Residential solar case study
Carbon Energy Savings case study: domestic solar leads at about £2,100 per fitted install
In just 2 weeks, Carbon Energy Savings turned a £2,200 test batch from TNW MARKETING into £32,000 in closed installations - a 14.5x ROI. With a cost per fit of just £2,100 and clear, transparent communication, TNW is now in line to become a main lead partner for their seven-figure annual spend.

Watch the full interview with Carbon Energy Savings. This page summarises what they told us on camera.
Full interview transcript
Read the full transcript of the Carbon Energy Savings interview
Word for word from the video, with filler words such as “um” left out.
hi everyone. So my name is Con, I'm one of the owners here at TNW and today I have Scott from Carbon Energy Savings. So Scott, could you care to introduce yourself? Hi there. My name's Scott. I'm one of the operations directors at Carbon Energy and we are doing extremely well.
I've just built this really fantastic relationship with TNW. Absolutely. Beautiful. And where are you guys based right now? We are based in Scotland sitting in sunny Glasgow just now. But we have got experience all over the UK so we are venturing down south of the border very soon. Okay, perfect.
And obviously based on our recent conversations, what's the sort of growth vision for the company right now and how big are you are looking to get? We were working under the banner of another company. We were writing about 70% of their business. And so from Companies House point of view, it looks like we went from zero to hero in a very short space of time.
And I suppose it's true 'cause the turnover projection we've got now from a standing start really of April is about 10 million pounds. So yeah, it's we're hope to double that in the next 12 months. Obviously going into that domestic model, then obviously the first test we did together, how many leads did you guys start with? A hundred? Was it a hundred? So it was 50 the first. I think we're going into a hundred now. Oh, we're gonna a hundred.
We're gonna a hundred. Yeah. What kind of revenue did that initial test bring in? What was your cost per acquisition on that? So we work in a couple of different metrics and we do cost per sale. And then cost per solid. So a solid sale is different from a sold sale because in the home improvement industry.
There's quite a lot of cancellations, so you can have your good KPIs and your good reps are converting at a one in three or one in four sales rate conversion wise. But actually it's less than that. We do cost per solid sale as in cost per fit. So the cost per fit came down to about 2,100 pounds, which is fantastic for us.
Perfect. Perfect. And has our sort of service delivery matched your expectations so far? Exceeded. Exceeded. Absolutely. It's it's been a pleasure. All the guys that are as forward thinking as you guys are you're open with what you're doing as well, so we don't feel like we're in the dark in terms of how you're generating those leads because it's important for us to know, because we're obviously got a different mix of inputs and we need to make sure there are not lots of overlaps and then effectively lots of duplicates because.
Through our experience, we actually like buying raw leads effectively. It just means that our contact center still has a degree of control and we know what's going into the guys' diaries. Whereas if we buy booked appointments doesn't tend to work. Even though it's an easier process. Yeah. We're not in control of that.
So even the, like using one of your competitors to book. Appointments. We still don't end up with a good conversion rate in terms of solid sales, only because it doesn't go through the rigorous, first call with us, then a quality assurance call, then a QC check, and then a nod on. So it goes through all those processes with us.
So there's many opportunities for us to ramp up the solidity of that sale. So when the rep actually gets there, it should be an easier, should be an easier haul. Yeah. And then it goes to solid seal quicker. Of course. Yeah. I think your sales process is quite in depth, so obviously when you take on a sort of site survey basis, that changes tho drastically compared to what you're normally used to.
But with that being said, how do you see us going in the future? I know we spoke with David the other day on the possible plans, but how do you guys see it? I think I think you have the ability to become our main partner. And that's a big opportunity for us.
It's almost a big opportunity for you guys. In terms of putting things into scale, I was talking to somebody at a very well known window company over the weekend actually. They were astounded by how much we actually spend in a week for leads. Yeah. It's a lot of money. And for a company your size and a company our size it's seven figures a year.
So we value leads like doing our own children and we've gotta treat them like that, so our relationship that we've got with you guys, open flexible you guys listen to what we want and you're delivering. So I think we've got a solid base for the future. Wicked. No, I appreciate that. And finally, would you recommend us to working with anyone else in the industry?
Hundred percent. Absolutely. A hundred percent. I feel recommend you. Thank you so much, Scott. I really appreciate your time for today, mate. No. What?
- Interviewee
- Scott, operations director
- Based
- Glasgow, working across the UK
- Type of work
- Residential (domestic) solar
- Test size
- 50 leads, then an order of 100
- Cost per fitted install
- About £2,100
Who Carbon Energy Savings are
Carbon Energy Savings is a home-improvement installer based in Glasgow, with experience across the UK and expanding south of the border. Scott, one of its operations directors, explains that the team used to write about 70% of the business of another company it worked under, so on Companies House it looks like it went from nothing to a turnover projection of about £10 million from a standing start in April, with the aim of doubling that within 12 months. Its spend on leads runs to seven figures a year.
The situation
This campaign was residential, not TNW's usual commercial site meetings. Carbon prefers to buy raw leads rather than booked appointments so that its own contact centre keeps control of what goes into its reps' diaries: each lead gets a first call, a quality assurance call and a QC check before an appointment is set. Scott says appointments booked by other providers have not converted as well into solid sales because they skip those steps.
Home improvement has a lot of cancellations, so Carbon measures cost per fitted install as well as cost per sale. Good reps convert one in three or one in four appointments, but fewer of those go on to be fitted.
What TNW delivered
TNW ran the campaign on Meta, testing static and video advert angles until it found the ones with the lowest cost per lead. People went to a website rather than a Facebook form, adding a little friction to filter out the uninterested, and a detailed quiz captured their details and screened out anyone who could not have solar, such as people living in flats. Qualified leads were sent by webhook straight into Carbon's CRM.
Carbon's side was the sales process: calling each lead within five minutes, a mapped follow-up of eight to ten calls, emails and texts over the first 24 to 48 hours for anyone who did not answer, agents prepared for every objection, and a fully mapped site survey.
TNW's own breakdown of the campaign gives the numbers: about £2,200 spent and about £30,000 of installations in under 14 days. Roughly one in five or six leads became an appointment, and about one sale came from every two pitches. Scott puts the cost per fitted install, after cancellations, at about £2,100, which he calls fantastic for the business.
The first test was 50 leads and the next order was 100. Scott says the service exceeded expectations, and that TNW's openness about how the leads are generated matters because Carbon buys from several sources and has to avoid overlaps and duplicates. He sees TNW as able to become Carbon's main lead partner.
TNW's commercial service works differently from this residential campaign: TNW finds and qualifies the business, books the site meeting into your diary and you pay per qualified, attended appointment, not per raw enquiry or a monthly retainer. Read how pay per appointment commercial solar leads work, or see the checks behind each booking in how to qualify commercial solar leads.
Results
- £2,200 spent → £32,000 closed installations in 2 weeks (14.5x ROI)
- Cost per fit of £2,100 - highly profitable in their model
- "Your delivery has exceeded expectations. Open, flexible, and you listen to what we want."
- "You have the ability to become our main partner - we spend 7 figures a year on leads."
“You have the ability to become our main partner”
More on this campaign
- How we closed £30K in solar installs in under 14 days (video): TNW's step-by-step breakdown of the Carbon Energy Savings campaign, with the cost-per-stage figures above.
Want results like Carbon Energy Savings?
TNW Marketing books pre-qualified, exclusive commercial solar site meetings for installers. TNW's show rate is 60%+, and you pay per qualified, attended appointment with no retainer and no minimum spend. See the commercial projects ready for survey now.
More client results
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Green Home People case studyA 30 to 35kW commercial job confirmed to go ahead within 48 hours of the meeting.
See all 28 commercial solar installer case studies, plus residential solar results.
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