Well there are a few differences when it comes to 80% and 90% systems. First and foremost efficiency. With the use of a 80% you are losing 20% of heat energy through your exhaust... while a 90% unit will lose anywhere from 5% to 10% depending on which unit you purchase. Loss of energy equates to loss of energy dollars. It also dictates what your annual energy bills are going to be.
The features between these systems vary as well, primarly the blower motors. A 80% furnance will operate at a single speed giving you its full capacity while it operates. While that is fine on the coldest days, it's wasteful during warmer temperatures. Although 2 stage 80% technology is available and will operate more efficiently. When it comes to 90%+ systems the technology is far more efficient. Many of these units come with ECM blower motors or electronically commicated blower motors which run continously at various speeds, thus slowly and evenly heat your home... giving you excellent ambient temperature inside your home not to mention your fuel utilization will give you excellent savings. Keep in mind also, these high efficient systems along with higher SEER ratings will generally come with excellent rebates and tax benefits as well. But we must also mention the cost of these units can be significantly higher but the long term benefits and savings make them an extrememly prudent choice!
A furnace with single stage operation has a fixed gas valve and a single speed blower motor. A two stage model has a two stage gas valve, a multiple speed motor. This allows the furnace to run at at lower speed in milder weather and at full capacity in colder weather. Two stage technology also saves energy which will allow you to save money on heating costs.
Variable speed technology enables your heating or cooling system to adjust its output based on the needs or ambient temperature in your homes. A huge advantage when it comes to energy costs! It’s a Verifiable fact that using variable speed technology running continuously at half speed will use up to 75% less power than a single stage motor used to move the same air additionally. Benefits include less temperature swings, excellent ambient comfort, dehuidification benefits.
A modulating furnance is a furnance that slowly ramps up and down in accordance to room temperatures. WITH this type of unit the flame itself increases or decreased in very minor increments so that the room temperature never varies more than a few degees based on thermostat settings. Bare in mind they do run more frequently but are considered to be more efficient than single or two stage furnances.
AFUE means Annual Fuel Utilazation Effiiency, It's the measure by which we speak of when it come to space heating, furnances, and boilers.
Anything over 79% 90+ is considered a better rating. 95+ is a superior rating.
HSPF is Heating Seasonal Performance Factor. In Layman's terms, the more efficient your heat pump is, which will result in less energy use, The larger the savings will be in and over the life of your system.
Manufacturers develop their HVAC systems, indoor and outdoor to work in unison. These are called matched systems, coils, wiring, and blower motors need to be compatible for optimum performance and greater ambient temperature.
A single zone mini-split system, in the most convenient definition term, is a two component air handling unit with indoor unit and condenser (outside). These systems can be used in residential, commercial, or industrial applications. Bear in mind also, that these systems have what we in the industry call conduits. These conduits encase power cables, suction tubes, and refrigerant for cooling.
A multi zone mini-split system contains two or more mini-split units or air handlers which are connected to a single outdoor compressor. Typically, a multi zone mini-split compressor can connect to eight indoor units.
