How to Lower Your Heating Bill This Winter in East Tennessee

HOW DO YOU Heat Your Home Cost-Effectively?

Originally published November 7, 2025. Updated August 2026.

Quick Answer

To lower your winter heating bill, use the correct thermostat strategy for your type of heating system, keep filters and vents clear, prevent duct leakage, maintain your outdoor heat pump, and schedule routine HVAC service. Heat-pump owners should be especially careful with deep thermostat setbacks, which can activate less-efficient auxiliary heat. East Tennessee winters can shift quickly between mild afternoons, freezing nights, and damp cold spells. Those temperature swings make heating costs difficult to predict, especially in homes that rely on electric heat pumps.

A higher winter bill does not automatically mean something is wrong with your HVAC system. Colder weather naturally requires longer heating cycles. However, poor thermostat settings, restricted airflow, leaky ductwork, auxiliary heat usage, and neglected equipment can push energy consumption much higher than necessary.

Why Is My Heating Bill So High in the Winter?

Common reasons for higher winter energy bills include:

• Colder outdoor temperatures
• More days included in the billing cycle
• Higher electricity or fuel rates
• Increased use of auxiliary or emergency heat
• A clogged HVAC filter
• Leaky or poorly insulated ductwork
• Air leaks around doors, windows, attics, and crawl spaces
• Thermostat settings that do not match the heating system
• Equipment that needs maintenance or repair
• An aging or improperly sized HVAC system

When reviewing your bill, compare actual electricity usage in kilowatt-hours—not only the amount due. A rate increase and a usage increase are two different problems.

1. Use the Right Thermostat Strategy for Your Heating System

There is no single thermostat strategy that works equally well for furnaces and heat pumps.

Thermostat Settings for Heat Pumps

Heat pumps operate most efficiently when maintaining a relatively steady indoor temperature. Large setbacks may force the system to make up several degrees quickly, potentially activating electric auxiliary heat. For better heat-pump efficiency:

• Select a comfortable temperature and keep it relatively steady.
• Make small temperature adjustments instead of large jumps.
• Use HEAT mode rather than AUTO during winter.
• Set the blower fan to AUTO unless a technician recommends otherwise.
• Use a thermostat designed and properly configured for heat pumps.
• Avoid manually selecting Emergency Heat unless the heat pump has failed or an HVAC professional instructs you to use it.

Seeing “AUX HEAT” temporarily is not always a problem. Auxiliary heat may operate during very cold weather, system recovery, or a heat-pump defrost cycle. It deserves attention if it stays on for long periods, appears during relatively mild weather, or accompanies a sudden increase in electricity use. Learn more about heat-pump services in the Tri-Cities.

Thermostat Settings for Furnaces

Homes with gas, oil, or electric furnaces may benefit from lowering the temperature while everyone is asleep or away.

The U.S. Department of Energy reports that appropriate thermostat setbacks can reduce annual heating and cooling costs, but actual savings depend on the home, system, climate, and schedule. Start with a modest setback and adjust it based on comfort and how quickly the home recovers. A smart thermostat can automate those schedules, but it must be compatible with the HVAC equipment. Heat pumps, multi-stage systems, and dual-fuel systems require correct setup to avoid inefficient operation.

2. Check Your HVAC Filter Regularly

A dirty filter restricts airflow. When the system cannot move enough air, it may run longer, produce less heat at the registers, or place additional strain on the blower motor.

During heavy winter use:

• Check the filter approximately once a month.
• Replace it when it appears dirty or according to the manufacturer’s schedule.
• Confirm the correct filter size before purchasing replacements.
• Install the filter with the airflow arrow facing the correct direction.
• Avoid choosing a very restrictive filter without confirming that the system can accommodate it.

A higher MERV rating is not automatically better for every system. Filtration and airflow must remain balanced. Ducted systems commonly need a filter change every one to three months, depending on the filter, pets, occupancy, dust, and runtime. Washable filters in ductless mini-splits may need cleaning more frequently.

3. Keep the Outdoor Heat-Pump Unit Clear

A heat pump needs unrestricted airflow through its outdoor coil... Even during winter! Homeowners should:

• Remove leaves, grass, and loose debris from around the unit.
• Maintain approximately two to three feet of clearance around it.
• Gently remove loose snow after a storm.
• Prevent gutters and roof runoff from draining onto the equipment.
• Avoid covering the unit during winter.
• Never chip ice from the coil or pour hot water over it.

A temporary layer of frost can be normal. Heat pumps periodically enter a defrost cycle to melt it, and homeowners may notice steam or a temporary change in sound. A unit that remains encased in ice or repeatedly fails to defrost needs professional attention.

4. Keep Supply Registers and Return Vents Open

Furniture, rugs, boxes, curtains, and closed registers can interfere with HVAC airflow. Walk through the home and confirm that:

• Supply registers are open and unobstructed.
• Return-air grilles are not blocked.
• Furniture is not positioned directly over or against vents.
• Interior doors allow sufficient air to circulate back to the return.

Closing multiple registers rarely saves energy. It can increase pressure inside the duct system, reduce comfort, and make some HVAC systems operate less efficiently. Uneven temperatures may indicate a ductwork, airflow, insulation, zoning, or equipment-sizing problem, not simply a need to close vents in warmer rooms.

5. Address Leaky or Poorly Insulated Ductwork

The U.S. Department of Energy estimates that a typical home can lose approximately 20% to 30% of the air moving through its duct system because of leaks, holes, and poor connections. Those losses become especially expensive when ducts run through an unconditioned attic, basement, garage, or crawl space.

Potential warning signs include:

• Weak airflow at distant registers
• Rooms that never reach the thermostat setting
• Excessive dust around registers
• Visible gaps or damaged duct insulation
• Heating equipment that runs longer than expected
• Large temperature differences between rooms

Accessible duct joints should be sealed with approved mastic or HVAC foil tape, not ordinary cloth-backed “duct tape.” More extensive duct repairs, airflow balancing, and insulation work should be evaluated professionally.

6. Reduce Air Leakage Around the Home

Your HVAC system cannot operate efficiently if heated air escapes as quickly as the equipment produces it. Homeowners can check:

• Weatherstripping around exterior doors
• Gaps around windows
• Attic-access doors and pull-down stairs
• Plumbing and wiring penetrations
• Fireplace dampers
• Crawl-space doors
• Unsealed recessed lighting or ceiling penetrations

Open curtains on sunny windows during the day to take advantage of passive solar heat. Close them after sunset to reduce heat loss through the glass. If the home remains drafty after basic weatherstripping, consider a professional energy assessment to locate larger leakage and insulation problems.

7. Schedule Preventive Heating-System Maintenance

Routine maintenance cannot eliminate the cost of heating a home, but it can identify conditions that reduce efficiency or lead to winter breakdowns. Depending on the equipment, professional service may include:

• Checking thermostat operation and configuration
• Inspecting electrical components
• Testing heating stages and auxiliary heat
• Evaluating airflow and temperature rise
• Inspecting blower components
• Checking the heat-pump defrost system
• Inspecting the outdoor coil
• Testing safety controls
• Identifying unusual noise, vibration, or wear
• Confirming that the system is operating as designed

ENERGY STAR recommends annual pre-season HVAC checkups, ideally before contractors become busiest during extreme weather.

Explore preventive HVAC maintenance from Phil’s Heating and Air.

8. Consider a Smart Thermostat or High-Efficiency Upgrade

A smart thermostat can help reduce wasted runtime, track energy use, and automate temperature schedules. The most important factor is choosing equipment compatible with the home’s HVAC system and configuring it correctly. Older heating equipment may also cost more to operate because of declining performance, outdated efficiency ratings, ductwork problems, or frequent use of backup heat.

As of August 2026, TVA EnergyRight lists incentives for certain qualifying improvements, including:

• Up to $800 for eligible ducted heat-pump installations
• Up to $300 for qualifying duct sealing, repairs, insulation, or replacement
• A $50 rebate for eligible heat-pump or central AC tune-ups
• Smart-thermostat enrollment and purchase rebates of up to $100 through participating local power companies

Programs, equipment requirements, and participating utilities can change. Confirm current eligibility before purchasing or installing equipment. Phil’s Heating and Air can help East Tennessee homeowners review current HVAC and TVA EnergyRight options.

When Does a High Heating Bill Indicate an HVAC Problem?

Schedule an inspection if you notice:

• A sudden usage increase that weather alone does not explain
• Auxiliary heat running frequently during mild weather
• Emergency Heat appearing unexpectedly
• A heat pump that remains covered in ice
• Heating equipment that cannot reach the thermostat setting
• Constant operation during relatively mild conditions
• Weak airflow from multiple registers
• Large temperature differences between rooms
• New rattling, grinding, squealing, or buzzing sounds
• Unusual burning or electrical odors
• Repeated breaker trips
• A steady increase in energy use over several months

Variable-speed heat pumps may run for long periods at a lower capacity. That can be normal and efficient. The concern is a change from the system’s usual behavior, inadequate comfort, persistent auxiliary heat, or unusually high energy consumption.

FAQ

Frequently Asked Questions About Winter Heating Costs

Get Your Heating System Ready for an East Tennessee Winter

Small HVAC problems can become expensive during the first major cold snap. If your heating bill is climbing, auxiliary heat is running excessively, or your home never feels comfortable, Phil’s Heating and Air can evaluate the entire system and explain what is happening.

We provide heating repair, heat-pump service, preventive maintenance, system replacement, thermostat assistance, and indoor-comfort solutions throughout Gray, Johnson City, Kingsport, Bristol, Jonesborough, and surrounding East Tennessee communities.

Call or text (423) 741-5459, or schedule HVAC service online. Phil’s Heating and Air has served the region since 1994, and we’re known for getting customers taken care of quickly when the heat goes out.