Concerned about formaldehyde in Houston's air, I bought a quality air quality meter. The outside air was fine, but inside there was more formaldehyde than expected. Decided to buy one of these kits to review. Some complaints are untraceable (unless changes have been made since they were submitted). The instructions are very simple and the color guide is easy to read. it matched the top end perfectly. Yes, you can do just one room, but if that's all you need, this is perfect for you.