Dealing with Lone Star Heating & Plumbing was a negative experience. I was left with no heat for 7 days during the recent cold spell this month (September, 2016). Lone Star didn't repair my furnace, and I'm out of pocket $330...for 2 hours labour and a new pressure switch that didn't fix the problem (and turns out, didn't need replacing).
I resorted to hiring another company to get the job done. This other company got my furnace up and running on the same day I called them (which was the 7th day of getting nowhere with Lone Star). The other company's technician diagnosed the problem within 15 minutes, had the correct part on hand, and installed the part quickly. He explained that the pressure switch on a Carrier furnace is often another indicator of the problem, rather than its source. It was same-day service, one-and-a-half hours from beginning to end, at my convenience (after work hours by Lone Star's standards), and at rates considerably less than Lone Star Plumbing & Heating ($30 PER HOUR less, to be precise).
Lone Star's owner and the repair technician assigned to this job made it clear that they are inflexible. Their focus seems to be on making money, not customer service. The owner told me he "needs to make money" so the 20% markup on parts and labour rates are non-negotiable, despite the fact the part replaced didn't fix the problem and the technician needed to come back a second time to replace a different part. When trying to schedule the second appointment, the technician expected me to accommodate his schedule even though he couldn't solve the problem the first time and required a second day to try to repair it. For Lone Star, work has to be done between 8 am and 4:30 pm.
Although I resorted to finding another company to do the job, things could've gone more positively with Lone Star. They could have accommodated my schedule for the second appointment, considering a second appointment was necessary because their technician couldn't solve the problem the first time. In hindsight, it probably should've been a red flag when the technician commented that he'd never seen this problem before and would consult his "heating guru" the next day. And they could have at least tried being open to negotiation on mark-up and labour rates, when they couldn't solve the problem in one 3-hour appointment, necessitating a second one. There are things that can be done to improve customer service.
Unfortunately, based on my experience, I suggest you do not look to Lone Star Plumbing & Heating to address your heating or furnace concerns. There are other companies, with more expertise and much better rates, to do the job.