About The Solar iBoost+

(56 customer reviews)

Get free hot water from your PV array with Solar iBoost+

Marlec’s innovative Solar iBoost+ enables you to automatically consume the excess energy generated at your home so you can just sit back and enjoy the extra savings! Read on to find out how with Solar iBoost+ fitted you will…

– Cut the cost of water heating in your home.

– Reduce the use of your boiler.

– Maximise the use of the free solar energy generated at your property.

Watch Your Savings Grow

If you have invested in Solar PV for your home then you will already be aware that there are periods of “export,” when you can’t consume all the energy being generated by the array.  This energy normally flows back to the grid seamlessly so you may not even be aware of it.

If your home has hot water storage with an immersion heater then Solar iBoost+ can be installed and start saving you more money on heating bills in less than 1 hour!

Solar iBoost’s built in display means that you can watch your savings grow, simply press the display button to see Saved Today, Saved Yesterday, Saved 7 Days, Saved 28 Days and Total Saved readings.
You can also see this remotely within the home by choosing the iBoost Buddy, simply keep it handy and you will see when you are Heating by Solar and Tank Hot.

There are 2 key parts to Solar iBoost+

And an optional iBoost Buddy

The Solar iBoost+ itself, typically installed in the airing cupboard next to the immersion.

A “Sender” and “Clamp” located at the main electricity meter at the property.

The iBoost+ Buddy is an optional in-home display with remote control function to Solar iBoost+.

…and they all talk to each other wirelessly which means no additional unsightly wires in your home.

This is the principle of how it operates:

Our Solar iBoost+ system detects when excess energy is being exported to the grid and measures it.  The main unit receives this information from the Sender and releases the equivalent level of energy (less a small reserve) to the immersion heater.   As the exported levels adjust in line with home consumption the Solar iBoost+ adjusts the levels delivered for water heating ensuring that only excess energy is used.

It’s as simple as

  1. Using a single clamp installed at the household meter the sender transmits vital export energy information to the Solar iBoost+ wirelessly.
  1. Solar iBoost+ is activated when excess energy is available. It intelligently controls and adjusts the flow of energy to the immersion in proportion with the fluctuating export levels.
  1. Water is heated over the course of the day using the free solar energy at your home.

and you cut down on your usual forms of energy needed to heat water!

Is my home suitable for a Solar iBoost+?

  • I have on-site power generation. (Solar PV and wind are most common).
  • The distance between the water tank and utility meter is less than 30m.
  • Energy usage in the household is less than the energy generated and excess is exported to the grid.
  • I would like to reduce my energy bills, especially for expensive water heating.

You may be out for periods during the daytime and generate more than is needed to cover the standby of all your appliances OR even at home during the day but rarely consuming energy up to the peak output of the solar array or wind turbine.

Whenever you are exporting more than 100W you could be “dumping” that excess energy into your hot water tank and saving even more money. Even if you have an export meter the cost savings possible on water heating may be greater than the export rate paid by the electricity companies.
Talk to your local PV installer or qualified electrician today.

How does it affect my Feed in Tariff Payments?

It doesn’t! In the UK FIT generation payments are not affected. As most export tariff contracts are based on deemed energy usage rather than actually metered self consumption is most beneficial. Solar iBoost+ enables you to usefully and automatically consume any excess energy generated rather than export it. Even with an export meter the benefits of Solar iBoost+ can still easily outweigh rising energy costs.

56 reviews for Solar iBoost+

  1. Mr Horton

    Very pleased with my Iboost. I have 8KW of solar PV and two solar thermal panels. We have a 300 litre hot water tank. The solar Iboost has achieved a great deal more than we thought it would and after 12 months it has saved 2300 kWh.

  2. S Madin (SDM Electrics Ltd)

    After upgrading to this unit and now having the iboost heating the top of my tank before switching to the bottom element this has had an extremely positive outcome. We have been amazed at the difference it has made

  3. D Lett

    Bought & fitted your iBoost 1 month ago. What a simple clever little unit, saving me money every day. Would recommend you to everybody.

  4. Robert Thorne

    I have installed the iBoost plus and since it was installed it has heated all our hot water for 4 adults. It originally was very noisy but after contacting Marlec very helpful phone line they sent out a rubber foot to fit to the unit. This holds the fan unit in place and reduces the original noise quite dramatically. They assured me that all units sold now come with this rubber foot. Highly recommended and a very simple 5 mins to fit. Many thanks from a happy customer 😊

  5. William Parr

    Phoned with a problem of a noisy fan in the Iboost and received details via an e-mail explaining how to check the fan. Once the cover was removed the small rubber stop had not been fitted leaving the fan able to move. Phoned Sarah at Marlec who is to post one next day. Brilliant service and thank you.

  6. Phil Whitworth

    Love my Solar iBoost+ that I had fitted with my panels in January this year. It has given me loads of hot water and I have switched my gas water heating off since May! I was recommended it by my father in-law who also has one fitted. Well done!

  7. Trevor Stokes

    Great product and easy to use. I got the Buddy too which is really handy.

  8. Gary Aked

    The Solar iBoost is essential for any Solar panel owner and the Marlec company are very helpful if anything goes wrong and provide a speedy turn-around of the product

  9. Jim Hughes

    Been having a problem with immersion heater connected to iBoost. Phoned up to ask for a downloadable pdf of a manual for the iBoost – but got Teresa who was extremely helpful, patient and knowledgeable and has hopefully solved our problem. I am very impressed and very grateful.

  10. Don Bruce

    I considered the iBoost when it looked like I was going to replace my Combi Boiler with a system boiler and hot water storage tank. I did quite a bit of research and it seems like a “No Brainer” for anyone with a hot water storage tank and Solar PV. I export more of the electricity I generate than I use. This would mean that I would cover most of my hot water generation, especially in the summer months, for 3p per kwh. However, the repair to my Combi was relatively cheap so the plan to install a System Boiler was placed on hold. If the boiler has to be replaced in the future I will come back to buy an iBoost.

  11. Jonathan Lihou

    Recently upgraded to iBoost+ and am very pleased with it. Marlec have been very helpful throughout – excellent service, including when we had a minor installation problem to resolve. Invested in a Buddy at the same time and it’s really useful – it has become our new obsession!

  12. Mrs Ann Norman

    We’ve had an i boost and it’s absolutely fantastic. Plenty of hot water We had a problem with the sender unit and the “Marlec team” went above and beyond our expectations. Thank you Julie and team for all your help. Would DEFINATELY recommend this company and the i boost.

  13. Ted Shepherd

    Does what it says on the tin. we had ours installed in March and since then we have saved 180 unit of electricity.

  14. Jean Bell

    We have had the iBoost system for a year now installed along with panels. Amazing gizmo, really does what they say and more. Our sender unit ran out of battery power and I changed them and followed instructions, unfortunately the sender unit had developed a fault. Fortunately I was advised to contact Marlec customer services and they provided a new sender unit by post the next day and everything is up and running again. After sales service is excellent.

  15. Jean Bell

    Excellent product great after sales customer care.

  16. Magdalena Harding

    What a superb company Marlec is. Not only does it supply this wonderful device (I’ve had mine now for over two years and love it) but, when I had a complication with my thermostat throwing the system all out of wack, Marlec did more than I could have ever dreamed of, sending out parts and eventually a whole new kit, determined to get me back up and running. They could not have been more helpful or supportive, such a joy these days. Thank you, especially Sarah, for your patience and commitment. It is so thrilling to be making hot water when the sun’s shining again. I recommend the iBoost to everyone I know who has solar panels.

  17. Gary May

    I had this installed and had a slight problem with it, how-ever the Technical department were excellent ( Thank you David ) the unit was returned and tested and replaced. Its very rare nowadays to have a company that was so helpful, the customer care was excellent, a special thanks to Julie Williams. So well done Marlec.

  18. John Hewitt

    The iBoost has been working really well and we are very happy to have it. Just recently it stopped working, our installers have ceased trading and did not give us a manual. Contacting Marlec customer services was easy by email and they were exceptionally helpful. and quickly help us to return to full operation. I have now printed off the manual and keep it convenient. This is a really great piece of kit and makes full use of the solar panels on your roof.

  19. Sue Meads

    Absolutely brilliant piece of kit. Delighted with my install which generates electricity for my use, gives me an income from my energy company and heats the water. Why doesn’t every new build have solar as standard?

  20. Andy Green – Director Green Park Renewables Ltd

    As a solar installer I have installed many iBoosts. I find that they are easy to install, smart looking, easy to use, and very efficient. The iBoost always saves my customers a significant money off their gas/oil fuel bills and I recommend it wherever appropriate. As many other reviewers have stated, the service from Marlec is second to none and I would not be at all worried if any of my customers chose to contact them direct (no need to do this customers) on the very rare occasion that things are not perfect.

  21. J Penrose

    Called through to the customer service line and didnt have to wait to get through, had my issue sorted out quickly and with a help full manner. Great job!

  22. J Penrose

    Call through the customer service line and was meet with really helpful and friendly staff.

  23. John Dalton

    Spent a long time “pairing” my Buddy to my newly fitted Iboost+ and failed miserably, due I think to my own fault misreading B Button info. I phoned Iboost and was advised by a charming and helpful lady,Therese I think, and within 2 minutes “Buddy” was working as advertised, BRILLIANT! Many thanks I-Boost, I shall tell all and sundry how great you were.

  24. Greg K

    New Zealand has plenty of sunshine and no solar subsidies. When considering a 5KW solar system, the economics only stacked up if I could use the excess generation to heat our hot water. I discovered the iBoost for NZ and Australia. It would fully manage our hot water. It now provides all of our water heating during summer’s sunny days, but its real benefit is the management of the water heating on cloudy and shorter winter days. The solar system reduced our electricity bill, but the iBoost has reduced it over the summer months by an additional 20%.
    An error on my part did damage the iBoost at one stage, but Marlec were very supportive and assisted with a repair. The iBoost is operational again and saving me money.

  25. Mike Aberdeen Uk

    I have used a system for two years and to date have captured 10% of the total solar production of my 3.6kw panel system in my hot water tank. Great Product. Would recommend.

  26. Eric Wheldon

    I retract my previous review stating that the unit was vibrating and noisy. I contacted marlec and advised them of my problem they responded within one hour giving me excellent clear advice. It turns out that the installer had not used the lower two securing points and had not fully secured the removable cover in place. This allowed the cooling fan to vibrate and was the cause of the vibration and noise. I fixed these issues in five minutes and the fan now produces a gentle hum. EXCELLENT CUSTOMER SERVICE.

  27. Alan F (Devon)

    Excellent device. I monitor my solar panels and consumption closely and in 8 months have recouped approximately 40% of my initial outlay. This does not include the peak summer months. so should pay for itself in around 2 years. If you have solar panels and an immersion heater you should fit this device.

  28. Andy H

    Excellent product and easy to follow instructions. The unit started working the day after install when the sun started shining. Very helpful staff at Marlec confirmed before installation the the unit would work with my Hive hot water system, and it did.

  29. Dominic Eldred-Earl

    Could not be easier to set up and use – we had a faulty EMMA unit which we had been using for 5 years – so for us the set up was as simple as disconnect the EMMA unit and wire this in its place. It started working immediately and we no longer have to worry about heating or hot water as it supplies plenty for the 3 of us.

  30. Deborah Cotterill

    Amazing support from Theresa, really understanding working at my pace completely (I’m a techno phobe). So kind and really helpful, problem solved WOW!!! You can just trust this company to help way after the sale which is so refreshing. Great support process and people, thank you.

  31. Martin Cohen

    We had a solar i-boost installed with solar panels approx 3 years ago. It stopped working, but the technical support staff talked through the problem and identified it was a fault with the second safety thermostat on the tank, not the unit itself, and explained how to reset the thermostat. Thanks for you help

  32. Simon

    Had our PV installed a few weeks ago along with an iBoost… well a few weeks later our oil boiler did an impression of a genie coming out of a lamp and gave up out of action… no problem we thought we have the iboost, it’s sunny and if all else fails we can override it manually… long story short..we’ve not turned the boiler back on even though it’s now repaired an we have not even had to manually override the iBoost..plenty of hot water everyday!

  33. John Chapman

    Fitted one of these three years ago with our new solar PV and in that time it has used 1.5MWh+ of solar electricity heating our water. This June 2017 we had two weeks when the gas boiler was not required at all. There are two of us in the house regularly.
    The gas heating thermostat is fitted 2/3 down from the top of the copper cylinder and set to 50C, the time clock being set to heat water for one hour morning and tea time. The iBoost is on all the time and set to 70C (to keep bugs at bay) and requires no attention in normal usage. As I have the time I switch the boiler off when there are sunny days forecast and a quick manual check of the heavily jacketed cylinder tells me if I need the boiler on or not.
    From a cost point of view, we are using solar energy which has already been subsidised by Ofgen and is saving boiler cycling and the cost of gas to heat the water. Nice to have a win, win situation for once.
    It may help to know our solar is 14 x 270kW panels with Enphase individual panel inverters facing SE at a rather low 30 degree angle. Maximum output 3.3kWh.

  34. Mrs Ann Norman

    We have the original iBoost and over the years it has saved us a great deal of money. Their is always a tank of hot water. The team at Marlec are absolutely fantastic, wish more companies had their work ethic, and the customer service team are always helpful….great company, great product, both definitely recommended.

  35. Ron Donnelly

    I’ve had a Marlec system fitted for a year. I’m extremely pleased with its performance. We have a big 300ltr tank and we export a lot from an unshaded 4kWp south facing system. From March through to Sept we’ve only needed to turn on gas boiler three times. And this with normal family usage. The only trouble is, we had to replace an immersion coil after only one year of operation (the primary coil – we have two in use). Perhaps bad luck or maybe the excessive cycling that’s involved.

  36. Brian Pounder

    I had Solar Boost fitted along with my p.v. panels two years ago. After twenty months the Solar Boost stopped working so I attempted to contact the p.v. installers who surprise, surprise, had moved premises twice and then disappeared. I then contacted Marlec and was pleasantly surprised at their attitude to my problem. ‘It’s still under warranty, send it to us along with proof of purchase and we’ll deal
    with it’ Two weeks later I had a replacement.
    Their service and attitude was amazing. Well done Marlec. Since getting the replacement I may have found the cause of the original failure. The installation instructions that came with it specify 100mm clearance above, below and either side of it to allow cooling airflow. Mine had been fitted with only 30mm above. Needless to say it’s now been repositioned.

  37. John Longworth

    The iBoost+ and the company Marlec go hand-in-hand at top position for product and customer service – they are fantastic!
    An iBoost+ was fitted by a contractor when replacing the central heating boiler in May 2016. It has performed perfectly since then until an accidental short circuit on the immersion heater wiring (my fault!) in November 2017.
    I contacted Marlec and a quick exchange of emails on diagnosis resulted in the failed unit (caused by the accidental short-circuit) being returned for replacement. Marlec’s staff are so courteous, kind, helpful and efficient. Nothing is too much trouble to them and the iBoost+ just sits there quietly getting on with the job of saving me money – as long as it has the energy!
    The attention I received from Marlec was so speedy that, within 8 working days, I received the new replacement unit and I fitted it the same day. I can’t sing their praises enough! Well done to all the team at Marlec.

  38. P Collett

    Wonderful. Our tank has two immersion elements, have set both for 70 deg C. Now have been able to reduce the thermostat for the boiler to about 41 deg, to come on from 8pm, so allowing boiler to come on if there have been a series of cloudy days. But be careful water at 70 C is very, very, very HOT.

  39. P Collett

    Further info: Suggest you resist having a SMART meter installed, I understand they may be able to measure exported electricity, which would mean because you have the immersion switch you won’t export anything so you will lose the estimated 50%.
    I’d hold off the smart meter as long as possible.

  40. Des Clarke

    Great product, and I most love being able to shut the boiler down for c.6 months as this heats all my water for 3-4 people throughout summer ‘for free’, and still produces some hot water (1.5-2kWh/day average during winter). I really can’t see why anyone would invest in solar thermal water heating at c.£3k when this does the same thing for a tenth of the price! However my only problem is payback period. After 2 years use (since Feb.2016) it’s saving me £29 a year in gas I would have otherwise used, which would make it c.10 years+ payback period. In my case my Solar PV Installers were offering these as a ‘freebie’ so I managed to get one included. That said I think I’d still be willing to pay the money, but on environmental grounds, not as an investment. If you don’t have mains gas and heat water by mains electricity (typically 4-5 times more expensive per kWh than gas) then it’s a ‘no-brainer’ as this would pay for itself in c.2 years!

  41. Sandra Haworth

    I’ve just had a little trouble with the iBoost, having lost connection when the battery life ran out. Talked to Theresa. After I’d tried and failed to reconnect, she talked me through the process resulting in success. She would be an asset to any firm!

  42. Sandra Haworth

    Many thanks to Theresa for her help in establishing wireless contact again

  43. K MacLennan

    We have always been impressed by the Solar iBoost+ and will continue recommending this product to folk we know, who have Solar PV

  44. P Halloran

    I can’t remember when I last received such fantastic customer support. Your company was attentive, open, and supportive. Kevin, was extremely knowledgable, patient and tenacious.

    The issue appears to be finally resolved, and while it appears that the iboost was only a trigger for the problem, rather than the problem itself, I’m fairly confident that we would not have resolved the issue (without a lot more pain) without your support.

    Many thanks. I wish your company the best of luck, and hope that you continue to foster and reward such good customer support.

  45. T Jones

    just to say a BIG thank you for sorting out the IBOOST : just hooked up
    the new one you sent me and its working perfectly ! :) : such a good

  46. Steve Palmer

    Loving my Solar iBoost+
    I fitted this in October 2018 and could not be more impressed. It detects the slightest amount of spare power and diverts it into my immersion heater and yet reduces power or switches off the moment power is needed elsewhere – e.g. kettle, washing machine etc.

    I turned down the thermostat driving hot water heating from the gas boiler to 50 degrees and set the immersion heater thermostat to the max. For a household of two, one good solar day then sustains the hot water without need for gas consumption for up to two or three days. Brilliant!

    I also fitted a 2kW glass panel heater adjacent to my airing cupboard so that when the water is at max temperature, the iBoost+ then diverts power to space heating, further reducing my gas bill!

    What I’d really like though, is for the iBoost+ to interface e.g. with Anker eufy sockets so that various other devices could be powered up via measured spare power – e.g. air conditioning, pond pumps, tool chargers etc.

    All in all though, this is an amazing product and no solar home should be without one. Payback is very fast [faster than the panels] and there’s a certain satisfaction in seeing practically 100% of power generation being usefully used within the home rather than being exported – whilst still being paid FiT as well!!

  47. Nathan Jowett

    Got a Haining Sanneng (18vac tubes) 120L Solar Water Heater .It has S/S immersion is only 1.5kW. got Project Solar to return to add Iboost & now getting full hot water tank in January(can store heat for up to 3 days) if its a clear day FAB

  48. Terry Hutton

    I’ve had my solar iboost about 4 months now. I’m very impressed with it. Since fitting it all my hot water has been heated by it saving about 2.5kwh a day.

  49. Michael Walker

    I had one of these installed with my solar PV array over three years ago and it’s worked unobtrusively and flawlessly, topping up the hot water in winter and providing pretty well all of it in summer. I only came to the website to see what to do when the unit reported the sender battery was low, which was quickly fixed.
    The only thing I’ve had to adjust is the thermostat setting for the gas boiler on the hot water tank so it doesn’t come on too much , as it measures near the bottom of the tank and the immersion heater one is at the top

  50. Shaun Tebble

    I had a query which I was struggling with, 2 minutes on the phone with a chap called Stuart explaining how things worked and its sorted. I don’t normally leave reviews but thought this might help others and as a well done to Marlec!

  51. Will Green

    Solar iboost is an essential addition to any solar pv installation if you also have a conventional immersion heater. The additional boost buddy gives a constant reading of how much you are saving and tells you when you are using power from the grid or exporting. Mine has saved me £££ by automatically using power I would have exported to heat my water free.

  52. Steve Huggons

    I would recommend the Solar iBoost. Here are my figures for a west facing 4 kW system. Hope it helps someone.
    591.8 kW Year 1 (2014/2015)
    523.06 kW Year 2 (2015/2016)
    462.06 kW Year 3 (2016/2017)
    370.35 kW Year 4 (2017/2018)
    501.63 kW Year 5 (2018/2019)
    478 kW Year 6 (2019/2020)

  53. Bob Wiltshire

    What a fantastic bit of kit! having had solar tubes this is hands down the best way to manage hot water in our home. no moving parts, pumps, antifreeze or a system to be serviced! Clear information on screen and with the addition of an Iboost buddy even me, the man of the house can see when the washing machine, dish washer or tumble dryer can be switched on with the traffic light system with minimal to no COST. If you have a solar system you need the Iboost, if you have the Iboost you need the Iboost buddy!


    This is not a review of the product which I have had for over 4 years, and have found extremely efficient, but feedback on some most helpful advice given by Rik Hawes – Support Engineer.

    I recently had an issue with my hot water cylinder which, by process of elimination was found to be a problem with a gas diverter valve not the iboost.

    A special thanks to Rik for his patience in dealing with the matter so helpfully and I would certainly recommend having an iboost installed.

  55. Nathan Jowett

    Have an 18evacuated tubes 200L Solar Thermal Water Heater(Haining Sanneng)+5yrs) with 1.5kW immersion .Didnt think if Voltage wasnt hitting full wack it would achieve much!WRONG,now maximising Solar Hot Water through Winter Months too 3.1kW system (6 SE&5 SW facing Panels)

  56. Ken Seager

    Have had this now for 2 years. What a fantastic bit of kit.
    Between April and October, with only using the gas about three times, this keeps us in hot water every day. We have a large tank, and using hot water normally for showers etc, once fully heated the tank keeps us supplied for 2/3 days.
    I hardly ever write reviews, but this is so outstanding, I felt I had to.
    Can’t understand why it is not more widely advertised. I only found out about it by luck. Would suggest getting the Boost Buddy+, saves looking into airing cupboard to check if working and how well.

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