Meta Ads results: a summary of Growth Room client case studies

When a prospect asks us what Meta Ads can do for them, the honest answer always starts with "it depends." It depends on the sector, the average order value, the quality of tracking, and the time allowed for testing. But we can also look at what has happened for real advertisers.

We have therefore gathered seven client case studies published on our site, in which Meta Ads (Facebook and Instagram) played a central role. For each: the starting point, what we changed, and the results achieved. At the end, we review what these results have in common and what an advertiser can realistically expect.

Key takeaways

• Across our Meta Ads accounts, we see an average increase of 32% in conversions and a 26% decrease in acquisition costs.
• Poiscaille divided its acquisition cost by 7 in 3 months thanks to Google and Meta.
• In B2B, Meta generated 5 times more leads than Google Ads for HAVR, at a cost 25 times lower.
• The best results come from reliable tracking, audience testing, and a funnel-based structure.
• Generally, allow 2 to 3 months to stabilize performance on a Meta account.

What average results does Growth Room achieve on Meta Ads?

Across all the Meta Ads accounts we manage, we observe on average:

• +32% in conversions;
• -26% in acquisition cost ;
• +3% click-through rate.

These averages smooth over very different situations. An e-retailer selling low-cost products and a smart lock manufacturer targeting city halls do not expect the same things from Meta. That is why the detailed case studies below are more telling than any average.

What results can you expect from Meta Ads for e-commerce and subscription models?

Poiscaille: acquisition costs cut by 7

Poiscaille delivers fresh fish via subscription, straight from the fishermen. The goal was to hit seasonal subscription targets across three distinct audiences: young urban professionals in Paris, eco-conscious women in coastal regions, and suburban seniors.

We built a funnel-based strategy. Meta handled brand awareness entirely, shared engagement duties with Google (70% Meta, 30% Google), and supported conversion (40% Meta, 60% Google). Cold and warm audiences were tested continuously, with creative assets tailored to each stage.

In 3 months, the cost per subscription on Meta dropped from €112 in December to €27 in January, and from €77 to €6 on Google. In total, Poiscaille cut its acquisition cost by 7 and gained over 2,000 subscriptions.

Le Chemin de la Nature: ROAS increased from 5 to over 9

Le Chemin de la Nature offers online courses and workshops on wild plants and mushrooms. Sales relied heavily on frequent promotions sent to an audience already familiar with the brand. Over time, this audience became saturated, and the ROAS began to decline.

We implemented two separate approaches. On one hand, an "always-on" campaign to reach new cold audiences, with a ROAS target of 2.5. On the other, shorter, more targeted promotions with a ROAS target of 7. The result: the overall ROAS rose from 5 to 9.2, exceeding the target, with peaks reaching up to 14 during certain periods.

What results can you expect from Meta Ads for B2C bookings and services?

EVA: ROAS tripled across a network of venues

EVA operates a network of virtual reality esports arenas in France and abroad. Each venue had its own ad accounts with no unified strategy. We audited, restructured, and harmonized these accounts, then launched acquisition and retargeting campaigns across 7 cities, creating a replicable model for every new location.

In 3 months, the overall ROAS tripled to reach 6, against a target of 3. The campaign generated 1,260 bookings, 822 of which came through Facebook Ads, with a cost per acquisition equal to 29% of the average basket value, against a 30% target.

The Sanctuary Group: 972 conversions for fitness studios

For this group of fitness studios, the first priority was tracking: without reliable data, it was impossible to know which campaigns were filling classes. Once the data was harmonized and a dashboard was in place, we launched three types of campaigns: acquisition, retargeting, and re-engagement.

In 5 months, the campaigns generated 972 session bookings, including 694 via Facebook Ads, with a 2x ROAS on Facebook and €37,000 in additional revenue.

Dreem: over 200,000 qualified leads

Dreem sells a smart headband that measures and improves sleep. Rather than pushing the product directly, the acquisition strategy relied on a free sleep test, followed by personalized email sequences tailored to each individual's profile. For Facebook Ads, one detail made all the difference: running ads around midnight, when people struggling with sleep are still on their phones. In total, the strategy generated over 200,000 qualified leads.

What results can be achieved with Meta Ads in B2B and healthcare?

HAVR: 5 times more leads than with Google Ads

Many B2B companies think Meta isn't for them. The HAVR case proves otherwise. This smart lock manufacturer targets integrators, distributors, and town halls. On Google Ads, they were paying €320 per lead.

We set up the Facebook Ads account, imported contact lists with phone numbers to help the algorithm find the right profiles, and launched three campaigns: acquisition, conversion, and retargeting. The result: 61 leads, 5 times more than before, with a cost per lead between €7.80 and €16.84—25 times lower than Google Ads—for an average order value of €1,000. The full HAVR case study also details the outbound strategy conducted in parallel.

Sevetys: a CPA 3 times lower than the target

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For Sevetys, a healthcare player, we organized Google and Meta campaigns around performance, with precise cost tracking. The resulting cost per acquisition was three times lower than the initial target.

What do the best Meta Ads campaigns have in common?

Reviewing these seven cases, the same ingredients appear almost every time.

• Reliable tracking above all else. At both The Sanctuary Group and Poiscaille, nothing was optimized until the data was clean.
• A structure based on the funnel : awareness, engagement, conversion, and then retargeting. Each stage has its own budget, creative assets, and KPIs.
• Continuousaudience testing , including cold, warm, lookalike, and CRM-based audiences.
• Creative assets tailored to each audience and stage, refreshed before audience fatigue sets in.
• Meta strategy integrated with other channels. In almost every case, Meta works alongside Google Ads : one generates demand, the other captures it.
• A clear business objective: ROAS, cost per subscription, or cost per lead. Never just click volume.

What results can you realistically expect from Meta Ads?

These cases show what is possible, not what is guaranteed. Here are some benchmarks based on our experience:

• The first few weeks are for learning. For Poiscaille, the Meta cost per subscription was still €112 in December before dropping to €27 in January.
• Generally, allow 2 to 3 months to stabilize an account, and longer if tracking needs to be rebuilt.
• ROAS depends heavily on average order value and margins: a ROAS of 2 can be highly profitable for a recurring service, but insufficient for a low-margin product.
• In B2B, Meta performs best when provided with quality signals: imported customer lists or qualified leads fed back from the CRM.

Behind every number, a repeatable method

None of these results came from a trick or a hidden setting. They come from patient work: fixing tracking, testing, cutting what doesn't work, and keeping our eyes on the cost per customer rather than clicks. If you're wondering what this approach could do for your own account, that is exactly the starting point of our Facebook and Instagram Ads management : an audit of your current setup, followed by a testing plan built around your objectives.

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