If you’re giving serious thought to a heat pump upgrade for your cooling needs, that’s a smart move. Heat pumps hold their own with A/C systems for cooling efficiency and dehumidification, and also provide energy-efficient water heating and supplemental heating to augment your furnace. Get to know heat pump basics of cooling and heating, and you may have a new BFF that saves you money and keeps you comfortable all year long.
Heat Pump Basics
Like an air conditioner, heat pumps use refrigerant to exchange heat between household and outside air for home cooling. The same refrigerant principles (in reverse direction) of heat exchange are used for home heating, as opposed to fuel combustion which furnaces employ for home heating. Follow these heat pump basics through the cooling and heating processes:
- A thermostat signals the heat pump for cooling.
- The compressor sends high-pressure liquid refrigerant into the evaporator, located inside the home, under low pressure.
- Warm household air is pulled through the return air ducts and across the evaporator by the blower.
- The warm air and low-pressure evaporator instigate the refrigerant to evaporate, during which it simultaneously absorbs heat from the air circulation and pulls out moisture which condenses and drains away, helping to dehumidify the home.
- The refrigerant leaves the evaporator as a cool low pressure gas.
- It flows to a reversing valve and is directed to the compressor, which is located outside the home in a cabinet next to the condenser.
- The compressor squeezes the refrigerant into a hot high-pressure gas.
- The hot gaseous refrigerant flows into the condenser.
- The hot refrigerant is condensed to a liquid under high pressure, where it releases stored heat with the help of another blower.
- The refrigerant leaves the condenser in a cooler liquid state and flows to the reversing valve.
- The reversing valve directs the refrigerant to the evaporator to repeat the cooling process again until the thermostat temperature is reached.
When the heat pump is in heating mode, these same heat-exchange principles and processes are followed, except the refrigerant flows in reverse.
- The reversing valve receives hot high-pressure refrigerant gas from the compressor.
- The refrigerant is directed to the evaporator, where the evaporator condenses the refrigerant gas to a liquid, releasing heat in the process.
- The blower sends the heated air through the supply air ducts to the living spaces.
- The cooler refrigerant liquid flows to the reversing valve and is directed to the compressor to repeat the heating process.
Heat Pump Efficiency
Heat pump efficiency is measured in SEER (Seasonal Energy-Efficiency Ratio) for cooling efficiency and HSPF (Heating Season Performance Factor) for heating efficiency.
- SEER indicates the level of cooling output divided by the total electricity input during a typical cooling season.
- HSPF is a ratio of heat output (in BTUs) factored by electricity consumed (in watt-hours) over the heating season.
- Read the EnergyGuide labels when comparing heat pumps. Higher numbers indicate higher efficiency.
Heat pumps with HSPF 8.5 or higher and SEER 15 or higher may qualify you for the Federal energy-efficiency tax credit ($300 for heat pumps, and enjoy up to $500 maximum credit by combining air sealing and insulation products to lower your home's cooling load).
Sizing Your Heat Pump
Sizing a heat pump must be included in the discussion of heat pump basics. Sizing a new heat pump is a process which entails an energy audit and retrofits (air sealing and insulation) to button up your home, measuring the cooling and heating loads of your home and matching the capacity of your heat pump system to meet the cooling and heating loads.
The duct system will undergo an inspection to ensure good design and sizing, too. Your HVAC contractor should use Manuals J, S and D from the Air Conditioning Contractors of America to conduct all sizing procedures.
Maximize Heat Pump Options
Heat pumps offer high-efficiency hybrid heating for homeowners that heat their homes with furnaces. Just like the cooling coil of an A/C utilizes the furnace blower, a heat pump does the same but delivers energy-efficient heating down to the balance point (near freezing point). The furnace takes over home heating responsibilities when temperatures dip below the freezing mark.
With a desuperheater option, heat pumps offer efficient water heating for less costs than a conventional storage water heater. With all the benefits of efficient cooling, hybrid heating and water heating that heat pumps provide, they certainly deserve a serious look for your next comfort-system upgrade.
For more information about heat pump basics, advanced features and all HVAC matters, contact Comfort24-7.com. We serve homeowners in greater Chicago, northwest Indiana and southwest Michigan areas.