Now that you know whether you have/want a gas or electric water heater, you’ll have to choose a heater that is the right size for your family’s needs, whether it is a conventional or tankless heater.
Conventional tanked water heaters range, on average, from 20 – 100 gallons. You don’t want to end up with a water heater that is too big because then you’ll be using more energy than is needed, meaning fewer savings for you. 👎 On the contrary, if you get a water heater that is too small, you’ll still be using more energy because you’ll run out of warm water faster and have to wait for the heater to catch back up. You definitely don’t want to find out that your water heater is too small in the middle of a nice relaxing shower! 😬 That’s why the First Hour Rating is important.
Determine the FHR
The FHR is the measurement of how much hot water the conventional tanked heater will deliver during a busy hour, such as first thing in the morning. The FHR is always on the heater’s yellow Energy Guide label, but if you want to double-check it yourself, use the following formula:
- Allot 12 gallons of hot water per person in the household.
- Figure the home’s maximum occupancy as the number of bedrooms plus 1. For example, we have 4 bedrooms, so we add 1 and get 5. Now multiply this amount times the 12-gallon allotment and you end up with an FHR of 60 (gallons). That’s the minimum FHR that this home should need from its water heater.
Tankless Heater’s Gallons Per Minute (GPM)
A tankless water heater’s size is based on a flow rate of Gallons Per Minute (GPM). There is no FHR because there is no reheat time for the refilling water (since there is no tank to refill!). The GPM is based on a given heat rise (typically 25 or 50 degrees), and it ranges from 4 gallons per minute to 8 gallons per minute. A tankless heater that heats 4 gallons per minute can handle about 1 shower plus one appliance operating at the same time. A unit heating more than 7 gallons per minute can typically handle two showers and a large appliance.]
Pros and Cons of Tanked Vs. Tankless Water Heaters