Refrigerated spaces held at temperatures below 32° F (0° C) must have an underfloor heating system installed to prevent freezing of the soil with subsequent damage to the floor and building. In cold climates where wintertime air temperatures fall below about 45° F (8° C) underfloor heating is typically accomplished by circulating glycol in a piping loop buried beneath the floor insulation. The glycol can be heated in a number of ways. It can be heated actively with an electric or gas boiler, with condenser heat from the refrigeration system, or with another source of waste heat.