Radiant heating takes forever to warm up. That may be true in some cases, but not all radiant heating systems are equal. The least responsive are those with hydronic tubes set into thick slabs of concrete. Though concrete can absorb and store a considerable quantity of heat, it's very sluggish. When used in home heating systems, it forces you to wait both while it warms up and cools down. Warmboard replaces concrete with aluminum, a material that conducts heat 232 times better than concrete. That way, when you adjust the thermostat, Warmboard panels respond right away.