Learning Center
HVAC & plumbing terms, in plain English.
Half our job is teaching. Here are the ratings and terms you'll see in our guides and on any quote you receive — defined without the jargon.
- SEER2Seasonal Energy Efficiency Ratio 2
- The current standard for rating air-conditioner and heat-pump cooling efficiency. Higher is more efficient — and cheaper to run all summer.
- HSPF2Heating Seasonal Performance Factor 2
- The heating-efficiency rating for heat pumps. A higher HSPF2 means more heat delivered per unit of electricity used.
- AFUEAnnual Fuel Utilization Efficiency
- The percentage of fuel a furnace turns into usable heat. A 96% AFUE furnace wastes only about 4% of the fuel it burns.
- MERVMinimum Efficiency Reporting Value
- How well an air filter captures particles. A higher MERV catches finer dust and allergens — but too high for your system can choke airflow.
- HEPAHigh-Efficiency Particulate Air
- A filtration standard that captures 99.97% of particles at 0.3 microns. Used in high-end air cleaners for allergy and asthma relief.
- UEFUniform Energy Factor
- The standard efficiency rating for water heaters. A higher UEF means lower operating cost over the heater's life.
- AHJAuthority Having Jurisdiction
- The local building department — city, village, or county — that issues permits and inspects work. In our area it varies by town across Lake and Cook County.
- R-454B
- The lower-global-warming refrigerant replacing R-410A in new AC and heat-pump systems as part of the 2025 transition. It affects what equipment gets installed today.
- Flat-rate pricing
- One upfront price for the job, quoted and approved before any work begins — not an open-ended hourly meter. No surprises on the invoice.
- Trenchless
- Sewer-line repair or replacement methods — like pipe lining or pipe bursting — that fix the line with little or no digging, sparing your yard and driveway.
- Mini-split
- A ductless heat pump with an outdoor unit and one or more indoor units. Heats and cools specific rooms without ductwork — ideal for older homes and additions.
- BTUBritish Thermal Unit
- The basic measure of heating or cooling capacity. Sizing a system to the right BTU load for your home — not just bigger — is what makes it comfortable and efficient.
Keep learning
Put these terms to work in a guide
Still unsure what something means?
Ask us — we'd rather teach than sell.
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