Insulating hot water can help reduce energy loss, especially in exterior walls, which are more exposed to cold outdoor temperatures. Aside from reducing energy loss it may even help raising water temperature 2ºF–4ºF. For the most efficient results it is best to use rigid foam or fiberglass batts. You may also use Pipe Sleeves made with polyethylene or neoprene foam, which wraps around the pipe. It is best to secure the sleeves with acrylic tape.
PEX tubing is made from HDPE (High-density Polyethylene Polymer). This type of water supply piping can replace most of the metal or rigid plastic piping. It also has several advantages over metal and plastic piping.

Flexibility

Faster installation

Resistant to scale build-up

Conserves energy

Requires fewer fittings

These water-heating systems have become the most common water heating system in the U.S. The heater’s efficiency is measured by the unit’s overall energy efficiency is based on the amount of hot water produced over a typical day. These tanks are rated based on the energy factor (EF) and as the EF increases, so does the heater’s efficiency. For a good level of efficiency it is best to have an EF of at least 0.60.Setting the temperature at 120 will also help save energy.

Although most water heaters have insulation with an average R-Value of 6 built into the tank, some heaters may have up to R-15 insulation.

Tank style heaters are constantly heating the water inside the tank. If the tank is not in use, then there is standby heat loss. Standby heat loss can be avoided by setting up a timer for the water heater or by using a different type of water heating system such as on demand heaters.

These systems turn on only when the water is running. Since it is not always heating water, Standby heat loss is avoided and therefore energy efficiency is easily achieved.

As the water flows through the heater, an electric element or gas burner heats the water delivering a constant flow of hot water. Electric tankless heaters may need and upgrade to the main panel.

Tankless water heaters generally provide hot water at a rate of 2 to 5 gallons (7.6 - 15.2 liters) per minute.

It is important to size the heaters to the necessities of the household in order to accurately calculate if an on demand heater is the proper system.

These are toilets that use less water than the U.S law standard of 1.6 GPF (Gallons Per Flush). HET’s use 1.28 GPF providing a savings of 20%. Some companies have been able to create toilets that use 1.1 GPF. You may also find dual-flush toilets, which have a low volume flush for liquid waste as well as a standard flush for solid waste therefore reducing unnecessary consumption for liquid waste.

When selecting a new toilet for you a project, it is best to purchase a WaterSense - labeled HET in order to ensure maximum efficiency.
Low-volume showerheads may use a maximum of 2.5 gpm (gallons per minute), which can help save 38 gallons of water per day when compared to older showerheads.

Bathroom faucets should use 1.5 gpm while kitchen faucets should use a maximum of 2 gpm.

It is very important to combine flow-reduction devices with an on-demand water circulation system since a lower flow of water may cause users to wait longer for hot water.
Appliances such as dishwasher and washing machines also have great potential to help conserve and save energy and water. When purchasing a dishwashers, make sure to choose and Energy Star Certified model. Some model may save both energy and water.

When purchasing a washing machine, it is preferable to choose a front-loading machine rather than top-loading models. High-efficiency machines may use up to 40% less water per wash. It is always best to search for Energy Star washers and dryers.