To find the best window and door installer company, start by checking online reviews and ratings on platforms like Google and Trustpilot. Look for companies with industry certifications and experience in installing high-quality products. Ask for recommendations from friends or family and request quotes from multiple providers to compare pricing and services. Ensure the company offers warranties and after-sales support for added reliability. Checking past projects and customer testimonials can also help in making an informed decision. If you are in the UK, King Limited is a trusted provider of premium orangeries, conservatories, windows, and doors.