The solar industry term "customer acquisition" is a euphemism for "convincing people to spend money."

The top solar installers have tens of thousands of potential customers who have expressed interest in solar. But turning those leads into purchases can be tough.

As GTM solar analyst Nicole Litvak pointed out in her recent report on customer acquisition, it can cost solar companies $0.49 a watt to close a residential sale. That adds up to $3,000 for a 6-kilowatt home system -- 10 percent of the total cost.

Reducing those costs means crafting better management software and more attractive financing options, as well as finding new retail outlets via which to reach consumers. But getting customers to actually sign a contract requires traditional sales tactics like door-to-door visits, phone calls and advertising.

It's not like solar executives are acting like Alec Baldwin in Glengarry Glen Ross, but these tactics inevitably make some people feel uneasy.

Anecdotally, I've talked with a handful of people over the years who say they felt overly pressured by salespeople in the solar industry. I've heard far more positive reviews about the installation process than negative; however, it's clear that hard sales tactics are the uncomfortable reality of "customer acquisition." 

But don't take my word for what people are saying. Let's turn to the business-review site Yelp to see what people are saying about the top five U.S. residential solar installers -- the most likely candidates to come to your door.

Those installers are SolarCity, Verengo, Vivint Solar, REC Solar and Sungevity. They are ranked in GTM Research's PV Leaderboard from Q2 2012 to Q2 2013:

Below, we look through the rankings for each company in California, the country's largest solar market. There are different locational reviews on Yelp, but we are targeting only California.

A word of caution before starting. This is a completely non-scientific evaluation of reviews from one site. We are simply looking at their scores and highlighting their most recent positive and negative reviews. We suggest going through all of the Yelp reviews yourself and doing as much research on each company as possible before making a judgment.

With that said, here's what people are saying about the top solar installers.

SolarCity: 3.5 stars, 63 reviews

With a 21 percent market share, SolarCity is America's biggest residential solar installer. It also has the biggest set of reviews on Yelp, highlighting a wide range of experiences. The ratings are mostly positive, with 27 5-stars ratings. There are thirteen 1-star ratings, many of which improved to 3 and 4 stars after COO Peter Rive personally responded to criticisms. 

One recent negative review came from Frank S., who has reviewed twenty-three companies with a wide range of ratings. Frank gave SolarCity a 1-star rating due to sales tactics and his dissatisfaction with not owning the system:

Again, if there were a zero star rating, they'd get it. Pushy, aggressive. The financing that they put together is really a lease, any way you call it. I don't own the system. I am just leasing it. So, now that it needs repair, no one is around. I cannot get another service company to do the repair, because it would "void" any warranty that I may have. 

I could go on, and I will. The system is sized poorly. Too small. For the cost, I should have had a larger system installed. My electric bill is still above tier one.

Finally, the price they give you is for the lease payment only. They IMPLY that you will not have an electric bill. BEWARE. The bill comes at the end of year, that's when you find out you owe $700 to the utility. It's called the true-up.

Seems like they really don't care about the solar, but the lease.

One of the most glowing recent reviews came from Shad R., who has reviewed 26 companies on Yelp. Shad gave SolarCity a 4-star rating, praising the PPA product:

Having explored solar options in the past, and being subsequently disappointed with the projected payout, I was not expecting the SolarCity angle. The PPA turned the tables for me to take the solar plunge. The convenience of installing panels without rails, and the innovation of voltage modulators tied to an intelligent inverter are wonderful enhancements that would not be possible for homeowners financing on a budget or fixed income. SolarCity opens up world of possibilities in the realm of solar electric power generation with a sales, design, and installation experience that is admirable.

SolarCity has done a great job responding to criticisms directly with a personal note from the executive team -- the best thing a company can do to manage their reputation. Many of the customer problems were related to pushy salespeople, a difficult installation process or not seeing savings that were promised. At the same time, numerous customers praised the ease of the installation process and knowledge of the salespeople and installers.

Verengo Solar: 3.5 stars, 11 reviews

Verengo also has a fairly positive ranking, with eight 4-star and 5-star ratings, and only three 1-star ratings. However, all of the 1-star reviews have been in the most recent comments.

Here's a 1-star review from Peter V., who has ranked 26 companies on Yelp:

First of all, I am SO TIRED of their scare-tactic commercials on the radio, trying to convince us that if we don't go solar now, the world will end and we'll all go to the poor-house.

That being said, I did have them look at my house. it was a terrible experience.

The salesman Jason almost didn't make it into the door. He wasn't a licensed contractor! When I asked him to show me his HIS (Home Improvement Salesperson) license, he said he left it at home, but didn't need it. ANY contractor who gives a quote for doing work on your house has to be licensed by the state of California. If my wife and kids were home, he wouldn't have come in. But I let him in out of curiosity.

I'm an engineer, but his explanation was unclear and misleading. He made promises which were not backed up by their complex contract, which is riddled with hidden fees and charges.

Matt D., who has reviewed 130 companies on Yelp, wrote Verengo's most recent 5-star review, contradicting the experience of Peter V.:

I did a lot of research on solar companies and was please to see what I found from some of my research. They are A rated, and have an electrical license. They are guaranteeing my system, inverter, and MY roof (to not leak where they installed or altered) for 20 years. 

From the very start I was a little skeptical, but the salesperson who helped me was very honest and didn't pressure me at all. After the sales process, there was a site analysis where someone comes out and surveys your house. I requested a few things as far as location, and he wrote them all down. He takes all the information to the design/engineering team.

Engineering made plans and sent them to me for approval. After I said yes, they had to get approved from my HOA.

After all was approved it was time for installation. Everything went better then I expected. The install was super clean. 

The worst reviews revolved around shady or aggressive sales tactics and advertising, which turned off customers. Verengo responded to some of the bad reviews with a non-personal message that looked like it came from an automated response bot. However, there were a couple of customers who raised their rating after Verengo customer service resolved a problem.

Vivint Solar: 2.5 stars, 5 reviews

With two 5-star ratings and four 1-star ratings, Vivint came out with the lowest ranking in California among the top installers. Since Vivint installs both solar and home security equipment, there were non-solar reviews on its page as well

Roman B., who only has two posts on Yelp, wrote one of the most recent 1-star reviews for Vivint:

So they have an interesting pitch but don't deliver on promises at all. They are from Utah doing business in CA but don't have the ability to attach to tile roofs. Hello? Seriously? CA has nothing but. I have been promised install dates 3 times over only to find out they are not coming. No calls, no schedule, no clue. This company sucks the big one. Not because the model is bad, but due to the fact they simply cannot deliver the goods. I am so bummed as my AC continues to run and Vivint doesn't.

Tom L., who only has one review on Yelp, gave a positive review about the outcome of his installation:

We weren't too sure what to think about Vivint's offer, it seemed too good to be true. Solar at no cost, we just buy the power at a cheaper rate then we pay SDG&E. After working closely with one of their energy consultants, we went for it. I have to say it was a great decision, we are saving over 30% off our utilities, and we didn't have to pay a cent. There [sic] staff has been helpful and informative. This is the only way to go if you want solar! Everyone should have this.

Parsing through the reviews of Vivint was difficult because very few users had a strong track record on Yelp. The negative reviewers seemed be focused solely on making negative comments, and most of the positive reviewers signed up only to give Vivint a ranking. 

REC Solar: 4 stars, 13 reviews

With six 5-star ratings and only one 1-star rating, REC Solar has the best absolute ranking. However, just like with other companies, some people didn't like REC's sales tactics. Here's a recent 2-star review from b.s., who, despite having a joke name, has a serious history of 46 reviews:

I contacted REC Solar as well as two Sunpower dealers and got proposals from all three. REC Solar did not bother to send someone who had technical training and could do a site assessment. REC Solar wanted $1000 upfront to do a site assessment which the two Sunpower dealers did at no charge before preparing a proposal.

With REC Solar I questioned the configuration and panels used and I was told to take it or leave it, end of "discussion." I felt like I was dealing with a used car dealer. With this level of support prior to the sale I was not going to trust them with my house and post sale support after they got my check.

They also were ready to proceed with no discussion of how to best do the installation and location of the inverter and how the stand-offs would affect the weather tightness of my roof or how to replace the roof 10 years later without a lot of extra expense to remove the panels, re-roof, and then reinstall the panels.

Shanda H., who has given twelve companies 5-star ratings, said she saw immediate results from the installation:

We had a great experience with REC Solar. They have an excellent pre-paid lease program, the prices are reasonable, and the customer service is great! We had issues with our HOA (and a cranky neighbor), so it took almost 8 months from the time we signed the papers, to the time we had our solar installed. Melissa and Lonnie were great at updating us with legal information and keeping us on target. The only problem we had was that we told them when we put our deposit, that we were getting a new roof.

They made the measurements before the new roof, came back to install, and realized things had changed (vent locations, etc.) with the new roof, so they had to leave and re-measure everything. It was fine and still totally worth it. Our PG&E bill went from $130 to $32 in the first month! I have told every one of my friends, everyone on Facebook, etc. about our experience. I even got an iPad (a promotion when we signed up). iPad or not, we've had a very good experience with REC and Sunrun. We even asked about using them for our vacation home. :)

The majority of customers seemed pleased with REC, and many of the positive reviewers had clearly done their homework when comparing installers. REC made no attempt to reach out to dissatisfied customers through its Yelp page.

Sungevity: 3.5 stars, 27 reviews

Sungevity had the second most active Yelp page behind SolarCity. The company brought in twelve 5-star ratings and six 1-star ratings.  

Interestingly, many of the negative reviews weren't from customers, but rather from people who didn't like Sungevity's evaluation process. A review from Richard H., a Yelp user with sixteen reviews, also illustrated frustration with a contractor Sungevity was using:

Most of the problems I've encountered were actually on account of Ally Electrical, the actual installers. There have been so many annoying things I've forgotten all [of them] by now. The most annoying was having me sit around for two entire days because I was told they needed to get inside the attic. They did but not until the third entire day at home. I had to loan them tools more than once or it would have ben even more time sitting at home. They showed up once without the parts they needed. When they left I noticed they bent up my rain gutter with a ladder. They never said a word thinking I would not notice, I guess.

That was a couple of months ago and it is still not fixed. I tried to be nice to Ally and not complain but I had to call Sungevity.  Lots of apology but after 3 weeks nothing, and the ongoing excuse has been that the roofer has not cooperated. They may not be at this point because they did give Ally an estimate long ago but Ally thought it was too high so just blew it off. My roofer is not the only person on the planet that can fix it.

There were problems early on with Sungevity staff not replying for a a couple of weeks time when I was trying to get documents done. They may or may not be the best deal but I can't recommend them.

However, Rudi H., a user with 25 total reviews, explained a completely different experience in his 5-star review:

I had a great experience with Sungevity who installed my system a couple of months ago. I thought it was great that they saved time and gave me a quick appraisal of my roof by using a satellite image from Google Earth. What really impressed me is that my sales consultant actually stopped by to verify it as I had told her that a tree had been removed since the satellite photo was taken! The installer made a site visit prior to the install and verified that my roof was ready and sufficient and that the system would fit as planned.

From there, it took a little while (mid summer and they were busy) and when install day came the team was nice, efficient and happy to answer my questions. The install of my rather large system was completed in one day and they did a super clean, professional job of it. The hardest part was waiting for PG&E to authorize my interconnection. The system is working great and my last utility bill was just around $12, most of which was for the gas we use!

Sungevity markets itself around a community-building mission and customer interactivity, which showed on the company's Yelp page. A member of the customer support team, Sloane M., reached out to both positive and negative reviewers, attempting to address questions and concerns. The responses were genuine and helped to influence some negative reviews.

What should we take away from this?

Clearly, upset customers were most annoyed with pushy sales tactics and hidden fees in contracts. The most positive reviews came from people who felt like the entire process was transparent.

For companies, having an active presence on review sites like Yelp makes a huge difference in rankings. Interacting with customers not only helps boost poor reviews, but it also allows installers to target serious experience problems that may not always be obvious.

Potential customers can learn a lot about companies based on these reviews. But they should also recognize that one review site shouldn't be the ultimate decision-maker. Readers should also keep each reviewer's credibility in mind as well. Many people sign onto sites simply to rant about a particular experience -- and it's important to look at a reviewer's full history before making a judgment.