House is 7 years old and so is the gas water heater, Low hot water pressure in all of my home, What can I do?

There should be a shutoff knob feeding your hot water heater on the cold water pipe near the heater. You may want to make sure it is turned on all the way or is not leaking. Otherwise I'm not sure, although I'm sure others may know. Hope this helped.

Low pressure looks just like low volume, I think that's what you have low volume. Check the flow from the drain spigot. If its great then I'd suspect the heat trap nipples on the outlet of the water heater. Hot Water Heater Replacement Parts - Heat Traps and Pressure Relief Valves (http://factoidz.com/hot-water-heater-replacement-parts-heat-traps-and-pressure-relief-valves/)

Do you have a water softener or filter for hot water only? If so, change the filter, or put the softener on bypass and see if pressure is better. If no filter or softener, the nipples or dielectric unions on top of the water are often times the culprit, as they can plug up over time. For this, just unthread the unions and take a look(make sure water is off and pressure is bled off before doing this). If they are plugged up, just clean our replace them and you should be all set.