Harvey TwinTec S4 Review 2026 Pros & Cons
We've supplied and supported Harvey water softeners for years and the TwinTec S4 is one of the most popular systems we recommend. In this review we'll explain its strengths, weaknesses, running costs and whether it's the right choice for your home. Click any link below to jump straight to that section.
Why Choose a Harvey Water System?
The Harvey brand is the UK and London’s leading water softener company. After inventing the twin-cylinder machine, Harvey now sells and manufactures some of the most efficient systems on the market.
There are many reviews of Harvey online and they are very well known in the UK, providing machines that are built to last 10-20 years.
What are the Different Harvey Models?
When researching Harvey water softeners, you may have come across several different models. When looking in more detail – most of these models may appear the same or very similar.
Harvey has a series of different sales channels including their own retail, online dealers and offline dealers.
They section distributors regionally, meaning only certain models are given to specific retailers in their given areas across the UK. Each dealer is given a branded product to sell which can include:
- The S4 (and other TwinTec models).
- The MiniMax M3 (and other MiniMax Models).
- The Harvey Crown
The Harvey Arc water softener is only sold by Harvey themselves via their own retail channel.
These models have different branding, cabinets - but are effectively all made the same with the same specification (NOTE: except the Harvey Crown which is a much older model and has a different specification).
Why is this Harvey Model the Best to Buy?
For a family home of 3-4 bathrooms – the Harvey S4 is the best model because it is the most cost-effective. This Harvey Model is one of the latest models and a leading non-electric water softener. When searching online it is a well-rated and reviewed water softener, with plenty of reliable knowledge available. Designed and manufactured in the UK, this model is perfect for hard water households wanting low-maintenance, efficient softening.
Key Benefits:
- Affordable price but most up to date technology: The S4 can be found for £1174.00. Other models such as the Crown can be cheaper but offer a older specification, lower efficiency and shorter warranty.
- Non-electric operation: No wiring, no running costs
- Compact twin-cylinder design: Delivers soft water 24/7
- Eco-friendly block salt: Simple, clean, and cost-efficient
- 10-year warranty when bought from authorised dealers like us
What are the Dimensions & Measurements?
This water softener is one of the smallest you can get. A Water softener must be fitted by the stop tap, which in most homes is in a cupboard underneath the kitchen sink, meaning the size is very important. The Harvey TwinTec S4 dimensions are:
490mm high and 205mm wide with a depth of 440mm.
TwinTec S4 pros and cons:
When looking at and comparing water softeners, you should be looking at:
- The type of system (non-electric is better and more efficient than an electric).
- The max flow rate (40 – 60 L/min for the family home).
- The pressure capability (a max pressure of 5/6 – 10 Bar)
- The efficiency (the amount of salt and water used per regeneration)
- The warranty
The S4 has one of the most appealing specifications when compared to any domestic system on the market! You can view the full spec on our product page by clicking here, including Pros such as:
- A twin cylinder tank
- A non-electric and block salt fed system.
- A high flow rate.
- One of the highest efficiencies.
- A 10 year warranty.
- Automatic & No Programming.
Cons include:
- No automated app or smart phone technology.
Is this softener suited for my water hardness?
All Harvey water softeners can come with different gearings. So if you do have exceptionally hard water - the S4 can handle it. Coming from London, the S4 has been built to tackle London’s hard water, which in some cases, can even exceed 600ppm.
How Much Does The TwinTec Cost to Own?
So how much should you be paying for a Harvey water softener? A good priced Harvey system will lie over £1000 but shoud be udner £1300. You can check today's latest price on our product page.
Real Customer Feedback & Testimonials
⭐⭐⭐⭐⭐ “I can’t believe the difference this has made to my son’s eczema. Within weeks of installing the S4, we were using fewer creams and his skin felt so much calmer.”
— Lisa, North Yorkshire
⭐⭐⭐⭐⭐ “We had awful limescale in our kettle and on our shower screens. After a month with the TwinTec S4, it’s like it never existed.”
— Mark, Durham
⭐⭐⭐⭐⭐ “As someone with dry, itchy skin and hard water hair issues — this softener was a game-changer. My skin feels hydrated again!”
— Sophie, York
💬 What Reddit Users Are Saying
Reddit users consistently highlight the TwinTec’s superior value, warranty, and reliability compared to other models:
“If it’s for a family home – definitely the Harvey TwinTec S4. Same spec as the Harvey Arc but much cheaper. Best efficiency and lowest running costs.”
— Reddit user, r/WaterTreatment Reddit
“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, r/DIYUK Reddit
“The TwinTec S4 at £1100 seems like a much better deal … quote was around £2200.”
— Reddit user, r/DIYUK Reddit
Harvey Vs Kinetico
Kinetico and Harvey Water Softeners are competitors. Kinetico is a very popular brand in the USA, also providing high quality, non-electric machines. But what about Harvey Vs Kinetico? There is little difference when comparing the specifications of this Harvey model and the Kinetico Premier Compact - but Harvey comes out on top with better flow rate, efficiency and salt usage. Despite this, the Premier Compact is retailed at £1795 and often set at this price with no discount available.
| Feature | Harvey | Kinetico Premier Compact |
|---|---|---|
| Type | Non-electric, twin-cylinder | Non-electric, twin-cylinder |
| Manufacturer | Harvey Water Softeners (UK) | Kinetico (USA) |
| Made in | United Kingdom | USA |
| Flow rate | 56 litres per minute | 41 litres per minute |
| Family size suitability | Ideal for 1–6+ people | Ideal for 1–4 people |
| Salt type | Block salt | Block salt |
| Warranty | 10-year manufacturer warranty | 10 years |
| Installation space | Very compact — fits under most sinks | Compact — fits under many sinks |
| Upgraded components | Yes – latest model includes improved seals, bypass, and internal design | No recent design upgrades |
| Noise level | Virtually silent | Quiet operation |
| Servicing | Available through local UK dealers | Available via Kinetico network |
| Price range | £1174.00 (with £25 off code) | Typically £1795 |
| Key Benefits | Made in the UK, higher flow rate, upgraded design, ideal for eczema & hard water areas | Reliable performance |
Is This Water Softener Easy to Install
The installation of a water softener is a relatively simple process for any plumber. It is about as difficult as installing a washing machine. A local plumber should be able to complete the job, using an installation kit in around 2-3 hours of a plumber's time. The time depends on the space and pipework.
Your main task is then to source a reliable plumber. If you don’t have or know a local plumber, you could try searching on Google or asking neighbours, family and friends.
How much does it cost to maintain a water softener?
The Harvey S4 water softener doesn’t use electricity. Therefore, you won’t need to pay for energy to have it running. The only thing you have to do is replace the block salt, which is needed for the system to work. As far as water and salt usage go – the S4 is the most efficient model you can get, so your running costs will be at a minimum.
Block Salt
All water softeners require salt to work and the latest designs use block salt Vs tablet. The salt itself is needed to remove the hard minerals from your water, using a brine solution. Without salt, the system won’t work.
The S4 uses standard block salt, which can be sourced online from multiple websites, including Amazon or Harvey direct. This system holds 2 blocks of salt at any one time. The average usage of salt in the family home is 1 block per person per month. The blocks of salt come in packs of two which cost £6.50 - £8 per pack depending on if you buy in bulk.
Other different Harvey models can use a special curved block salt – this can only be sourced from Harvey directly. But this system uses standard block salt.
💧 Summary: Our Verdict
★★★★★
As experts in the industry for over 20 years and having sold a range of both Harvey and Kinetico systems, we believe the Harvey TwinTec S4 offers one of the best balances of reliability, efficiency and running costs available. For the majority of UK households it's the Harvey model we'd recommend.
If you live in a hard water area, investing in a Harvey water softener is more than just a luxury — it’s a long-term money-saving solution for your home.
On average, UK households can save over £400 per year by softening their water. That includes lower spending on:
- Cleaning sprays and descalers
- Shampoo, conditioner, soap and laundry products
- Heating and energy bills (due to more efficient boilers)
- Replacement appliances and plumbing repairs caused by limescale
- But it’s not just about annual savings — it’s about long-term value.
⚠️ What We Don't Reccomend: Cheap Water Softeners Cost More in the Long Run
If you see a water softener priced around £400–£600, it’s likely an electric model made with cheaper parts, often imported. These machines may look cost-effective up front, but they’re often inefficient, noisy, and prone to breakdowns — especially over time.
They typically come with shorter warranties and don’t last nearly as long.
✅ Why this softener Is a Smarter Investment
It is a non-electric, twin-cylinder softener built in the UK and designed to last. It comes with a 10-year manufacturer warranty, but many customers report it lasting well beyond 15+ years with minimal servicing.
You can purchase on the product page for £1174 (and save an extra £25 using code: HARVEY). That includes the latest spec — with upgraded components, improved seals, and more efficient salt usage.
🌿 More Than Just Savings — Real-Life Benefits
Switching to softened water with the Harvey S4 doesn’t just save money — it also improves daily life:
- Protects your plumbing and appliances from limescale
- Unblocks shower heads, taps and boilers
- Reduces dry skin, eczema and irritation naturally
- Leaves hair feeling softer, shinier and easier to manage
- Improves lather so you use 50% less soap and shampoo
Who shouldn't buy The TwinTec
You may want to consider another model if
- You live alone
- You have extremely limited or no cupboard or outdoor space
- You want an app-controlled smart system
- You only have temporary accommodation
Where Can You Buy The TwinTec?
The TwinTec range is a premium range that is distributed only by very few retailers in the UK. You can now purchase this system online at North East Water Softeners at a great price. If you are after a very specific Harvey retail model – this needs to be purchased directly from Harvey and you won’t find this online.
Do you have any questions?
Enquire below for more information & exclusive discount codes.