When you’re considering purchasing a new gas water heater, several key factors will determine how efficient it will be over time. Understanding factors that may affect your gas water heater efficiency before purchasing can help you choose a suitable model to meet your needs and budget. It will save you money on energy bills in the long run and reduce your carbon footprint. To understand these factors, you need to know what they are first. Read on to learn more about the five key factors that determine the efficiency of your gas water heater!
1. System Pressure
A gas water heater’s efficiency is, in part, determined by how much pressure it’s running at and its capabilities. As a result, lower water pressures increase energy efficiency, but you need to ensure that your system has enough flow to do its job. If not, it could run too hot or break down. You can control your water pressure by adjusting a knob on your tankless water heater.
High pressure reduces flow and increases energy use, while low pressure wastes hot water and doesn’t provide enough volume for larger jobs, such as showering or washing dishes. Choose an affordable, efficient system with just enough pressure to handle your needs. You can refer to rinnai gas heaters prices and pressure setting guides to help find a good fit. It’s also worth noting that installing an external booster pump can help if your home’s water pressure is low.
2. Burner Design
The design of a burner can significantly impact how efficiently it heats the water. Two factors are crucial to efficiency:
- The placement of burners
- The number of total burners in use at any given time
For example, if your water heater has two or three large burners (20,000 BTUs), you’ll want to ensure that no more than one or two are in use at once. If all three are working at once, you could be wasting up to 50% of your energy.
Also, keep in mind that different types of burners work better for different types of water heaters—in general, natural gas burns hotter than propane and provides more even heating. If you’re looking for an energy-efficient model, look for models with multiple small burners rather than a few large ones.
3. Ambient Air Temperature
The temperature of your ambient air (the air in your home) affects how energy efficient and how well your water heater works. You’ll use more power to heat water if it’s cold outside, so you should keep your thermostat at 68 degrees or higher to avoid wasting energy. In addition, cold temperatures can prevent hot water from reaching fixtures—another factor that reduces efficiency.
To maximize efficiency, turn down your thermostat and invest in energy-efficient upgrades for your house. New windows, insulation, and heating systems will help you save money on gas bills while keeping your family comfortable.
4. First Hour Rating
A gas water heater’s first-hour rating is a number that indicates how many gallons of hot water you can heat per hour from your water tank. Look for a model with high-efficiency ratings in its first hour, which will provide hot water when you need it most, like when multiple people take showers and run faucets at once. Higher first-hour ratings also mean lower monthly utility bills. An efficient unit should have a first-hour rating of 100 to 120 gallons per hour (gph).
You may see some units boasting as much as 150 gph or higher, but unless you’re regularly running multiple simultaneous showers or taking long soaks in your tub, those won’t do much good. Most households require an 80-100 gph unit; look for models rated between 95 and 115 gph if you’re on a budget. If you want extra capacity without sacrificing energy efficiency, consider a hybrid water heater—it offers several temperature settings, so it only heats enough water for what you need.
5. Frequency of Use
How frequently you use your water heater can affect its overall efficiency depending on its size and capabilities. If you use it every day, for multiple hours, and extended periods, then it’s bound to be less efficient than if you’re using the gas water heater once a week for short amounts of time. If you run out of hot water often, try installing a larger tank or thermostat so that you don’t have to run your tank all night to shower in the morning!
The efficiency rating of a gas water heater tells you how much energy it uses compared to its capacity, expressed as its annual fuel utilization efficiency (AFUE). You can calculate it by dividing a unit’s total energy input by its total output. When buying a new water heater, choose one with close to 100 percent AFUE rating. In most cases, a reasonable estimate is 80 percent. If your home has multiple bathrooms or showers, consider investing in a more efficient model. According to Energy Star, water heaters rated at 90 percent or higher can save up to $250 per year on utility bills—not bad for a relatively small investment!