So you’re on the web, exploring and investigating your options for replacing your heating and cooling system. And you come across all these mysterious words in ALL CAPS. They sound important, but what exactly do they mean? What are you getting yourself into?
We explained quite a few common acronyms in Part 1, but here's a few more to help you understand the jargon in the HVAC industry, including IAQ products (that’s Indoor Air Quality... FYI).
The Annual Fuel Utilization Efficiency (AFUE) is a thermal efficiency measure of combustion equipment like furnaces, boilers, and water heaters. The AFUE differs from the true ‘thermal efficiency’ in that it is not a steady-state, peak measure of conversion efficiency, but instead attempts to represent the actual, season-long, average efficiency of that piece of equipment, including the operating transients. It is a dimensionless ratio of useful energy output to energy input, expressed as a percentage. For example, a 90% AFUE for a gas furnace means it outputs 90 BTUs of useful heating for every 100 BTUs of Natural Gas input (where the rest may be wasted heat in the exhaust). A higher AFUE means higher efficiency.
Electronically commutated motors (ECMs) were developed to offer a greater range of operability choices, and to minimize noise in an HVAC system. ECMs are variable speed, DC voltage motors that function using a built-in inverter and a magnet rotor, and as a result are able to achieve greater efficiency in air-flow systems than some kinds of AC motors and can reduce operating costs. (Although AC voltage is used to supply power to an ECM, it’s internal rectifier converts the current to DC). Additionally, ECMs are not prone to overheating and are also relatively low-maintenance; the use of true ball bearings reduces the need for oiling, and varied start-up speeds reduce stress on mounting hardware.
An energy efficient motor (EEM) is one which consumes less power while it is in operation as compared to a standard motor. EEMs run at a constant speed and are characterized by cost efficiency, lower operating cost, and lower demand charges and are also suitable for operations at higher ambient temperatures. EEMs run an AC power and perform better than normal motors under adverse conditions like unbalanced voltages.
High Efficiency Particulate Arresting (HEPA) filters are a type of air filter that have a high efficiency at arresting, or capturing particles. It is not a brand or manufacturer. True HEPA air filters are 99.97% effective in capturing particles as small as 0.3 microns, and a micron is 1/10,000th of a centimeter. This is as efficient and effective as an air filter gets. If you suffer from allergies or simply want to breathe clean air, then a HEPA air filter system is what you are looking for.
The Minimum Efficiency Reporting Value (MERV) is a measurement scale designed to rate the effectiveness of air filters. The scale allows for improved health, reduced cost and energy efficiency in HVAC design. For example, a HEPA filter is often impractical if placed in a standard central HVAC system due to the large pressure drop that the dense filter material causes. Experiments indicate that less obstructive, medium-efficiency filters of MERV 7 to 13 are almost as effective as true HEPA filters at removing allergens, with much lower associated system and operating costs. The MERV rating is from 1 to 16. Higher MERV ratings correspond to a greater percentage of particles captured on each pass, with a MERV 16 filter capturing more than 95% of particles down to 0.3 microns.
North American Technician Excellence (NATE) is an independent organization that certifies installation and service technicians with a knowledge-based test. Organizations that are part of the NATE coalition include the U.S. Environmental Protection Agency and American Society of Heating, Refrigeration and Air-Conditioning Engineers. To become a NATE certified installation and/or service technician, a technician must pass both the core part and a specialty part of either an installation or service test with a score of 70% or better. Specialties include heat pump, air conditioning, air distribution, oil heat and gas heat. The NATE test is not easy, and not all technicians pass it the first time. NATE certification verifies that the technicians who pass are the best in the trade when it comes to knowledge and experience installing or servicing your home heating or cooling system.
R22, also called Freon, is a refrigerant of hydro-chlorofluorocarbon (HCFC) which has been used for many years in industrial cooling, air-conditioning and heating applications. The chlorine component of R22 is an element known to damage the ozone layer of the earth’s atmosphere and therefore the use of R22 refrigerant has been severely limited and will soon be completely banned.
R410A is a 50/50 blend of two hydro-fluorocarbon (HFC) refrigerants. Because it does not contain chlorine most HVAC equipment manufacturers are now embracing the use of this refrigerant.