Have you checked your furnace filter, insulation lately?

It's been a mild winter throughout most of the country so far. That means we still have time to run through a foul-weather checklist. Here are 10 "must do's" to have a warm, cozy and safe winter.

1. Check attic insulation. A foot of blown-in or batt insulation (R-38) in the attic reduces heat transfer from heated interior space to the great outdoors. This is a do-it-yourself job. If your attic is not insulated, blow in or roll out 12 inches of loose or batt insulation. If the amount of insulation is less than 12 inches, simply roll out unfaced fiberglass batts over the existing insulation to create a heavier thermal blanket. This is a case where more is better. Make sure to leave soffit vents unobstructed.2. Install or replace weatherstripping, if necessary. Check the rubber threshold gasket at the bottom of exterior doors and replace if worn or torn. Next, make sure the top and sides of the door are weatherstripped and fit tightly. If there are gaps, replace the weatherstripping.3. Check exterior doors and windows for gaps. Modern windows are probably OK, but older windows may need some help. To reduce air leakage, casement windows might need some weatherstripping at the joint where fixed and movable panes meet. Old double-hung wood windows are notorious air leakers. Place pieces of narrow self-adhesive rubber weatherstripping on the bottom sides and at the joint where the top and bottom panes meet.4. Check the outside of doors and windows for voids, and caulk any gaps you see.5. Change the filter in the heater. In older furnaces, filters should be changed monthly. Change or service newer, more efficient filters according to the manufacturer's instructions.6. Replace your old thermostat with a new programmable model. This allows you to regulate the heater to warm the house when you're there and to reduce the temperature when you are at work or asleep.7. Have your heater inspected by a licensed heating and air conditioning contractor. An inspection ensures that the heater is operating safely and efficiently. In many cases an inspection can alert you as to whether the unit is at the end of its life. It's nice to have the option to replace an old heater before it quits and becomes an emergency on a cold January day.8. Check the carbon monoxide (CO) detector. If you don't have one, get one. Carbon monoxide is an odorless and colorless gas that kills. An operating CO detector can prevent a tragedy. While you're at it, check the smoke detectors to ensure they're operable.9. Clean gutters and downspouts so fallen leaves won't clog them. Make sure that downspouts discharge away from the foundation and that soil is graded away from the foundation and at least 6 inches below the siding.10. Clean the fireplace of ashes; visually check the chimney for loose or missing mortar. Also consider having the chimney professionally inspected and swept by a licensed and bonded chimney sweep.Even in these days of belt tightening, installing replacement windows remains a virtual mania among homeowners. Take a walk through any suburb built before 1980, and you may find that half the houses no longer have their original windows. Alas, the usual replacements -- extruded PVC or "vinyl" windows -- are dismayingly easy to spot, what with their wavy, cellophane-like glass and glaring white plastic frames.Considering the impact window replacement can have on your home's appearance, it shouldn't be taken lightly. To wit: The last big window-replacement fad happened during the 1960s, when that era's perceived "modern" upgrade -- sliding aluminum windows -- were retrofitted to countless traditional homes, from Victorians to bungalows. The aesthetic fallout from this campaign is still painfully obvious in many old neighborhoods.In retrospect, of course, aluminum sliders installed in a traditional home are rightly seen as a glaring anachronism, and frequently bring a penalty in resale value over homes with their original windows.Today, thanks to the same kind of offhand, insensitive and often just plain unnecessary ways in which vinyl windows are installed in older homes of all eras, they've essentially become the modern-day version of the aluminum slider. And with a little historic distance, the aesthetic results will be just as regrettable.Window replacement is often cannily advertised as a great energy-saving investment, which is probably why so many well-intentioned homeowners choose this route. And it's true enough that switching from single-glazed windows to double-glazed ones will save roughly half the energy lost through the glass. But here's the catch: In the average house, windows typically make up a relatively small fraction of the total heat loss. Hence, dollar for dollar, there are far more cost-effective ways to improve your home's energy efficiency.Upgrading attic insulation ranks first among them, since ceilings are typically the single greatest source of heat loss. The current standard for attic insulation is R-30; so if your house has appreciably less than this, adding insulation will be far more cost effective than replacing your windows.The same holds true if your furnace and ductwork predate 1980 or so. Modern furnaces now have thermal efficiencies in the neighborhood of 95 percent, versus typically dismal efficiencies in the 70s and even down into the 50s for some older gravity furnaces). Because a furnace upgrade addresses the root of inefficiency rather than just nipping at the leaves, the resulting energy savings can be truly dramatic.One more thing to consider: Aside from offering double glazing, there's very little that's green about vinyl windows. Vinyl is, of course, the plastics industry's more euphonious name for polyvinyl chloride, which a number of environmental authorities consider to be the most toxic plastic in the environment. Bury it in a landfill, and it just sits there. Burn it, and it produces dioxin, a toxic chemical compound that's a known teratogen, mutagen and carcinogen.The bottom line? Think twice about replacing your current windows with vinyl ones for energy-efficiency reasons alone. Chances are you'll get more bang for your energy buck with simpler upgrades that don't even show on the outside.