Unless you’ve had to suffer through an ice-cold shower, you probably haven’t given your water heater much thought. But did you know they’re responsible for nearly 20% of your home’s energy costs? Whether your water heater is approaching the end of its life or you’re simply thinking about a money- and energy-saving replacement, consider these factors in choosing your new appliance.
Fuel Source
- Electric water heaters use heating elements. They’re less expensive to purchase but are less efficient than other types.
- Gas water heaters cost less to run but have higher purchase prices. Because they use a burner, they have to be installed in an area allowing plenty of air circulation.
- Hybrid water heaters use energy from the air to heat the water—either from the room where they’re installed or from the outside. Up-front costs are significant, but they’re highly efficient and can drastically reduce energy bills.
Types of Water Heaters
- Storage tank water heaters are the most common residential option. Available in 20- to 100-gallon capacities, these units heat up the water in an insulated tank and then hold it until you need it. Tank heaters vary in purchase price and efficiency ratings—with gas-powered units ranking the highest on both counts.
- Tankless or on-demand water heaters don’t have a storage tank. Rather, water flows over a series of coils, heating it up as you need it. They’re energy-efficient, but they can only produce approximately 3.5 gallons of hot water per minute (GPM).
- Hybrid water heaters use a pump to extract heat from the air around the unit, making them highly efficient. While they deliver more hot water in less time than a standard electric water heater, they’re more expensive and they require quite a lot of space above and around the unit.
- Solar water heaters are roof-mounted and transfer heat from the sun to your water tank. Although they’re the most environmentally friendly option, they’re inefficient on cold or cloudy days and expensive to purchase and install.
Water Heater Capacity
To determine what size water heater you need, factor in both your household size and how much hot water you need in peak hours. For instance, if during the first hour of the day two people take 10-minute showers (40 gallons), you run the dishwasher (6 gallons), and you start a load of laundry (25 gallons), you need a water heater with a first-hour rating (FHR) of at least 71 gallons.
For tankless water heaters, it’s important to consider how many appliances may be running simultaneously. For example, if you start the dishwasher (2-4 GPM) before you jump in the shower (up to 3 GPM), one, 3.5 GPM tankless heater won’t be sufficient.
HOW TO CALCULATE PEAK HOUR USAGE NEEDS
Information and example chart from Energy.gov
| Usage | Average Gallons of Hot Water per Usage | Times Used During One Hour | Gallons Used in One Hour | ||
|---|---|---|---|---|---|
| Shower | 10 | x | 3 | = | 30 |
| Shaving | 2 | x | 1 | = | 2 |
| Hand Dish Washing / Food Prep. | 4 | x | 1 | = | 4 |
| Dishwasher | 6 | x | = | ||
| Clothes Washer | 7 | x | = | ||
| Total Peak Hour Demand | 36 |
Based on the example above, this family would want a hot water heater with a first hour rating of 34 – 38 gallons.
The Consumer Energy Center determines peak hour usage a little differently, taking into consideration only the number of bedrooms and bathrooms.
| How many Bathrooms? | 1 - 1.5 | 2 - 2.5 | 3 - 3.5 |
| How many Bedrooms? | 1 / 2 / 3 | 2 / 3 / 4 / 5 | 3 / 4 / 5 |
| First Hour Rating Requirement: | 43 / 60 / 60 | 60 / 70 / 72 / 90 | 72 / 82 / 90 |
To decide what’s right for your family, you may want to use both charts and determine an average number.
DETERMINING THE RIGHT SIZE FOR YOUR FAMILY
We talked about first hour rates based on the busiest times of day, however, another important detail to consider is the size of the tank itself. Most households need about a 50 gallon tank. To determine if that is large enough for your household, consider the following:
- Most bathtubs hold approximately 40 gallons of water.
- Large soaking tubs can hold up to 140 gallons.
- Have you upgraded your bathroom with vertical spa type shower heads?
- Does your family use multiple appliances during peak periods of use?
If you are considering a size upgrade for your water heater, always remember to measure the height and width to compare to your space restrictions and doorway sizes before making your final decision.
Maplewood Plumbing and Sewer has been helping St. Louis homeowners choose the right water heater for more than 40 years. Our family owned business prides itself on our solid reputation in the community. Give us a call and see for yourself why our loyal customers won’t use anyone else!
We offer a one-year warranty on all parts and labor excluding washers.
We are also experts in Kitchen plumbing, basement plumbing, bathroom plumbing and tankless water heater installation. Give us a call at 314-645-6350 or fill out the contact form here to request a bid.