Chapter 7 Exercises: Hot Water Systems

These exercises are designed to give you firsthand knowledge of your home's water heating system. Most can be completed in an afternoon. A few — like the anode rod inspection — may require tools you'll need to purchase or borrow. All of them are worth doing; this chapter's information is only useful if you apply it to your actual equipment.

Exercise 7.1: Identify Your Water Heater

Estimated time: 15 minutes Materials needed: Phone camera, notepad

Task: 1. Locate your water heater. Note whether it is in a basement, utility closet, garage, or other location. 2. Photograph the rating label (the large sticker on the side of the tank). Record: - Manufacturer and model number - Serial number - Tank capacity (gallons) - Energy source (gas or electric) - First-hour rating (how many gallons of hot water it can deliver in the first hour of heavy use) - Energy Factor or Uniform Energy Factor (UEF) 3. Determine the age of the unit. Use the serial number decoder at waterheatersrescue.com or search "[manufacturer name] water heater serial number date code." Record the manufacture date. 4. Photograph the complete installation: the tank, all pipe connections at the top, the T&P valve and discharge pipe, and the drain valve at the bottom.

Record your findings: - Manufacturer: __ - Type: gas tank / electric tank / gas tankless / electric tankless / heat pump - Capacity: ___ gallons - Age: ___ years - UEF or Energy Factor: ___ - First-hour rating: ___ gallons - Notes on condition: __

Exercise 7.2: T&P Valve Inspection and Test

Estimated time: 15 minutes Materials needed: Bucket or container (if no floor drain near discharge pipe)

Task: Read Section 7.3 completely before beginning this exercise.

  1. Locate the T&P valve. It is a valve on the side or top of the water heater tank with a lever arm. A metal or plastic pipe (the discharge pipe) should connect to its threaded outlet and run downward.
  2. Inspect the discharge pipe: Does it run downward or horizontally without upward loops? Does it terminate within 6 inches of the floor or into a floor drain? Is it free of caps, plugs, or diameter reductions? If any of these conditions are not met, note it as a code violation/safety issue to address.
  3. Place a bucket under the discharge pipe end if there is no floor drain.
  4. Carefully lift the lever arm to the open position for 1–2 seconds. Hot water should discharge from the pipe. Release the lever.
  5. Confirm the valve closes completely with no dripping.

Record your findings: - T&P valve present: Yes / No - Discharge pipe present: Yes / No - Discharge pipe terminates correctly (within 6 inches of floor or into drain): Yes / No - Valve releases water when lever lifted: Yes / No - Valve closes cleanly (no drip): Yes / No - Approximate age of valve (from manufacturer label on valve body): ___ - Action needed: Replace valve (if over 7 years old, if it doesn't release, or if it won't stop dripping) / Correct discharge pipe / No action

Exercise 7.3: Check and Set Your Thermostat Temperature

Estimated time: 20 minutes Materials needed: Candy or meat thermometer (instant-read), wrench or screwdriver (electric heater only)

Task: Measuring the actual temperature of your hot water tells you whether your thermostat is calibrated accurately. The recommended setpoint is 120°F.

  1. Run hot water at the faucet closest to the water heater for 2 minutes to flush the pipes and get water directly from the tank.
  2. Hold a thermometer in the stream and read the temperature. (An instant-read meat thermometer from the kitchen works well.)
  3. Record the temperature.
  4. If the temperature is significantly above 120°F (above 125°F): Turn the thermostat down. On a gas heater, adjust the dial on the gas valve. On an electric heater, turn off the breaker, remove the access panel (usually two panels, upper and lower), and adjust the thermostat with a flathead screwdriver.
  5. Wait 2–4 hours and test again.
  6. If temperature is below 115°F: Consider turning it up slightly. At 115°F or below, Legionella bacteria (which causes Legionnaire's disease) can colonize water heater tanks.

Record your findings: - Measured temperature: ___°F - Current thermostat setting: ___ - Action taken: Adjusted to ___ / No change needed

Exercise 7.4: Flush the Sediment from the Tank

Estimated time: 30–45 minutes Materials needed: Garden hose, bucket (if no floor drain)

This exercise applies to tank water heaters only. Skip for tankless or heat pump units.

  1. Connect a garden hose to the drain valve at the bottom of the water heater. Route the hose to a floor drain or outside (the water will be very hot — use caution).
  2. Turn off the cold water supply to the water heater (there should be a valve on the cold supply pipe above the heater).
  3. Open a hot water faucet nearby to prevent vacuum lock.
  4. Open the drain valve. Let water run until it appears clear. For a heater that has never been flushed, this may take 10–20 minutes and may include visible sediment. For a heater flushed regularly, it clears within a few minutes.
  5. Close the drain valve. Turn on the cold supply. Wait for the tank to fill (the nearby faucet will run continuously, then produce steady water flow, indicating full).
  6. Close the nearby hot water faucet. Restore gas or electricity.

Note: If the drain valve leaks after you close it (a common issue on valves that have never been opened), replace it with a full-bore ball valve — a $15 part and 15 minutes of work.

Record your findings: - Sediment observed in drained water: none / light / moderate / heavy - Drain valve condition: seals well / leaks slightly / replace needed - Time spent: ___ minutes

Exercise 7.5: Anode Rod Inspection Planning

Estimated time: 20 minutes (inspection planning); allow 1 hour for the actual inspection

Materials needed: Socket wrench with 1-1/16" socket, breaker bar, garden hose

Task: This exercise may be more involved than the previous ones, but the anode rod inspection is the most important maintenance task for water heater longevity. Before doing the inspection:

  1. Locate the anode rod port on your water heater. This is typically a hex plug (1-1/16 inch hex) on the top of the tank, sometimes under the insulating jacket or foam cover. In some Bradford White models, the anode rod is in the hot water outlet fitting — check your model's documentation.
  2. Check whether there is adequate clearance above the tank to pull the rod out. The rod may be 40–48 inches long. If the heater is under a low ceiling, you may need to buy a flexible (segmented) anode rod, which bends as it comes out.
  3. Research your specific model's anode rod location and size using a YouTube search for your brand and model.
  4. Purchase or locate: 1-1/16" socket and long ratchet or breaker bar; Teflon tape; replacement anode rod matching your tank's thread size and water conditions (magnesium for most situations; aluminum or aluminum/zinc for soft water or water with sulfur smell).

When ready to proceed: 1. Turn off the cold water supply to the heater. 2. Open a hot water faucet and drain 5–10 gallons from the drain valve to relieve pressure. 3. Turn off gas or electricity. 4. Locate and remove the hex plug using the socket and breaker bar (it will be tight — this is normal). 5. Pull out the anode rod and inspect: Is more than half the original diameter remaining? If so, it can remain. Is it mostly a bare wire? Replace. 6. Apply Teflon tape to the threads of the replacement rod and install finger-tight, then tighten a quarter turn with the socket. 7. Restore water supply and check for leaks. Restore power or gas.

Record your findings: - Anode rod condition: healthy / moderate wear / needs replacement / was missing - Material of anode rod found: magnesium / aluminum / other - Replacement rod installed: Yes / No - Water softener present in home: Yes / No (if yes, plan annual anode rod inspections)

Exercise 7.6: Energy Usage Estimate

Estimated time: 20 minutes Materials needed: Utility bills (last 12 months), calculator or spreadsheet

Task: Estimating how much your water heater costs to operate helps you evaluate whether upgrading is financially justified.

For gas water heaters: 1. Collect your gas bills for the past 12 months. Note the total therms consumed and total cost. 2. In months when heating season is minimal (summer months), your gas usage is closer to water heating only. Average 2–3 summer months' gas usage and multiply by 12 for an annual water heating estimate. 3. Alternatively: a 50-gallon gas water heater with a UEF of 0.62 and a family of four uses roughly 250–300 therms per year for water heating. At $1.20–$1.60/therm, that's $300–$480/year.

For electric water heaters: 1. Collect your electric bills. Summer months (when no heating is running) give a cleaner baseline. 2. Alternatively: a 50-gallon electric resistance heater at a UEF of 0.93 uses approximately 4,200–5,000 kWh per year for a family of four. At $0.12–$0.17/kWh, that's $500–$850/year.

Upgrade comparison: - If you have an electric resistance water heater and are considering a heat pump water heater: estimate 60–70% energy reduction. With electricity at $0.15/kWh and current usage of 4,500 kWh, savings would be approximately 3,000 kWh/year, or $450/year. - Calculate payback period: (Installed cost of heat pump heater - Rebates and tax credits) / Annual savings = Payback in years

Record your findings: - Estimated annual water heating cost: $ - Current water heater type and age: ___ - Estimated annual savings if upgrading to heat pump (if applicable): $ - Estimated payback period for upgrade: ___ years

Exercise 7.7: Locate and Assess Available Rebates

Estimated time: 20 minutes Materials needed: Computer or phone

Task: If you're considering replacing your water heater — now or in the future — understanding available financial incentives dramatically changes the economics.

  1. Go to dsireusa.org (Database of State Incentives for Renewables and Efficiency). Select your state and search for water heater incentives.
  2. Go to your electric or gas utility's website and search for "rebate" or "appliance rebate." Many utilities offer $200–$600 for heat pump water heaters.
  3. Review current federal tax credits: as of 2024, the Inflation Reduction Act (IRA) provides a 30% tax credit for heat pump water heaters, up to $2,000 (combined with heat pump space heating). Search "IRA heat pump water heater tax credit" for current program details.
  4. Calculate the effective purchase price for a heat pump water heater after applicable rebates and credits.

Record your findings: - State incentives found: ___ - Utility rebate available: $ - Federal tax credit applicable: $ - Net cost of a heat pump water heater after all incentives: $___

Exercise 7.8: Insulate the First Six Feet of Pipe

Estimated time: 30 minutes Materials needed: Foam pipe insulation (matching your pipe diameter), utility knife or scissors, tape

Task: Heat lost through bare hot-water supply pipes near the water heater is pure waste. Insulating the first 6–10 feet of hot water outlet pipe (and optionally the cold water inlet) reduces heat loss and helps hot water arrive faster at near fixtures.

  1. Measure the diameter of the hot water outlet pipe. Standard sizes are 1/2 inch or 3/4 inch. Purchase foam pipe insulation to match.
  2. Cut sections of insulation to fit the accessible portions of the hot water outlet pipe, using a utility knife to slit the foam lengthwise if it's not pre-slit.
  3. Snap the insulation over the pipe and tape seams.
  4. Optionally, wrap the cold water inlet pipe as well — this prevents heat from migrating backward into the cold supply.

Note on gas water heaters: Do not insulate pipe within 6 inches of the flue/vent pipe — there must be clearance from heat.

Exercise 7.9: Develop a 10-Year Water Heater Replacement Plan

Estimated time: 20 minutes Materials needed: Notes from Exercise 7.1

Task: Using the information gathered in Exercise 7.1 and the cost comparison table from Section 7.5, create a simple decision framework for your next water heater replacement.

Answer these questions: 1. How old is your current water heater? If over 8 years old, you are in the replacement planning zone. 2. What fuel source do you have available (gas, electric, or both)? 3. Do you have adequate space and temperature conditions for a heat pump water heater? (See Section 7.5 requirements.) 4. What is your utility's electricity rate? Is natural gas available? This determines which fuel source is more economical. 5. What is the likely installed cost for each type (from Section 7.5 comparison table), minus available incentives (from Exercise 7.7)? 6. What is the estimated payback period for a heat pump water heater compared to a standard electric tank?

Write a simple one-paragraph "my next water heater" plan: what type you would choose and why, roughly when you expect to need it, and how much you're budgeting.