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This Vaillant flexoTHERM review delves into its specs, features, pros and cons, and price.
German manufacturer Vaillant is best known for its boilers, but its venture into renewable heating systems has resulted into some of the best ground source heat pumps on the market.
The flexoTHERM range is as multi-source heat pump, meaning it can harness power from the ground, water or air. Read on to find out whether this heating solution is right for your household.
The Vaillant flexoTHERM ground source heat pump is designed with state-of-the-art Enhanced Vapour Injection (EVI) compressor technology to deliver high heating performance. As the name suggests, it is highly flexible and can be combined with multiple units to heat a large space or build a hybrid system run via a single controller.
Vaillant provides installation and commissioning support and offers an extended range of accessories, including a water heat exchanger, passive cooling and brine filling station.
The Vaillant flexoTHERM is suitable for ground collectors or boreholes. It’s available in 230V models (5kW, 8kW or 11kW) or 400V models (5kW, 8kW, 11kW, or 15kW).
The Vaillant flexoTHERM incorporates a EVI (Enhanced Vapour Injection) compressor to provide maximum heat transfer and an optimal Seasonal Coefficient of Performance (SCoP) that is much higher than a standard heat pump cycle.
EVI compressors also ensure higher efficiencies while using considerably less power. The compression process is split into two stages to increase capability and the temperature lift. This enables the Vaillant flexoTHERM heat pumps to achieve higher outlet flow temperature at low source temperatures.
You can connect your Vaillant flexoTHERM to a passive cooling module to assist with climate control, removing thermal energy stored in an airtight building to discharge it into the ground.
Vaillant offers several accessories including the fluoCOLLECT water-to-water stainless-steel heat exchanger for water source adaptation, or aroCOLLECT for air-to-water adaptation. Passive cooling modules can be added to enable passive cooling via the flexoTHERM pump. All accessories are available at an additional cost.
The Vaillant flexoTHERM is a premium heat pump, and prices start above £5,000 for the unit alone, but for the output and efficiency you get, we think it’s worth the price.
Vaillant is rated a high 4.6 stars out of 5 on Trustpilot from over 22,000 reviews. Many reviews are about the company’s boilers and annual services, but this is a good sign for prospective customers.
“Engineer No. 829 (Nick) visited to fix my heat pump. He was knowledgeable, helpful, phoned before his arrival and sorted out the problem quickly – he provided excellent service. My only issue was with the prior organisation of his visit as my first appointment wasn’t booked properly on the system, but a replacement appointment was made for the following day so overall I was happy with the service I received.”
“Although the repair that Alex was called out for was straightforward, he then went above and beyond checking a number of things on the set up of the controls and heat pump itself, and was able to answer all my questions and explain how to best use the system to run effectively and economically.”
“We’ve had a Vaillant heat pump for a few years now and it has been great. We usually had our installer do the annual service but this time went for Vaillant. They did a very thorough job for a fair price.”
We recommend the Vaillant flexoTHERM for larger households or those who want flexibility in their installation. This heat pump can be adapted into an air-to-water heat pump, and is suitable either for boreholes or ground collectors.
While not the cheapest on the market, but it’s powerful and efficient enough that the price tag is worth it.
We considered several factors when reviewing the Vaillant flexoTHERM ground source heat pump, including the following weighted criteria: design (20 per cent), durability (20 per cent), efficiency (25 per cent), performance (25 per cent), and guarantee options (10 per cent). We also compared the Vaillant flexoTHERM with some of the best outdoor heating systems and ground source heat pumps in the UK in terms of both performance and price.