Custom Renewables Ltd

Mark and the team were professional throughout. A number of visits to our house to check all the work that was required prior to the installation, all prep work done on time and the installation also done as planned and on time. All works were done with minimal intrusion and at all stages the house was left clean and tidy. Follow-up visits have been completed to ensure the installation is working as expected and all waste was tidied up within a day or two. Thoroughly recommend.

Helpful team, easy to deal with, great tidy job.

I found Mark and the team via Heat Geek's Elite Installer listing after being disillusioned by multiple MCS-certified installers who proposed oversized heat pumps (2 x 15kW in one case) without considering anything beyond the building's floor area. The team at Custom Renewables employed modern heating engineering processes to design an underfloor heating and domestic hot water system for my new build. The process started with system sizing based on detailed heat-loss and hot water usage calculations for the building. With this, they sized and selected a Viessmann ASHP and the cylinder, then created a plumbing and UFH pipe layout. They used a snail pattern to minimise hot and cold spots on the floor. I had many questions throughout the process, which were always answered promptly and with confidence. The installation, which was done in phases, was conducted in a neat, tidy, and professional manner. As a freebie, Mark even instructed my bathroom plumbers on how best to join MLCP pipework to avoid leaving gaps in the insulation.

A redesign of our existing ASHP system, first installed 5 years ago. Work carried out was fast and without fuss. I was kept informed throughout the process as to the changes being made and the benefits. Final adjustments a week later have shown the new system to be a significant improvement. House is warmer and controls seem more responsive. Would highly recommend. Many thanks to Liam and Jordan

Liam and the team at Custom Renewables installed a SigenStor system with 2 batteries and 12 solar PVs at my residential home. I felt at all times I received generally good all-round energy advice, and was invited to ask questions. Liam spent plenty of time engaging with these as well as working around various other building work going on at the time. The quote I received was complete, there wasn't any surprise add-ons needed to get something that actually worked and the kit seems decent quality. On the install, everything was tidy, they responded to requests around placement of the devices. When they were short some materials due to an unexpected upgrade in PV size and output (nice), they came back straight away to finish, even on a Saturday. When they noticed by monitoring after the install (without any prompting from me) that a PV string was not delivering output, they came and fixed the connection without needing any request. I get the impression they want to install a good system that works, not just do what they need to get paid, then leave it. I'll use them again in future for a heat pump and air-conditioning.

Excellent service from start to finish We had a fantastic experience with Custom Renewables. From the first meeting, Liam took the time to understand exactly what we wanted from our replacement air source heat pump and carried out a very detailed room-by-room survey to design the right system for our home. The installation team, Karl and Justin, arrived exactly when scheduled and did a brilliant job. They were friendly, hardworking and very tidy. After installation, Karl explained the system clearly and Liam returned a few days later to check everything and fine-tune the settings so each room reached the desired temperature. Great service, great communication, and a very professional team throughout. We couldn’t be happier and would highly recommend Custom Renewables.

Just to say a huge thanks for all the crew at Custom Renewables LTD who have just fitted a new air source heat pump for me. The survey was carried out by Liam, the plumbing installation by Carl and the electrics by Justin. The works were carried out to a high standard and all the lads were very neat. Emma, from the office kept the whole process ticking along, keeping me informed of what was happening when. All in all, a great company and one I will be using again and one I can not recommend high enough.

True professionals! Liam and his team rescued us when the installer we had selected for our heat pump let us down. Liam's knowledge of heat pumps is epic! We've been warm and cosy through our first winter AND reduced our energy costs . Our CoP has never gone below 4.4 since October. Carl did most of our installation. He's justifiably proud of his pipework and it was a pleasure to have him in our home. Whatever your project, you really should speak to Custom Renewables. We cannot recommend them highly enough.

Such an unfortunate way to handle an install. I wish I could rate higher, because the pump itself is quite good and most of the pipe work looks very neat. The contractors though, wow, all except two (out of six or so) were just plain unprofessional. If it was just the cursing I could live with it, but when you hear them bad mouthing the last guys work (and more than once) you can't help but wonder what you're getting, and mixed with not keeping you in the loop, it added a lot of stress to the situation. The lead contractor tried to blame it on guys being guys, sorry that's a sad cop out, for us as a gender and professionals everywhere. Worth remembering most people don’t know much about how these things happen and you’re working on their house which is likely the largest investment they’ll ever make. Beyond that, the damage to the house. Walked out into the hallway to see they'd torn the fittings off around my loft hatch and damaged the ceiling. No one thought to get my opinion on that. That's just one instance as well. Luckily that was repaired, albeit with filler, not exactly as good as. Some other stuff I've had to fix myself. Like after they dumped the dirty old system water down the toilet leaving a black stain, they said they would sort it but its been months and we've had people over so I couldn't just leave it. Minor other bits too. What really gets me is, you'd think someone in this profession would think around what they're doing - "How will this affect the rest of the house, are there any concerns" but no, they caused two leaks and damage to my shower with the increased pressure. All of which could have been easily avoided by closing the shut off valves we have to the shower or checking the state of the pipes you'd just been cutting before going on lunch. The guy did have a look at the shower a little while after but only managed to make it worse really, the temperature and pressure dials are lose now and it can take a long time to get warm sometimes. Update: He came by a few months later and updated some pipes under the bath which was nice. At the same time though he tried to offer me a restaurant voucher if I tweaked my review and raised the rating. He claimed he had no control over the pricing of the job even though I was ccd on an email to him from heatgeek saying he could revise the offer if he wanted to “or keep the extra cash”. My loft hatch isn’t vaguely as it was even though it was “fixed”. Maybe they have changed, but I doubt it.

Highly recommend custom renewables, Liam was great to deal with from start to finish always responsive and really knows his stuff. Carl did an amazing job on the install and has a real attention to detail, these are who you need for your project, over the moon, thanks guys.

From the first initial information enquiry, through to our system being fully comissioned and live, Mark and the Custom Renewables Team have been absolutely fantastic. The knowledge and guidance we recieved throughout the process was incredible, with Mark answering any and all of our questions (of which there were lots) and helping us to get our heads around moving from an LPG to Air Source Heat Pump installation. The work was done to a fantastic quality, the team who were here were a joy to have in the house and the follow up customer service has been superb. I could not recommend Custom Renewables highly enough - thank you!

We had a great experience with Liam and the team at Custom Renewables. We did a lot of research to find the right installer for our ASHP system and we couldn't be happier.

Liam and his team were fantastic from start to finish, really profesional and we were kept upto date with all actvities during the instalaton of our Air Source Pump and Underfloor Heating. They were Clean and efficient and turned up exactly when they said they would! We would fully recommend! S&K BL

I would unhesitatingly recommend Mark and his team to anyone. We had two separate jobs to be done - installing air con and then replacing a boiler with a heat pump. Mark gave us loads of time to scope out what was needed and the best options for us. He turned up exactly when he said he would, delivered on budget, did the job perfectly, ran a hoover round(!), then made sure we were happy with understanding how the equipment worked. He also checked in afterwards to make sure we're happy and everything's working ok. It's a high-quality service.

Absolutely phenomenal service from Mark and his entire team! From start to finish, the installation of my complete air conditioning system was handled with exceptional professionalism, precision, and care. The units look sleek and modern — a flawless finish that speaks volumes about their workmanship. Mark also maintains my heat pump system, and his reliability, deep technical knowledge, and genuine commitment to quality are second to none. He’s always available, incredibly thorough, and ensures everything runs smoothly and efficiently. I couldn’t recommend this team more highly — truly first class in every way! Thank you to Mark, Sam and all the crew.

I’m writing this review 6 weeks after installation of my heat pump by Custom Renewables. I can’t fault anything! Liam who did the original assessment & design was very knowledgeable and open to discussion of options. Carl and Jordan who did the install and repipe were great, professional, very nice guys and worked to a very high standard. I was a little concerned that no storage space would be left in our only cupboard once the cylinder and plumbing had been installed - but that turned out not to be an issue, everything was very nicely done and minimal extra space taken. The only issue experienced was when our electric shower lost power, not a big issue for us but the guys insisted it was fixed same day and the electrician (sorry, can’t recall the name) kindly travelled some distance to make the fix. Now knowing more about heat pumps I can appreciate some of things Custom Renewables did that other installer perhaps wouldn’t … changing all radiator values, cleaning the system & the installing various valves to remove air, all pipework was insulated to a high standard. Happy customer!

Thankyou to Mark and his team for the A1 Airsource Heat Pump installation at our new property . Mark was able to work seamlessly alongside our builder which was huge help to us.Everyone involved with this company works to such a high standard and are extremely knowledgeable.

Five star experience all round. Would highly recommend custom renewables to any potential renewables.. Mark was really user friendly in his approach prior to and during the commissioning works. shout out to Gary who was on site every day - apologies to the others - their names slip my memory but all were exceptional throughout I am extremely pleased with the work and how efficiently the system runs and should the need for another project arise these guys are the only ones in the running

Liam and the team at Custom Renewables did a great job replacing our tired old fired central heating. Fantastic attention to detail and support. For us it was critical that they fitted into a challenging house rennovation schedule with other trades which worked seamlessly. Would strongly recommend as Liam offered a design way above some of the standard offerings available from the usual well known suppliers.

This is a really trustworthy, knowledgeable and confidence inspiring team of people. We had a great customer experience from initial visit to system commissioning. The quality of the whole install is obvious. Special thanks to Karl who was on site throughout, though the whole team were great. Highly recommended.

We recently had an air source heat pump installed by Liam and his team at award-winning Custom Renewables as part of a full house refurb, and I honestly can’t recommend him highly enough. From start to finish, Liam was professional, knowledgeable and incredibly helpful. He carried out a detailed heat loss calculation, designed and installed our underfloor heating system, and fitted new radiators and plumbing upstairs – all with real care and precision. He was also super patient in explaining everything, took the time to sort out all the BUS paperwork for us (a lifesaver), and made sure we understood the system fully. He came back to walk us through the controls and even helped us to install the app, which we can all monitor remotely to check things are running smoothly in the future and control the settings. Liam genuinely goes above and beyond. We’re really happy with the whole experience and wouldn’t hesitate to recommend him to anyone looking to make the switch to renewables. There are a lot of people out there claiming to be experts in renewables and installation but Liam is the real deal and is award-winning for a very good reason. He’s your man!

Custom Renewables have installed a Viessmann ASHP for my house in May 2025. The quotation phase was very informative looking at all possible opportunities. Whilst explaining the options available. The installation work was done very professionally by Carl, Jordon, and Liam, and also the electricians Justin, and Connor. The start of each day always summarised the work being done for the day, at the end of the day they would always summarise the work done and what the plan was for the next day. All the team ensured the house was left as tidy as possible at the end of each day. Any unexpected problems encountered, Custom Renewables would always explain and ask for my opinion, and strive for the best outcome. I would say to anyone considering the transition to an air source heat pump to definitely enquire with Custom Renewables.

Excellent service and workmanship throughout the upgrade on our 7 year old Air Source Heat Pump installation. From initial visit to assess what might be required, to ordering relevant parts and arrival to undertake the work, on time, - all were completely and totally satisfactorily . Both Liam (over 3 days) and Carl (one day) - both extremely pleasant and friendly, have done a great, neat, job, leaving the place completely tidy. Liam clearly understands the system's 'workings' intimately, and he even replaced 5 bricks, perfectly, in the wall where the old oil boiler flue had passed through! The old boiler was also removed with some difficulty and collection was arranged by third party the day after the work was completed. Would highly recommend Custom Renewables.

Liam is one of the best heating installers / engineers in the UK. Liam is passionate about efficient heating systems and he absolutely knows his stuff. I trusted Liam with an upgrade from a 15 year old gas boiler to an air source heat pump in my house. From the initial discovery email, heat loss survey to the final commissioning it has been a pleasure to deal with Liam. I was always informed about what was happening, arrived on time and cleaned up at the end of the day. This is an experienced review as the system is over 1 year old. My house has been more comfortable all over winter, especially compared to the gas boiler. We always remark from when we come in from outside how nice and warm it is during the colder months. Liam was constrained in the location of the hot water tank but managed to get it in with the rest of the pipework. I was one of the first installs in the UK with the Heat Geek hot water cylinder, which was co-designed by Liam and Heat Geek. If you want the best heating system install, speak to Custom Renewable, you will not be disappointed.

Custom Renewables Ltd has given us a professional and efficient service in relation to installing an air source heat pump and underfloor heating system. They have been a pleasure to work with. I would highly recommend the firm.

What a great experience! Custom renewables designed & installed a low temperature heating system for our home, powered by an air source heat pump. Liam and the wider team were very generous with their time and are extremely knowledgeable. The level of support we received before, during and after the install has been excellent. We were also really impressed with the quality of the work. Carl, Jordan & Justin were organised, tidy and clearly took pride in their work and we enjoyed the time they spent with us during the project. Finally, we're very happy and impressed with the heating system. We're nice and warm and it works seamlessly. Highly recommended!

I chose Custom Renewables because of the passion demonstrated by Liam, who carried out my heat loss survey and followed up with a design that I felt I could have confidence in. His two man team who installed my Air Source Heat Pump were just as passionate about their work and did a very professional job in my opinion. Liam also did a follow up visit a short time after installation to ensure we were happy and the system was set up and working properly. Don't let anyone tell you Air Source Heat Pumps don't work and are noisy and expensive to run, because Custom Renewables continually prove otherwise. Thank you, Liam and your team.

great service. All the guys who came to install our heat pump were helpful, friendly and considerate, and worked really hard. We are delighted that we now have a warm house!

Custom Renewables was great to deal with on my ASHP project, Liam is very knowledgeable an made the design and install journey as painless as possible.

Custom Renewables come highly recommended. Liam and his team have done a great job throughout the process, from the initial heat loss survey through to system design and installation. We had been considering replacing our aging gas combi-boiler with a heat-pump system for some time, but having received inconsistent recommendations from initial discussions with a few installers we were hesitant to commit. Liam came out to conduct a thorough heat loss survey to determine exactly what the heating requirement would be for our property before designing and recommending a system to suit. He was able to answer all of our questions and walked us through what was being proposed and why, once agreed the pre-install survey to run through practical details was really helpful. The installation itself has gone very smoothly. Liam, Carl and Jordan worked hard all week and have done a great job with minimal disruption. Heat-pump unit installed, hot water cylinder plumbed in and radiators changed over. The end result is really neat and tidy work all over. The house is now at a comfy, consistent temperature throughout, we're really happy with how the whole process has gone.

Very happy with the work and they obviously know their stuff.

Liam and his team were professional, polite and arrived and finished on time for what was a complex heat pump install and commissioning. Liam is extremely knowledge on such systems and we are very pleased with the results to date. Plenty of hot water and the house is nice and warm.

We have a typical 1930s semi, which we had previously insulated. Liam surveyed and designed the heat pump solution. Liam, Liam and James were superb during the installation of a 7kW heat pump, hot water cylinder and replacement radiators which took four days with relative little disruption to us. The 200l hot water cylinder had to be installed in a tight and small space. All of the team were very professional, prompt, worked hard, and kept us informed. If that is the quality of the young UK workforce, Britain is in a good place! Really happy with the outcome. The house is now always warm, the heat pump is remarkable quiet, our SCOP is currently running at greater than 4.0, and the surprise for us is that our utility bills are 0.6 of the year before (we have a solar and a battery).

Our existing boiler setup was poorly installed, very inefficient and not heating our home properly. We were keen to move to a heat pump as part of drive to go fully electric/renewables. After numerous visits from local heating engineers, none of which gave me confidence they could deliver what I was after, I contacted Liam through the Heat Geek network. Liam at Custom Renewables is extremely knowledgeable when it comes to heating systems. He was able to answer all my questions and offer a solution that matched what I was after. He did a full heat loss survey, and then came in with the team to install the heat pump, new water tank, correctly sized rads and new electrics. While such work can be a little disruptive, they are organized, tidy and show great attention to detail. I’m very happy with the result, we now use far less energy to heat our home, its comfortable and cosy and no more cold rooms. Happy to recommend them.

A tremendous team of knowledgeable professionals. Custom Renewables removed our gas boiler and fitted an ASHP system to our home. Liam did our survey and system design. Jordan came for 3 days to replace/fit 8 new bigger radiators and get the house ready. Then came 5 days of installation with Carl. The 2 make a great team, were a delight to host and left us with a magnificent install. Liam then returned for a half day of commissioning and customer training! His knowlege on the subject is unquestionable and he is a great communicator. We are now enjoying a warm house/hot water with all the benefits of ASHP technology. I would have no hesitation in using Custom Renewables again and whole heartedly recommend them. They are professional, reliable, friendly and trustworthy.

Liam, Carl and the team have been brilliant. We have renovated a 1960s property and Liam has helped from early on and has given excellent advice (he's extremely knowledgeable). Custom Renewables installed underfloor heating (downstairs), a heat pump (we removed the boiler) and radiators (upstairs) for us as part of our renovation. Liam and Carl have done the work to really high standards (it's so neat!), they have been flexible, highly responsive and got on really well with our builder and other tradesmen. In addition, they have both been very easy to work with (and Carl was great with our kids too). We really wanted to make the shift to a heat pump but were hesitant about whether it would work. We are now in, in a British winter (!), and have found it has worked very well for us. Thanks Liam and Carl! In short, they come with our highest recommendation.

Great service

I would highly recommend Liam from Custom Renewables for your ASHP system. Liam surveyed, designed, planned and installed our system. He explained and documented everything about it, the expected performance, answered all my questions and offered advice about the best configuration for us.

Always good to get the system retuned with some cleaning thrown in. Service with a smile and friendly knowledgable chat about ashp's

Liam and the team did a great job replacing our old gas boiler with a Vaillant Arotherm plus ASHP. Really smooth process from the heat loss assessment to the commissioning of the new system. Thoroughly recommended 👍

Custom Renewables have been so helpful in improving our central heating system. After speaking to many heating installers and still not feeling confident about how to proceed, Liam was informative and took time to answer my questions. He carried out a very helpful heat loss report on our property and discussed all the relevant options for improvement. He advised and carried out the work on upgrading our radiators to get heat pump ready and has advised about how to run our boiler most efficiently until we complete the upgrade. All work was carried out with minimal disruption. Would not hesitate to recommend. Thank you.

Renovating our 4 bed solid stone house, we had Custom Renewables support us in replacing the aging oil boiler with a Vaillant Heat Pump, full replacement of all the radiators and pipework, and full DHW system. Liam and the team were fantastic throughout (the house was chaotic during the early renovation!) and the best tradesmen on site. From the initial heat loss survey through to the installation; Liam provided us with support and guidance in the best options for us. His knowledge and expertise are evident through every step of the process. The whole installation process was much faster than we expected; and very neat and tidy. We have been left with a fantastic (and efficient) heating system that works as we'd been expecting. If you're in any doubt about how a Heat Pump could work for you, we'd highly recommend speaking to Custom Renewables!

Liam was a ideal to work with: - a self-confessed heating system/heat pump geek, he obviously lives and breathes fitting good quality systems. - excellent phone and WhatsApp communication - reliable: always there when he said he would be - high standard of workmanship (including rectifying poor work from other people on site!) He was the best tradesmen we had work on our extension project. Liam designed and installed a central heating system (underfloor heating downstairs and radiators upstairs) running off an air source heat pump into our 1930s, fairly standard semi-detached house to replace existing night storage heaters. He was very thorough in ensuring the design of the system was going to achieve the heating that we needed considering a pretty mixed insulation situation in our house (good insulation in the new-build elements and pretty poor insulation in the original building). The installation of our system was fiddly as we had other trades working all over the house and we were trying to live there. Liam was very flexible about the sequencing of the work and quickly returned to complete elements when the progress of the build allowed. The standard of the work and attention to detail was absolutely first class. The system was commissioned and has been running flawlessly - it is difficult to tell if the heat pump is actually running (very low noise and low temperature output from the underfloor heating and radiators), the only way that we know it is working properly is that it heats the house perfectly and there is hot water on demand! Liam is a proper heat pump installer who really understands the fundamentals behind systems design and installation - in an industry where there are some iffy operators, Liam is someone you can 100% trust to do a good job.

Outstanding replacement of our gas boiler with an air source heat pump carried out very professionally. Thanks to Liam Barry who took care of the responsibility of the whole procedure of heat loss report as well as the installation. His knowledge about different dimensions of energy efficiency is remarkable. Pleased that we made a right decision in choosing Custom Renewables Ltd as an experienced and knowledgeable company and Liam himself in particular. All work carried out on time and to our satisfaction. I would highly recommend their technical expertise and quality of their services when installing heat pump.

Excellent company that really understands about heat pumps. Very tidy installation, even under the floorboards where others might not be so careful.

Very pleased with our Heat Geek Assured heat pump project as installed by Liam Barry from Custom Renewables - quality workmanship, very knowledgeable and committed to a job done RIGHT. For those interested, we have a 3 bed 70s property with cavity wall insulation (retrofit) and in February 2023 we achieved a COP of 4.93 for the full month and have maintained a very comfortable 19C indoors even through some subzero days (that's our target temp - the system can do more we just don't need it). Monthly costs seem about similar to being on gas for us but the house is a much nicer place to live in (we used to turn gas on only when we needed it - if we had run the system to maintain temperature we'd probably be saving a fair bit). All good so far and happy we chose someone who knows their stuff.

Reading this you may already be aware of Heat Geeks. Liam of Custom Renewables is their guru on heat pump installations and optimisation. I called Custom Renewables to investigate the poor performance of our recently installed air source heat pump. The developer had wrongly sized the system. Our SCOP was so poor we were haemorrhaging cash, Liam calculated the heat loss for the house, identified hydraulic issues, and quoted to correct the system including swapping the 16kw heat pump for a 7kw. We are now 3 weeks post install and the difference is amazing. Our SCOP has gone from 2.3 to 4.6 and climbing. This means our energy consumption has halved, the house is warmer with heat distributed evenly throughout the home. The ASHP runs quieter and smoother following the work done by Custom Renewables. Liam has prepared the system so that when our new solar PV system is installed, we'll use it to power the DHW (domestic hot water) making even greater savings, his knowledge and attention to detail have made our heating system impressive. Couldn't recommend this company highly enough, no BS, honest advice with stunning results, and that's what matters in the end.