There are several ways to keep a Beagle’s house warm during cold weather:

1. Insulate the house: Make sure the walls, floor, and roof of the Beagle’s house are properly insulated to keep the warm air inside and the cold air outside.
2. Use a heating source: You can use a heating lamp, a heating pad, or a small space heater to keep the Beagle’s house warm. Just make sure to keep the heating source out of the dog’s reach and always supervise your dog when using it.
3. Raise the floor off the ground: If the Beagle’s house is on a concrete slab or directly on the ground, it can get very cold. Raising the floor off the ground using a pallet or bricks can help keep the house warmer.
4. Provide extra bedding: Give your Beagle extra bedding, such as blankets or a dog-specific bed to burrow into.
5. Consider a sweater or jacket: Beagles have short fur, so a sweater or jacket can help keep them warm.
6. Keep the house dry: Make sure the Beagle’s house stays dry, so they don’t get wet and cold. Use a waterproof cover or a tarp to protect the house from rain and snow.

It is important to note that it’s also important to make sure your Beagle is healthy, as a healthy dog will be able to regulate his temperature better.