OneSDR contains affiliate links and is a member of the Amazon Services LLC Associates Program, eBay affiliate program, Etsy Affiliate Program. If you make a purchase using one of these links, we may receive compensation at no extra cost to you. This helps support our research, testing and writing.

Ecobee Not Heating to Set Temperature: How to Fix It

My Ecobee thermostat showed 68°F as the set temperature, but my house stayed at 63°F. The heat ran constantly but never reached the target. I checked the thermostat display – it showed “Heating” with the flame icon, but nothing changed after an hour. This happened during a cold snap last January when I needed reliable heat most.

I spent that evening methodically testing different fixes, starting with the simplest possibilities and working toward more complex solutions. After checking settings, wiring, and system compatibility, I discovered multiple small issues combining to prevent proper heating.

Here’s the complete troubleshooting process, organized from easiest fixes to more involved solutions, so you can solve your heating problem efficiently.

Understanding Why Ecobee Shows Temperature But Won’t Heat

Before troubleshooting, I needed to understand what should happen during normal heating.

Normal heating process:

When room temperature drops below set temperature:

  • Ecobee calls for heat
  • Sends signal to heating system
  • Furnace or boiler activates
  • Heated air or water circulates
  • Room temperature rises
  • System shuts off when temperature reaches set point

Common failure points:

The system can fail when:

  • Thermostat settings prevent heating
  • Wiring connections are loose or incorrect
  • Heating system itself has problems
  • Power supply is inadequate
  • Sensors read temperature incorrectly
  • Smart features interfere with normal operation

Temperature difference expectations:

Normal temperature variance:

  • 1-2°F below set point: Normal during cold weather
  • 2-3°F below: System struggling but might be normal
  • 3-5°F below: Definite problem exists
  • 5°F+ below: Serious issue requiring immediate attention

My situation: Set temperature 68°F, actual temperature 63°F. This 5-degree gap indicated a real problem, not normal system behavior.

Check Current Temperature Display

Start with the simplest verification.

What to check on thermostat:

  • Set temperature (what you want)
  • Current temperature (what sensors read)
  • Heating mode active (flame icon showing)
  • System status (should say “Heating”)

On my Ecobee:

  • Set temperature: 68°F
  • Current temperature: 63°F
  • Mode: Heat
  • Status: “Heating” with flame icon
  • Everything looked correct on the display

Verify room actually feels cold:

  • Walk around different rooms
  • Check if some rooms warmer than others
  • Feel air coming from vents
  • Confirm problem is real, not sensor error

My house genuinely felt cold in all rooms, confirming this wasn’t just a sensor reading problem.

Verify Thermostat Is in Heat Mode

Sometimes the simplest explanation is correct – wrong mode selected.

Check current mode:

  • Tap thermostat screen to wake it
  • Look at main screen
  • Check which mode is active
  • Should show “Heat” not “Cool” or “Off”

Changing to Heat mode:

  • Tap on thermostat screen
  • Find mode selector (usually at bottom)
  • Options: Heat, Cool, Auto, Off
  • Select “Heat”
  • Confirm selection

Understanding mode options:

Heat mode:

  • Only heating runs
  • Most reliable for cold weather
  • Use this during winter

Cool mode:

  • Only cooling runs
  • System won’t heat at all
  • Wrong choice for winter

Auto mode:

  • Switches between heating and cooling automatically
  • Can cause problems if thresholds set incorrectly
  • Not recommended unless you understand settings

Off mode:

  • No heating or cooling
  • Fan may still run if set to
  • Obviously wrong if you need heat

My situation: Mode was correctly set to “Heat” so this wasn’t the problem. But checking this takes 10 seconds and solves many issues.

Turn Up Temperature Significantly

Test if system responds at all.

Why this test matters:

  • Eliminates uncertainty
  • Forces system to run
  • Reveals if heating works at all
  • Quick diagnostic test

How to perform test:

  • Note current temperature (example: 63°F)
  • Note current set temperature (example: 68°F)
  • Increase set temperature by 5-10 degrees (to 75°F or 78°F)
  • Wait 5 minutes
  • Listen for heating system to start
  • Feel vents for warm air
  • Check if temperature rises at all

Interpreting results:

Temperature starts rising:

  • Heating system works
  • Problem is with settings or calibration
  • Continue to settings-related solutions

Temperature doesn’t change:

  • Heating system not responding
  • Problem is with wiring, power, or furnace
  • Continue to hardware-related solutions

Temperature rises slowly:

  • System working but undersized or struggling
  • May need furnace service
  • Check air flow and filters

My test results: After raising temperature to 78°F, I heard furnace start within 2 minutes. Temperature rose from 63°F to 64°F over 10 minutes, then stalled. This told me heating worked but something limited its effectiveness.

Check Hold Settings and Schedules

Ecobee’s smart features sometimes work against you.

Understanding holds:

Temporary hold:

  • Overrides schedule until next scheduled change
  • Might be set without you realizing
  • Can prevent temperature from reaching set point

Permanent hold:

  • Overrides schedule indefinitely
  • Stays until you manually cancel
  • Common cause of temperature issues

Checking for active holds:

  • Look at main screen
  • Check for “Hold” message
  • See if hold temperature differs from desired temperature
  • Note if “Hold” or “Hold Until” appears

Removing holds:

  • Tap thermostat screen
  • Look for “Remove Hold” or “Cancel Hold” option
  • Tap to remove
  • Confirm removal
  • Set temperature to desired level

Checking schedule settings:

View current schedule:

  • Main menu
  • Tap Settings
  • Select Schedule
  • Review times and temperatures

Common schedule problems:

Setback too low:

  • Schedule sets temperature to 60°F during day
  • You manually increased to 68°F
  • Next schedule change drops it back to 60°F
  • Appears like thermostat won’t reach temperature

Wrong schedule active:

  • Away schedule running when you’re home
  • Sleep schedule during daytime
  • Vacation mode still active

How to adjust schedule:

  • Settings
  • Schedule
  • Select period to edit (Wake, Day, Evening, Sleep)
  • Set desired temperature for each period
  • Save changes
  • Verify schedule matches your routine

Disabling schedule temporarily:

  • Settings
  • Schedule
  • Turn off “Enable Schedule”
  • Set manual temperature
  • Test if this solves problem

My situation: I found “Hold Until 5:00 PM” was active, set to 65°F. This explained why temperature wouldn’t go above 65°F despite my setting 68°F. Removing the hold allowed temperature to rise properly.

Disable Smart Home/Away

Smart occupancy detection can interfere with heating.

What Smart Home/Away does:

  • Uses motion sensors to detect presence
  • Automatically adjusts temperature when you leave
  • Returns to normal when you arrive
  • Designed to save energy but can malfunction

Problems with Smart Home/Away:

False absence detection:

  • Thermostat thinks you’re away
  • Lowers temperature automatically
  • Even though you’re home
  • Common if you’re sitting still (reading, watching TV)

Wrong thresholds:

  • Away temperature set too low
  • Home temperature set incorrectly
  • Doesn’t return to proper temperature quickly

How to disable Smart Home/Away:

  • Main menu on thermostat
  • Settings
  • Preferences
  • Smart Home/Away
  • Toggle OFF
  • Confirm change

Alternative: Adjust sensitivity:

If you want to keep feature but fix problems:

  • Settings
  • Smart Home/Away
  • Adjust motion sensitivity
  • Change temperature thresholds
  • Modify delay times

Testing after disabling:

  • Disable Smart Home/Away
  • Set desired temperature manually
  • Wait 30 minutes
  • Check if temperature rises properly
  • If yes, Smart Home/Away was the problem

My experience: Smart Home/Away wasn’t causing my problem, but I’ve seen it cause issues for others. Disabling this feature solved heating problems for a friend whose thermostat thought he was away while he sat reading in another room.

Check Temperature Correction Setting

Ecobee allows temperature calibration that can cause confusion.

What Temperature Correction does:

  • Adjusts displayed temperature
  • Compensates for sensor placement
  • Can make thermostat read higher or lower than actual
  • Useful if sensor in unusually warm or cold spot

How correction causes problems:

If correction set to +3°F:

  • Room temperature actually 65°F
  • Thermostat displays 68°F (65 + 3)
  • Thinks target reached so stops heating
  • Room never actually reaches desired temperature

Checking correction setting:

  • Settings menu
  • Installation Settings
  • Thresholds
  • Temperature Correction
  • Note current value

Typical correction values:

  • 0°F: No correction (normal)
  • +1 to +3°F: Sensor reads too cold, correcting up
  • -1 to -3°F: Sensor reads too warm, correcting down
  • Values outside this range unusual

Resetting to zero:

  • Settings
  • Installation Settings
  • Thresholds
  • Temperature Correction
  • Change to 0°F
  • Save setting

Testing after reset:

  • Wait 5 minutes for change to take effect
  • Check displayed temperature
  • Set desired temperature
  • Monitor if heating reaches target

When correction is actually needed:

Use correction if:

  • Thermostat in unusually warm spot (near lamp, sunny wall)
  • Thermostat in unusually cold spot (exterior wall, drafty area)
  • Temperature varies significantly from room comfort
  • Verified with separate thermometer

My finding: Temperature Correction was set to 0°F so this wasn’t my issue. But this setting causes problems if someone adjusted it incorrectly during installation.

Verify Heat Differential Setting

This setting controls when heating turns on and off.

What Heat Differential means:

Heat Differential determines temperature drop before heating activates:

  • Setting of 0.5°F: Very tight control, frequent cycling
  • Setting of 1.0°F: Normal, balanced
  • Setting of 2.0°F: Loose control, allows wider temperature swing

How this affects temperature:

Example with 68°F set temperature:

  • 0.5°F differential: Heating starts at 67.5°F
  • 1.0°F differential: Heating starts at 67°F
  • 2.0°F differential: Heating starts at 66°F

If differential too high, room temperature drops significantly before heating activates.

Checking Heat Differential:

  • Settings
  • Installation Settings
  • Thresholds
  • Heat Differential
  • Note current value

Recommended setting:

  • Most homes: 0.5°F to 1.0°F
  • Well-insulated homes: 0.5°F
  • Poorly insulated homes: 0.5°F (tighter control needed)
  • Very few situations need 2.0°F+

Adjusting differential:

  • Settings
  • Installation Settings
  • Thresholds
  • Heat Differential
  • Change to 0.5°F or 1.0°F
  • Save setting
  • Test heating performance

My situation: Heat Differential was set to 1.5°F, slightly higher than optimal. I changed it to 0.5°F for tighter temperature control. This helped but didn’t completely solve the problem.

Check Room Sensors and Averaging

Remote sensors can cause temperature reading problems.

Understanding Ecobee sensors:

Main thermostat sensor:

  • Built into thermostat unit
  • Always active
  • Reads temperature at thermostat location

Remote room sensors:

  • Wireless sensors in other rooms
  • Can participate in temperature averaging
  • Optional – not all systems have them

How sensor averaging works:

If you have remote sensors:

  • Multiple sensors read temperature
  • Ecobee averages readings
  • Uses average to control heating
  • Can cause confusion about temperature

Example causing problems:

Living room (thermostat location): 63°F Bedroom (remote sensor): 72°F (sunny, warm) Average: 67.5°F Set temperature: 68°F Ecobee thinks house is almost warm enough, barely heats Living room stays cold while bedroom is hot

Checking sensor participation:

  • Settings
  • Sensors
  • View list of sensors
  • Check which sensors are “participating”
  • See temperature reading from each

Understanding comfort settings:

Sensors can participate in different periods:

  • Home: Certain sensors active
  • Away: Different sensors active
  • Sleep: Different sensors active

Adjusting sensor participation:

To use only thermostat sensor:

  • Settings
  • Sensors
  • Select remote sensor
  • Disable “Participate in Comfort Setting”
  • Repeat for each remote sensor
  • Only thermostat sensor remains active

To change which sensors participate:

  • Settings
  • Sensors
  • Select period (Home, Away, Sleep)
  • Choose which sensors participate in that period
  • Save changes

Testing with different sensor configurations:

  • Note which sensors currently participate
  • Disable all remote sensors
  • Use only thermostat sensor
  • Test if heating reaches proper temperature
  • If yes, remote sensor was causing problem

My discovery: I had two remote sensors – one in a sunny bedroom reading 71°F, one in basement reading 58°F. Averaging these with the thermostat sensor (63°F) gave 64°F average. The sunny bedroom sensor made Ecobee think the house was warmer than it actually was. I disabled the bedroom sensor and temperature control improved significantly.

Restart the Thermostat

Simple restart clears software glitches.

Why restart helps:

  • Clears temporary software errors
  • Resets communication with HVAC system
  • Forces fresh sensor readings
  • Resolves hung processes

How to restart Ecobee:

Method 1 – Menu restart:

  • Main menu
  • Settings
  • Reset
  • Restart Thermostat
  • Confirm restart
  • Wait 2-3 minutes for full restart

Method 2 – Power cycle:

  • Turn off furnace breaker
  • Wait 30 seconds
  • Turn breaker back on
  • Thermostat restarts automatically
  • Wait 2-3 minutes

What happens during restart:

  • Screen goes black
  • Thermostat reboots
  • Logo appears briefly
  • Normal screen returns
  • May take 2-3 minutes total

After restart:

  • Wait 5 minutes for system to stabilize
  • Check temperature reading
  • Verify mode still set to Heat
  • Set desired temperature
  • Monitor if heating improves

When to restart:

Restart if:

  • Settings changes don’t take effect
  • Display shows errors
  • Heating behavior seems erratic
  • Haven’t restarted in months
  • Just trying simple fixes first

My experience: Restart didn’t solve my main problem, but it’s quick and fixes many issues. Takes 5 minutes total and worth trying early in troubleshooting.

Check Air Filter

Dirty filter restricts airflow, preventing proper heating.

How dirty filter affects heating:

  • Restricts airflow through system
  • Furnace runs but can’t circulate heat effectively
  • Causes furnace to overheat and shut down
  • Makes system work harder without heating better
  • Can trigger safety shutoffs

Where to find filter:

Common locations:

  • Return air vent (usually large vent in wall or ceiling)
  • Furnace itself (side panel or bottom)
  • Air handler unit (inside panel)
  • Return duct near furnace

Checking filter condition:

  • Remove filter from housing
  • Hold up to light
  • Can you see through it clearly?
  • Is it grey or brown with dust?
  • Is it visibly clogged?

Filter condition guide:

Clean filter:

  • White or light colored
  • Can see through easily
  • Little to no dust accumulation
  • Installed within last 1-3 months

Dirty filter:

  • Grey or brown color
  • Can’t see through clearly
  • Visible dust and debris
  • Installed 3+ months ago

Very dirty filter:

  • Black or dark brown
  • Completely blocked
  • Heavy dust accumulation
  • May be bent or damaged
  • Causes immediate problems

Replacing filter:

  • Note filter size (printed on frame: 16x25x1, etc.)
  • Buy replacement at hardware store
  • Remove old filter
  • Check arrow on new filter (points toward furnace)
  • Install new filter with correct direction
  • Close access panel

Testing after replacement:

  • Turn on heating
  • Feel airflow from vents (should be stronger)
  • Listen to furnace (should sound less strained)
  • Monitor temperature over next hour
  • Check if heating improves

Filter maintenance schedule:

Standard filters:

  • Check monthly
  • Replace every 1-3 months
  • More often if pets, allergies, or high dust

HEPA or high-efficiency filters:

  • Check every 2-3 months
  • Replace every 3-6 months
  • Follow manufacturer recommendations

My situation: My filter was moderately dirty (about 2 months old). I replaced it even though not critically dirty. Airflow improved slightly but didn’t completely solve the heating problem.

Verify Furnace Is Actually Running

Sometimes thermostat calls for heat but furnace doesn’t respond.

Checking furnace operation:

Listen for furnace starting:

  • Stand near furnace location
  • Should hear clicking or ignition sounds
  • Blower motor should start
  • Distinctive furnace noise when running

Feel for warm air from vents:

  • Stand at nearest heating vent
  • Wait 2-3 minutes after heating starts
  • Air should be noticeably warm (100-130°F)
  • Should feel strong airflow

Visual furnace inspection:

Go to furnace:

  • Look at furnace status light
  • Should be steady or blinking in normal pattern
  • Check display if digital
  • No error codes should show

Normal operation indicators:

  • Steady green light (most furnaces)
  • Blower motor running
  • Warm air exhausting from vents
  • Furnace sounds normal (not unusual noises)

Problem indicators:

  • Red light or rapid blinking
  • Error codes on display
  • Furnace clicking but not starting
  • Cold air from vents
  • No blower motor sound

Common furnace problems:

Pilot light out (older furnaces):

  • Look for pilot light
  • Should see small flame
  • If out, follow lighting instructions
  • Usually near burner access panel

Ignitor not working (newer furnaces):

  • Clicking sound but no ignition
  • Requires professional repair
  • Electronic ignition system failed

Gas supply issue:

  • Gas valve closed
  • Empty propane tank
  • Gas line problem
  • Check other gas appliances working

Blower motor problem:

  • No air circulation
  • Furnace warms but doesn’t distribute
  • May need motor replacement

Safety shutoff triggered:

  • Overheating protection
  • Carbon monoxide sensor
  • Pressure switch failure
  • Often due to dirty filter or blocked vents

My finding: My furnace started normally and blower ran, but air from vents wasn’t as warm as expected. Furnace ran continuously but seemed to be producing less heat than normal. This indicated a furnace problem rather than thermostat problem.

Check Circuit Breakers

Power issues prevent proper operation.

Why breakers matter:

Thermostat breaker:

  • Powers thermostat itself
  • If tripped, thermostat won’t work at all
  • Usually you’d notice dead display

Furnace breaker:

  • Powers heating system
  • If tripped, furnace won’t run
  • Thermostat works but can’t control furnace

Finding breakers:

Locate breaker panel:

  • Usually in basement
  • Sometimes garage or utility room
  • Metal panel with switches

Identify relevant breakers:

  • Look for labels “Furnace” or “HVAC”
  • May say “Heating” or “Air Handler”
  • Might not be clearly labeled

Checking breaker status:

  • Open breaker panel door
  • Look at each breaker
  • ON position: Switch fully to one side
  • TRIPPED position: Switch in middle, not fully either side
  • OFF position: Switch fully opposite from ON

Resetting tripped breaker:

  • Flip switch fully to OFF
  • Wait 5 seconds
  • Flip switch fully to ON
  • Listen for furnace to power up
  • Check thermostat responds

If breaker trips again immediately:

  • Serious electrical problem
  • Short circuit or overload
  • Don’t keep resetting
  • Call electrician

Testing after reset:

  • Turn thermostat to Heat mode
  • Set temperature above current temperature
  • Wait 5 minutes
  • Listen for furnace to start
  • Check if heating begins

My situation: Both breakers were in ON position so this wasn’t my problem. But checking breakers takes 2 minutes and is worth eliminating as cause.

Inspect Thermostat Wiring

Loose or incorrect wiring prevents proper heating.

When to check wiring:

  • After eliminating simple causes
  • If heating intermittent
  • After recent thermostat installation
  • If no other solutions worked

Safety first:

  • Turn off furnace breaker before checking wiring
  • Don’t touch wires with breaker on
  • Low voltage (24V) but still be careful

Accessing thermostat wiring:

Removing thermostat from wall:

  • Pull thermostat display straight off wall plate
  • Should disconnect easily
  • Wall plate with wires remains mounted
  • Display connects to plate via connector pins

Examining wall plate wiring:

Common wire terminals:

  • R or Rc: Red wire, power from furnace (24V)
  • W or W1: White wire, heating control
  • G: Green wire, fan control
  • Y or Y1: Yellow wire, cooling control (not needed for heat)
  • C: Blue or black wire, common/return power

Checking wire connections:

  • Look at each wire terminal
  • Wire should be inserted firmly
  • Screw terminal should be tight
  • No exposed copper except in terminal
  • Wire shouldn’t pull out easily

Testing wire tightness:

  • Gently tug each wire
  • Should not pull free
  • If loose, tighten terminal screw
  • If wire pulls out, reinsert and tighten

Signs of wiring problems:

Loose connections:

  • Wire pulls out of terminal
  • Terminal screw loose
  • Intermittent heating indicates this

Corroded wires:

  • Green or white crusty buildup on copper
  • Wire looks damaged or discolored
  • Poor electrical connection

Frayed wires:

  • Insulation damaged
  • Copper strands broken
  • Exposed copper touching wrong terminals

Wrong wire in terminal:

  • Compare to installation manual
  • Common mistake: W and Y swapped
  • Or R and Rc confused

Fixing loose connections:

  • Turn off furnace breaker
  • Loosen terminal screw
  • Remove wire
  • Strip 1/4 inch of insulation if needed
  • Insert wire firmly into terminal
  • Tighten screw
  • Tug gently to test
  • Repeat for each loose connection

Testing after fixing wiring:

  • Reattach thermostat display to wall plate
  • Turn on furnace breaker
  • Wait 2 minutes for system to boot
  • Set thermostat to Heat mode
  • Raise temperature
  • Check if heating responds properly

My discovery: I found the W terminal (heating control) screw was slightly loose. Wire hadn’t fallen out but connection wasn’t solid. This caused intermittent communication between thermostat and furnace. Tightening the screw significantly improved heating reliability.

Check C-Wire Connection

Missing or faulty C-wire causes power and communication issues.

What C-wire does:

C-wire (common wire):

  • Provides return path for 24V power
  • Required for reliable Ecobee operation
  • Completes electrical circuit
  • Supplies continuous power

Problems without proper C-wire:

  • Intermittent power to thermostat
  • Communication errors with HVAC
  • Thermostat randomly restarts
  • Heating commands not sent reliably
  • Display dims or goes dark

Checking for C-wire:

Look at thermostat wiring:

  • Remove thermostat display from wall plate
  • Look at terminal labeled “C”
  • Wire present? Usually blue or black
  • No wire? C-wire might be missing

C-wire alternatives:

Power Extender Kit (PEK):

  • Ecobee includes PEK with thermostat
  • Installs at furnace
  • Uses existing wires differently to provide power
  • Alternative when C-wire not available

Using extra wire:

  • If extra unused wire in wall
  • Can repurpose as C-wire
  • Requires connecting at both ends

Verifying C-wire connection:

At thermostat:

  • Wire firmly inserted in C terminal
  • Terminal screw tight
  • Wire not damaged

At furnace:

  • Follow C-wire to furnace control board
  • Should connect to C terminal there too
  • Both ends must be connected

Installing PEK if C-wire missing:

Warning: This requires working at furnace control board. If uncomfortable, hire HVAC technician.

PEK installation overview:

  • Turn off furnace power
  • Access furnace control board
  • Install PEK at furnace
  • Reconnect certain wires through PEK
  • Configure thermostat for PEK use
  • Restore power and test

When to call professional:

  • Uncomfortable with electrical work
  • Can’t access furnace control board
  • Unsure about wire identification
  • Want reliable professional installation

Testing C-wire:

Using multimeter (advanced):

  • Set multimeter to AC voltage
  • Test between R and C terminals
  • Should read 24V AC
  • If no voltage, C-wire not working

Observing thermostat behavior:

  • Properly powered thermostat has bright display
  • Shouldn’t dim significantly
  • Shouldn’t randomly restart
  • Responds immediately to commands

My situation: I had C-wire connected and tested at 24V. Power wasn’t my problem. But many heating issues trace to C-wire problems, especially after DIY installation.

Verify Heating Equipment Type Setting

Wrong equipment setting prevents proper operation.

Why equipment type matters:

Ecobee must know what heating system it controls:

  • Gas furnace (forced air)
  • Oil furnace
  • Electric furnace
  • Heat pump
  • Boiler with hydronic heat
  • Dual fuel systems

Wrong setting causes:

  • Incorrect heating commands
  • System doesn’t respond
  • Inefficient operation
  • Heating cycles problems

Checking equipment type:

  • Settings menu
  • Installation Settings
  • Equipment
  • View selected heating type
  • Verify matches your actual system

Common equipment types:

Conventional heating:

  • Gas furnace
  • Oil furnace
  • Electric furnace
  • Boiler

Heat pump:

  • Air source heat pump
  • Geothermal heat pump
  • Has both heating and cooling capabilities
  • More complex settings

Dual fuel:

  • Heat pump plus backup furnace
  • Switches between systems based on temperature
  • Requires additional configuration

Correcting equipment type:

  • Settings
  • Installation Settings
  • Equipment
  • Select correct heating type
  • Follow configuration prompts
  • Answer questions about equipment
  • Save settings

Heat pump specific settings:

If you have heat pump:

  • Must identify as heat pump, not conventional
  • Configure reversing valve (O or B wire)
  • Set auxiliary heat thresholds
  • Define compressor protection settings

My situation: Equipment type was correctly set to Gas Furnace. This wasn’t my issue but it’s critical to verify, especially after new installation.

Check for Furnace Problems

Sometimes problem isn’t thermostat at all.

When furnace is the issue:

Indicators:

  • Thermostat calls for heat properly
  • Wiring all correct
  • Settings configured right
  • But still not heating adequately

Common furnace problems affecting temperature:

Dirty burners:

  • Incomplete combustion
  • Less heat produced
  • Furnace runs but heating is weak
  • Requires professional cleaning

Failed limit switch:

  • Safety device that shuts off furnace if overheating
  • Can fail and shut off prematurely
  • Furnace cycles on and off frequently
  • Professional replacement needed

Cracked heat exchanger:

  • Serious safety issue
  • Reduces heating efficiency
  • Can leak carbon monoxide
  • Requires immediate professional attention

Undersized heating system:

  • System simply too small for house
  • Can’t keep up in very cold weather
  • No thermostat adjustment will fix
  • Needs system upgrade

Ductwork problems:

  • Leaks in ducts lose heated air
  • Blocked vents reduce circulation
  • Closed dampers restrict flow
  • Disconnected ducts at furnace

Low gas pressure:

  • Not enough fuel reaching furnace
  • Weak flame, less heat
  • Affects all gas appliances
  • Gas company must check

When to call HVAC professional:

Call immediately if:

  • Smell gas
  • Smell burning (not dust, actual burning)
  • See smoke from furnace
  • Hear loud banging or grinding
  • Carbon monoxide detector alarms
  • Furnace completely won’t start

Call soon if:

  • Heating inadequate despite thermostat working
  • Furnace cycles on/off frequently
  • Unusual noises during operation
  • Furnace hasn’t been serviced in 2+ years
  • Error codes on furnace display

What professionals check:

  • Burner condition and flame pattern
  • Heat exchanger for cracks
  • Blower motor operation
  • Gas pressure and flow
  • Electrical components
  • Safety switches
  • Ductwork connections
  • Overall system efficiency

My outcome: After checking all thermostat settings and wiring, I called HVAC technician. They found my furnace burners were dirty and flame sensor had carbon buildup. Professional cleaning restored proper heat output. Thermostat was working fine – furnace was the problem.

Professional Diagnosis When Nothing Works

Sometimes you need expert help.

When to call professional:

After trying these steps:

  • Verified all settings correct
  • Checked and tightened wiring
  • Replaced air filter
  • Confirmed furnace running
  • Restarted thermostat
  • Still not heating properly

What professionals bring:

Specialized tools:

  • Multimeters for electrical testing
  • Manometers for pressure testing
  • Combustion analyzers
  • Thermocouple testers
  • Advanced diagnostic equipment

Expert knowledge:

  • Experience with many systems
  • Understand complex interactions
  • Recognize subtle problems
  • Know manufacturer-specific issues

Finding qualified technician:

Look for:

  • HVAC contractor, not just handyman
  • Licensed and insured
  • Good online reviews
  • Established business
  • Clear pricing

Questions to ask:

  • Do you service Ecobee thermostats?
  • What’s your diagnostic fee?
  • Do you work on my heating system brand?
  • What are typical repair costs?
  • Do you warranty your work?

Typical service call costs:

  • Diagnostic fee: $80-150
  • Thermostat issues: $100-300
  • Furnace repairs: $150-800+
  • Emergency service: 1.5x to 2x normal rates

Preparing for service call:

Information to provide:

  • Heating system type
  • Thermostat model
  • Age of equipment
  • Description of problem
  • What you’ve already tried

Make accessible:

  • Clear path to furnace
  • Access to thermostat
  • Access to breaker panel
  • Remove stored items blocking equipment

What to expect during visit:

Technician will:

  • Inspect thermostat wiring and settings
  • Test voltage and connections
  • Examine furnace operation
  • Check system pressures and temperatures
  • Perform safety checks
  • Provide diagnosis
  • Quote repair costs
  • Explain recommended solutions

My experience: Professional visit cost $120 for diagnostic. Technician found dirty burners and failed flame sensor in 15 minutes. Cleaning and sensor replacement cost $280. Total: $400. Problem solved, heat working properly, and I learned furnace maintenance matters.

Summary of Solutions

Organizing fixes from simplest to most complex:

Simple fixes (5-10 minutes each):

  • Verify Heat mode selected
  • Check for hold settings
  • Turn temperature up significantly to test
  • Disable Smart Home/Away
  • Restart thermostat
  • Check circuit breakers

Moderate fixes (15-30 minutes each):

  • Adjust schedule settings
  • Check temperature correction setting
  • Verify heat differential setting
  • Review room sensor participation
  • Replace air filter
  • Verify furnace actually running

Advanced fixes (30-60 minutes):

  • Inspect and tighten thermostat wiring
  • Check C-wire connection
  • Verify equipment type setting
  • Test with multimeter (if experienced)

Professional help needed:

  • PEK installation if no C-wire
  • Furnace repair or service
  • Complex wiring issues
  • Safety concerns
  • Problem persists after trying everything

My complete solution:

My heating problem had multiple contributing factors:

  • Hold setting preventing temperature increase (removed)
  • Sunny bedroom sensor skewing average temperature (disabled)
  • Loose W terminal wire (tightened)
  • Dirty furnace burners (professional cleaning)
  • Failed flame sensor (professional replacement)

Cost breakdown:

  • My time troubleshooting: 3 hours
  • Air filter replacement: $15
  • Professional service: $400
  • Total: $415

Result: Heat now reaches set temperature reliably. House comfortable. Problem solved.

Prevention going forward:

Monthly:

  • Check air filter
  • Verify thermostat settings
  • Test heating operation

Seasonally:

  • Professional furnace maintenance before winter
  • Check all wiring connections
  • Review and update schedules

Annually:

  • Complete HVAC service
  • Replace air filter even if looks clean
  • Verify C-wire connection solid
  • Update thermostat firmware if available

Ecobee not reaching set temperature frustrates homeowners because the thermostat appears to work correctly while the house stays cold.

Systematic troubleshooting starting with simple setting checks and progressing to wiring inspection and equipment verification identifies most problems.

Smart features like holds, schedules, Smart Home/Away, and room sensor averaging frequently cause temperature control issues by overriding your manual settings or averaging temperatures incorrectly.

Physical issues like loose wiring, dirty air filters, and furnace problems prevent adequate heating even when thermostat functions properly. The solution often combines multiple small fixes rather than one major repair.

Starting with simple setting adjustments and working toward more complex hardware checks provides efficient path to identifying and solving heating problems without immediately calling expensive professional service.