Q. I want to replace my roof with one that is efficient, attractive, and long-lasting like slate, tile, or heavy shakes. With a limited budget, what are the best types of roofing to consider? — S.C.

A. The type of roofing materials you select impacts not only upon the appearance of your house, but upon your utility bills. Many have warranties up to 50 years and can make your house more fire safe and valuable at resale.

Installing contoured shingles, shakes, tiles, or slate forms small air gaps above the roof sheathing. In the summer, this produces a natural air flow under the roofing to reduce the roof temperature in the hot sun. This increases your comfort and cuts your air-conditioning costs.

Some new roof materials simulate the look of expensive heavy slate, tiles, and shakes at a fraction of the cost and weight. For example, new lightweight fiber-cement roofs (now use cellulose fibers instead of asbestos) are difficult to distinguish from real clay or slate.

Fiber-cement tiles have a high insulation value of R-2.4. Since they are relatively lightweight, your roof should be able to support them. Real slate, weighing more than 1,000 pounds per square (100 square feet), requires extra-strong roofing construction.

Another option to simulate the expensive look of slate or clay tile is polymer roofing. It is made of the same high-strength plastics used in cars and aircraft. It costs only about one-third as much as real clay tiles and weighs only one-10th as much. They are guaranteed for 50 years.

Cedar shakes or shingles are also very attractive. Many are now treated with chemicals for fire and mold resistance. Cedar is lightweight enough to be used on any roof. They weather to a beautiful silvery color. Good-quality, heavy shakes should last for 40 to 50 years.

A less expensive alternative (about half the price of cedar) is treated pine shakes. These use yellow pine grown in the Southeast. As the old growth Western cedar forest gradually disappear, treated fast-growing pine is an environmentally preferable roofing material.

Another attractive option to cedar is wood fiber. This is made by pressure bonding wood fibers into shake and shingle shapes. Each piece is 25 percent larger than standard roofing, so they are quicker to install. They have a temporary “walkable coating” for safer do-it-yourself installation. Extra-heavy architectural fiberglass shingles also look like slate or wood.

Write for Utility Bills Update 726 showing a buyer’s guide of 31 roofing material manufacturers (10 material types), prices, weights, minimum roof slope, life, and fire rating, and listing 31 roofing material manufacturers. Please include $2 handling fee — cash or check. Send to James Dulley, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.

Q. I am planning to get replacement windows for my home. How can I compare the energy ratings of various windows? Each window manufacturer seems to do different efficiency tests. — W.K.

A. Until recently, each manufacturer used its own performance tests for insulation value and airtightness. This makes it difficult, if not impossible, to use the figures for any meaningful comparison.

Some windows now come with an “energy-use” sticker similar to appliances. The National Fenestration Rating Council (NFRC) sets the test standards. The window manufacturers who want to be rated must have their window tested by a private testing lab for impartial results. Ask for a NFRC rated window.

James Dulley studied energy management at the doctoral level at Harvard.