There are generally 2 reasons for someone to purchase an optional HVAC device. Increased comfort or increased efficiency. Some options offer both.
High Efficiency Units
Several different grades of air conditioner, heat pump, oil furnace or gas furnace may be available as options for your new heating or air conditioning system. It is important to remember that in most cases a higher efficiency unit will not heat or cool any better than a standard efficiency unit. They merely do it at a reduced cost. There are some side benefits to high efficiency units however; high efficiency air conditioners and heat pumps are usually quieter and may have better warranties than standard units. High efficiency gas and oil furnaces also reduce the drafty feeling in a home by using outdoor air for combustion. Most also have a lifetime heat exchanger warranty. As far as how much energy the unit will save, it depends on several factors. Most, however, will save 30 to 50 times their cost over the lifetime of the unit.
Efficiency Ratings & Return on Investment
There are several ratings used to grade heating and air conditioning equipment. The minimum Federal DOE standards as of 1992 are AFUE 78%, SEER 10.0, and HSPF 6.8 It is important to note that while higher efficiency units will drastically cut the cost of operation, they generally do not heat or cool any better than standard efficiency units.
For gas furnaces and oil furnaces, the rating used is A.F.U.E. (Annual Fuel Utilization Efficiency), and is represented by a percentage. A rating of 100% is the absolute best. Standard efficiency gas furnaces made before 1992 have an efficiency of about 65%. This means that for every dollar worth of gas that you burn, 65 cents of heat go into the house as usable heat and 35 cents go up the chimney. Medium efficiency gas furnaces and most oil furnaces have an A.F.U.E. of about 80%. High efficiency gas furnaces and some oil furnaces have an A.F.U.E. of about 90 to 97%. In the case of high efficiency gas or oil furnaces, the comfort level is increased by the fact that the combustion air is drawn from outside. This reduces drafts in the house. Another added feature of these units is that most of them carry a lifetime heat exchanger warranty to the original owner. It becomes apparent that it is in your best interest to go with the highest efficiency possible to reduce chimney losses but balancing that with the added cost of the high efficiency unit.
This is where return on investment (R.O.I.) comes in. R.O.I. represents the savings you realize by having the high efficiency equipment by a percentage (the same as interest rate on savings account). For instance, if it cost $500.00 more for a high efficiency air conditioner but it cuts the operating cost $100.00 a year the return on investment is 20%. This makes the high efficiency unit a good buy because the R.O.I. is much higher than the interest rate you could get by putting the $500.00 in the bank. In this example it would even pay to borrow the $500.00 at a 12% rate from the bank to get the 20% R.O.I. from the high efficiency unit. In new homes it even pays to add the high efficiency option to the mortgage. Even though you will be paying interest on the option over the life of the mortgage, the energy savings derived from the option will more than pay for the added amount on the mortgage payment.
Air conditioning units and the cooling side of heat pumps are rated in S.E.E.R. (Seasonal Energy Efficiency Ratio). SEER is a comparison of the amount of (cooling BTUs) unit procedures divided by the amount of electricity (watts) it consumes. The result is then averaged over an entire cooling season to make it more accurate. The higher the SEER the better. (A 13 SEER unit will use 30% less electricity than a 10 SEER unit). While 10.0 SEER is the D.O.E. minimum as of 1992 it is possible to obtain a SEER of 13.0 or better.
Heat pumps are rated on their heating side by H.S.P.F. (heating seasonal performance factor). Like S.E.E.R., HSPF compares BTUs of heat produced to electricity consumed. Again, the higher the rating the better. 1992 DOE standards require an HSPF of 6.8 minimum. Ratings of up to 8.5 or higher are available.
Efficiency Option, Comfort Option: Clock Thermostats
These thermostats “setback” automatically at night and unoccupied periods to save energy. In the average working household where the system is being setback during sleep and during daytime working hours savings of 10 to 20% over non-setback operation can be achieved. In addition, since most clock thermostats being installed are digital, there is the added benefit of knowing exactly what temperature the thermostat is set for and reading. Electronic clock thermostats are much more accurate than electro-mechanical thermostats and will do a much better job of holding the temperature at the set point. It’s for this reason that many customers buy clock thermostats not for the setback features, but for the added comfort. The last benefit of electronic clock thermostats is that they usually have a 5-minute compressor delay built into them. This will keep your air conditioning or heat pump compressor from starting for five minutes after it has turned off. This reduces the stress on the compressor that results from rapid thermostat adjustments and power failures. This should make the compressor last longer.
Efficiency Option, Comfort Option: Humidifiers
All homes (even those with hydronic heat) will dry out in the cold weather. In very cold weather the humidity could drop below 20%. Most people need around 35% to feel comfortable. Some other problems that can be reduced with a humidifier are high static electricity, shrinkage and splitting of furniture and wood products, and reducing the amount of colds you get by keeping the mucous membranes in your nasal passages moist. There is an efficiency aspect to humidifiers as well. Just as when your skin evaporates perspiration it makes you feel cooler, it would make you feel warmer if you could lower the evaporation rate. This can be accomplished by installing a central humidifier, which would raise the relative humidity causing the evaporation rate to be reduced. A room unit will not work well since it will, in effect, be trying to humidify the whole house anyway. (Humidity cannot be contained in one room without insulating the walls, weather-stripping the doors, and disconnecting all the heating supply and return air ducts.) For this same reason if you have a large home with more than one heating system you may only need a humidifier on the unit that runs the most in the winter. (Normally this is the downstairs unit) This works well this way especially considering that most upstairs units are located in attics where freezing temperatures occur. We recommend Aprilaire humidifiers since they are high output. They do not spread molds like humidifiers with reservoirs do, and since the only water that is put into the air is evaporated (not atomized) they will not rust out your heating system.
Efficiency Option, Comfort Option: Air Cleaners
The quality of indoor air has become more important as new homes have become tighter. The average heater filter is only around 5% efficient and cannot trap very fine dust, molds, pollen, bacteria and viruses. A high-efficiency filter is needed to do this.
High-efficiency filters also help keep your heating and air conditioning equipment last longer and stay efficient by keeping the indoor coil clean.
- Electronic air cleaners have the highest efficiency obtainable. The efficiency normally runs about 80 to 95% (provided the fan is “on”). They use about the same amount of electricity as a 40-watt light bulb. They need to be cleaned monthly in your laundry tub or dishwasher.
- Pleated type filters are about 50 to 60% efficient (provided the fan is “on”). They use no electricity but need to be replaced every 3 to 4 months.
- Electrostatic filters are about 30 to 50% efficient (provided the fan is “on”). They use no electricity but need to be washed every month.
Efficiency Option, Comfort Option: Zoning
In new homes, and in some existing homes, it is possible to zone the heating and cooling. Adding thermostats and a motorized damper system does this. If this option is taken it is then possible to set different areas for different temperatures. This greatly increases the comfort in a building and also can lower bills since you don’t have to condition the whole house to change the temperature in one room.
Efficiency Option, Comfort Option: PerfectAire Fresh Air Exchanger
This option permits you to bring healthy fresh air into the home while saving energy. The energy efficient homes of today have done wonders for lowering operating costs. The problem may occur, however, if a home is so tight that it builds up stale odors. The PerfectAire air exchanger permits you to exhaust stale air and bring fresh air into the home while extracting most of the heat energy from the leaving stale air.
Efficiency Option, Comfort Option: Geothermal Heat Pumps
These heat pump systems are different from standard heat pumps because they absorb their heat from the ground rather than the outdoor air. This gives them the advantages of a stable heat source, elimination of the defrost cycle, no outdoor unit to complicate landscaping, lower maintenance frequency, higher efficiency, greater comfort, and lower operating costs. A geothermal unit should outlast a conventional heat pump by 30%. Since ground temperature stays at about 53 degrees year round, it can supply much more heat than the air can, especially when the outdoor temperature drops into single digits. For this reason the geothermal unit will produce warmer air than a conventional unit. In many homes, supplemental heat may not be required at all. This advantage becomes even more pronounced during the air conditioning season. Rejecting unwanted heat from the house into the ground at 55 degrees is a lot easier to do than rejecting it into 95 degree outside air. These units also have the option of heating the domestic hot water with inexpensive geothermal heat as well. In the summer, water heating is totally free when the air conditioner is running. Geothermal units can be installed virtually in any house using either a loop of buried tubing with a methanol mixture circulating through it (closed loop) or with a conventional well providing water for heat absorption and elimination (open loop). In open loop units, wastewater can be used for lawn irrigation. In either case, these units help conserve natural resources while providing low operating cost and a superior comfort level.
Reasons to invest in a geothermal heating system
- Efficiency- There is no air conditioner, oil furnace, gas furnace or air source heat pump on the market that can come close to the efficiency of a geothermal system
- Operating cost- Geothermal systems have the absolute lowest running costs of any of the above mentioned systems.
- Esthetics- With no outdoor unit to try to hide, landscaping becomes easy.
- Quietness- Since there is no outdoor unit, backyard noise has been eliminated.
- Hot water generation- Geothermal units can reduce the cost of making hot water in the winter by 50% and make it FREE in the summer.
- Low maintenance- Geothermal units are in the basement, not in the backyard, so they do not suffer from weather extremes. Also, since they do not have a defrost system, their reliability is very good.
- Constant temperature output- Since a geothermal heating system is absorbing its heat from the ground and not the air, fluctuations of temperature in the supply duct are greatly reduced.
- Environmentally friendly- Since 2/3 of the heat that the system produces is absorbed from the ground, it is much more environmentally friendly than either gas or oil furnaces that produce large amounts of carbon dioxide, a greenhouse gas.
- Longevity- American Society of Heating, Air Conditioning, & Refrigeration Engineers (ASHRAE) has estimated that geothermal heating systems should last on average about 20 years. This is twice the expected lifespan of standard air conditioners and fossil furnaces such as gas or oil. With proper maintenance, we feel that 30 to 40 years with a geothermal system is likely.
- PECO Energy rate reduction- PECO offers a discount of about 25% on the winter electric rates on any home heated by a geothermal system. This discount applies to all the electric used in the house, not just the energy consumed by the heating system. With a gas or oil furnace in your home, your winter electric rate is about $ 0.14 /kWh. This would be reduced to about $ 0.10 with a geothermal heating system.
- Safety- There is no safer heating system. All electrical circuits that geothermal heating systems utilize are protected by circuit breakers or fuses.
There is NO DANGER from: GAS LEAKS, OIL TANK LEAKING, NATURAL GAS EXPLOSIONS OIL FURNACE PUFF BACKS, LIMIT SWITCH FAILURE, BURNS, CARBON MONOXIDE POISONING, COMBUSTION ODORS.
Comfort Option: Supplemental Fossil Heat for Heat Pump Systems
This type of heat pump system uses one of the fossil fuels (natural gas, oil, and propane) to supplement the heat pump instead of electric resistance heat. The heat pump provides all the heat needed in the warmer weather (above 30 degrees F) when it is the most efficient type of heat available. Below 30 degrees F, the heat pump cannot provide enough heat to heat the house by itself and some type of supplemental heat is required. The advantage of a fossil fuel for supplemental heat over the standard electric heat is that its cost of operation is a lot less. This is especially true if it is necessary to run the unit on “EMERGENCY HEAT”. In weather below 20 degrees F, the supply air coming out of a heat pump can be below 90 degrees F. While the unit is still operating efficiently, the cooler air may not achieve the comfort level desired. Switching the thermostat to “EMERGENCY HEAT” and running the supplemental heat will produce warmer air, but at a high cost if the supplemental heat is electric. The cost is quite reasonable if a fossil fuel is used for supplemental heat. This type of system still qualifies for the “RESIDENTIAL HEATING” electric rate from PECO. By being on this rate, all of the electricity that you use is discounted, not just the electric to run the heat pump. If you are not on the “RESIDENTIAL HEATING” rate your costs are about 40% higher.
Efficiency Option, Comfort Option: Radiant “In Floor” Heat
This is the ultimate in heating comfort. The special tubing is buried directly in the floor of the bathroom (wet bed tile) or in the concrete under the basement floor. Bathrooms or the entire home can be heated with radiant floor heat including areas that are hardwood or carpeted. The heat that you experience is extremely comfortable, even, and noiseless. In addition there are no baseboard convectors or radiators to trap dust and make it difficult to furnish around. Radiant floor heat can be easily zoned so that you have a thermostat in every room where one is needed. The operating cost is very low with radiant heat. Since the floor is warm, you feel comfortable at a cooler temperature and can set the thermostat lower, saving money. Radiant in floor heat can be roughed into concrete floors for future finishing. Remember, once the floor is poured, it becomes very costly and inconvenient to tear it out. Once you’ve lived with radiant in floor heat, you will swear that everything else is just a compromise.
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