Your home energy efficiency playbook.

Your complete guide to air conditioning, ducts sealing, air sealing, insulation and HVAC maintenance.

Index

Click on the links to jump to the sections that are most relevant to your long-term home energy efficiency and money-saving goals.

Introduction

Chapter 1: Duct sealing & ductwork maintenance

Chapter 2: Air sealing your house & attic (AKA: Home envelope sealing)

Chapter 3: Home & attic insulation solutions

Chapter 4: High efficiency HVAC & central air conditioning

Chapter 5: Seasonal HVAC maintenance & tune-ups

Chapter 6: How to hire a qualified contractor

Glossary

References

Whether you’re a renter, homeowner or landlord who’s considering upgrading aging systems, understanding the fundamentals of home energy efficiency is important. We’re working closely with local power companies throughout the seven-state Tennessee Valley region to help people like you lower your energy bills with energy-saving recommendations, rebates and more.

Although we often think about each of these systems individually, they all work together to improve comfort, protect indoor air quality, lower your monthly heating and cooling costs, and extend the effective lifespan of your HVAC system. 

That’s why we’re taking this opportunity to put everything you need to know about duct sealing, air sealing, insulation and HVAC in one place for easy reference. We hope you’ll find this comprehensive playbook useful and share it with your neighbors!

As you read through this guide, you’ll find expert-backed tips from energy authorities like ENERGY STAR, the U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency (EPA), research publications and building-science standards from Air Conditioning Contractors of America (ACCA). Feel free to click around and keep on learning from trusted sources.

And don’t forget duct sealing, air sealing, insulation and HVAC maintenance all qualify for rebates from TVA EnergyRight and your local power company. You can search our Quality Contractor Network for TVA-vetted, licensed and insured contractors near you who can help you apply for valuable rebates on home energy upgrades.

Chapter 1: Duct sealing & ductwork maintenance.

Duct sealing key takeaways:

• Rebates of up to $300 are available on duct sealing.
• Leaky ducts can allow up to 30% of your conditioned air.
• If your home has hot or cold spots, or your energy bills are higher than usual, it may be time to check your ducts.

What is duct sealing, and how much energy can duct sealing save?

Wasting energy before it enters your home is hard on your home energy bills — and your personal comfort. Unfortunately, it’s an incredibly common way for energy loss to occur. Research shows that leaky ducts can lose a staggering amount of conditioned air — up to 30% — as it travels through the system. 

Not only does this waste lead to higher energy bills, but it also means your HVAC system is working much harder than it needs to. Ducts leaking just 20% of conditioned air passing through them can cause your heating and cooling unit to work 50% harder!  

Reading the signs: How do you know if your ducts are leaking?

What you can’t see can hurt your energy bill. For the most part, your home’s ductwork won’t be visible to you. However, just because you can’t see a crack or feel a leak doesn’t mean your home won’t give you some helpful signs that maintenance is needed. If any of the following symptoms sound familiar, it may be time to consult with your local heating and cooling expert.

• Higher-than-normal or unpredictable energy bills.
• Difficulty maintaining your desired temperature.
• Hot or cold spots or drafty rooms.
• Noticeable dustiness.
• Whistling or whooshing sounds when your HVAC runs.
• Dirt, dust, mold or condensation around air vents.

It may be tempting to run to your local hardware store and grab a roll of standard duct tape (quick note here: mastic sealant or metal tape are both more efficient, longer-lasting options), but unless you really know what you’re doing with your ductwork, you may want to leave maintenance to the professionals. 

Best practices for duct sealing.

Use mastic sealant or foil-backed duct tape to seal all joints, seams and connections. Check out our duct sealing upgrade page for more information. Insulate ducts that run through unconditioned spaces such as your attic, crawl spaces and garage to reduce thermal loss.

When to call a duct sealing pro.

If you’re not confident in your DIY skills, if ducts run through hard-to-access areas, or need extensive sealing, a professional familiar with ACCA standards or local building codes is the way to go. If you suspect disconnections or serious leakage, you should look for a trusted expert. Plus, they’ll also have the equipment to run pre- and post-sealing leakage testing to help ensure the best results. 

Rebates on duct sealing are now available and you can find a contractor who can help you with AC ductwork sealing and rebates by searching the Quality Contractor Network!

Chapter 2: Air sealing your house & attic.

Air sealing key takeaways:

• Rebates of up to $300 are available on air sealing.
• Sealing gaps creates a barrier between the inside of your home and the outside, keeping conditioned air inside.
• Air sealing and insulation can reduce heating and cooling costs by an average of 15%. 

What is air sealing? And why air sealing matters.

Air sealing is the process of closing small cracks, gaps and holes in your home’s building envelope — the barrier between indoors and outdoors. It’s especially important to have older homes inspected, but new construction shouldn’t get a free pass! As new homes settle, cracks and gaps often appear. Sealing up these gaps before winter (or summer) can dramatically reduce drafts, energy loss and discomfort. 

Where to find air leaks in homes:

• Attic and crawlspace hatches.
• Window and door frames, sashes, jambs, sills.
• Plumbing and electrical penetrations (pipes, wires).
• Recessed lights, vents, fans and vent ducts.
• Around baseboards and where walls meet ceilings.
• Refrigerator, dishwasher or exhaust fan penetrations.
• Outlets, switch boxes and vent registers.

How to detect air leaks.

DIY-friendly and renter-friendly method.

For a low-cost preliminary check, you can take the DIY route. Here’s how:

• On a windy day, close all windows and exterior doors. Turn on exhaust fans (bathroom, kitchen hood).
• Light an incense stick (or use a damp hand) and slowly move around door frames, window edges, baseboards — feel or watch for air movement.
• Common leaks are at doors, windows, attic hatches, rim joists, plumbing or wiring penetrations and vents.

Want to get your kids in on the fun? Check out “Calling all junior detectives! Use your sleuthing skills to spot sneaky leaks.” 

How much can air sealing save you?

Lower energy bills: According to ENERGY STAR, air sealing and insulation can reduce heating and cooling costs by an average of 15%, and in some cases even more.

Improved comfort: Cut down on drafts, promote more stable indoor temperatures, reduce cold spots and take the burden off your HVAC systems. You can learn more about R-value (the higher the R-value, the greater the material’s insulating power) and find your climate zone on the Department of Energy’s website.

Better indoor air quality: Sealing leaks reduces infiltration of dust, pollen, mold spores, moisture and pests — which is especially relevant if vents, crawlspaces or attics are connected to living spaces.

Moisture and maintenance: Sealing leaks and home weatherization help prevent condensation, mold, mildew and structural damage from moisture infiltration.

Best practices for air sealing.

You don’t have to do everything at once! Remember, every improvement helps. To get started, we recommend focusing on key areas that can make the biggest difference.

Seal doors and windows.

• Use weatherstripping around doors and movable window sashes.
• Apply caulk to seal cracks around stationary window frames and exterior trim.
• Install door sweeps to block drafts at the bottom of exterior doors.
• Apply window film to especially drafty windows.

Address the attic and crawlspace.

• Look for gaps around plumbing vents, electrical wiring and chimneys in your attic.
• Use expanding foam or caulk to seal small holes and install covers or gaskets where needed.
• In crawlspaces, sealing gaps between the foundation and framing can stop cold air from entering your floors.

Fortunately, rebates on air sealing are available from TVA EnergyRight and your local power company! 

Chapter 3: Home & attic insulation solutions.

Insulation key takeaways:

• Rebates of up to $500 are available on insulation.
• 9 out of 10 homes in our region are underinsulated.
• The higher the R-value, the better the insulating power. 

Uneven temperatures, drafty rooms and high (or unpredictable) energy bills could mean your home is under-insulated or letting your conditioned air out and unconditioned air in. Shockingly, nine out of 10 single-family detached homes in the U.S are under-insulated (ENERGY STAR)! 

What is insulation?

Insulation slows heat flow (via conduction, convection or radiation), helping keep warm air in during the winter or out during the summer months. Proper insulation reduces the load on your HVAC system and lowers energy use. 

Types of Insulation.

The type of insulation you use may depend on where it’s being installed and your home’s specific needs. Some common insulation types include:

Blown-in (loose-fill) insulation
Ideal for attics and wall cavities, this type of insulation is made of fiberglass or cellulose and is blown into place using special equipment.

Batt insulation
These pre-cut panels of fiberglass or mineral wool are one of the most affordable and widely used forms of insulation. They’re ideal for open areas like between wall studs, floor joists and attic rafters.

Spray foam insulation
Expands to fill gaps and create a tight air seal. Available in open-cell and closed-cell varieties, spray foam is especially effective for sealing around pipes, wiring and small crevices.

Foam board insulation
Rigid panels made of polystyrene or polyurethane are typically used on foundation walls, basement interiors and exterior walls under siding. Foam boards offer high insulating value with a relatively thin profile.

What does insulation R-value mean?

Insulation is measured in R-values, which indicate its resistance to heat flow — the higher the R-value, the better the insulation power. Visit our insulation and air sealing upgrade page for more information.

In the South, many homes are under-insulated — especially older houses. If the floor joists are exposed in your attic, for example, that’s a strong indication that you need additional insulation. Fortunately, rebates are available. 

Insulation works best when the building envelope is tight. Installing insulation first, then sealing leaks, can leave gaps behind insulation or make leaks harder to find. Professionals and building-science guidance recommend sealing first, then insulating.

Where should you consider insulating or improving your existing insulation?

Attic insulation

Attic insulation can help regulate your home’s temperature all year long; plus it can help prevent moisture buildup, which could lead to mold or structural damage. Consider blown-in cellulose or fiberglass batt insulation to reach the recommended R-values for your region. 

ENERGY STAR recommends hiring a qualified insulation contractor to make sure your attic is well-sealed and properly insulated, with the correct insulation levels and insulation type for your home’s age and construction. You can search the Quality Contractor Network for TVA-vetted insulation contractors near you.

Crawlspace insulation

Insulating between the floor joints of your crawl space not only helps keep your toes warm in the winter, but it also improves energy efficiency year-round, helping you save money.

Wall insulation

Proper wall insulation helps you save on heating and cooling costs, but it doesn’t stop there — it also improves soundproofing and offers a degree of moisture control that can minimize mold and mildew. Wall insulation is harder to retrofit, but it’s possible with dense-pack cellulose or foam injection.
Or, if your home needs to be resided, that’s a great time to consider adding insulation as well!


You don’t always need a full insulation overhaul. Even topping off attic insulation or insulating around rim joists can make a big difference. Not sure where to begin? A member of our Quality Contractor Network can help. 

For maximum efficiency, we recommend combining air sealing with insulation upgrades. 

Chapter 4: High efficiency HVAC & central air conditioning.

Air conditioning key takeaways:

• Rebates of up to $400 are available on high-efficiency air conditioning systems.
• Air conditioners help control humidity.
• Systems that are 10+ years old are less efficient than modern models.

How does a high-efficiency AC system improve comfort?

If you live in a home without central air conditioning, an upgrade will be an undeniable improvement! And if your existing air conditioner is more than 10 years old, it may be working overtime without keeping you comfortable. Many older systems also often lack variable-speed technology and precision controls that today’s high-efficiency air conditioners use to maintain steady, consistent comfort throughout your home.

Modern high-efficiency AC systems, especially ones that are rated at 15 SEER2 or higher, are built to do more than just cool: They modulate their output based on what your home actually needs at any given moment, rather than cycling on at full blast and shutting off suddenly. 

Steadier, even operation leads to more consistent temperatures and humidity levels throughout your home. 

For more on how humidity impacts comfort, check out “Humidity, heat and your home: How SEER2 15+ systems tackle our region’s tough conditions,” and “How high-efficiency AC systems and duct sealing eliminate hot spots.”

Be sure to check out rebates on high-efficiency air conditioners from TVA EnergyRight and your local power company.

Chapter 5: Seasonal HVAC maintenance & tune-ups.

HVAC tune-up key takeaways:

• $50 rebates are available on HVAC tune-ups.
• Tune-ups help your system run more efficiently.
• Routine maintenance can help reduce the need for emergency repairs.

HVAC maintenance is essential for comfort, safety and efficiency — and helps prevent unexpected breakdowns when you need your system the most. We recommend scheduling a tune-up twice a year — once in fall before heating season and once in spring before cooling season. Certainly, if you notice strange sounds coming from your unit and higher-than-normal bills, call in the pros regardless of whether or not your inspection is due.

Why does seasonal HVAC maintenance matter?

If you have your home air sealed or insulated, it may be a good idea to add a tune-up to the list. Why? Because home envelope sealing may change airflow and pressure dynamics, which can affect how your system operates. 

Why does seasonal HVAC maintenance matter?

1. Avoid costly emergency repairs — A well-tuned system is less likely to break down during extreme cold or heat.
2. Improve energy efficiency: Clean systems run more efficiently and maintenance can catch issues (dirty coils, malfunctioning parts, airflow restrictions) that cause efficiency losses.
3. Enhance indoor air quality: Regularly changing or cleaning filters helps trap dust, pollen and other particles rather than circulating them throughout the home.
4. Extend equipment lifespan: Routine maintenance reduces wear and tear and lets you catch small problems before they become major.
5. Ensure safety: Technicians can inspect for gas leaks, cracked heat exchangers, faulty wiring or improper ventilation — especially important if you have combustion appliances.
6. Peace of mind: Proper airflow, clean components, calibrated thermostats — all lead to a more consistent, comfortable indoor environment.
7. Take advantage of rebates: Get $50 off HVAC maintenance with a rebate from TVA EnergyRight and your local power company.
8. Save money: Using less energy, helping your HVAC system last longer and taking advantage of rebates all add up to saving money.

What does a typical HVAC maintenance visit include?

Chat with your HVAC technician to make sure their inspection includes the following:

• Filter inspection/change.
• Coil cleaning (evaporator and condenser).
• Checking refrigerant levels (for cooling systems / heat pumps).
• Lubricating moving parts.
• Inspecting electrical connections and wiring.
• Testing safety controls, airflow and thermostat calibration.
• Checking defrost cycles and reversing valve in heat pumps.

Chapter 6: How to hire a qualified contractor.

Upgrades like duct sealing, air sealing, insulation and HVAC maintenance/installation often benefit from a trained, licensed and experienced contractor — especially when you want quality, safety and long-term performance.

What should you look for in a trusted contractor?

We hope you’ll take advantage of our Quality Contractor Network (QCN) to find a TVA-vetted contractor near you. As you think about home energy efficiency upgrades and consider your options for a qualified contractor, keep the following recommendations in mind:

Licensing & insurance: Ensures compliance with state/local codes and protects you in case of accidents. (Members of the QCN are licensed and insured.)

Proven experience: Specifically, look for experience with the system and climate you have — whether that’s traditional furnaces/AC, heat pumps, ductless mini-splits or combinations.

Knowledge: They should have demonstrable knowledge of energy-efficiency standards and building science (air sealing, insulation, load calculations, duct sealing, ventilation).

Customer references and positive reviews: Look for consistency, on-time accolades and comments about professionalism, transparency and good communication.

Clear written estimates: Your quote should include labor, materials and scope of work; no vague or open-ended pricing.

Training: They should be willing to show their certifications or talk about their training.

Transparent communication and customer care: You should feel like they’re listening to you and explaining their work in clear terms. 

Glossary

ACCA: Air Conditioning Contractors of America; publishes national HVAC installation and quality standards.

Air Sealing: The process of closing leaks, cracks and gaps in a home’s building envelope to prevent unintended airflow.

Blower Door Test: A diagnostic test using a powerful fan mounted in an exterior door to depressurize a home and identify air leaks.

BTU: British Thermal Unit; a measure of heating or cooling output.

Combustion Safety Test: Inspection of gas-fired appliances to ensure proper ventilation and safe exhaust.

Duct Sealing: Repairing and sealing HVAC ductwork to prevent air leaks and improve airflow efficiency.

ENERGY STAR: A U.S. government-backed symbol for energy efficiency, managed by the EPA and DOE.

Heat Pump: A heating/cooling system that moves heat in or out, rather than generating it via combustion.

HVAC: Heating, Ventilation and Air Conditioning

Load Calculation (Manual J): A standardized method (published by ACCA) to determine the correct size HVAC system for a home.

Mastic: A durable sealant used to seal ducts; more effective and long-lasting than standard “duct tape.”

QCN: Quality Contractor Network; a network of TVA-vetted, licensed and insured contractors who can help you with home energy upgrades and applying for rebates.

R-value: A measure of an insulation material’s resistance to heat flow; the higher the R-value, the better its thermal resistance.

SEER2: Seasonal Energy Efficiency Ratio; a metric for air conditioner/heat pump cooling efficiency (new standard).

Supply/Return Ducts: The ducts that deliver conditioned air to living spaces (supply) and return air back to the HVAC system (return).