HVAC Energy Efficiency

Not too long ago energy efficiency and comfort were very unrelated terms. To achieve energy efficiency and energy conservation comfort had to be sacrificed. Setting thermostats lower in winter months and raising them in summer months was considered energy efficiency. Turning the thermostat even lower at night until your teeth would rattle was energy efficiency. Size the heating and air conditioning large enough so when the system comes on to be certain it only runs for a short period of time. The shorter time the system runs the less energy it consumes.  Not only homes but offices, schools and industry all oversized their systems, ran them early in the morning to get the building warm and then shut it off the rest of the day if possible. The theory was correct because years ago and too many times today that is the way heating and air conditioning systems were designed. Oversize them like giant behemoths to blast the energy and then shut them off as quickly as you can. Longer operating times meant more energy consumption.

For many of you this may be the way you see heating and air conditioning systems today. Turn off that light, you're wasting energy. Close that door, you're wasting energy. Turn off the heat you're wasting energy. Night setback thermostats aren't new. We have some dated to 1946. Primarily their use was to turn off systems and reduce temperature whenever possible. In the 1970s energy audits were first introduced. During the research phase of establishing actual sound data for energy conservation and efficiency it was discovered that if the temperature was reduced for at least 10 hours there were energy savings lowering the temperature eight degrees. If the temperature was lowered for more than 10 degrees on a 12 hour reduction time period there was also energy savings. But if the temperature was lowered for less than 10 hours there was insignificant energy savings as the cost to bring the house up to temperature equaled and in some cases exceeded the energy saved. So temperature reduction in any building is dependant on the type of building material, the climate, the temperature reduction and the time in which the temperature was reduced. In heat pumps where electric heat was used as the back up heat there was no energy saved and it would cost more to actually reduce the temperature and bring it back up when the electric heat was used to do so. Today's intelligent thermostats take this into consideration when raising temperature after a temperature reduction.

Today in the heating and air conditioning industry they don't make them like they used to and we're glad for that. HVAC systems and equipment are more efficient, reliable. last longer, a have better and longer warranties and provide more exacting levels of comfort than ever before.

Technology and information on how to be energy efficient have come a long way since those days. With the new information and data to support it came energy management systems which take into account the outside temperature and humidity and based on the building's previous performance which is stored in a computer the amount of temperature reduction for heating is no longer a simple time on and time off at predesignated intervals. Some building control systems are sophisticated to also take into account the solar radiation and wind speed and direction in addition to the temperature and humidity.

There are also significant advances in the way a furnace or air conditioner operates. Instead of 100% on and 100% off newer systems provide staging which provides two different capacity levels. One for mild days and other for extreme days whether it is summer or winter. The latest technologies enhance performance more exacting by providing modulation of the capacity of the system. Similar to a car with a throttle the new variable modulation systems will match the required capacity at is required at any given day under every climatic condition for the specific location.

Variable speed fan motors as developed by General Electric are used widely today in furnace blowers, heat pump blowers and every type of forced air system. The variable speed blower motor provides many benefits to achieve maximum comfort and efficiency only previously possible in critical temperature controlled environments such as hospitals and manufacturing for industry. The variable speed motor or ECM motor will use 1/10th the energy of a standard multi speed blower motor. ECM motors ramp up and down in speed when starting or stopping providing totally quiet starting and stopping. ECM motors are adjustable for a wide variety of air flows which can also be trimmed to exacting performance and maintain a constant air flow regardless of minor obstructions or partially dirty air filters. New technology added to ECM motors also prevents cold air blasts from furnaces and heat pumps previously an accepted annoyance and source of discomfort. ECM newer technology referred to as Auto Comfort Mode which slows the start up of the motor to 100% capacity for up to 5 minutes allowing indoor air conditioning coil temperatures to reach low enough temperatures for dehumidification in 2 minutes or less compared to the customary 12 to 15 minutes required in older standard conventional systems called auto comfort mode.

Gas furnaces have new igniter technology which only energize the igniter coil for minimum time periods greatly increasing igniter life and performance of the furnace eliminating nuisance failures and repairs. The control system in these furnaces monitors the time it takes to prove ignition on the furnace and continually reduces this time by decreasing the igniter firing time. Eventually reducing this igniter time period until he furnace actually fails to prove ignition. The furnace then restarts and the igniter is then firing for a slightly longer period of time as the computer monitoring system continually monitors these conditions and adjusts time periods while you have no idea all of this happening as none of this affects the performance or comfort in your home.

Two stage heating on gas furnaces provides 60% of the original capacity on mild days while providing 100% capacity on colder days. Why? In a conventional gas furnace which operates at 100% capacity every time it is fired, the furnace is essential oversized for all times except when it is the coldest temperatures. By providing two stages of heating the furnace is now able to provide more even levels of capacity for mild and colder days. Two stage operation increases comfort by matching the load requirements of the house more exactly eliminating short cycles of hot blasts of air. In addition there are less stack losses as the lower capacity setting produces less heat, runs for loner periods and has less flue losses.

Keeping in mind that to achieve efficiency and comfort the traditional thinking of short blasts of hot air form oversized heating systems are counter to everything required to save energy. All the strides made to improve efficiency have been superseded by old thinking that continues in the minds of HVAC contractors and homeowners. If you can change your thinking and how you approach the concept of efficiency and comfort you will be able to better utilize the new technologies and the benefits they offer. The first concept of bigger is better works against all the basic fundamentals of efficient heating and air conditioning. Here's why. Typical furnaces of yesteryear are 60 to 80% efficient. The warm up time for these furnaces to achieve operating conditions and efficiency was 5 minutes or less. Homeowners wanted these older inefficient furnaces and boilers to run less because of all the wasted energy they could see going up their chimneys. You could not only feel the heat in the chimney stack but also burn your hands form it. Today new furnaces require 12 to 15 minutes of operating time to achieve operating efficiency. Unlike the older furnaces and boilers you won't feel much if any temperature difference going out a PVC plastic stack. The longer today's furnaces operate the more efficient they become. Using a variable speed blower motor the longer run cycle of the blower motor is minimal so there aren't large amounts of electric energy required for the new hi tech condensing gas furnaces. By having longer run cycles of lower heating output the house maintains a more consistent comfort level while using less gas and electricity. Energy efficiency and comfort today go hand in hand.

Air conditioning systems today are greatly improved form the previous systems of even 10 or 15 years ago. With two stage operation in many new higher efficiency units the system cooling requirements are more evenly matched to the outside conditions. The first stage is generally 50% of the total capacity and the second stage is 100%.  This feature combined with the newest feature of auto comfort mode produces exacting indoor temperature and humidity levels while saving energy due to the systems matching of cooling requirements and the overall efficiency of the equipment. Again decreased energy costs coupled with increase comfort.

Dual fuel systems are becoming more important and popular to natural gas users toady. Dual fuel systems provide the best payback and level of comfort of all other systems available. With the combination of heating with a very efficient heat pump on the mild to milder day and then an ultra efficient two stage gas furnace on cold and the coldest days a dual fuel system is the most economical investment you can make. Four stage of heating and two stage of heating on the highest efficiency systems.

Hi tech begins at the thermostat with energy management and comfort control. Until several years ago dual fuel systems required cumbersome control cabinets with confusing and complex control centers. Today those big control centers have been eliminated with the new hi tech thermostats. Hi tech thermostats have not only eliminated large complex control systems for dual fuel systems but also control moisture for humidification and dehumidification. By outdoor sensing the new hi tech thermostats also determine when too much humidity could cause condensation with in the house. Hi tech thermostats also monitor hours of heating and cooling operation, save energy through energy management and w some will even communicate and can be adjusted remotely through the internet. There are many more features and benefits to the new hi tech thermostats but we only want you to be ware of the most commonly used features.

Heat pumps have increased in efficiency and comfort to the point they are considered for usage in many parts of the United States and Canada. Producing the same comfort and efficiencies which rival any other system with two stage and variable speed compressors and variable speed ECM motors.

There are also high efficient duct systems which can be pre cut for your specific application requirements available. The fiberglass duct systems are energy efficient, less costly. easier to install, quieter and have extremely low leakage at joints. Compared to traditional sheet metal duct systems which are expensive, require expensive specialized tools to produce and leak an average of 25% of a house's energy, fiberglass ducting is much easier and less time consuming to install. 

In floor radiant heat is the maximum comfort and energy efficient system. Today's new hot water boilers are loaded with more technology to provide outdoor reset to adjust water temperatures as outside temperatures change, modulating firing which adjusts heating requirements to the load required at any given time, ultra efficiencies up to 98% and hi intelligence ignition and energy management systems. Manufacturers put the hi tech l boilers in a small package which can mount ton a wall and take u to no more than a 2 foot x 2 foot wall space. There are also radiant control systems which can adjust temperature settings to variable speed pumps to produce temperatures that have less than one degree variance.

You can either be afraid of the new technological advances made in the HVAC industry or embrace them. The technologies of the electronic systems are not new this year but have been in service for many years. What has changed is your awareness to these technologies and how they can work for you to save energy and increase comfort. General Electric's ECM variable speed motors have been in production in HVAC systems for over 15 years and have proven total reliability. Ultra tech thermostats have been around for over 5 years as well as two stage heating and cooling compressors. Two stage furnaces are over 10 years old. Variable speed air conditioning and heat pump compressors will soon be launched into many more manufacturers in the next few years.

By being aware of these new to you technologies, realizing their proven reliability and cost effective performance you can see how changing the old attitude that more is good and bigger is better to just the right size with the best proven technologies will help you in your goal of energy efficiency and comfort. It is far better to embrace these new technologies and to fear the high energy costs plaguing every homeowner than to fear this technology and embrace more energy consumption. As you see you can achieve energy efficiency without sacrificing comfort. Today energy efficiency and comfort go hand in hand.

Some older concepts lost in the years that need to be considered also. Humidification is the single most important part of any heating system. Today's new tech humidifiers require far less maintenance and much easier to service. Many of us can remember the old drum type humidifiers that were prone to growing all types of bacteria and molds and funguses. Today's new hi tech plastics make cleaning and serving of humidifiers easy as changing an air filter. There are no drum types of bacteria humidifiers available at DESCO Energy. The newer flow thru or mist humidifiers are free of any water reservoirs. Humidifiers have many positive benefits including health and comfort and ultimately energy conservation. You can safely reduce the temperature in your house 3 to 4 degrees with out any sacrifice in comfort with a humidifier. Each degree of temperature reduction produces a 2% decrease in energy consumption. Regardless of your location winter air is dry air and it produces even drier conditions and static electricity when it is heated. Asthma, sinus and respiratory conditions as well as viral infections are reduced significantly with humidified air. Heat pumps should have specialized steam producing humidifiers to effectively add sufficient moisture due to the lower discharge heating air produced by a heat pump. More than any other heating system heat pump owners should consider the use of a humidifier essential for energy efficiency and comfort.

All forced air systems should use proper air filtration to keep their equipment energy efficient and reduce indoor dirt and pollen and other contaminants. Finding high media filters the most effective and reliable method of filtering air and protecting your valuable investment. High media filters are essential to the new ultra efficient condensing gas furnaces. Inside each furnace there is a coil similar in appearance to an air conditioning coil where the gas is condensed and the final heat is extracted into the house. Poor or leaking filtration systems allow dirt to bypass them and then catches on he condensing coil of the furnace. Here the dirt will literally melt on to the furnace coil blocking heat transfer and effectively ruining the furnace and increasing energy consumption. To alleviate this problem High Media filters which o not need constant attention are more effective and more reliable over electronic air cleaners and cost less too. Hi media filter which is generally 4 to 5" thick will survive for months before needing changed. If you're they type of homeowner who is forgetful or doesn't want to be bothered every moth changing filters, the high media filter is perfect for you.

Now you've learned the basics of features and benefits of HVAC systems and the connection between energy efficiency and maximum comfort. For further information see our Library/Downloads section as well as our product section n this web site. For questions call DESCO Energy toll free at 877-265-9764 or email info@descoenergy.com

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