The federal government this spring enacted new requirements for residential water heaters designed to improve their efficiency and use less energy. The standards apply to all water heaters regardless of what sources they use for heating: electric, gas, propane or oil.

The least efficient water heaters under 55 gallons that have previously been available to consumers will no longer be, once the existing stocks are sold. Homeowners replacing units will need to purchase the more efficient units.

For those who have less efficient models in their homes, the dimensions of the available replacement products may be a few inches wider or taller requiring minor adjustments to spaces and plumbing. However, no new venting or draining systems will be needed for these products. Another option would be to have the same-sized product with about 10 percent less capacity. For those who currently have the most efficient electric resistance products, there will be no change.

All residential electric models over 55 gallons must be of the hybrid electric heat pump water heater type design. Hybrid electric heat pumps will use less electricity than traditional electric resistance water heaters, but also have additional space and plumbing requirements.

It is unclear how prices will be affected at this point, but they will likely increase. The greatest impact is anticipated for the larger than 55-gallon units, as the hybrid electric heat pump equipment is generally more expensive than the previous electric water heater technology (see graphic).

Natural gas water heaters will also increase in size, will have new technology and installation requirements for the larger units, and will likely be more expensive.