I'm in need of an expert opinion as to what type of hardwood floor to install over a radiant heat system. I understand there is plainsawn or quartersawn wood. Which is better? Does it matter much?

If you are choosing to use a solid wood floor instead of an engineered wood floor, the using quartersawn is recommended over using plain sawn flooring. Many radiant panel manufacturers recommended using an engineered floor instead of solid wood due to the fact that engineered floors are more stable and resist expansion and contraction better than solid wood. Some even recommend only a floating type of installation. However, if you are set on using solid wood flooring, then selecting quartersawn is a wiser choice. Also, limit the width of a solid floor to three inches or less.