Evaluating Microwave Performance and Reliability
Microwaves fall into three main categories: countertop, over-the-range (also called microhoods) and built-in models. Our report focuses on countertop and over-the-range microwaves, which can be added to any kitchen. We do not cover built-in microwaves in this report, as they usually require customized installation.
Countertop microwaves don't require any installation and they plug into a standard electrical outlet. They are available in a variety of sizes -- from 0.5 cubic-foot units that can barely accommodate a bag of microwave popcorn to 2.2-cubic-foot models that can swallow a 9-by-13-inch baking pan. Full-size countertop models generally run in the $150 to $350 range and produce 1,100 to 1,300 watts of cooking power. Compact microwave ovens are cheaper, often costing less than $100, but they also have less cooking power -- around 800 watts -- which makes for longer cooking times. Some countertop microwaves can also be installed under a cabinet with an optional hanging kit, or installed as built-ins with an optional trim kit (typically between $100 and $150).
Over-the-range microwaves can cost anywhere from $200 to $1,000. In addition, they often require professional installation, which adds to their total cost. They include extra vents to move heat and fumes away from the stovetop, although experts warn that they don't vent as well as a dedicated range hood. Most models fit into a 30-inch-wide space -- the typical width of a range -- and capacities vary from 1 to 2 cubic feet. Both countertop and over-the-range microwaves typically come with a one-year warranty, although many brands provide lengthier coverage for the magnetron (the tube that produces microwave energy). In general, over-the-range microwaves are reviewed less often than countertop models.
Advanced cooking Features
There have been several new developments in microwave technology in the last few years. Perhaps the most useful is the addition of cooking sensors, which monitor the humidity in a microwave and adjust cooking times accordingly to prevent overcooking. Experts and users alike say this feature works well on most microwaves, although we did read occasional complaints about liquids overheating on the sensor setting. Inverter technology is another feature that's becoming popular with some consumers. Unlike standard microwaves, which cycle between periods of full cooking power and no power, a microwave with inverter technology can run continuously at half power, which results in more even cooking. While owners say this feature does work, reviews indicate it's not a must-have.
One of the most advanced microwave oven innovations is convection cooking. Convection microwaves circulate hot air throughout the oven, a process that promotes even cooking and surface browning -- something many conventional microwaves don't do well. Convection microwaves can bake cakes, roast chickens and cook hamburgers, although experts say they usually can't do any of these jobs as well as a range. Moreover, a convection model can cost significantly more than a conventional microwave; if you plan only to reheat and defrost foods, a standard microwave will be more cost effective. Top-rated microwave ovens without convection functionality usually cost $100 to $300 less than comparably sized convection microwaves.
A few manufacturers also are starting to offer models that can steam-cook food; fill a reservoir with water and as it evaporates it steams your food. Steam can help heat penetrate food and retain moisture. However, at present this feature appears only on higher-end microwaves. Only one of the microwaves covered in our report -- the over-the-range Whirlpool Gold GH7208XR (*Est. $920) -- includes a steam function, and the reviews we found for this microwave do not consider the steam function an important enough feature to make any mention of it.
Overall, we found the most useful microwave reviews at ConsumerReports.org. The organization posts test results for more than 130 countertop and over-the-range microwaves on its website, rating each on heating evenness, noise, auto-defrosting and ease of use. Another trustworthy source, the Good Housekeeping Research Institute, has tested 21 microwaves and evaluated them with letter grades, summing up their most important pros and cons. However, editors do not outline their testing methods or criteria, and the write-ups are brief.
We also found reviews for individual microwave models in Wired and the home decorating website ApartmentTherapy.com. To supplement the professional reviews we found, we also looked at user reviews at ABT.com, Amazon.com and Sears.com, as well as user review sites such as Viewpoints.com and Epinions.com. We found the feedback from users helpful for gauging long-term reliability.