If you have a husky like I do or some other cold-weather-loving breed, you know that they beg to go out even at temperatures that might be too cold. I knew an Alaskan malamute who steadfastly refused to come inside during New England winter months, but would occasionally make an exception for a dog house.
The Dogloo is a classic design and one of the most popular of the insulated dog house options. The structural foam that makes up the walls provides excellent insulation from heat and cold, which can be further enhanced with the addition of the optional door flap and pad. The floor is raised up off the ground to provide further protection, and the entire structure is coated in Microban to keep bacteria at bay.
The large fits dogs 25 to 50 pounds, while the extra large works for dogs up to 125 pounds. The medium option found here works for dogs from 15 to 25 pounds. The also have one in a gray color, if you prefer.
Alternatively, the version from K&H features a heating pad.