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Frequently Asked Questions about Heat Pumps, and their Answers
1. What type of Heat Pump is best?
The efficiency of the heat pump when used as an air conditioner is known as Seasonal Energy Efficiency Ratio (SEER). A SEER of at least 13.0 is the minimum standard for 2006. Higher SEER’s are available and are encourage should a customer want equipment that is even more efficient.
A fair method of comparing the heat pump to other heating systems is to use the Heating Seasonal Performance Factor (HSPF). The HSPF compares relative equipment efficiencies. A HSPF of 6.8 or higher is recommended.
2. Is the Heat Pump an economical or
expensive way of heating and cooling
and how does it operate?
A heat pump may actually provide more than three units of heat for each unit of electricity used. If a kilowatt-hour of heat is needed for comfort, it can be supplied by a one-thousand watt electric heater. To provide the same amount of heat, the heat pump might use a little as 330 watts in an hour. This is a ratio of three to one. The ratio is referred to as the Coefficient of Performance (COP). Electric resistance heaters have a COP of 1 because they are using electricity to create heat. A heat pump moves heat from the outside to the inside of the home and vice versa, not using energy to create heat. We recommend a COP of at least 1.8 at standard test conditions of 17°F dry bulb and 15°F we bulb.
3. Can I move the thermostat on my heat
pump up and down like other heating
systems?
During the heating season, recommend a setting that is comfortable for your household. Once your thermostat is set, the best policy is to leave it alone. Raising the thermostat as little as 2°F may cause the supplementary heat to come on, thereby increasing your energy usage. Although night setback is recommended during the winter for most types of heating systems, to save energy and reduce costs, it is not generally recommended for a heat pump unless a programmable thermostat designed expressly for a heat pump is used. When you have a heat pump and raise the house temperature in the morning, the supplementary heat may come on using more electricity than you saved during the night. Reduce the thermostat temperature setting for weekend trips or vacations during the heating season.
4. What is the suggested temperature
setting for a Heat Pump in the
winter? In the summer?
In the winter, we recommend a temperature setting that is comfortable for your household. Once your thermostat is set, the best policy is to leave it alone. Raising the thermostat as little as 2°F may cause the supplementary heat to come on, thereby increasing your energy usage. In the summer, a setting of 78°F or higher is recommended for cooling. For each degree you set the temperature below 78°F, you will increase your cooling energy usage approximately three percent. Raising the temperature when you are away from home during the day is recommended to save energy. If you will be away for several days, turn the system off during the cooling season. Frequent changing of the thermostat setting reduces the economical operation of the heat pump and tends to shorten the life of the compressor.
5. Should the thermostat be set back at
night or should I close off registers
to cut back usage?
Although night setback is recommended during the winter for most types of heating systems to save energy and reduce costs, it is generally not recommended for a Heat Pump unless a programmable thermostat designed expressly for use with a heat pump is used. When you have a Heat Pump and raise the house temperature in the morning, the supplementary heat may come on using more electricity than you saved during the night. Reduce the thermostat temperature settings for weekend trips or vacations during the heating season. The use of a standard automatic nighttime setback control with a heat pump is not recommended.
Many manufacturers now provide programmable thermostats designed for night setback so that the supplemental heaters will not normally be energized during the time that the heating system is recovering. Do no block registers and return grills with furniture, draperies, or rugs. Although cutting off heat to unused rooms is frequently suggested as a conservation measure, re recommend that all supply registers in a Heat Pump be left open. The system is designed to heat or cool a specific space. If air circulation is reduced drastically, the compressor may be damaged.
6. What do lights on my indoor
thermostat mean?
The lights on your thermostat indicate the backup auxiliary heat is on. The colder it becomes outside, the less amount of heat is in the air to heat your home. This causes the Heat Pump to hit its balance point meaning it is running at full capacity. If the home requires more heat, the supplemental heat is used. This is when the lights are on at the thermostat.
If your thermostat does not have indicator lights to show when the backup auxiliary heat is on, it would be beneficial to have a contractor replace it. This would allow you control of your resistance heat as well as indicate when this heat is being used. Some of the new digital thermostats do not have lights indicating auxiliary heat, but will show it in another format.
7. Should the outdoor unit run
continuously?
Below the balance point, around 30°F, it is normal for the outdoor fan to continually run. If the outdoor unit continually runs during normal heating (30-50°F outside), possible problems are:
· Thermostat set too high
· Thermostat needs adjustment
· Low refrigerant level in unit
· Thermostat exposed to cold draft
· Outside unit coil is blocked by snow, ice, etc.
If the outdoor unit continually runs during normal cooling, possible problems are:
· Low refrigerant level in unit
· Very warm weather (over 90°F)
· Thermostat located near heat source, such as appliances, TV, etc.
· Dirty filters or too many registers closed limiting air movement
· Improperly designed duct work
· Unit may be undersized
8. How do you evenly heat the house if
the vents are in the ceiling?
Ceiling grills are practical, efficient and economical to install. The temperature must be carefully balanced by adjusting the air flow in these rooms. Proper sizing and low placement of the return grills will help to ensure even heat throughout the home.
9. Are Geothermal Heat Pumps more
economical and efficient than air to
air Heat Pumps?
Geothermal Heat Pumps use the ground to heat and cool the home. In this area the ground four feet below the surface is between 58 and 62°F year-round. At this temperature, a Geothermal Heat Pump will deliver a constant BTU output year-round regardless of outdoor temperatures. This can provide a higher seasonal performance factor (SPF) than some air source machines can deliver. Because of the near constant temperature of the ground below four feet, supplementary (resistance, backup or electric) heat is generally not necessary. The Geothermal Heat Pump has no defrost cycle because there is no outside unit. Typically, Geothermal units have higher efficiency ratings than air to air units. However, due to recent advances in air to air technology the efficiency of some air to air units is now comparable to Geothermal Heat Pumps.
10. What are some ways to help control
my heating and cooling costs?
Once the thermostat is set, it should be left alone. The air filters inside the system need to be checked, cleaned or changed every month. The outdoor fan should not be covered or obstructed, so it can receive proper air flow. Annual maintenance checks should be performed which include refrigerant level checks, indoor/outdoor coil inspections (cleaning, if needed) and duct inspections.
11. Why does the air at they supply grill
feel cooler in the heating mode than
other types of heating systems?
The accelerated movement of the supply air varies from 85 to 106°F in the winter. Air movement causes some evaporation of skin moisture causing the sensation of coolness. By setting the proper supply air speed on a Heat Pump it will provide comfortable air temperatures.
12. How often should I change filters?
Inspect each month and change or clean the filters as needed. Time intervals frequently vary with each family. The most important aspect of efficient operation of your Heat Pump is proper air flow. Dirty air filters will severely limit air flow which can cause the compressor to run continuously. A 20 percent or more increase in operating costs could be caused by dirty filters. The outdoor units should be free of debris to ensure uninterrupted movement of air.
13. Why does my outdoor unit
sometimes have ice buildup during
the winter?
Under certain weather conditions, the outdoor unit will develop ice buildup. When the unit defrosts this ice, it gives off water vapor which appears to be smoke. If excess ice builds up on the outdoor unit after more than 90 minutes elapsed time, switch emergency heat to “on” and call us if the condition does not clear.
14. What is the service life of the Heat
Pump and compressor?
The average service lif of the heat pump is 15 to
20 years. The average service life of the
compressor is approximately 10 to 15 years.
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