These articles need to include images that you take with your cell phone. Example: High quality content that shows the process of replacing an air filter on a furnace or showing how to vacuum a furnace safely. These are not highly technical, but highly informative how to articles that any homeowner can do. These will go on a website that does these as a service.
Typical Articles could be:
How do you know you need to replace your furnace?
Replacing your furnace air filter, 5 steps to success.
Choosing a good HVAC contractor.
Please submit one site you have done this type of work for, it should be in the home services industry.