To see more reviews or write your own review please visit

We were concerned that as our property is a Victorian brick building with draughty single glazed sash windows a Heat Pump would not cope with heating it. AOS carried out a detailed survey and after analysis they were able to assure us that even with a midsize unit (11Kw) the system it would work fine in our environment. We (somewhat nervously) bit the bullet and AOS installed the ASHP in October of 2020.

I can happily report that the house has never been cosier. I waited to give feedback until we had been through a cold snap. The temperature is constant room to room (even when the outside temperature is below zero) and there is always hot water available. Electricity usage is obviously higher than it used to be but we no longer have to buy oil for the old boiler - so no risk of running out.

I would encourage anyone thinking of replacing their heating system to consider a heat pump solution. It is a sustainable, environment friendly option, and this doesn't only apply to modern properties.

Another big plus is that the external fan unit (Mitsubushi Ecodan) is almost silent - even when it is running at the maximum speed.

AOS were a joy to do business with - no hard sell and everything that they promised came to fruition. The actual installation team were excellent and left the place in a good state after they finished the work. I would recommend this company to anyone who may be considering getting an Air Source Heat Pump installed.

Rob & Swantje, Great Gransden, Sandy

Outstanding service and support - highly recommended AOS is an outstanding company. We have been delighted not just with the ASHP installation itself but also the full support we have received both before and after the installation. Our project was particularly problematic because of neighbours' objections but, throughout the process, AOS helped at every step. The installation itself was impeccably carried out - the team were great: courteous, efficient, friendly and highly skilled. AOS are highly professional but also provide a very personalised service. Would not hesitate to use them again in the future.

Mr & Mrs Simmons, Cambridge

My wife and I attended presentations in June 2018 by AOS in our village hall regarding air source heat pumps and were impressed. We requested a survey and decided to go ahead and replace our oil fired heating and 30-plus years old boiler.

We were impressed with the swift and tidy work of the installation team, who not only installed the new pump but replaced the hot water cylinder and eight radiators, all within five days.

The support we received from the team back in the office was excellent and AOS have done everything they said they would do, at the price they quoted. Highly recommended.

Mr & Mrs Keeling, Royston

AOS replaced our oil boiler with an air source heat pump. Excellent service from my initial enquiry to installation. Professional quality result from very friendly people. Highly recommended.

Mr Temple, West Wickham

Excellent service and communication throughout. Very customer focused in all aspects - from patience in explaining Air Source Heat Pumps through to tidying up, laying dust sheets down, and explaining how to use. Plus follow up very quick and clear on how to apply for RHI (which took about 5 mins). Definitely recommend.

Miss Mayers, Buckinghamshire

We recently took the decision to replace an unreliable oil fired boiler with a Mitsubishi Air Source Heat Pump. Everything has worked out well. We were impressed with the AOS village meeting presentation. Within a week, we had requested a comprehensive survey of our property and all options had been identified. Thereafter, we requested the EPC and subsequently received a full proposal and quote from the office, including RHI explanations. At that point we decided to proceed, impressed by the Mitsubishi product and expertise of the AOS team. 7 new radiators were recommended by the Mitsubishi heat calculator. The Air Source Heat Pump and new radiators were fully installed just 4 weeks after our first consultation. This was first class service. Engineers were professional and skilled, got on with the job; always arriving on time; used dust-sheets and left the property tidy each day. Following completion (which took just 4 days, including fitment of radiators) the lead engineer, who had great knowledge, provided a comprehensive operating run-through and explanation of the aftercare. The install was carried out in cold, winter conditions. The system had a tough initial test and we were impressed that it does achieve target temperature in the property even with below freezing temperatures outside. We would have no hesitation in recommending AOS EEHS Ltd. and the Mitsubishi heat pumps. We have applied for RHI - the payment has been confirmed, and is in line with initial calculations

David Boyd, Cambridge

AOS staff did a brilliant job to trace and then fix a recurrent fault with ur heat source system. Having found what the issue was and following an 'on-site' telephone conference between AOS and Mitsubishi, it was agreed that the unit be replaced despite it being out of warranty. In all of this, AOS engineers turned up on time and their admin/support staff kept us informed by phone. AOS did a great job sorting this out for us.

Martyn Waters,, Cublington

AOS installed an air source heat pump in my house in June 2017. From an initial presentation given in our village hall to an in depth discussion in my house AOS presented themselves as a very professional, experienced and knowledgeable company. As we were having a low temperature system we were advised that some radiators would need to be upgraded to achieve the living temperature of 21C in the house. The calculations done on our house indicated precisely which needed changing along with the size required. Eventually we changed 12 rads which meant AOS had work all around the house. Throughout the 4+ days of work the workmen were always prompt arriving, worked steadily through the day and more importantly to us in a very clean manner. Putting down dust sheets every day, working as cleanly as possible and tidying things away at the end of the day as if no one had been around. Whilst we had a small problem in the first few days AOS were quick to attend and solve the problem and we have not had that issue since that time. I would certainly recommend them to others.

Mr Tate, Aylesbury

The engineers worked extremely hard and did a very good job on the complex installation of our air source heat pump. They were without exception polite, considerate and a pleasure to have working here. All the AOS representatives we came across, on site or otherwise, were helpful and responsive. On the basis of this experience I would recommend AOS without hesitation.

Bobby Gittins, Bedfordshire

Abbey and Lee installed air source heat pump and radiators and thermostatic valves and new how water cylinder and immersion heater in our home. They were punctual and efficient.

David, Milton Kenynes

We just wanted to say a big thank you for doing a brilliant job. Everything seems to be working well, and we are lovely and warm. Can you pass on our thanks to Sam, Sam and Tom. They were such a hard workers and left the house clean and tidy.

Victoria, Hertfordshire

Excellent installation of a Heat Source pump to replace our oil burner. Very efficient and helpful installers, and effective communication from office staff. Now have constantly cosy house.

Mr & Mrs Smith, Cambridge