Few regions in the nation were spared winter's frigid fury this week.

Parts of the Northwest and Rocky Mountain regions were still digging out of four weeks of snow as temperatures iced California's citrus crop. San Francisco Bay Area residents kept an eye out for the first snow flurries in years.

Frigid air flowed into New England as wind chill factors pushed some temperatures in the upper states' hinterlands to 35 below zero. Ocean-effect snow showers were forecast for Cape Cod.

New Orleans shivered through 30 degree temperatures and Mother Nature put central and southern Texas into the deep freeze. The Deep South and Southern California held onto "heat waves" with temperatures in the 40s and 50s.

And in the Midwest, well, it's winter. Highs were in the 20s and 30s.

Only south Florida's balmy peninsula appeared to escape the arctic blast.

When you go home after a day on the bone-chilling tundra, your igloo ought to be toasty.

The U.S. Department of Energy (DOE) and the Comfort Institute, an indoor comfort research, training and consumer protection organization based in chilly Bellingham, WA, offer these tips to get your house in order for what's likely to be a long, bleak winter even Punxsutawney Phil can't stop.

• Seal duct leaks. The DOE says the typical duct system loses 25 to 40 percent of the energy put out by the central furnace, heat pump or air conditioner. That puts a strain on your wallet as well as comfort levels in your home. Heating ventilation and air conditioning (HVAC) contractors can diagnose and pinpoint duct leak locations and check the static pressure in your ducts and ventilation system. The exam is often part of an energy audit used to also examine insulation, air leaks and other energy inefficiencies in your home.

• Consider a new furnace or HVAC system. Newer more efficient systems coupled with sealed ducts, better home insulation, weatherized windows and doors, programmable thermostats and other steps to tighten your home, can remove uneven heating and cooling patterns and cost less to operate. Don't assume you need a larger unit. A new unit and overhauled duct and ventilation system may shock your budget over the short term but provide a payback in energy cost savings over the long run.

• Don't neglect maintenance on your furnace or HVAC. Get a checkup of your heating system to make sure it's performing efficiently and safely. Clean or replace your system's air filter regularly as instructed by your manual.

• Insulate to the max. Missing insulation can also cause discomforting cold spots in your home. Especially add insulation in attics, rooms adjacent to attics, and next to or over garages. Your contractor can perform an infra-red camera scan to find cold spots and inspect insulation levels. Hollow wall cavities behind sheet rock also need internal attention. Forget external insulation.

• Manually close off rooms, closets and shut doors to unused spaces or consider installing a controlled damper system that is tied to thermostats and automatically open and close as needed.