On average, showers were 18% of U.S. indoor water use in 1999, at per minute traditionally in America. A simple method to reduce this use is to switch to low-flow, high-performance showerheads. These showerheads use only 1.0-1.5 gpm or less. An alternative to replacing the showerhead is to install a converter. This device arrests a running shower upon reaching the desired temperature. Solar water heaters can be used to obtain optimal water temperature, and are more sustainable because they reduce dependence on fossil fuels. To lessen excess water use, water pipes can be insulated with pre-slit foam pipe insulation. This insulation decreases hot water generation time. A simple, straightforward method to conserve water when showering is to take shorter showers. One method to accomplish this is to turn off the water when it is not necessary (such as while lathering) and resuming the shower when water is necessary. This can be facilitated when the plumbing or showerhead allow turning off the water without disrupting the desired temperature setting (common in the UK but not the United States).