Harvey Arc Vs TwinTec S4
A TwinTec, MiniMax & Harvey Arc Water Softener Review
If you've been looking to purchase a Harvey Water softener, but are confused about the difference between the Harvey Arc Vs TwinTec S4 Vs MiniMax - we've got you covered.
In this review we highlight all the key points you need to know before purchasing a Harvey system. How do we know? Well we've been selling Harvey products and working in the water softening industry for over 15 years. As experts in the water softening industry and Harvey distributors we can highlight everything you need to now about these different makes and models.What You Need to Know About the Arc
The Difference? The differences lie soley in 2 factors:
- 1. The Arc & other 5th generation models use a smart phone app. This app simply exists to tell you if salt is running low - a pretty easy and often predictable task to do manually (you can see into the water softener easily).
- 2. The 5th generation models use special curved Harvey salt - meaning you must purchase this salt from Harvey direct or a dealer. The 4th generation systems use standard block salt which is more widely available.
Aside from this, there is a marked difference in price. If you can overlook the use of a smart phone app, The TwinTec might save you anything between £500 - £700. The Harvey Arc Price is usually a direct quotation only, but several forums often share these quotations - including this reddit source - click here.
A Technical Specification Comparison
The TwinTec S4 has the Same Technical Spec as the Harvey Arc
Because the TwinTec S4 water softener was created in 2019 and the Arc in 2020 - the technical specifications are actually the same:
Type of System: The Arc, TwinTec & MiniMax are all Twin Tank systems.
Flow Rate: All 3 have a flow rate of 56L/min - so generally can handle homes with multiple bathrooms and family members without any water pressure reduction.
Efficiency: All are very efficient models - they are non-electric, using only 300g of salt & 17L of water per regeneration.
Regeneration Time: all models regenerate in 11 minutes.
Size: The size of the Arc differs by 3 and 2 mm. TwinTec Height: 49.0 cm, Width: 20.5 cm, Depth: 44.0 cm
Pressure: All 3 models have the same pressure scale of 1-10 Bar. All are geared for combi boilers, high pressure and low pressure systems (note - a pressure reducing valve may be necessary in high pressure cases).
Salt: The 4th generation Twintec Series 4 and MiniMax M3 use Standard Block Salt. The MiniMax Innova, S5 & the Arc use Harvey Curved salt.
Warranty: Here's where things get interesting - the TwinTec S4 has a 10 Years on parts & 2 Year labour - so does the MiniMax models. But the Arc offers only a 3-5 years, which can bbe extended at an extra cost.
More Comparision Details...
| Feature | Harvey Arc | TwinTec S4 |
|---|---|---|
| Distribution | Retail (direct through Harvey via quotation and full installation packages only.) | Exclusive dealer network but you can often purchase online. |
| Installation | Harvey supplied & installed | DIY, 3rd-party plumber or Dealer-supplied & installed |
| Warranty | 2–5 years (basic cover, 10 years available at extra costs) | 10 years (parts & 2 years labour) |
| Efficiency | Highest salt/water efficiency in class | Highest salt/water efficiency in class |
| Flow Rate | 56L/min (ideal for 3-4 bathroom homes) | 56L/min (ideal for 3-4 bathroom homes) |
| Build Quality | Premium recycled composite casing | Premium recycled composite casing |
| Eco Credentials | Made using recycled materials | Made using recycled materials |
| Service & Support | Via Harvey | Direct from Harvey or local dealers |
| Best For | Homes with high usage or multiple bathrooms | Budget-conscious buyers & homes with high usage or multiple bathrooms |
🤔 Frequently Asked Questions About the Arc (FAQs)
Q: Is the Harvey Arc superior to the TwinTec S4 or the MiniMax?
A: No not at all, unless you specifically would like a smart phone app that can alert you on salt. While the Harvey Arc is marketed as a newer model, it was produced only 1 year after the TwinTec S4. Many professionals and experienced users still recommend the TwinTec S4 because the two softeners have the same technical specification and the S4 is known for its long-term reliability, low salt usage, and proven twin-cylinder non-electric performance. In fact, the S4 remains the go-to choice for many UK installers due to its affordability and lomger term warranty.
Q: How much does the Harvey Arc cost compared to the TwinTec S4?
A: The Harvey Arc is generally more expensive, but quotations are given through Harvey directly - we suggest looking on online forums such as reddit for accurate quotations. The TwinTec S4 often offers better value for money at £1149.99 — with the same features — and is more widely available online or through independent installers. This makes it easier to shop around for the best deal.
Q: Is my warranty still valid if a plumber installs my water softener?
A: Yes. With TwinTec, as long as the unit is installed correctly by a qualified person and following the supplied guidelines, the warranty remains valid — even if you don't use a Harvey-approved dealer. But always check the fine print and ask the question to whom you purchase from. With the Arc you would have to purchase an installation package and this is also the case with many MiniMax dealers. We recommend weighing out the pros and cons and the extra costs.
Q: Is there a difference in the warranty between the Arc and the TwinTec S4?
A: Yes. The TwinTec S4 usually comes with a 10-year parts warranty and 2 year labour - especially when bought through a recognised supplier. The Harvey Arc comes with a shorter warranty of 3-5 years. The S4’s longer warranty coverage is one of the reasons it’s so highly rated. You can extend you warranty for the Arc, but it is an addd cost.
Q: Can I switch from an Arc to an S4 easily?
A: Absolutely and visa versa. Both systems are similar in size and plumbing requirements, so switching from an Arc to a TwinTec S4 is straightforward — especially if you already have plumbing in place.
Q: Are there any performance differences between the Arc and the S4?
A: They have the same performance on paper.
Q: I've Been Told My TwinTec is Not Geared for My Specific Water Hardness - Is That True?
A: No that is not true. All of the 4th and 5th generation Harvey Softeners are geared for very hard water conditions. Ultimately the installer can change the gearing if necessary but this isn't general practice and the systems themselves are already geared up.
Q:Why Are There Different Brand Names?
A: You can think of this like your local supermarkets. You can buy vegetables from Aldi, Tesco, Asda or Sainsbury's. But often all of the supermarkets have the same suppliers - it is quiet literally the label and branding that is different. Okay back to water softeners - the branding creates different distribution channels for the products that create less internal competition. But ultimately the products are all made and assembled in the same warehouse, in the UK.
Q:Can a MiniMax or TwinTec Dealer also Sell The Arc?
A: No, usually each dealer is given a brand, so MiniMax or TwinTec - but never the Harvey Culligan Arc, as this is a Harvey only product. It is done this way to create exclusivity and to prevent price fluctuations. Occasionally you may get a dealer selling both a Twintec or MiniMax but they are essentially exactly the same - so it's rare! Also a note of Kinetico - this is a different company entirely and is manufactured in the USA vs the UK.
Q:I've Been Told the Arc is Superior to the TwinTec & MiniMax?
A: Unless you are specifically looking at that smart phone feature - this is incorrect. All the systems are extremely similar with the same parts and internal resin and really its just about what is the best priced. Remember, sales reps who come to your home to sell - are often in commission based roles. Their job is to sell the product to you.
💬 What Homeowners Are Saying About Harvey Arc & TwinTec S4 - Real User Opinions (from forums & Reddit)
These user experiences reflect a common theme: the Harvey Arc and TwinTec S4 deliver comparable performance under the hood—but the Arc often costs more upfront and comes with a shorter warranty. Many buyers prefer the TwinTec S4 for better long-term value and broader availability.
Why People Choose The TwinTec Vs The Arc
🗣️ “Harvey are definitely worth it but you can get cheaper models like the Harvey TwinTec S4. Basically most of the softeners have the same interior.” — Reddit user on r/DIYUK
🗣️ “Consider buying a Twintec, which is rebranded Harvey but with no frills (who the heck needs WiFi on their softener???) like from here… then get a good plumber to fit it for you.” — Reddit user r/DIYUK, recalling Harvey Arc warranty issue post-3‑year period
🗣️ “Harvey’s Arc Curve salt is only produced by them currently, so you pay a premium... ” — Reddit user, r/WaterSofteners (comparing Arc and TwinTec S4)
🗣️ “We’ve had the TwinTec S4 for a few years now — it’s been flawless. No issues, soft water all the time, and barely uses any salt. It just works. Honestly one of the best home purchases we’ve made.” — Reddit user, r/HomeImprovementUK
🗣️ “Was looking at the Harvey Arc but ended up with the S4 after speaking to installers — they all said it’s better made, easier to service, and runs more efficiently. Zero regrets.” — Homeowner from a UK Plumbing Forum
🗣️ “TwinTec S4 is what most pros install in their own homes. That was enough for me.” — Plumber’s comment quoted on r/AskUK
🗣️ “Everyone seems to push the Arc but it’s mainly because it’s newer marketing. The S4 is still the better system overall — less salt, longer warranty, and it’s been proven for years.” — Customer comment, Trustpilot summary
🧬 Harvey Arc & TwinTec S4 Evolution Over The Years
The TwinTec brand, along with the MiniMax, are manufactured by Harvey, but have been specifically branded differently in order to be sold through different distribution channels. Over the past two decades, Harvey have developed each range of these softeners, improving them as they go:
🏷️ Harvey Retail Water Softeners Timeline
The Harvey HV3
🔹 Released in early 2000s 🔹 Twin-cylinder, block salt 🔹 Non-electric with basic resin efficiency 🔹 Early model
The Harvey HV4
🔹 Successor to the HV3 🔹 Improved water flow and salt usage 🔹 Compact enough for under-sink installation 🔹 Harvey models can last up to 10 years, so the HV4 is still widely seen in UK homes
The Harvey Arc
🔹 Current model. 🔹 Sold via Harvey direct. 🔹 Typically comes with a 2–5year warranty 🔹 Connects to a smart phone app for salt usage alerts.
🛠️ TwinTec Water Softener Range Timeline
The TwinTec S3
🔹 Comparable with the HV3 🔹 Reliable and compact system 🔹 Non-electric with dual-cylinder design 🔹 Very popular for mid-sized UK homes 🔹 Good efficiency but older internal tech
The TwinTec S4
4the Generation Model
🔹 Fully upgraded for modern plumbing systems 🔹 Best-in-class salt and water efficiency - lowest running costs. 🔹 Flow rate up to 56L/min – ideal for homes with 3+ bathrooms. 🔹 Made with recycled plastics. 🔹 Full 10-year parts & labour warranty via approved dealers
The Harvey Cobalt
🔹 Same as the Arc but different cabinet 🔹 Enhanced smart features & advanced internal monitoring 🔹 Sleeker casing, slimmer under-sink fit 🔹 Connects to smart phone app 🔹 Currently available through select dealers only
🧠 Final Thoughts: Harvey Arc or TwinTec S4 or The MiniMax?
If you’ve been comparing the Harvey Arc water softener with the TwinTec S4, it’s easy to see why both are popular choices in UK homes. The Harvey Arc offers modern touches like smartphone connectivity and sleek branding — but under the hood, it shares the same core technology as the S4. Not only that, but the S4 can b up to £700 cheaper.
For most households, the TwinTec S4 comes out on top. It delivers the same twin-cylinder, non-electric performance, but with added benefits:
- - A longer 10-year warranty
- - Lower price point
- - Broader installer support and online availability
- - Proven reliability with years of real-world performance
Unless app notifications or newer branding are critical to your decision, the TwinTec S4 water softener offers better overall value, long-term savings, and peace of mind — making it the trusted recommendation for installers, engineers, and homeowners.
If you have any further questions - that's what we're here for! We work directly with Harvey Water Softeners daily and we have serviced, fixed and installed a range of different models over the years.
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