Including smart thermostats — Jake explains how the “brain” of your system really works
If your HVAC system were a truck, the thermostat would be the steering wheel.
Not the engine. Not the fuel. But the part that decides where you’re going and how aggressively you get there.
I’ve seen brand-new Goodman systems struggle because of one cheap thermostat installed wrong.
And I’ve seen older systems run beautifully because the thermostat was dialed in perfectly.
This guide breaks down:
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How thermostats actually control comfort
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How to check and improve accuracy
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Common calibration mistakes
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Smart thermostat realities (the good and the bad)
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Simple maintenance steps that prevent comfort complaints
No fluff. No sales hype. Just control logic and common sense.
🎯 Why the Thermostat Matters More Than You Think
Your thermostat controls:
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When heating or cooling starts
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How long cycles run
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How often the system stops and restarts
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Whether your system short-cycles or runs smoothly
A poorly set thermostat can cause:
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Temperature swings
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High utility bills
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Uneven comfort
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Excessive system wear
Jake’s rule:
If comfort feels inconsistent, check the thermostat before blaming the equipment.
🌡️ Understanding Thermostat Accuracy (Calibration Basics)
Most homeowners assume:
“If it says 72°F, it must be 72°F.”
That’s not always true.
🔍 How Inaccuracy Happens
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Age and sensor drift
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Poor mounting location
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Sunlight exposure
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Drafts from returns or doorways
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Internal dust buildup
Even a 2–3°F error can cause longer run times and discomfort.
🧪 How to Check If Your Thermostat Is Accurate
🛠️ What You Need
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A reliable digital thermometer
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10–15 minutes of stable room conditions
✅ Step-By-Step
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Place thermometer next to thermostat
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Wait 10 minutes
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Compare readings
If the difference is more than 2°F, calibration or relocation may be needed.
🔧 Calibrating a Traditional (Non-Smart) Thermostat
Many older thermostats allow manual calibration.
⚙️ Common Calibration Methods
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Adjustment screw behind the cover
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Offset setting in internal menu
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Mechanical anticipator arm (very old models)
Important:
Not all thermostats are adjustable. Some must be replaced if inaccurate.
👉 U.S. DOE thermostat basics:
https://www.energy.gov/energysaver/programmable-thermostats
📍 Thermostat Placement: The Silent Comfort Killer
Where your thermostat lives matters as much as how it’s programmed.
❌ Bad Locations
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Direct sunlight
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Near supply vents
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Exterior walls
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Kitchens
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Hallways with drafts
✅ Ideal Location
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Interior wall
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Average room temperature
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About 5 feet above the floor
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Away from heat sources
Jake’s rule:
A thermostat should feel the house — not the weather or the oven.
🔄 Cycle Rate & Differential: Why Systems Short-Cycle
Thermostats decide how often your system runs.
🧠 Key Terms (Plain English)
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Cycle rate: How often the system can turn on per hour
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Differential: How far temp drifts before the system reacts
Too tight = short cycling
Too loose = temperature swings
Most homeowners never touch these — but they matter.
📱 Smart Thermostats: Helpful Tool or Overcomplication?
Smart thermostats can be great — if installed and configured correctly.
👍 Benefits
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Scheduling automation
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Remote access
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Energy usage insights
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Learning behavior (sometimes)
⚠️ Common Problems I See
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Over-aggressive “learning”
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Excessive cycling
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Incorrect system type setup
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Wi-Fi dropouts causing lockouts
👉 Energy Star smart thermostat overview:
https://www.energystar.gov/products/smart_thermostats
🔌 Compatibility Matters (Especially With Goodman Systems)
Before installing a smart thermostat, confirm:
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Proper voltage (24V control)
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Heat type (gas, electric, heat pump)
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Staging compatibility
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C-wire availability
Incorrect setup can cause:
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No heat
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No cooling
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Constant fan operation
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Control board errors
👉 Goodman compatibility resources:
https://www.goodmanmfg.com/resources
🧼 Thermostat Maintenance (Yes, It’s a Thing)
Thermostats collect dust — especially older models.
🧽 Simple Maintenance Steps
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Remove cover annually
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Gently blow out dust
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Check wiring connections
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Replace batteries yearly (if applicable)
Dust can insulate sensors and skew readings.
🔋 Battery vs Hard-Wired Thermostats
🔋 Battery-Powered
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Easy install
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Needs regular battery replacement
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Low battery can cause system failure
🔌 Hard-Wired
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More reliable
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Requires C-wire
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Preferred for smart thermostats
Jake’s rule:
Dead batteries cause more “no heat” calls than bad furnaces.
🌙 Scheduling for Comfort (Not Just Savings)
Schedules should match how you live — not just energy goals.
❌ Over-Aggressive Setbacks
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Long recovery times
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Comfort complaints
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System strain
✅ Smarter Scheduling
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Small setbacks (3–5°F)
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Consistent wake/sleep patterns
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Minimal weekday/weekend changes
👉 EPA indoor comfort guidance:
https://www.epa.gov/indoor-air-quality-iaq
🚨 Signs Your Thermostat Is the Problem
Watch for:
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System runs but doesn’t hit setpoint
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Frequent on/off cycling
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Fan runs constantly
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Display resets or blanks
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Temperature feels wrong compared to display
When in doubt, bypassing the thermostat temporarily can isolate the issue — but that’s a pro move, not a homeowner task.
🧠 What Homeowners Should NOT Attempt
Avoid:
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Jumpering terminals randomly
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Rewiring without diagrams
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Changing installer-only settings blindly
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Mixing smart thermostats with incompatible systems
👉 ACCA control & system standards:
https://www.acca.org/standards
📅 When to Replace a Thermostat
Consider replacement if:
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Calibration can’t be corrected
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Display is inconsistent
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Buttons don’t respond
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System upgrades require compatibility
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Comfort complaints persist
A good thermostat should last 10–15 years, but technology moves faster than hardware.
🧠 Jake’s Final Word: Comfort Is a Control Problem First
Before blaming:
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The furnace
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The AC
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The refrigerant
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The ductwork
Check the thermostat.
Because when the brain is confused, the body follows bad instructions.
Dial it in.
Mount it right.
Program it realistically.
Do that — and even the best HVAC system finally gets a chance to do its job right.
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In the next topic we will know more about: DIY Tools Every HVAC Owner Should Have (and How to Use Them)
