Skip to main content
Learning Center

HVAC, in plain English.

Definitions, decision guides, maintenance know-how, and honest cost answers — written by Delta T technicians for Kansas City homeowners. 33 HVAC terms defined and growing.

Most-asked HVAC terms

Start with the basics

All 33 terms

AFUE (Annual Fuel Utilization Efficiency)

The percentage of fuel a furnace converts into usable heat over a typical year. An 80% AFUE furnace turns 80 cents of every $1 of gas into heat; the other 20 cents leaves through the flue.

Read full definition

SEER2

The current efficiency rating for residential air conditioners and heat pumps in cooling mode — higher is more efficient. SEER2 replaced the older SEER rating in 2023; a SEER2 number is ~5% lower than the old SEER on the same unit because the test conditions are stricter.

Read full definition

HSPF2 (Heating Seasonal Performance Factor)

The efficiency rating for heat pumps in heating mode — higher is more efficient. Like SEER2, HSPF2 replaced HSPF in 2023 with stricter test conditions, so HSPF2 numbers are ~15% lower than the old HSPF on the same unit.

Read full definition

BTU (British Thermal Unit)

The unit of heat used to size HVAC equipment. One BTU is the heat required to raise one pound of water by one degree Fahrenheit. A typical 2,000 sq ft KC home needs around 24,000–36,000 BTU/h of cooling and 40,000–80,000 BTU/h of heating, depending on insulation, windows, and orientation.

Read full definition

Ton (of cooling)

The capacity unit for air conditioners and heat pumps in cooling mode. One ton = 12,000 BTU/h. A 3-ton AC delivers 36,000 BTU/h of cooling.

Read full definition

Load calculation (Manual J)

The engineering math that determines what size HVAC system your home actually needs, room by room. Manual J is the industry-standard procedure published by ACCA; running it before quoting a replacement is the difference between a system sized to your home and a system sized to what's stacked on the truck.

Read full definition

Every article, grouped

35 in-depth articles by section.

HVAC 101, maintenance, cost & sizing, troubleshooting, the compare-and-decide guides, and plan-and-act playbooks — written by Delta T engineers for Kansas City homeowners.

35 articles6 sections · Written by Delta T engineers · Updated regularly

HVAC 101

How a furnace, AC, and heat pump actually work in a KC home — written for non-technicians who want a real answer.

7 articles
HVAC 1017 min

How a Heat Pump Works in a Kansas City Winter

Heat pumps confuse a lot of KC homeowners — including some HVAC techs. Here is how they actually work in a Kansas City winter, where their efficiency falls off, and how to plan for the 10–20 nights a year that go below 20°F.

Read article
HVAC 1017 min

Indoor Air Quality in Older KC Homes — What Actually Helps

Indoor air in older KC homes is genuinely worse than newer construction — pollen, dust mites, humidity, and aging duct systems all stack up. Here is what actually fixes it in tiers, and what is mostly sales theater.

Read article
HVAC 1016 min

How Long Furnaces, ACs & Heat Pumps Last in Kansas City

KC equipment ages faster than the brochure says, because our summers and winters both push it hard. Here are the honest lifespan ranges we see in the field, what shortens or extends them, and when age alone should start your replacement planning.

Read article
HVAC 1017 min

Upstairs Hot, Downstairs Cold? The Kansas City 2-Story Fix

The hot-upstairs problem is the number-one comfort complaint in KC two-story homes, and the expensive fix is not always the right one. Here's why it happens and the fix ladder in honest order: damper balancing, return-air fixes, zoning, then a mini-split.

Read article
HVAC 1017 min

Why Your House Feels Humid With the AC On in Kansas City

Kansas City summers are as much a moisture problem as a heat problem. If your home feels clammy at 72°F, the AC is probably winning the temperature battle and losing the humidity one. Here's why — and the fixes that don't involve just setting it colder.

Read article
HVAC 1017 min

Dry Winter Air in Kansas City: Do You Need a Humidifier?

Static shocks, cracked knuckles, wood floors opening gaps — KC winter dryness is real physics, not a furnace defect. Here's why heated winter air goes desert-dry, the 30–40% target that fixes it, and an honest comparison of bypass, fan, and steam humidifiers.

Read article
HVAC 1017 min

Are Mini-Splits Good for Kansas City Homes? Where They Fit

Ductless mini-splits are the right answer to certain KC comfort problems and the wrong answer to others. Here is what they are, exactly where they win in Kansas City's housing stock, and where central systems still make more sense.

Read article

Maintenance Guides

What a real tune-up includes, what's worth doing yourself, and how often to call a tech for what.

3 articles

Cost & Sizing

What HVAC equipment costs, what sizing actually means (Manual J), and which efficiency upgrades pay back in KC.

4 articles

How-Tos

Step-by-step homeowner troubleshooting before calling — thermostat, filter, breaker, condensate line.

6 articles
How-to5 min

AC Not Cooling in a KC Summer? Try This Before You Call

In a KC heat wave, AC service slots fill up fast. Walk through this 5-step homeowner checklist before you book — half the time it solves the problem in under 15 minutes.

Read article
How-to5 min

Furnace Won't Heat? KC Homeowner Diagnostic Guide

Furnace out on a cold KC morning? Walk this 6-step diagnostic before you call. Half of "no heat" calls in our service area come down to a tripped switch, a clogged filter, or a flipped breaker.

Read article
How-to6 min

Why Your AC Freezes Up in Kansas City & How to Thaw It

Ice on your AC in the middle of a KC heat wave feels backwards, but the cause is simple physics: starved airflow or low refrigerant. Here is the thaw-it-first protocol, what you can safely check yourself, and where DIY ends.

Read article
How-to6 min

Furnace Short Cycling in Kansas City: Causes and Fixes

Short cycling wastes gas, wears out parts, and never quite heats the house. The causes run from a five-minute filter fix to a sizing problem baked in on install day. Here they are in order of likelihood, with what's safely yours to check.

Read article
How-to7 min

Furnace and AC Noises Explained: A Kansas City Sound Guide

Your HVAC system narrates its own problems if you know the language. Here is what squealing, grinding, clicking, buzzing, banging, and gurgling each mean — and which sounds mean turn it off right now versus book a normal visit.

Read article
How-to6 min

EM Heat vs Aux Heat: What They Mean on a KC Thermostat

That EM HEAT setting confuses more KC heat-pump owners than any other button on the thermostat. Here is the difference between aux and emergency heat, when each one should run, and why flipping EM heat by choice is the most expensive mistake you can make.

Read article

Compare & Decide

Side-by-side breakdowns: heat pump vs gas furnace, repair vs replace, dual-fuel vs all-electric.

10 articles
Compare & decide8 min

Heat Pump vs Gas Furnace for KC Homes — The Real Math

Heat pump or gas furnace — which actually makes sense for a Kansas City home? Here is the unfiltered decision framework with real climate math, upfront-cost ranges, and the dual-fuel hybrid option most KC homes should at least consider.

Read article
Compare & decide6 min

Repair vs Replace Your AC — The 5,000 Rule + KC Reality Check

Got a big AC repair quote and trying to decide whether it's worth the money? Here is the simple 5,000 rule plus the real KC-specific factors that should actually drive the call.

Read article
Compare & decide6 min

Dual-Fuel Systems in KC — When the Hybrid Setup Makes Sense

Dual-fuel pairs a heat pump with a gas furnace and switches between them based on outdoor temperature and operating cost. For a lot of KC homes it is the right answer — but it has to be set up correctly.

Read article
Compare & decide7 min

Single-Stage vs Two-Stage vs Variable-Speed AC in KC

Every AC and heat pump quote now comes in three flavors: single-stage, two-stage, and variable-speed. Here is what each one actually does, who feels the difference in a KC summer, and who should keep their money.

Read article
Compare & decide7 min

Furnace Repair vs Replace — The KC Decision Framework

A big furnace repair quote in the middle of a KC cold snap is the worst time to make a ten-year decision. Here is the age-times-cost framework, the cracked-heat-exchanger special case, and how to plan the replacement instead of panic-buying it.

Read article
Compare & decide7 min

Mini-Split vs Central HVAC for Kansas City Homes

Whole-home ducted system or zone-by-zone ductless heads? Where each one wins in Kansas City, how multi-zone mini-split quotes quietly balloon, and the hybrid setup that's often the honest answer.

Read article
Compare & decide6 min

Tank vs Tankless Water Heater for KC Homes

Endless hot water sounds like an easy yes — until you price the gas-line and venting work, and meet KC's hard water. Here is the honest tank-vs-tankless comparison, including who should absolutely keep a tank.

Read article
Compare & decide6 min

Smart vs Programmable Thermostat — What Saves Money in KC

Do you need the app-connected learning thermostat, or does a basic programmable do the same job? Here is what each one actually does, the heat-pump trap that can make setbacks backfire, and which KC homes get real value from going smart.

Read article
Compare & decide7 min

Does HVAC Brand Matter? Brand vs Installer in KC

"What brand do you carry?" is the first question most homeowners ask — and it's the wrong one. Here is what genuinely differs between HVAC brands, why installation quality decides the outcome, and the checklist for vetting an installer in KC.

Read article
Compare & decide7 min

Air Filter vs UV Light vs ERV — Which IAQ Upgrade for KC?

IAQ add-ons get sold as interchangeable magic boxes. They aren't. Here is the capture / kill / dilute framework, which symptom each one actually fixes in a KC home, and the most common way homeowners buy the wrong category.

Read article

Plan & Act

You've decided — now do it right: reading quotes, prepping for install day, emergency triage, financing questions to ask.

5 articles