Finding HVAC services
To answer your question about how people in the US find heating, ventilation, and air conditioning services I analyzed multiple market trend websites. This research is based on the US only and on residential consumers of HVAC systems and services. I found through my research that the majority of HVAC services are found by customers online through Google searches and reviews, Yelp, and Home Advisor and Angie's list.
According to this source, 85% of consumers now use online resources to find local HVAC companies. It also references email marketing as a way to connect with potential clients. On average, over 5,000 searches for HVAC installation are made on Google and 135,000 searches are made regarding additional information on HVAC repair services every month. Home Advisor/Angie's List receive 11,000 searches on suggestions and advice for home services. While I was unable to find the exact number of searches for HVAC installation on Homeadvisor, it is worth paying attention to the high volume of requests for suggestions that the website receives. Yelp provides a list of the top 10 HVAC installation services anywhere that a consumer searches. Each installer that is suggested receives multiple reviewers of their services. For example, multiple HVAC installation companies in New York have received well over 90 reviews from potential consumers of HVAC installation services.
COMPARED TO "WORD-OF-MOUTH" DISCOVERIES
Many people who are looking for HVAC installation services take to websites such as Facebook to ask friends and family members for suggestions on HVAC services. Wikihow suggests using friends as a starting point and from there researching online based on suggested HVAC services. The WikiHow page for "How to Choose a HVAC Contractor" has over 14,000 views. While it recommends that people use friends as resources, the fact that the page has so many searches shows that people tend to Google search as a way to find HVAC contractors. This source reports that when companies improve their "online Google presence" their return on ad spend improves as much as 1,214%. This finding is supported by multiple case studies and proves that with an online presence supported through Google "adwords", there is a high probability that the money a company spends on the online Google ad is worth it, because consumers' searches lead them to these ads and ultimately are more likely to chose these businesses.
In short, while consumers of HVAC services still rely on suggestions from friends to an extent, there is an increasing trend in online suggestions and searches for HVAC installation and general services.