecting tubing can be performed with Pex tubing reducing the need for soldering of copper piping. Hot water baseboard heating can also be combined with floor radiant heating. For example an older house that presently has baseboard heat can have an addition using radiant floor heating all from the same boiler.
Many times homeowners with the old cast iron radiators believe their heating system is inefficient. SEER - Solutions for Energy Efficient Results strongly recommends continued use of these systems when it is practical. Cast iron radiators provide excellent comfort systems. Cast iron hot water radiators can be very efficient when the interconnecting piping is properly insulated and the boiler is efficient. The main problem associated with these types of systems is zoning. large three or four story older homes may only have one pump and one zone. Redesigning the system for more zones may be all that is required to achieve ultimate comfort and efficiency.
If the system is using steam by all means consider converting it to hot water or scrap the system. Steam heat is not efficient regardless of how well it is maintained. Even with a more efficient boiler the maximum efficiency of a steam boiler can be no more than 80%. The basic concept of using steam is too hot to achieve efficiency due to the thermal losses. Many times steam lines were installed in walls with little or no insulation. The wasted heat radiates to the external walls of the house or provides overheating when run on interior walls. There are also losses in condensate return due to faulty or ineffective steam traps if the system has two pipes. Scrap the steam if you are interested in any type of energy efficiency.
Hydronic Heating in Forced Air Systems
For infinite control of heating with a forced air system hot water heating is perfect. Air handlers using hot water coils are called hot water or hydronic furnaces. Manufacturers produce hydronic furnaces with hot water and cooling coils. In addition there are pumps inside the furnace to circulate the hot water from a boiler on demand from the thermostat. The advantage to this type of furnace is it can also use a domestic hot water heater in lieu of a boiler for economical installation costs. The heating system however is only as efficient as the water heater or boiler producing the hot water. Hydronic forced air systems also lend themselves perfectly for controlling space temperatures. When applied with proper controls, modulating three way valves or variable speed pumps the discharge air, room temperature, or humidity levels can be achieved to within almost perfect conditions. For spaces requiring perfect dehumidification where the cooling is operated only to remove moisture from the air the hot water coil can be controlled to reheat the air to a perfect desired level. To achieve this comfort realize additional controls and valves are required. If you are designing for comfort or need an economical method of heating your home a hydronic furnace could be your best choice.
Air conditioning systems have improved in efficiency and performance in the past 5 years. Features and benefits such as Auto Comfort Mode, two stage compressors, variable speed compressors and new refrigerants have made a world of difference in comfort levels and performance. As efficiencies increase so do the size of systems. More coil surface is required to achieve higher efficiencies. Beginning in 2006 the Department of Energy has mandated 13 Seer as the minimum efficiency air conditioning system that can be produced. Before this time 10 Seer systems were the minimum standard. Manufacturers are allowed to produce 10 and 12 Seer system until the end of 2005 so there will be some remaining inventory that will continue to be offered in 2006 until inventories are depleted.
The most favored compressor by all HVAC manufacturers is the scroll. Manufactured by Copeland the scroll compressor has been marketed as more efficient and quieter. Before scroll compressors there were reciprocating compressors which served the air conditioning industry since the beginning. There are new two stage compressors being introduced which greatly enhance comfort and allow systems to operate at different capacities to match cooling requirements on mild days and hot days. The two staging permits sufficient operating cycles at light load or mild days to permit sufficient dehumidification. The problem since the beginning of air conditioning systems has been those days when the air conditioning system doesn't operate for long enough periods of time to properly remove moisture from the air. With two stage compressors the problem is resolved allowing sufficient operating cycles to match the required cooling required for any given time. You can expect two stage compressors to be the standard in the not to distant future as they are also far more efficient. Presently 2 stage compressor systems are manufactured using the new refrigerant R410A. Two stage systems are producing 15 to 18 Seer efficient systems. In the future variable speed compressors will become more common resulting in resolving most comfort problems as well as oversizing. Beginning in 2006 manufacturers such as Nordyne with their Tappan and Maytag systems variable speed compressors will be offered with Seer or efficiencies up to 18 and 19. Mitsubishi has been using variable speed compressors successfully for a number of years now with their
mini split tandem systems.
Expect more systems offering the new R410A refrigerant which is to replace the use of R22 refrigerant in equipment. As R22 refrigerant is phased out due to potential environmental hazards to the ozone layer newer replacement refrigerants will be introduced in the next 5 years until refrigerant R22 is no longer available for new equipment production. Don't be alarmed about purchasing new systems with R22 as over 95% of systems manufactured in 2005 used R22. There will be a phase out of equipment using R22 over the next 5 years. But refrigerant R22 will continue to be manufactured and available until the year 2020. And there are and will be many direct replacements for R22 introduced over the next 15 years making any R22 system capable of providing many years of service without concern of a viable replacement refrigerant. The new R410 refrigerant is not a direct replacement or substitute for existing or new systems using R22. R410 operates at much higher pressures and is not compatible with the oil used in the compressors of R22 systems.
In an air conditioning system there are split systems where the outdoor unit is placed outside and the coil and blower are inside. The indoor blower can be part of the furnace or a separate air handler. In a packaged system all components are placed in one wrapper and ducting is connected to the wrapper. It is extremely important to understand in all systems it is the combination of the indoor components and the outdoor unit that determines efficiency and reliability. Insist on such features as variable speed and properly matched coils to achieve maximum energy efficiency. There are also other features on gas furnaces that can increase system comfort and efficiency such as the Auto Comfort mode offered by several manufacturers which increases the systems capacity to remove humidity. Proper dehumidification or the process of removing moisture is as important as lowering temperature. Selection of matching components and features determines the total performance and also qualifies the system for tax credit and utility rebates. Effective January 1, 2006 Energy Tax Credits will be available for 15 Seer or higher efficiency air conditioning systems and variable speed.
As efficiencies for air conditioners and heat pumps continue to increase so does the physical size of the equipment. You can expect a new system to be significantly larger than your existing system. Technologies, features and benefits have also increased significantly. The new technologies are sometimes viewed as something else to go wrong and can be intimidating when not fully understood. The choice is to embrace the new technologies realizing they have a long track record of proven performance or opt for the lesser builder's models and expect short term life expectancy, poor comfort and higher energy costs. The newer features such as two stage compressors and variable speed blowers may be new to you but they have been around for over 10 years. All the new features will save you energy, increase reliability and performance and significantly increase comfort levels. You can opt to pay a little more now for higher efficiency equipment and save significantly in energy consumption with a longer lasting system. With skyrocketing energy costs and tax credits for energy efficiency the choice for a better system is an absolute win win situation. And if a feature having a one year payback seems too costly then how do you plan on paying for your energy bills. Pay a little more and save forever or pay a little less and pay more and more to the energy giants forever.
Heat pumps have become very popular in the past decade as reliability and efficiencies have improved tremendously. The same improvements that have been described above for air conditioning have also taken place in heat pumps. Heat pumps use more durable compressors and valves than air conditioning systems. 20 to 30 years ago heat pumps were a nightmare to the HVAC industry as they had low performance and short life expectancies on average of 5 to 7 years. A lot of the bad reputation remains today but only as problems from the past. Today's heat pumps have come a long way and are as reliable as all other types of heating and cooling systems. Heat pumps are critical to air flow and must be installed correctly. In any instance where there are significant service problems or short term life cycles the problems are almost always related to improper design and installation. Heat pumps are similar in physical outside appearance to air conditioning systems but inside they are very different. There are more components and controls. A heat pump works the same as an air conditioner in the summer months. In the winter months heat pumps take heat out of the outside air and compress it to the indoors reversing the cycle of what occurs in the summer time. A heat pump's efficiency and capacity drops off significantly below 35 degrees outside temperature. As the capacity of the heat pump decreases electric back up heat is used to supplement the loss. In most regions of the country there are many hours and days in the fall, winter and spring where the outside temperature is 35 degrees or above. At those outside temperatures a heat pump is more cost effective due to it's efficiency than other competing fossil fuel systems. With skyrocketing fuel oil, natural gas and propane prices heat pumps are becoming more cost effective in northern parts of the country. Previously heat pump applications were limited to southern regions of the country. With substantially increased efficiencies and reliability heat pumps are competing effectively with all other types of heating systems in all climates. With the exception of California where electric utility costs are the highest in the nation don't discount the use of a heat pump for any part of the country and Canada.
Heat pump efficiencies are rated as Seer value for air conditioning and HSPF value for heating. Seer - Seasonal Energy Efficiency Ratio and HSPF - Heating Seasonal Performance Factor. Effective January 23, 2006 manufacturers are mandated to produce no less than 13 Seer and 7.7 HSPF heat pumps. Heat pumps with 15 Seer and 9.0 HSPF or higher and with variable speed blowers are eligible for energy tax credits.
a major improvement to heat pump performance has been the newer Copeland scroll compressors. The scroll compressor is quiet and more efficient than the typical reciprocating compressors used since the beginning of the air conditioning industry. Two stage scroll compressors will provide a level of comfort to a heat pump system never imagined before. In designing for comfort a two stage scroll compressor is a must to obtain maximum comfort and reliability.
The most critical and important design consideration for heat pumps is the duct or air distribution system. Because heat pumps operate in all types of temperature extremes they need to have the proper air flow across the indoor coil as well as proper air distribution throughout the house. Fossil fuel furnaces have more tolerance to varied air flows while the heat pump system has zero tolerance. Proper design and installation of the duct system for heat pumps is not only required but failure to do so will inevitably result in major service problems in and after the warranty and premature equipment failure. Almost 98% of service problems with heat pumps are a result of undersized and insufficient air flow. Sized accurately and with proper design of the air handling system heat pumps will compete with any other gas or oil furnace system for efficiency and longevity.
Read the previous section on air conditioning above as the same benefits and features apply to heat pumps.
Three additional important components are important to the efficient and long term operation of any heat pump. A humidifier, hi tech thermostat and variable speed blower. All winter air is dry air when heated no matter where you live. By adding a humidifier you will increase comfort eliminate the chilling effects of dry air and create a healthy indoor environment. Hi Tech thermostats with intelligent energy management are a must for optimum energy savings and comfort. And last but not least a variable speed blower will help avoid problems with air flow which is the sole cause of most heat pump failures. Not to mention the many other features and benefits of variable speed it should be considered a necessity for any heat pump.
To learn more about heat pumps go to the subtitle under our Products section.
Geothermal Heat Pumps
Geothermal heat pumps are similar in principle to the standard heat pumps outlined above with one exception. Heat pumps described above are air to air. A geothermal heat pump derives and rejects it's energy to and from the earth using water. A geothermal heat pump is a water to air heat pump. Geothermal heat pumps employ either tubing serpentines in the earth in loops or using wells to provide a constant source to reject heat for cooling and absorb heat for heating. By using a constant earth temperature of 50 to 55 degrees the geothermal heat pump uses less energy than any other source. A typical 2,000 square foot house can be heated in the coldest of climates for $100 a month or less. Although geothermal heat pumps are the most efficient and least costly to operate they are the most expensive types of heating and cooling systems to purchase and install. Unfortunately the cost for this type of system exceeds any reasonable payback. Typical payback periods are 13 to 18 years at which time the equipment needs replaced. Typically a contractor installation of a geothermal heat pump is $14k to $25k. As an effective do it yourself project we don't recommend this type of system. The high cost of geothermal heat pumps, associated components, complexity and the need for professional assistance don't allow significant cost savings to make this a cost effective do it yourself project. SEER Solutions for Energy Efficient Results makes recommendations based on reasonable payback periods. SEER recommends projects that achieve substantial savings as a do it yourselfer. Geothermal systems don't provide a reasonable solution for energy efficient results at this time. DESCO Energy continuously reviews the geothermal market and due to the lack of interest by homeowners and insufficient payback periods we no longer stock geothermal heat pumps. You won't find geothermal products listed in or Products section. If you have a large body of water close to you such as a large pond or two wells separated by at least 40 to 50 feet, geothermal may be effective to you as a more cost effective solution. If you are so inclined to find geothermal heat pumps of interest you may also want to consider electric generation products. You will find more information about his new concept below which is expected to be a leading source of heating and cooling in the not too distant future.
Dual Fuel Systems
Dual fuel systems are the most efficient and cost effective form of heating in all parts of the country except California. California's excessive electric energy costs reduce the cost effectiveness of a heat pump. However for the rest of the country dual fuel is superior to even geothermal heat pumps for cost effectiveness and payback. A dual fuel system is a combination ultra efficient condensing natural gas or oil furnace combined with an ultra efficient heat pump. Understanding the efficiencies of both the natural gas furnace and heat pump as described above it quickly becomes understandable why dual fuel systems are the best. Dual fuel systems are now the most popular choice for homeowners with natural gas. The air conditioning part of a dual fuel system operates the same as any air conditioning system. The difference of a dual fuel system is how it heats. The heat pump system provides heating between outdoor temperatures of 35 to 70 degrees. Below 35 degrees the gas furnace operates on a call for heating. Dual fuel heating utilizes the efficiencies of both systems during their most efficient periods creating ultimate energy efficiency. Dual fuel systems are efficient and cost effective in all parts of the country and Canada regardless of winter climate. The payback to a dual fuel system is typically only two months longer than a gas furnace with air conditioning. And dual fuel systems continue to save energy every day of every year. Dual fuel systems reduce energy consumption by 30 to 60% over a gas furnace air conditioning only system at the same efficiencies.
Dual fuel systems aren't new. In fact the dual fuel concept has been around since the late 70's and early 80's. Up until the past five years dual fuel systems required large bulky complex dual fuel control systems which were complicated and beyond the realm of most service technicians. Today there's absolutely no need for a complex dual fuel control center or even board. With the new hi tech dual fuel thermostats all the technology required is in the thermostat. Many skilled homeowners are able to perform the set up and wiring of the dual fuel system with the technical support information provided by DESCO Energy.
Dual fuel systems cost $300 to $500 more than an equivalent gas furnace with air conditioning with that difference returned in energy savings in less than one heating season. More importantly is the energy efficient cost savings you'll achieve year after year with a dual fuel system. If you have natural gas or oil forced air heating you should definitely consider a dual fuel system.
Packaged units contain both the outdoor and indoor units in one sheet metal wrapper. Packaged units are also referred to as roof top units or RTU and can be mounted on slabs or on roofs. Packaged systems are available for air conditioning alone or with electric heating, gas furnaces, oil furnaces and heat pumps. Packaged systems are convenient for do it yourselfers as there is no requirement for connecting refrigerant lines. When it comes to efficiency for gas or oil heating 80% efficiency is the maximum available. Ultra efficient condensing furnaces generally are not available due to the problem of freezing water condensed from the gas. A major disadvantage to packaged units is finding a proper location that is out of sight and functional requiring the shortest duct runs. The advantages of a packaged system are no floor space required inside the house, no refrigerant lines to connect, easy to replace, easier to service, and less costly than a split system. The disadvantage is the entire unit must be replaced in the event of a major failure such as a heat exchanger or compressor. Packaged units are not available in ultra efficiencies. They have limited features. The potential for water and air leaks from exposed interconnecting ducting is not only high but common. The exposed large packaged unit and ducting is unsightly to most homeowners. Longer duct runs required cause efficiency losses. The ability to find a location for the packaged unit suitable for aesthetics and close proximity for the shortest duct runs and allow large penetrations through the exterior of the house make packaged units less appealing. Packaged systems in comparison to split systems have more warranty problems, after warranty problems and shorter life expectancy. As a result packaged units have shorter warranty periods. Even if you presently have a packaged system SEER recommends changing the system to a ultra efficient split system with higher efficiency, performance, comfort and equipment longevity. Or at the very least consider the highest efficiency packaged system. SEER Solutions for Energy Efficient Results does not recommend the use of packaged systems in residential applications except as a replacement where a split system can't be practically installed or for modular homes that were designed solely for packaged system application.
Typical applications of packaged system installations occur in the southwest part of the country. During the building boom that had launched areas such as Phoenix and Las Vegas during the 1980s and 1990s there was a severe shortage of HVAC
contractors and installers. To remedy this problem packaged units were installed in most housing developments in the direct sunlight. No regard was given to efficiency and operation or packaged units would have never been installed in direct sun light in the hottest part of the country. The decision to use packaged units was simply pragmatic on the part of the builders to overcome a shortage of qualified personnel in the HVAC industry. It was quicker, cheaper and more cost effective. Today most of the newer homes in those regions are now constructed with split systems with the outdoor condensing units being placed in the shade rather than in direct sunlight. Homeowners having to replace packaged systems aren't thinking about other choices they could make. HVAC contractors aren't offering other choices or explaining the potential benefits. Air conditioning capacity ratings are certified at 95 degree outside air. They are not rated for direct sunlight in a 120 degree ambient temperature. As a result of placing these packaged systems in direct sunlight the capacity is decreased by 30% to 50%. A 5 ton packaged system located on a roof in direct sunlight at a 120 degree ambient temperature will have a decrease in capacity to 3 tons or less. But a split system properly located will have less effect on capacity resulting in less energy consumption and much longer equipment life. Typically most of our customers are replacing their packaged systems of only 7 to 10 years old with more efficient split systems that will last significantly longer.
There are also other pockets in the southeast parts of the country where packaged units are more widely used. These homes are modular designs built for packaged unit applications. The reason for this design is to advertise more square footage as a selling tool, not because packaged systems are better systems. The other advantage to the modular manufacturer is to be able to provide an HVAC system that can be installed without need for an HVAC technician. Notice there was not an advantage to the homeowner for the use of packaged systems.
Packaged systems are excellent for large commercial and industrial rooftop applications where the systems do not take up valuable floor space and outside air can be easily incorporated for cooling during 55 degree days or colder. The packaged system offers many advantages to commercial and industrial applications such as serviceability, ease of replacement and many options which can increase performance, efficiency and reliability. Rooftop packaged systems are used successfully in over 90% of commercial applications.
Other Types of Commonly used Systems
In addition to the types of systems outlined above there are mini split systems and PTAC units. Mini split systems are in the form of air conditioning with electric heat or heat pumps with and without electric heat. Mini split systems can be used for single rooms or additions where supplemental cooling and heating is required. They are attractive, efficient and effective sources of heating and cooling. Mini split systems can provide whole house air conditioning. There are mini split systems available that can use up to four or more indoor units with one outdoor unit and a variable speed compressor. The indoor units can be ceiling, wall or floor mounted units. Mini split systems are quiet and provide excellent dehumidification due to lower air flows. Mini split systems have significantly reduced in price in the past two years to the point where they are competitive with window air conditioners. Chinese and other imports have reduced the cost of mini split systems to where they sell for less than 25% of their cost five or ten years ago. Most homeowners don't like the noise and appearance of window units nor the fact they require blocking a window opening. Mini split systems can be effectively used in areas where there are rooms that can't obtain sufficient cooling or heating from a central system or where the aesthetics of the house need to be protected such as historical buildings. Mini splits come with remote controls and allow each room or area to be controlled separately thus saving energy over a central system. The downside to mini split systems is they can only cool or heat one room and their low air flow limits the distance to where they can effectively cover. Mini split systems come in capacities of 9.000 to 24,000 btus.
PTAC Packaged Terminal Air Conditioner units are through the wall air conditioning and heating units typically found in hotels. PTAC units are similar to window units with air conditioning and electric heating or heat pumps and are floor mounted. There are also specialized PTAC units with gas heating available. PTAC units are also used in additions, individual rooms and small offices. PTAC units are an easy solution for spot heating and cooling. The disadvantage is the noise factor. Similar to window air conditioners but an advantage to size. The vast majority of PTAC units are the same size using the same size wall sleeve. In the event a unit needs to be replaced years from now the same manufacturer or another brand or capacity will fit in the same size sleeve.
Space Pak systems are high velocity split air conditioners requiring small 2" ducts to be run throughout a house. Space Pak systems permit small ducts to be run creating a much easier installation on an existing home that needs to protect the internal architecture and integrity of the construction of the house. Space Pak systems require 1/10 the space of standard systems. Examples of perfect applications of Space Pak systems are historical buildings and houses having rich interior materials such as finished rare wood panels and decorative ceilings, etc. Space Pak systems are limited to single floor usage and can't be installed to accommodate more than one floor per system due to non ducted return air systems. Space Pak systems are ideal for the above applications and where humidity control is imperative but should not be considered for new construction or houses where standard ducting can be applied. Space Pak systems have slow recovery times and limited efficiencies and limited heating options.
Built to provide fresh air efficiently into today's new tight energy efficient homes, heat recovery units provide fresh air exchanges to control humidity and indoor air pollution. Exhaust air is passed through a heat exchanger to retrieve energy to fresh air being introduced into the house. HEPA filters provide optimum filtration removing the finest of air pollutants. Today's tight energy efficient construction methods leave houses so tight allowing toxins and pollutants to build to levels 10 times greater than fresh outside air. In addition to pollutants moisture also builds within the house causing high humidity levels which can cause condensation to form on walls and inside walls and resultant destruction and a perfect breeding ground for molds and mildew. ERV and HRV systems control and dilute pollution and moisture build ups.
There has been a lot of publicity about fuel cells and other types of systems coming in the future. As with the last energy crises in the late 1970s there are also a lot of snake oil gimmicks that crawl out of the woodwork with hoaxes and claims that can't be supported by any sound engineering analysis. Quite frankly there are no mysteries to energy conservation, usage or production. The mysteries are always the hoaxes such as the little black box you can add to your furnace, boiler or electrical system guaranteed to reduce your energy costs. Or the heat recovery box that can go on a dryer or the liquid that can be added to your fuel oil to increase efficiency. The best marketed gizmos are those that have magnetism that can soften your water, increase fuel efficiency or by some magical power make your electrical system more efficient. The manufacturers of these gizmos are never reputable and their claims are never supported by any reputable engineering or reasoning. Many times they are advertised on infomercials with the entire set being staged by actors. Simply use one rule that if it sounds too simple or too good to be true or something from another planet it probably is.
There is a lot of research and talk about fuel cells. Our opinion is fuel cells will never become a practical source of energy because of the leakage hazards with hydrogen. Engineers working with hydrogen on a daily basis at refineries and chemical plants explain how dangerous and explosive hydrogen is. They also explain the difficulties they face in trying to contain hydrogen safely. Hydrogen will leak where nothing else will due to the small molecular size. Large energy producers regularly working with hydrogen continue to have difficulty in containing leaks in production processes. Many concepts and theories sound great on paper but bringing these products to market in a safe efficient cost effective manner is where theory is often lost to reality.
What does seem promising is home electric generation. Some major energy companies and government sources project small generation of electric will become more effective, practical and efficient in the next five years. It is presently anticipated that home electrical generation will become 25% of the source of heat in homes the next five years and 75% in the next ten years. What is promising about home electrical generation is the heat generated by the water cooled engine will provide free heating. Taking the idea one step further and adding a compressor driven by the same engine driving the generator will provide efficient heat pump operation. The system will become it's own self contained home power plant with heating and cooling. The concept takes the same amount of natural gas we use now to heat our homes with a furnace or boiler. That same amount of gas powers an engine which supplies the same amount of heat to our homes and also generates enough electricity to supply our house and provide excessive electrical power to sell back to the electric utilities. York had a similar system they introduced 10 years ago that was ahead of it's time. But now the time has come for this concept to become reality. Many manufacturers are taking this idea from the drawing board to developing efficient home generation systems with heating and cooling. From an engineering viewpoint and practical standpoint electrical generation with essentially free heating makes sense and will be available in the near future.
Wood pellets have become very popular in some sectors and markets in the country. Wood pellets are used in boilers and some furnaces or boilers combined with hot water coils in air handlers. Although the cost of wood pellets are significantly less than other fossil fuels, the boilers are initially very expensive and are labor intensive. Coal also remains a very inexpensive form of heating. The problem with these types of fuels is the initial cost of the equipment, large space required and they are labor intensive in that you can't just fire them up and walk away from them. These systems do require attention even in automatic feed systems. We aren't recommending these types of systems as they are only slightly better than burning firewood which we consider a step backwards and not something that fits into most lifestyles. Wood pellet systems have caused a number of house fires due to improper maintenance or attention.
50 years ago coal was used quite extensively in the Northeast. Coal was then as it is today, dirty and labor intensive and very unhealthy for the homes occupants and environment. Byproducts of coal burning are extremely deadly and even in small concentrations, lethal. Coal burns hotter and produces 100 times the amount of carbon dioxide and monoxide as natural gas. Future technological advancements will make the use of coal clean and safe for homeowner use. There is sufficient coal in Pennsylvania alone to supply the country's energy needs for the next 200 years.
What we can all expect is new heating and cooling technologies to emerge in the near future. We as homeowners have to be smart enough to separate the hoaxes from what makes sense. Hoaxes and poor manufacturing ideas can emerge from anywhere. When it comes to heating and cooling our homes or producing electrical generation or storing of energy we need to have reliability as well as efficiency. There was a flood of poorly engineered, designed and manufactured products evolve from every HVAC manufacturer in the 70s and 80s during that energy crises. Expect the same again but learn and research to distinguish great ideas with reliability from hoaxes and products that are rushed to the market before they've been properly refined and tested. Read more about the products outlined in this section in our Product section of our website. You will learn more details as well as the history and how each product has evolved to where it is today. Products and features are recommended by DESCO Energy because of their proven reliability. Although some may be new to you most have been in successful use for ten or more years. The criteria for a recommended product, feature or concept from SEER - Solutions for Energy Efficient Results requires proven results and in successful operation for at least 5 years. New products from manufacturers are often provided to DESCO Energy while in the field testing phase for performance, functionality and reliability. It is the feedback provided during this field testing phase where manufacturers are able to determine any changes that need to be made. Many new ideas are passed by us before they ever reach homeowners providing more insight to their development. The keyword is caution when considering new concepts and products. Remember what was learned from hoaxes and scams that surfaced during the last energy crises - "If it sounds too good to be true it is!"