Ao Smith Tall Electric 40 Gal Hot Water Heater Plumbing Guide

Running out of hot water in the middle of a shower is more than just an inconvenience—it’s a daily frustration most homeowners dread. If you’re considering upgrading or installing a reliable unit, the Ao Smith Tall Electric 40 Gal Hot Water Heater stands out as a top choice for consistent performance and energy efficiency. Designed for households of 2–4 people, this model balances capacity, durability, and ease of plumbing integration—a perfect fit for U.S. homes seeking dependable comfort.

What Makes the Ao Smith Tall Electric 40 Gal Water Heater Unique?

The Ao Smith Tall Electric 40 Gal Hot Water heater is engineered for longevity and efficiency. Unlike compact units, its “tall” design offers a higher recovery rate and better hot water delivery—ideal for multi-bathroom homes.

Key Specifications:

• Capacity: 40 gallons
• Voltage: 240V
• Wattage: Dual 4500W heating elements
• First Hour Rating: ~78 gallons
• Energy Factor (EF): 0.95 (highly efficient for electric models)
• Warranty: 6–10 years (depending on model and retailer)

According to the U.S. Department of Energy, water heaters account for about 18% of home energy use. Choosing an ENERGY STAR–recognized model like this Ao Smith unit can reduce consumption while delivering consistent hot water.

How to Properly Install the Ao Smith Tall Electric 40 Gal Water Heater – Step by Step

Professional installation is recommended, but understanding the process ensures you can verify quality work or prepare for a DIY project (if permitted by local codes).

Tools & Materials Needed:

• Adjustable wrench
• Pipe wrench
• Teflon tape
• Dielectric unions
• Garden hose
• Voltage tester
• 240V electrical circuit (dedicated)

Installation Steps:

1. Turn Off Power & Water Supply
   Shut off electricity at the breaker and close the main water valve.
2. Drain Existing Tank (if replacing)
   Attach a hose to the drain valve and empty into a floor drain or bucket. Open a hot water faucet upstairs to relieve pressure.
3. Disconnect Old Unit
   Remove water lines and electrical connections. Take photos before disconnecting for reference.
4. Prepare New Location
   Ensure the area is level, dry, and meets Ao Smith’s clearance requirements (typically 0” side clearance, 6” front access).
5. Install Dielectric Unions & Pipe Connections
   Use dielectric unions to prevent galvanic corrosion between copper and steel pipes—this extends tank life significantly.
6. Connect Cold Inlet & Hot Outlet
   Apply Teflon tape to threads. Cold water enters the dip tube at the bottom; hot water exits from the top.
7. Electrical Wiring
   Connect to a dedicated 30-amp double-pole breaker with 10/2 NM cable. Follow the wiring diagram inside the unit’s junction box.
8. Fill & Test
   Open the cold water supply and let the tank fill completely (check for leaks). Once full, restore power and set thermostat to 120°F—the EPA-recommended safe and efficient temperature.

⚠️ Never energize an empty tank—this can burn out heating elements in seconds.

Common Plumbing Mistakes to Avoid

Even minor errors can lead to leaks, inefficiency, or premature failure:

• Skipping the T&P Valve Extension: The Temperature & Pressure (T&P) relief valve must discharge within 6 inches of the floor—per plumbing codes (IPC Section 504).
• Ignoring Expansion Tanks: In closed water systems, thermal expansion can damage tanks. Install an expansion tank if required by local code.
• Using Non-Dielectric Fittings: Mixing metals without dielectric isolation causes rapid corrosion. Always use dielectric nipples or unions.
• Incorrect Thermostat Settings: Setting above 125°F increases scald risk and energy use. The American Burn Association reports over 5,000 ER visits yearly from water heater scalds.

For a deeper dive into water heater safety standards, see the Wikipedia entry on domestic water heaters.

Ao Smith Tall Electric 40 Gal vs. Competitors: Quick Comparison

Verdict: Ao Smith wins on longevity, efficiency, and reliability—especially in hard water areas thanks to its glass-lined tank and robust anode rod.

Maintenance Tips to Extend Your Water Heater’s Life

A well-maintained Ao Smith unit can last 10–15 years—well beyond the average 8–12 year lifespan.

• Flush the Tank Annually: Sediment buildup reduces efficiency. Attach a hose to the drain valve and flush 3–4 gallons until water runs clear.
• Inspect the Anode Rod Every 2 Years: Replace if >50% corroded. This sacrificial rod protects the tank from rust.
• Test the T&P Valve Every 6 Months: Lift the lever briefly—it should release a burst of water. If not, replace immediately.
• Check for Leaks Monthly: Look around fittings, valves, and the base of the tank.

💡 Pro Tip: Install a drip pan with a drain line if the unit is in a finished space (like a garage or basement). It prevents water damage from slow leaks.

FAQ Section

Q1: Can I install the Ao Smith Tall Electric 40 Gal water heater myself?

A: If you’re experienced with plumbing and 240V electrical work, and your local code allows it—yes. However, improper installation voids the warranty and risks safety hazards. Most homeowners hire a licensed plumber or HVAC technician.

Q2: What size breaker do I need?

A: A 30-amp double-pole breaker and 10-gauge copper wire are required. Never use a smaller gauge or shared circuit.

Q3: How long does it take to heat up?

A: From cold, it takes about 2–3 hours to fully heat 40 gallons. With dual 4500W elements, the first usable hot water is ready in under 30 minutes.

Q4: Is this model suitable for hard water areas?

A: Yes—Ao Smith uses a glass-lined tank and a magnesium anode rod that performs well in hard water. For extreme hardness, consider adding a water softener.

Q5: Does it qualify for energy rebates?

A: Many utility companies offer rebates for high-EF electric water heaters. Check DSIRE (Database of State Incentives for Renewables & Efficiency) or contact your local provider.

Q6: What’s the difference between “tall” and “short” models?

A: “Tall” units are ~9–12 inches taller but offer higher first-hour ratings and better performance in high-demand households. “Short” models fit tight spaces but deliver less hot water per hour.

Conclusion

The Ao Smith Tall Electric 40 Gal Hot Water Heater is a smart, durable, and efficient choice for U.S. homeowners seeking reliable hot water without constant maintenance headaches. With proper plumbing, annual flushing, and correct thermostat settings, it delivers comfort for over a decade.

If this guide helped you understand your water heater options, share it with a friend or on social media—someone in your network might be battling cold showers right now! 💧🔥

Got more questions? Drop them in the comments below—we’re here to help you stay warm and informed.