Insulate Tankless Heater: Slash Bills & Boost Hot Water!

Considering how to insulate a tankless water heater to cut down on energy waste? That's a smart move. A quality insulation wrap, easily found at stores like Home Depot, is a key component. Understanding the impact of heat loss, especially in colder climates, demonstrates the return on investment. Companies like Rheem, a leader in tankless heater technology, often provide guidelines that complement the basic principles of how to insulate a tankless water heater, guaranteeing optimal savings and a consistent hot water supply.

Image taken from the YouTube channel Matt Risinger , from the video titled 3 Things to Know about Exterior Tankless & Freezing Weather .
How to Insulate a Tankless Water Heater: Your Step-by-Step Guide
A tankless water heater is already an energy-efficient choice, but properly insulating it can take those savings even further. Insulation helps prevent heat loss, leading to lower energy bills and more consistently hot water when you need it. This guide will walk you through everything you need to know about how to insulate a tankless water heater.
Why Insulate Your Tankless Water Heater?
Before diving into the "how-to," let's understand the "why." While tankless heaters don't constantly heat water like traditional tank heaters, they still experience some heat loss, especially in colder climates. Insulating key components minimizes this loss and offers several benefits:
- Reduced Energy Bills: Less heat loss means your heater doesn't have to work as hard, saving you money.
- Faster Hot Water Delivery: Insulation helps maintain water temperature in the pipes, so you get hot water faster.
- Freeze Protection (In Some Cases): In extremely cold environments, insulation can help prevent pipes from freezing, especially outdoor units. However, insulation alone is not a sufficient freeze protection method and may require additional measures such as heat tracing.
- Increased Efficiency: By minimizing heat loss, you're maximizing the efficiency of your tankless water heater.
Identifying Insulation Needs
Not all tankless water heaters require insulation. Consider these factors:
- Location: If your unit is located in an unheated area like a garage or crawl space, insulation is more critical. Indoor units in climate-controlled environments may not benefit as much.
- Climate: Colder climates necessitate more insulation to combat heat loss.
- Existing Insulation: Check if the manufacturer already provides some insulation. Some units have built-in insulation around key components.
What You'll Need: Materials and Tools
Gather the following before you begin:
- Pipe Insulation Sleeves: These are pre-formed foam or rubber tubes designed to slip over pipes. Choose the correct diameter for your pipes.
- Insulation Tape: Used to seal seams and secure insulation. Foil tape is a good option as it's heat resistant.
- Measuring Tape: To measure pipe lengths accurately.
- Utility Knife or Scissors: For cutting insulation materials.
- Safety Glasses: To protect your eyes.
- Gloves: To protect your hands.
Step-by-Step Insulation Guide
Follow these steps to insulate your tankless water heater:
- Safety First: Turn off the power to your water heater at the breaker box. Also, turn off the water supply to the unit.
- Identify Target Areas: The most important areas to insulate are the hot and cold water pipes leading to and from the unit. Some people may also insulate the main unit itself but follow manufacturer's instructions to prevent overheating.
- Measure and Cut: Measure the length of the pipes you want to insulate. Cut the insulation sleeves to the correct length using a utility knife or scissors. It's better to cut slightly longer than shorter, as you can always trim excess.
- Install Pipe Insulation:
- Open the slit in the insulation sleeve and carefully slide it over the pipe.
- Ensure the sleeve is snug against the pipe.
- If the sleeve has an adhesive strip, peel off the backing and seal the seam. Otherwise, use insulation tape to secure the seam along the entire length of the sleeve.
- Seal Seams and Joints: Use insulation tape to seal any gaps or joints between insulation pieces. This prevents air from penetrating and reducing the effectiveness of the insulation.
- Insulating the Unit (Optional, Check Manufacturer's Instructions): Only insulate the unit itself if the manufacturer explicitly allows it. Wrap the unit with a pre-cut insulation blanket designed for water heaters, ensuring ventilation around critical components like the exhaust vent and burner access panel. Secure the blanket with tape. Never block ventilation openings.
- Double-Check Your Work: Inspect all insulation for gaps or loose areas. Seal any imperfections with tape.
- Restore Power and Water: Turn the power and water supply back on.
Selecting the Right Insulation
Choosing the appropriate insulation is crucial for optimal performance. Consider the following:
Pipe Insulation Types
- Foam Pipe Insulation: Cost-effective and easy to install. Good for basic insulation needs. Often made from polyethylene or neoprene.
- Rubber Pipe Insulation: More durable and heat-resistant than foam. Provides better insulation in colder climates. Usually made from EPDM (ethylene propylene diene monomer) rubber.
Insulation Thickness
The thicker the insulation, the better the heat retention. A thickness of 1/2 inch to 1 inch is typically sufficient for most applications. Check local building codes for specific insulation requirements.
R-Value
R-value measures an insulation's resistance to heat flow. A higher R-value indicates better insulation. Choose insulation with an R-value appropriate for your climate.

Troubleshooting Common Issues
Here are some common problems you might encounter:
Issue | Solution |
---|---|
Insulation won't stay in place | Use more insulation tape to secure it tightly. Consider using cable ties for extra support. |
Gaps between insulation pieces | Cut additional pieces of insulation to fill the gaps. Seal the seams with insulation tape. |
Condensation forming on the insulation | This indicates a leak or insufficient insulation. Identify and repair the leak, or add another layer of insulation. |
Manufacturer doesn't allow insulation | Do not insulate the unit. Focus solely on insulating the pipes. |
Maintenance Tips
- Regular Inspections: Periodically check the insulation for damage, gaps, or signs of wear and tear.
- Replace Damaged Insulation: If you find any damaged insulation, replace it immediately.
- Re-Tape Loose Seams: Over time, the tape may loosen. Re-tape any loose seams to maintain insulation effectiveness.
Video: Insulate Tankless Heater: Slash Bills & Boost Hot Water!
FAQs: Insulating Your Tankless Water Heater
Have questions about insulating your tankless water heater? Here are some common queries and their answers to help you boost efficiency and save money.
Why should I insulate my tankless water heater?
Insulating your tankless water heater, especially the pipes, reduces standby heat loss. This means less energy is used to maintain water temperature, resulting in lower energy bills and faster access to hot water.
What parts of my tankless water heater should be insulated?
The most important parts to insulate are the hot and cold water pipes connected to the unit. Focus on the first few feet of piping as they exit the heater. While insulating the unit itself isn't usually necessary, pipe insulation is crucial.
What type of insulation should I use?
Foam pipe insulation sleeves are the easiest and most effective for insulating pipes. Ensure they are the correct diameter for your pipes. Self-adhesive or wrap-around insulation can be useful for tight spaces or odd-shaped pipes.
How difficult is it to insulate a tankless water heater's pipes?
Insulating a tankless water heater’s pipes is a relatively simple DIY project. Most pipe insulation has a slit, allowing you to easily fit it around the pipe. Secure with tape. There are plenty of resources on how to insulate a tankless water heater with a quick online search if you need step-by-step visual assistance.