Selecting the Best System for your House

The most critical decision you make in the process of a do it yourself HVAC project is the system you select. The factors that go into making this decision are the fuels that are available to you as well as their cost, the type of construction of your house, your location, your desired level of comfort, your goals in energy reduction, the payback of the system selected and finally your budget. Your decision should not be made on the basis of first cost and least expensive type of system, what type of system you presently have and what is most familiar to you or a local contractor.

For years it could be said with total truth that a natural gas system was the least expensive type of fuel available followed by fuel oil, heat pump and then electric heat. Today with skyrocketing costs for natural gas and fuel oil there is tremendous volatility in the energy markets. While fossil fuel costs have skyrocketed electric costs have increased marginally in comparison. While some areas of the country are served by hydro, nuclear and coal those generating costs have remained relatively stable with only marginal increases while electric that is generated by natural gas and fuel oil have risen more. The rate of electric increases is slower to follow in comparison to fossil fuel prices can change overnight. As these fuel prices increase and decrease nobody is certain were electric rates will level out. Or they may not level out at all.

Today electric rates are more effective in many parts of the country making heat pumps a better choice than ever before. But as any homeowner attempts to glaze into that futuristic crystal ball and determine where energy costs are going to be the most advantageous, lots of luck. But rather than base any decision on luck it would be better to rely on certain given facts. Energy costs will continue to rise and as world conditions become more unstable the cost and availability of any given fuel hang by a thread. None of us can control world energy costs but we can reduce the usage of that energy source. To what degree we can reduce our energy usage depends largely in part on how energy efficient our house is as well as the heating and air conditioning system. How much can you reasonably expect to reduce energy consumption by changing your heating and air conditioning system largely depends on the age and efficiency of that system. A house that was an energy star rated only 5 years ago can reasonably reduce energy costs today by 25% by upgrading to more efficient heating and air conditioning equipment. A house that was energy efficient 10 years ago by the standards established at that time can reasonably expect to reduce energy consumption by 30 to 50%. Houses 15 years or older can reasonably expect to reduce energy consumption by at least 50% or more.


Two very important don'ts should be remembered when selecting any forced air HVAC system. Don't select any system on the premise of future upgrades to the house that may be completed. If there aren't definite funds and plans for that work it is best to keep your selection based on how the house exists now. In other words don't size and select a system based on the hope that in the future you may be upgrading windows or adding more insulation, etc. Secondly don't select a system based on a possible addition that may be added in the near or far future. Equipment should be selected on the house is now, never on a possible or definite addition unless that addition is part of a major remodeling of the entire house. First always upgrade the house first with new windows and more insulation and then select an HVAC system based on that present condition and efficiency. Otherwise if you later upgrade the house the system selected now will be oversized. If you don't make the upgrades and size the system for potential changes the system will be undersized. Also NEVER size or select a system based on a possible or even definite addition. Additions always have higher energy efficiency than the existing house and are located at the furthest distance form the existing house duct or air distribution system. Almost always the heating and air conditioning requirement for the addition will be less per square foot than the main house. As a result the heating and air conditioning system in the house will be out of synch with the heating and air conditioning requirements for the addition. Let's say for example you do size the system for an addition. What do you do with the extra heat and air conditioning and excess air required for the addition until the addition is completed? What happens if economic circumstances change and force cancellation of the addition or other intended household upgrades? You will end up with a system that will always be oversized causing you to waste energy rather than conserve it. Additions are always best handled with their own separate systems.

Forced Air or Radiant Heat?

If you want comfort and comfort is the most important goal as well as energy conservation than hot water in floor radiant heat is the best choice of all types of heating. It is comfortable, quiet, efficient, versatile, flexible and clean. In fact in all the mentioned areas it is not only all those things, it's the best. In floor radiant heat has generally been applied to high end homes because of it's high costs. However what drives the cost so high is the high amount of labor required. Installed costs can run $6 to $12 a square foot. Making this a do it yourself project you can install the same system saving 50% to 75% including the ultra efficient Trinity boiler. Forced air systems circulate hot dry winter time air which is detrimental to allergy sufferers or people who have respiratory problems including asthma. Forced air systems also produce objectionable air movement creating chilling skin effects to elderly persons with circulatory problems. Forced air systems also create stratification which wastes energy and creates significant discomfort. Most two story homes have open stair cases. In a forced air system the hotter air produced by the furnace rises to the second floor always creating an uncomfortably warmer second floor area and cold first floor. If you take thermometer readings on that 2 story forced air system the temperature at the first floor flooring and the temperature at the second floor ceiling area will read a temperature difference of 25 degrees which is common. And the colder it becomes outside the greater the temperature difference or stratification will become. The thermostat located on the first floor is satisfied at 72 degrees. The actual floor temperature on that first floor is 60 degrees and the ceiling on the second floor can be 85 degrees. That is what we call stratification. Because the hot air on the second floor ceiling is so hot more energy is transmitted to the ceiling and then out the roof. Due to the method in which a forced air system heats, the discharge air coming out of the furnace is 115 degrees or hotter. Hot air rises and so the natural convective flow of the hotter air rising to the second floor creates the stratification. The hotter the air coming out of the furnace the greater will be the resultant stratification or difference in temperature between the first and second floor.  Taking the same temperature readings of the same house with an in floor radiant heating system you will have a first floor flooring temperature of 75 degrees, a thermostat reading of 72 degrees and a second floor ceiling temperatures of 74 degrees. What a difference with little or immeasurable stratification. As you can see the heat in an in floor radiant system is where it belongs and none is wasted. A radiant heating system reduces energy consumption by 25 to 50% over a forced air system using equipment with the same energy efficiency ratings. Another advantage and cost saving feature of radiant heating is the ability to heat only those areas or rooms that are occupied. In a forced air system the entire house is heated. But in an in floor radiant system you have the flexibility and versatility of lowering the temperatures in this rooms when they are not in use. For example during the day you can heat up the living room, dining room etc. while reducing the temperatures in the bedrooms. At night you can raise the temperatures in the bedrooms and bathrooms and lower the temperatures in all other areas of the house. Radiant heat is maximum efficiency, comfort, cleanliness, flexibility, versatility and quietness. For complete details on boilers and radiant heat go to our products section.


If you presently have an existing forced air system you will most likely decide to continue with it's use. If you are building a new house or complete remodeling and hove decided you want to use a forced air system you will want to explore your options as to the type of system will be best for you. If you live in the mid-atlantic, northeast or mid-western parts of the country you are extremely concerned about natural gas prices and what the future will bring. Due to the enormous cost increases for natural gas in the past several years you may be thinking natural gas is cost prohibitive as a source of heat. You may also think heat pumps are not a wise choice due to their inefficiencies but gun shy of natural gas. If you live in New England you most likely think fuel oil is about your only choice as the majority of homes are heated this way. But like homeowners with natural gas you've also been stunned as fuel oil and natural gas prices have been following the same path.

For any homeowner who has natural gas or fuel oil SEER strongly recommend a dual fuel system. Look at our energy comparison and return on investment sample below to see exactly why dual fuel systems make sense for you if you have natural gas or fuel oil.

Selecting Your System Based on (ROI) Return On Investment

SEER Solutions for Energy Efficient Results recommends the following guidelines for determining which system is best for you. Do not use price as your guideline for determining which system is best for you. Payback is the main criteria which should be used when determining which system makes sense for you. To determine payback you will need four items - (1.) 1 or 2 Competitive quotes from HVAC contractors for the exact type of system you've selected at the same efficiency with the same features and benefits (2.) Your existing system efficiency (3.) Your energy consumption for the past 2 to 3 years (4.) Your present energy costs  By taking the quote form a contractor and comparing this to the cost of the system provided by DESCO and then adding the cost for the final start up you will have the payback or money saved as a result of making this a do it yourself project. By determining the previous energy consumption and existing system efficiency we can then compare this cost to the now energy costs and reduction in energy consumption you will enjoy from the new HVAC system.

As our example for this let's call our homeowner Harry. Harry Homeowner wants to replace his existing HVAC system. Harry has selected a dual fuel system with 14 Seer efficiency on the air conditioning 8.0 HSPF efficiency for the heat pump's heating and 95% efficiency for the gas furnace with 2 stage and variable speed furnace. Harry's present system is a gas furnace with standard air conditioning. The air conditioning is rated at 8 Seer when it was new so we allow for losses of heat transfer till today and decrease this conservatively to 7 Seer. The gas furnace has an 80% operating efficiency but no AFUE rating because the furnace is too old and that ratting didn't exist then. So we've conservatively determined the AFUE or Annual Fuel Utilization Efficiency at 73%. Harry had two quotes for a dual fuel system form local HVAC contractors with one at $8700 and another at $10,200. Harry has a quote form DESCO Energy for $2,800 for the complete materials he will need to do the job. Harry also has a price from a licensed HVAC technician for the final hook up and start up of the system for $500. Harry's cost to do his own installation will cost him $3,000. Harry has also added an additional $200 to this figure for incidental materials he may have overlooked for a grand total of $3,200. For this project Harry will save $8,700 minus $3,200 or $5,500. Harry's energy usage and costs for his existing system were calculated to be $1,650 at today's energy costs. Harry's cooling costs were calculated to be $1,260 for the existing  system at today's energy costs. These figures are exact because they are based on a known history of energy usage using the costs of energy today. Harry's new dual fuel system will reduce his heating costs by 53.5% for heating and exactly 50% for cooling. Keep in mind the reduction in heating energy consumption for Harry's new dual fuel system is based on winter heating degree days determined by Harry's specific location. The calculation is very complex and is not based simply on the increased efficiency of one gas furnace tot he new furnace. The furnace on Harry's dual fuel system has two stages with variable speed and a high performance heat pump. Harry will save 53.5% of $1,650 or $882.75 on heating costs. Harry will also save 50% on cooling costs which was simply the efficiency difference of the older existing system and compared to the new efficiency which is 50% greater. Harry will save 50% of $1,260 or $630. Total energy saved is $1,512.75 per year. So Harry has a system that has an overall savings of $5,500 in contractor savings and $1,512.75 in energy savings for a total savings the first year of $7,012.75. In related time this system has an ROI or Return On Investment or will pay for itself in 5.5 months. This is determined by taking the cost of the system complete at $3,200 divided by $7,012.75 which is the contractor quoted system plus the first year energy savings. If you want to also look at this from an energy conservation payback we will then take the cost of the system complete at $3,200 divided by the total energy savings at $1,512.75 per year and the payback period is 2 years and 1 month. Another perspective view on this installation would be if you opted to have a contractor do the installation. Based on these costs and the same energy savings we take the $8,700 contractor costs and divide this by the $1,512.75 and Harry would see a 5 year and 9 month return on his investment. Although this isn't a bad return on investment the 5-1/2 month payback is far better. The dual fuel system ROI and information provided is typical and actually conservative. These are normal paybacks homeowners see continually for their dual fuel systems.

AS SEER Solutions for Energy Efficient Results reminds you: The best investment you can make is on your street, not on Wall Street! Imagine if you had this type of investment opportunity on Wall Street. Everybody would jump at the chance to make this kind of return on their investment. But Wall Street has high risks. This is a guaranteed safe investment which will continue to save you money with a return on investment year after year that only grows more as energy costs continue to rise. The only risk to this investment is if energy costs decreased and continued to decrease continually. Any chance of that happening?

In selecting a system insist on an air conditioning efficiency of no less than 13 Seer - Seasonal Energy Efficiency Ratio. In January 2006 The Department of Energy has mandated 13 Seer as the minimum efficiency system allowed to be manufactured. 13 Seer will then become the builders model. Seer ratings are now up to 19 and 20 in some manufacturers. Air conditioning systems over 14 Seer are using the newer R-410 refrigerants and are using two stage compressors. Two stage compressor operation increases cooling comfort and performance for light days as well as the hottest days creating amore perfect indoor climate. Look for the auto comfort mode in air handlers or gas furnaces to further enhance cooling performance for dehumidification. If you live in a humid area two stage compressors with auto comfort should be a requirement. 

For heat pumps we also recommend nothing less than 13 Seer for air conditioning and 7.8 HSPF or Heating Seasonal Performance Factor which is the measurement of heating efficiency for a heat pump. Note that HSPF ratings increase in tenths as significant increases whereas Seer increases are in whole numbers in significance.

For air handlers and furnace blowers we strongly recommend variable speed blowers. Variable speed blowers allow such features as auto comfort mode, quiet start and stop, 10% energy consumption or 90% energy reduction in comparison to standard multi speed blowers, varied ventilation options of 70% or 30% of normal air flow, dehumidification cycle to provide true fan reduction for more exacting dehumidification, constant air flow providing varied fan speeds to compensate for dirty filers, moderate obstructions or imperfections in duct design, wide variety of air flow capacity settings and 10% increase or decrease trim feature to adjust final air flow. As you can clearly see variable speed provides energy efficiency, tremendously increased comfort levels and constant air flow that can't be achieved with standard multi speed blowers.

Gas furnaces should have no less than 95% efficiency with variable speed blowers and two stage control. This style furnace with these options will provide a quiet efficient comfort level you never thought possible. Until the past 5 years these features and comfort levels were reserved only tot he expensive more elaborate commercial and industrial systems used in hospitals and critical manufacturing operations. But today you can have the same exacting comfort and control at a fraction of the cost. In addition there is up to a $200 rebate available from the Department of Energy on your income tax for any furnace with these requirements installed after December 31st, 2005 and until December 31st 2007.

Make certain the equipment you chose meets the basic energy efficiency requirements of Energy Star and has the Energy Star label. The Energy Star label provides a basic guide towards minimum energy efficiency standards and has met the requirements for energy efficiency through the Department of Energy. However if a system meets Energy Star Requirements do not automatically assume it is eligible or meets the specifications for Energy Tax Credits. The Energy Bill for 2006 has much higher requirements of eligibility than the lower limits established by Energy Star.

AQ - Indoor Air Quality

In any forced air system three important items are required to make a complete comfort energy saving system: Thermostat - Humidifier - Air Filter


Not just any thermostat, humidifier or air filter will work.

Thermostats - The new ultra high tech thermostats make a substantial improvement to control temperature accurately and optimize energy savings. In addition to controlling temperature high tech thermostats can also control humidity levels both to add or remove humidity. And there are also remote controlled thermostats which can be controlled over the internet.

Humidifiers - The most important accessory you can add for the least cost with the most benefits. Viruses including the flu survive better and are more easily spread in winter months because dry winter air supports their survival. People suffer more respiratory infections and problems as a result of dry winter air removing protective fluids from the body. Dry winter air increases static electricity detrimental to the operation of electronic systems such as computers and dries out wood and other materials in your home. A humidifier significantly reduces and most times eliminates these problems and provides a lower temperature setting with more comfort. For health, protection  comfort and energy savings a humidifier should be considered as a necessary integral part of every HVAC system regardless of your location. Winter air is dry air in every part of the country from Florida to Minnesota. The further north you live the greater the requirement for humidification and the more benefits you will receive.

Air Filtration - A misconception for every homeowner is that air filters are installed to make your house cleaner and less polluted. The air inside your home is significantly more polluted than outside air but air filters do not correct or clean inside air sufficiently to improvement human conditions. Air filters are essential to protect the HVAC equipment so as not to interfere with essential heat transfer and control the build up of contaminants within the duct system. Dirt in an HVAC system becomes a breeding ground for all types of creatures in duct systems.

High media filters are perfect for protecting your HVAC system and eliminating build up of dirt in the duct system. SEER Solutions for Energy Efficient Results does not recommend the use of electronic air cleaners as they have been and continue to be a product that does not have a long life span. As well it is difficult to determine when an electronic air cleaner fails. High media filters are essential for today's new high tech HVAC systems protecting coils and heat exchangers from build up and decreasing system efficiency and ultimately premature failure of the system. New high efficiency gas furnaces have a secondary heat exchanger that looks similar to an air conditioning coil. Unfiltered air will build up and actually melt on to the surface of the furnace significantly reducing efficiency and ultimately destroying the furnace. This melted dirt can't be removed even with steam pressure cleaning. Protect your new investment in your HVAC system with a high media filter.

Heat Recovery Ventilators HRV or Energy Recovery Ventilators ERV - Today's tighter homes seal in air. Fresh, outside air can't get in. Stale, inside air has nowhere to go. Moisture build-up from sources inside the home can cause costly structural damage. Likewise, the build-up of indoor pollutants from throughout the home can aggravate respiratory ailments and in some cases even cause them. HRVs and ERVs offer effective solutions to poor indoor air quality problems. Each helps maintain good indoor air quality by introducing fresh air from outside while expelling stale air from inside. A must for any tight home such as ICF construction and other highly insulated homes.

For more information on the above accessory products in our IAQ or Indoor Air Quality Section under Products.

For complete assistance in selecting the best system for you call our technical support associates at 877-265-9764 or email at info@descoenergy.com

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