In 2000 I became aware of the quality of the polystyrene hives made in Europe and for approximately the next 18 months spent a great deal of time investigating whether they were appropriate for our climates and whether they could be manufactured and sold at a reasonable price. While I eventually decided to not manufacture, I became a complete convert to the concept. If I were starting over, and know what I know now, I would use only polystyrene for deeps and supers, but would still use wood for covers and wood/wire mesh for floors. I will add a couple of comments to what has been said so far: 1. Their added insulating value is of little to no benefit. Wood has an R factor of .5 per inch of thickness. (If that is not right, it is very close to it.) So the standard wood hive in the US has an R factor of less than 1. The hives offered now by Betterbee and Dadant are as good as they get, and only have an R factor of 3. While more than 200% better than wood, an R factor of 3 is nothing of any value in keeping out cold or heat. 2. I spent many days and hours asking how warm moist air would get out of these things, as they close up so tight. I know well that winters in Northern Europe are cold and dry, while for much of the US winters are cold and humid. I also knew that for most of Europe their winters are even more humid than our own. I could not understand why the warm moist air would not condense more than the wood hives. While I considered it bunk at first, I now believe the statement that the cut provided by the hand hold condenses the warm moist air so that the water runs down the side of the hive and out or through the bottom board. With an R factor of 3 for most of the box, and only .5 (or so) for the handhold area, the warm air has an area to condense before it cools at the top of the hive. With wood hives, the hand hold area might have an R factor of .1, compared to .5 elsewhere, so there is no place for the warm air to condense other than at the hive top. 3. They are so light they are wonderful, they take normal abuse with little to no damage, can be stacked 6-8 deeps high, and can easily be moved on trucks with tight strapping. I forget the load factor a hive will take (the weight that the hive sides will take before they crumble) but it is impressive and well beyond what would be involved with 4-6 deeps full on honey on top of a single brood nest. 4. The Kelley hives gave plastic a bad name in US beekeeping. However, these were not polystyrene but were either cast or injection molded with a different material. A classic case of plastic molders not understanding beekeeping, and beekeepers knowing nothing about plastics. I would not use polystyrene covers because a migratory cover or piece of 3/4" plywood is just as good at a fraction of the cost. Likewise, polystyrene bottom boards are just too expensive compared to alternatives. Will polystyrene equipment become prevalent in the US? In my opinion, it will depend almost entirely on price. Last year a polystyrene deep (in quantity) sold for $15, while the same dealer sold a wood hive (also in quantity) for $10. At that price difference, I can't imagine a serious hobbyist, sideliner, or commercial beekeeper going to plastic. Moreover, excellent quality wood hives are readily available elsewhere for around $5-$7. Competition or other factors may result in the prices for polystyrene and wood hives being much closer to one another. If that happens, I predict that 20 years from now those with fewer than 1,000 or so hives will largely use polystyrene. Frankly, it will take so long to change beekeepers with larger numbers that I am certain I won't be around long enough to see those using plastic. The exception would be if gasoline prices get up to European levels, in which case changes could take place pretty fast as the payback for pollinators should be almost immediate. Lloyd Lloyd Spear, Owner of Ross Rounds, manufacturer of comb honey equipment for beekeepers and Sundance pollen traps. http://www.rossrounds.com [log in to unmask]