What is the difference between a heat pump and a straight cool system?
Straight cool systems are great for customers that almost never turn on their heat. It costs less up front, but costs more to use in heat mode than a heat pump system. Straight cool systems are air conditioning systems that use a heat strip, or resistance heater, for heating. The heating cycle of a straight cool system use approximately 3 to 4 times more electricity to run than a heat pump.
A heat pump is a reverse cycle system. It uses the same refrigerant system your air conditioner does, but in reverse, to heat instead of cool. In heating, the refrigerant in the condenser absorbs heat energy in the outdoor air and transfers it into your home.
Why does my heat pump steam and drip water in the winter?
Just like air conditioners, heat pumps use heat transfer, but in reverse. Heat pumps pull heat from the outside air and transfer it to your indoor coils. It takes more energy to generate heat than cool air. It should take at least 15 to 20 minutes of operation on startup to raise the indoor temperature. Heat strips help back up the heat pump to lessen the time the system needs to generate heat. Heat pumps are efficient at temperatures above 20-degrees Fahrenheit (this is why you don’t see many in the northern states).
Because of the reversed cycle of your system, it is now removing heat from the outside air, which causes condensation on the outdoor coils. When the temperature is low or freezing, the condensation produced by the heat exchange will freeze. When the system is on, it is pulling cold air through the wet condenser coils, causing frost to form on the coils which slowly builds up ice and covers the unit. To prevent ice accumulation, your heat pump has a defrost device on a timer. Once ice is present, the defrost sensor will close, causing a chain reaction. Most have selections of 30, 60, 90 or 120 minutes. The colder it is, the more often defrost mode is initiated.
Signs of defrost mode: Once the sensor detects ice forming, it sends a signal to the defrost board. With the sensor closed and the timer set for maximum operation, the outdoor fan stops completely. The reversing valve then switches position, reversing the flow of the refrigerant. Some heat is removed from inside of your home to melt the ice off the pump. You may hear loud noises resembling air brakes on a bus. You may notice puddles of water underneath the outdoor unit. You may see steam rising from the top of the system. Heat from the coils mixes with cold ambient air to make steam. These are all normal signs of the defrost cycle. Believe it or not, the system is actually in air conditioning mode during the defrost cycle. This is your system working properly.
Signs of defrost problems: As long as the system is maintaining the desired temperature set on the thermostat, then there is probably no system failure. If the defrost mode is not working correctly, it will struggle to maintain the required temperature. If you see excessive amounts of ice accumulated on the coils for more than two hours, there may be a problem. If the ice melts only when the sun comes out, that could be a concern.
What is a SEER rating?
The Seasonal Energy Efficiency Ratio (SEER) is a metric used to measure how much cooling a system puts out for each unit of energy it consumes. The higher the SEER rating, the more efficiently the air conditioner operates. The minimum SEER rating for residential system installations today is 14 SEER. The SEER ratings available range between 14 SEER to over 20 SEER. Some utility companies offer rebates for replacing your old system with a new, higher SEER system. Call us today for a free estimate, and we can explain all your options and what makes the most sense for your home.
Should I increase the tonnage of my system? Will that make it more efficient?
A heat pump’s job is two-fold. Not only does it remove the heat from your home, it also must remove the moisture from the inside air in order for you to feel comfortable. When the unit first turns on, it will take about seven to 10 minutes for the unit to get to its peak efficiency and remove the moisture from your home. An oversized system will have shorter run cycles, hindering its ability to remove humidity. Also as the system short cycles, the unit shuts on and off–on and off–which can be hard on the system. Keep in mind also that by increasing the tonnage of your heating and cooling system, you may need to increase ductwork and copper as well to accommodate the larger system.
What should I check or make note of prior to calling for HVAC service?
Check for a dirty filter, is the power switch on, is the circuit breaker tripped, is the thermostat set to heat or cool and the proper temperature?