To make sure you're not testing too early, assume the sperm had very long lives (5 days is considered a very long sperm life) and that conception occurred then. Then allow 14 days for the embryo to implant and develop enough hCG to show up on a pregnancy test (96% of pregnant women will test positive by then.)
A gas water heater will recover in half the time of an electric unit. A 40-gallon gas water heater can recover in about an hour. Recovery for a 40-gallon electric water heater takes about two hours.
The energy costs from electric water heaters can be substantially higher in some areas, and these units are susceptible to power outages, while natural-draft gas water heaters are not. Calculating how quickly a gas water heater can raise the water's temperature requires a little bit of math work. 1  credit: Minerva Studio/iStock/Getty Images. 2  credit: KatarzynaBialasiewicz/iStock/Getty Images. 3  credit: Jupiterimages/liquidlibrary/Getty Images. 4  credit: KatarzynaBialasiewicz/iStock/Getty Images. 5  credit: Gudella/iStock/Getty Images.