Which should I buy?

Finding the right stuff for your projects

Cheap vs. expensive furnace filters

The furnace filters at my hardware store range in price from 75¢ to $40. What am I really getting with a more expensive filter?

Filters work harder in summer!

Changing filters isn't only a heating season chore. Many blower motors work at a higher speed in air conditioning mode than in heating mode, meaning you should change the filters more often in the summer. A clogged filter can make both your furnace and your air conditioner work harder and less efficiently.

You can buy a dozen 75¢ filters (left), for $5 filters or one $20 to $50 filter to get you through the year. Which you should buy depends on how good your memory and health are.

Basically, you’re getting a filter that requires less changing and captures more, and smaller, particles. The 75¢ woven fiberglass filters do one thing—screen out dirt and debris that could damage your furnace blower motor, though they do take out some pollen and mold spores. If you can remember to swap them out every month and air quality isn’t an issue, these will do the job.

But if you’re the kind of person who forgets to change the oil in your car, buy $4 pleated filters, which require changing only every three months. If you stretched out the accordion-like material in these filters, you’d find two, three or four times the amount of surface area. This means they can capture smaller particles for longer periods of time without impeding the airflow of your furnace.

If members of your household smoke or have allergies or asthma, or if you have pets, look into the more expensive, high-efficiency electrostatic filters—ones that both filter and magnetically attract contaminants. Some are effective for up to a year. They can filter out bacteria, dander, odors and smoke particles. But health experts warn that you may be wasting your money on these $20 to $40 filters unless you take the following steps: Use them in conjunction with a high-efficiency vacuum cleaner, install a dedicated air purifier, wash or vacuum the filter monthly and take other steps to clean up your air and house as well.

Many filters carry a MERV (minimum efficiency reporting value) rating, which indicates their effectiveness. The higher the MERV rating, the more effective. Most spun filters have a MERV rating of 4. Standard pleated filters average MERV 6. Electrostatic pleated versions start at MERV 8, with the highest quality ones hitting MERV 12.

Water-based vs. oil-based poly

WATER-BASED polyurethanes provide a clear finish and have low odor. You can recoat them in two hours and clean your tools with water. If you start early enough in the day, you can apply the recommended four coats and sleep in the room that night.

OIL-BASED polyurethanes leave an amber glow and require fewer coats. But the five-hour wait between coats and 12-hour wait after the last coat will put a bedroom out of commission for a few days—and you’ll have to put up with a strong odor.

We’re installing tongue-and-groove maple flooring in our newly remodeled master bedroom. We love the natural look of the maple but want a finish that will protect it. Is water- or oil-based polyurethane better?

Both offer good protection; the biggest difference is in appearance. If you love the natural look of maple, apply a water-based (water-borne) polyurethane. They appear milky in the can, but go on clear and remain clear. They’ll slightly accent the character of your wood without giving it the amber tint of an oil-based poly. (However, some woods, like the oak shown, cry out for that amber tint.) Water-based finishes dry fast—most within two hours—so you can apply several coats in a day and use the room that night. They have minimal odor and clean up with water too.

But water-based polys have their tradeoffs. They cost twice as much as oil-based polys. They won’t give wood the rich glow that oil-based polys impart; some even consider them cold looking. When I applied waterborne poly recently, I found that it went on so clear I had to use a bottle cap to mark each 8-in. wide swath of finish as I went.

Most water-based polys contain only 30 to 35 percent solids, compared with the 45 to 50 percent solids in oil-based products. Since these solids create the protective finish, you need to apply four coats, as opposed to two or three. And you may need to apply additional coats every two years or so.

There’s debate over which finish is harder, but some experts maintain that hardness isn’t necessarily a good attribute of a floor finish. You want a finish that will flex along with the floor. And a super-hard finish shows scratches more readily.

You’ll prolong the protective life of any finish by eliminating its No. 1 enemies: dirt and grit. Sweep or vacuum the floor often and put throw rugs in high-traffic areas.

Oriented strand board or plywood?

I’m building a garage this spring. The sheathing I use for the walls and roof will be exposed on the inside of the garage. Does it matter whether I use plywood or oriented strand board?

The short answer is, you can use either. Building codes, the Engineered Wood Association, architects and most builders rate plywood and oriented strand board (OSB) equal in strength and durability. Like-thicknesses of these two products can span the same distances between studs or rafters, weigh about the same and offer similar nail-holding abilities.

THE EDGES of the 1/2-in. oriented strand board (OSB) that soaked in my bathtub overnight swelled almost 1/4 in. (and stayed swollen), while the plywood remained stable. The lesson? Don’t store OSB in a full bathtub. Kept high and dry during storage and after installation, OSB has the same strength and durability as plywood but is $3 a sheet less.

OSB has its advantages. Some panels have a textured surface, which makes them less slippery when used for roof sheathing. OSB panels often have lines at 16- and 24-in. intervals so you know where underlying studs, rafters and joists are for nailing. In our area, 1/2-in. OSB costs $3 less per sheet than 1/2-in. plywood. And OSB is available in 4 x 9-ft. sheets, which means you can sheathe an 8-ft. tall wall and the joists below with a single sheet.

OSB has one irritating characteristic—but only if you abuse the stuff. The edges tend to swell when they get wet and remain swollen even after drying out. This results in ridges that can “telegraph” through shingles, and even carpet when OSB is used for subfloors. So store your OSB in a dry place, then cover it with tarpaper or siding ASAP to protect it from the elements.

FAST FACT: Last year, oriented strand board surpassed plywood in terms of square footage produced. OSB is now used for about 70 percent of all floor, wall and roof sheathing in North America.

Art Direction • BECKY PFLUGER and GREGG WEIGAND

Photography • RAMON MORENO, ZUEHLKE PHOTOGRAPHY