If you're going to service residential equipment, you'll definitely want a name the average consumer would understand like Texas Heating and Cooling. If you used a name like Texas Refrigeration, the average consumer would think that's a place to buy refrigerators. Texas Mechanical would be associated with construction equipment, car repair, etc.
A lot of funny names here. I laughed when I first saw Big Ass Fans. But it worked in their market.
A resi company name is usually more personal or sends a message like economy or quality or locality. If you have a good last name, consider using it. It puts a person in the company's name. I'd avoid initials like J&B T&M, because it's common and can be confused or mixed up. An exception is 3 initials like IBM. For some reason they seem to work.
A lot of commercial companies like names that sound corporate. They won't use a name like El Cheapo Heat/cool. They want to sound solid and like they have been around.
So gear the name to your market. When I named my company I didn't want calls from the general public. I was after contractors, facility managers, and architects. I named it HVAC New Mexico. Most of the public doesn't know what HVAC means so they didn't call.
The worse names are ones that don't tell a thing about the company. Just confuse. Like using names that don't relate.
That's about all I know. What I.m really good at is naming bucking bulls. Like Aces N' Eights, or Buck Naked.