Air Duct Cleaning Glossary

This glossary breaks down the key air duct cleaning terms every Somerville homeowner should know in plain English. Learn what these terms mean for your HVAC system, indoor air quality, and energy bills—so you can make confident decisions about keeping your home’s air clean and your system running smoothly.

If you’re new to owning a home in Somerville, terms like SEER rating or AFUE might feel confusing. Don’t worry—this straightforward glossary explains the most important air duct cleaning and HVAC terms you’ll encounter when maintaining your system. Whether you’re comparing services, checking pricing, or deciding whether your ducts need attention, these definitions will help you understand what’s really going on inside your walls. We’ve also included links to local resources like air duct cleaning in Cambridge and our team so you can explore next steps with confidence.

SEER rating

SEER stands for Seasonal Energy Efficiency Ratio. It measures how efficiently your air conditioner or heat pump cools your home over an entire season. The higher the SEER number, the less energy it uses to keep you comfortable. In Somerville’s humid summers, a higher SEER can mean lower electric bills and a cooler indoor climate without overworking your system.

AFUE

AFUE stands for Annual Fuel Utilization Efficiency. It tells you how efficiently your furnace or boiler converts fuel into heat. Expressed as a percentage, a 90% AFUE means 90 cents of every dollar spent on fuel becomes heat for your home. For older Somerville homes with drafty ductwork, upgrading to a high-AFUE system can cut heating costs significantly.

Heat pump

A heat pump is a two-way HVAC system that both heats your home in winter and cools it in summer. It moves heat from one place to another instead of burning fuel. In Somerville’s mild winters and hot summers, a heat pump can be a cost-effective, all-in-one solution—especially if your ducts are clean and well-sealed.

Air handler

The air handler is the indoor part of your HVAC system that circulates air through your home. It contains the blower fan, evaporator coil, and air filter. If your air handler is dirty or clogged, it can’t move air efficiently, which leads to uneven temperatures and higher energy bills. Regular cleaning helps keep Somerville’s dust and pollen out of your living spaces.

Condenser

The condenser is the outdoor unit of your air conditioning or heat pump system. It releases heat absorbed from inside your home into the outside air. If it’s clogged with Somerville’s summer dust or debris, your system will struggle to cool your home and may run longer than necessary—driving up your electric bill.

Evaporator coil

The evaporator coil is the indoor component that absorbs heat from your home’s air, turning refrigerant from liquid to gas and cooling the air before it circulates through your ducts. Over time, this coil can collect mold, dust, and grime—especially in Somerville’s humid climate—reducing efficiency and spreading contaminants. Cleaning it is a key part of whole-home air duct cleaning.

Refrigerant

Refrigerant is the chemical compound that absorbs and releases heat as it circulates through your HVAC system. If your system is low on refrigerant, it won’t cool your home properly and may run constantly, increasing energy use. In Somerville, where summer heat can be intense, low refrigerant can also shorten your AC’s lifespan—so leaks should be fixed promptly.

BTU

BTU stands for British Thermal Unit. It measures the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit. In HVAC terms, BTU ratings tell you how much heating or cooling power an appliance delivers. For Somerville homes, choosing the right BTU capacity ensures your system runs efficiently without wasting energy or leaving rooms too hot or cold.

Ductwork

Ductwork is the network of tubes that carries heated or cooled air from your HVAC system to every room in your Somerville home. Over time, ducts can accumulate dust, mold, pet dander, and even pests. Leaky or dirty ducts reduce airflow, lower indoor air quality, and force your system to work harder—leading to higher bills and uneven temperatures.

Zoning

Zoning divides your home into separate temperature-controlled areas using dampers in the ductwork and multiple thermostats. It lets you heat or cool only the rooms you’re using, saving energy and improving comfort. In Somerville’s older homes with drafty spaces, zoning can help balance temperatures and reduce the strain on your HVAC system.

MERV rating

MERV stands for Minimum Efficiency Reporting Value. It rates how well an air filter traps particles like dust, pollen, and pet dander. A higher MERV (9–12) captures smaller particles and improves indoor air quality—important in Somerville where seasonal allergies and urban pollution can affect your family’s health. Just make sure your system can handle a high-MERV filter without restricting airflow.

Load calculation (Manual J)

Manual J is the industry-standard method for calculating how much heating or cooling your home needs based on its size, insulation, windows, and local climate. A proper load calculation ensures your HVAC system is sized correctly for your Somerville home—not too big (which wastes energy) or too small (which struggles to keep you comfortable). Many older homes are oversized, leading to inefficiency and poor humidity control.

Thermostat setback

Thermostat setback is the practice of lowering (in winter) or raising (in summer) your thermostat when you’re asleep or away from home. Programmable or smart thermostats make this automatic, helping you save energy without sacrificing comfort. In Somerville’s four distinct seasons, setback can reduce your HVAC bills by 10–15% while keeping your home cozy.

Short cycling

Short cycling happens when your HVAC system turns on and off too frequently, never completing a full heating or cooling cycle. It’s often caused by a dirty air filter, low refrigerant, or an oversized system. In Somerville homes, short cycling can lead to higher energy bills, uneven temperatures, and excessive wear on your system—so it’s important to diagnose and fix the root cause.

Duct cleaning

Duct cleaning removes built-up dust, mold spores, pet dander, and other debris from your home’s HVAC ductwork. Over time, these contaminants circulate through your air, lowering indoor air quality and forcing your system to work harder. In Somerville’s humid climate, mold growth in ducts is a common issue—so regular cleaning helps protect your family’s health and your HVAC’s efficiency.

Ventilation

Ventilation is the process of bringing fresh outdoor air into your home while expelling stale indoor air. Good ventilation prevents stuffiness, reduces indoor pollutants, and controls humidity—especially important in Somerville’s older, tightly sealed homes. Without proper ventilation, your ducts can become breeding grounds for mold and bacteria.

HEPA vacuum

A HEPA vacuum uses a high-efficiency particulate air filter to trap 99.97% of particles as small as 0.3 microns—including dust, pollen, and mold spores. Professional duct cleaners use HEPA vacuums to ensure debris is captured and not released back into your Somerville home during cleaning. It’s the gold standard for protecting indoor air quality after ductwork maintenance.

Frequently Asked Questions