Choosing the right window Upvc profile is essential to ensure energy efficiency in your home. With double and triple glazed windows becoming increasingly popular, it’s important to understand the features that make them energy efficient. Low-e glass is a key factor, as it helps reduce heat loss and keeps your home warm in winter and cool in summer. Other features like airtight seals, insulated frames and special coatings also play an important role in making windows more energy efficient.