Increased use of electric space and hot water heating can cut carbon emissions from U.S. homes and buildings, a major source of greenhouse gases, a new analysis from the nonprofit Rocky Mountain Institute concludes.

The big picture: The report underscores how achieving extremely steep emissions cuts in the coming decades will require far more than just increased use of low-carbon power generation sources.

The details: The analysis concludes that in new construction, and existing buildings that currently use propane or oil, it's already cost-effective to use electricity instead. It may be economical for some homes already running on natural gas, but the results are less decisive.

Even a wholly carbon-free power system would only cut U.S. emissions by 30 percent, RMI notes. This is far from enough for the 14 states with official plans to cut emissions by 75 percent or more by 2050. Electrification may play a key role in closing that gap.

• "Widespread electrification of buildings, ground transportation, and half of industry would boost reductions to more than 70% if powered by zero-carbon electricity," the report states.

One level deeper: Here are the most immediate steps to bring about more widespread building electrification, according to RMI:

• Nearly all buildings running on propane or fuel oil (9 percent of homes and 11 percent of commercial buildings) stand to gain financially by switching to electricity.
• In most cases, new buildings made to run on electricity will cost less, emit less and allow for greater flexible grid demand in home energy management.
• States and cities with deep carbon-cutting goals should halt their natural gas infrastructure development.

The catch: The report lays out several obstacles. For one thing, contractors and customers still have little awareness of heat pumps as a cost-effective and cleaner alternative to natural gas, which is the default energy source in nearly all new construction.

And changes are unlikely to be made without strong support from municipal and state governments. One example is California Assembly Bill 3232 (awaiting approval in the state Senate), which would require all buildings to run fully on electricity and be emission free by 2030. It's getting a lot of pushback from natural gas consumer and industry groups.