Buyers Guide to High Efficiency Toilets
High efficiency toilets are the advanced generation of the 1.6 gallon low-flow toilets that have been required since the 1990s. Toilets must use 20% less water to earn the high efficiency rating, so most use 1.28 gallons and some require as little as 1.1 gallons per flush.
With these basics in mind, let’s examine the key factors that drive performance and should be considered during the buying process.
Most feature one of three basic technologies:
- Gravity fed toilets rely on gravity and the weight of the water. When the toilet is flushed, gravity pulls water into the bowl and water and waste out of it.
- Pressure-assisted models have a smaller tank inserted inside that holds water under pressure. When the toilet is flushed, a fast and powerful gush of water efficiently removes waste.
- Power-assisted versions incorporate a small pump that boosts water velocity, but the pump requires a 120-volt power source to operate.
Overall, people tend to prefer pressure-assisted models. They’re noisier, but they perform well and are less likely to clog, a complaint common with gravity-fed toilets. Power-assisted versions also work well, but because they require power, they’re more expensive and challenging to install.
These primary technologies are sometimes combined with secondary ones to further reduce water usage. The dual-flush option, for example, allows you to choose a light flush using less than a gallon of water or a full-force flush using 1.6 gallons.
A well-engineered high efficiency toilet will incorporate a combination of elements that work together to maximize performance, but the features critical to long-term satisfaction are hidden from sight. These include a:
- Large flush valve. Most toilets have 2-inch valves, but those with oversized 3-inch valves are able to release a larger volume of water in a single rush. This helps move out waste and provide enough water to more efficiently rinse the bowl clean.
- Large trapway. Waste and water exit the bowl through the trapway, the curved channel located inside the toilet base that connects to the opening at the back of the bowl bottom. Large ones (2 or more inches in diameter) increase efficiency and reduce the likelihood of clogs.
- Straighter trapway. The straight design allows waste to exit quickly and reduces clogging.
- Fully glazed trapway. The fully glazed surface reduces friction to expedite waste removal and helps reduce staining as well.
Study product specifications to determine if the models you’re considering meet these basic criteria, and visit bathroom showrooms and plumbing supply houses to examine different models in person. Once you’ve narrowed the list to your top picks, take time to read online user reviews and focus on issues like water pressure, flush efficiency and clogging. The average toilet lasts between 10 and 20 years, so it’s worth investing the time to choose wisely and well.