Endorsed by Which?

AOS Energy Efficient Heating Systems Limited

4.9

253 Reviews

Opening Hours
Today - 08:00–17:00
  • Monday 08:00–17:00
  • Tuesday 08:00–17:00
  • Wednesday 08:00–17:00
  • Thursday 08:00–17:00
  • Friday 08:00–17:00
  • Saturday - Closed
  • Sunday - Closed

What is a Which? Trusted Traders Hertfordshire Trading Standards Approved Endorsement?

Which? Trusted Traders has partnered with Hertfordshire Trading Standards to create a Hertfordshire Trading Standards Approved endorsement. In addition to our standard trading standards assessment, this trader has had a DBS check and is subject to a Trading Standards intelligence check

About

AOS Heating has been one of the industry's leading experts in the Heating & Boiler industry for over 36 years.
Established in 1984, AOS are family run business who is proud of the reputation we have accomplished over the years.
AOS are a trusted company due to our outstanding customer service record, not only do we provide an honest, reliable service we also offer first class central heating, electrical & plumbing services for all.
Whether you need repairs or servicing to an existing heating system or you are interested in a completely new central heating installation we'll make sure you get the best results.
What's more AOS are also specialists in the most up-to-date heating advancements, including renewable & green technologies such as the latest energy efficient boilers and air source heat pumps. Whatever the job, you can rest assured that you are in expert hands.

What we do

  • Plumbers

    • Emergency plumbing services
    • Unvented cylinder installation and maintenance
  • Boiler, central heating and gas engineers

    • Boiler installation
    • Boiler repair
    • Boiler servicing
    • Radiators and central heating
    • Gas safety testing and inspection
  • Renewable energy

    • Air source heat pumps

Customer reviews

Why you can trust these reviews

All reviews are verified as being genuine and a true customer of this trader.

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100% of the reviews we publish have been through our stringent moderation process.

4.9
253 reviews
Customer Service
4.9
Quality
4.9
Value
4.8
Sort by
Works completed as promised
Customer Service
Quality
Value
We are very pleased with the efficient manner in which the whole operation was conducted, particularly with Ryan and his team and their professionalism and work ethic. They couldn't have been more helpful with everything including clearing up on a daily basis. The office team, Charlotte & Sian, were equally on the ball and were able to provide us with answers to all of the questions we raised. We have no hesitation in recommending the AOS team.
Jane & Martin in Buckinghamshire Posted on 10/04/2021 , work completed 08/04/2021
The trader replied (on 15/04/2021)
Hello Mr & Mrs Kempt, Thank you very much for your kind words. It is always so lovely to be able to pass on such positive feedback to our installation engineers and office teams and they really do appreciate it. Kind Regards The AOS Heating Team.
Excellent Professional Service
Customer Service
Quality
Value
Sam and his team installed a large air source heat pump, installed 18 radiators, converted two water cylinders into one all whilst working round an oil fired boiler that had to be retained for other purposes. They were on site when they said they would be and always tidied up at the end of the day before leaving. There were many unforeseen challenges along the way which were overcome without quibble or additional cost. At the end of every day, we were updated with progress and goals for the following day. In addition, we were given plenty of advanced warning for when we were going to be without electricity, hot water and heating which was a godsend whilst three of us were working from home. Sam and his team were polite, courteous, professional and often went above and beyond the scope of the project. In summary, from the initial meeting with Andy on the Sales team through communication with Charlotte and Sian for co-ordination of the project and site survey by Lee, the whole experience with AOS has been a pleasure and we would have no hesitation in recommending them.
Customer in Cambridgeshire Posted on 06/04/2021 , work completed 27/03/2021
The trader replied (on 15/04/2021)
Hi Mr & Mrs Scott, Thank you very much for your review it is really appreciated. We are very glad to hear how happy you are with the service you received throughout the whole heat pump installation progress. Your installation was very large and required a lot of precise planning so we appreciate you noticed the effort made. It was a pleasure to work with you both throughout and we are extremely happy you are so pleased with everything. Kind Regards, The AOS Heating Team.
Best install of a new boiler system I could hope for!
Customer Service
Quality
Value
The AOS team arrived promptly each day and were very conscientious right from the start. All of their colleagues wore masks, put down sheets, and made sure to leave the house as clean and tidy as you could hope for. The works carried out were delivered to a high standard, and they even improved a number of additional items at our property at no extra cost (sorting out some creaking floorboards and a free washing machine install). Their rates are very competitive, and I am so happy we went with them over British Gas. Most importantly, they were friendly and approachable and I felt at ease with their team in our house.
Customer in Hertfordshire Posted on 31/03/2021 , work completed 12/02/2021
Very professional organisation
Customer Service
Quality
Value
AOS Energy Efficient Heating Systems Ltd recently installed an air source heat pump and replaced the hot water cylinder and most of the radiators in my home. Everything was completed according to the schedule. Staff in the sales and service departments were helpful and knowledgeable and communication was clear and easy. The installation team were pleasant, polite and obliging. They made an extra effort to meet the particular requirements of this job. There were a couple of issues with radiators but these were resolved satisfactorily. Everyone has been utterly professional and I'm very happy with the result. I would definitely recommend this company.
Sue in Buckinghamshire Posted on 16/03/2021 , work completed 12/03/2021
The trader replied (on 18/03/2021)
Hi Sue, Thank you very much for your kind works. It was a pleasure working with you on your renovation project. We hope you enjoying your new heating system. Kind Regards The AOS Team.
Service call
Customer Service
Quality
Value
My air source heating did not reach the require temp. booked a service. The previous service was only 6 months ago the office told me that I should have the mobile thermostat in the warmest room. Rubbish. cost of service £150 +vat...I was only asking the system to reach 20 degrees it never makes it. The engineer was helpful and obliging and suggested that the anti freeze/inhibitor be topped up. Phoned the office to pay extra for it. Shock horror they want to charge £250 + vat just to top up. This was on top of the service charge. I have insulated walls and attic with double glazing. How disappointed I am with the system. When it was installed the service was excellent and I had no complaints. Whilst this has been a cold winter to have a system that only reaches 14/15 degree is not good enough.
Customer in Essex Posted on 04/03/2021 , work completed 04/03/2021
The trader replied (on 15/03/2021)
When your heat pump was installed you were advised to upgrade radiators in your home but you chose not to proceed. It was made clear that we cannot guarantee room design temperatures if our recommendations are not followed. You were given 3 x free services which were carried out over the years, the 3rd service was completed 24/06/20 but we advised that the anti–freeze was low & should be topped up. We provided quoted but you chose not to proceed. On 25/02/21 you reported the system not reaching temperature & our service manager explained that you need to keep your thermostat in a room which is designed to react 21c if your thermostat is left in a room designed to 18c then the system won’t reach temp. You did not wish to take this advice & asked for a service instead. As all your FOC services had been used we explained that this visit would be chargeable. We suggested that you wish to take out a service cover plan as a service & labour are included. You decided not to & paid £150+VAT for a service upfront. When you booked you were told that if chemicals were required the charge would be £215+VAT. You were contacted the day before the service for payment & it was explained again that a top up would be £215+VAT. Once the service was completed it was confirmed that chemical was needed. You called to make payment but argued that you had previously been told £30. We explained there was a note on the system confirming that you were quoted £215+VAT but you put the phone down.
Central heating repair
Customer Service
Quality
Value
I needed AOS's help to repair a bent central heating pipe. Although the initial quote was high, they came and did the necessary work which turned out to be less than envisaged and so they reduced the fee without my asking. Tom (the engineer) turned up on time and worked without fuss. I was impressed by the fact that they didn't do anything unnecessary, for example the anti-freeze levels didn't in fact need topping up. Recommended.
Customer in Hertfordshire Posted on 10/02/2021 , work completed 05/02/2021
The trader replied (on 18/03/2021)
Hi David, Thank you for your review. AOS pride ourselves on being upfront and honest so we would always reduce our costs if not all the work was carried out. The same applies to the anti -freeze chemical, if a top up is not needed then we would never recommend for the sake of it. We are glad your experience was such a positive one. Kind Regards The AOS Team.
Professional throughout
Customer Service
Quality
Value
From start to finish a very professional service. Max and his team were polite, did a very good job and went the extra mile to do any of the little extras that might have needed doing - I was very impressed.
Customer in Cambridgeshire Posted on 06/02/2021 , work completed 03/02/2021
The trader replied (on 18/03/2021)
Thank you very much for your review. We will be sure to pass your comments of praise onto Max and his team. Kind Regards The AOS Team.
Air Source Heat Pump installation
Customer Service
Quality
Value
I was most impressed with the service provided by this company. The office staff were invariably helpful and knowledgeable and always responded promptly to my requests for information. The installation team were highly professional, efficient and friendly. They always kept us informed about what they were going to do and ensured that they left the house tidy and with access to hot water each evening. They also supplied electric fan heaters whilst the central heating was disconnected. When we experienced a couple of teething problems after the system was commissioned, these were rectifed on the same day that they were reported. I would highly recommend this company to anyone considering a similar installation.
Customer in Cambridgeshire Posted on 04/02/2021 , work completed 29/01/2021
The trader replied (on 18/03/2021)
Thank you for your positive feedback. We are so glad to hear that you were impressed with the high level of service AOS provided throughout your heat pump installation journey. It is of upmost importance to us that every customers experience is positive. please do let us know if we can be of any assistance in the future. Kind Regards The AOS Team.
Great service
Customer Service
Quality
Value
AOS answered the emergency call of my tenants, whose boiler had broken down and was beyond economical repair. They quoted competitively for a replacement boiler and installed within a couple of days - excellent service given that it was just a couple of (very cold) days before Christmas! Thank you, AOS
Customer in Hertfordshire Posted on 15/01/2021 , work completed 21/12/2020
The trader replied (on 18/03/2021)
Hi Theo, Thank you for your review. We are very glad that we managed to get your tenants up and running in time for the Christmas break. Kind Regards, The AOS Team.
Good installation but beware of expected efficiency benefits
Customer Service
Quality
Value
AOS installed an air heat pump system for us in June 2020. The work was carried out quickly and efficiently by professional installers and we were initially happy. However, when we subsequently had our property re-assessed for energy efficiency to claim the RHI rebate, we found that the energy efficiency had actually got worse on water heating than with our old oil boiler, with our EPC rating for water heating falling from average (with our old boiler) to poor (with the new air pump.) This risk was never explained to us when we signed up to have the work done. The EPC is a public document and can influence future buyers of your property. The “poor” rating for our new system’s water heating efficiency was most definitely not what we expected. Check carefully before you have one of these systems installed. The efficiency improvements you expect for your home may not happen in practice. They didn’t for us.
Customer in Buckinghamshire Posted on 21/12/2020 , work completed 24/06/2020
The trader replied (on 05/01/2021)
Due to a word limit our reply below has been reduced : Hi Mr Drew, As you are aware EPC's are carried out by independent assessors using the government tool & we have no control over the information documented within these EPC’s nor could we predict what efficiency will be calculated on a new EPC after an install. Although your EPC states that your hot water is rated has gone from ‘average’ to ‘poor’ your heating rating has improved from ‘average’ to ‘good’ along with the heating control improving from ‘good’ to ‘very good. The important thing to highlight is your system will actually be in ‘heating mode’ for an estimate of 75% of the time (13,207kWh) and the hot water only 25% (2,960kWh), these usage figures have been taken from your EPC. When you consider that your old oil boiler in heating was graded at ‘average’ & the new heat pump is now ‘good’ for heating this improvement to 75% of your overall energy demand completely outweighs the ‘poor’ grade for the 25% hot water usage. We have spoken to Elmhurst Energy the EPC accreditation for clarification and they have confirmed that when looking at air source heat pumps for hot water purposes, combined with a immersion boosts the system does not recognise the efficiency of modern heat pumps from previous inefficient models that required a immersion heater to top up the hot water which your system does not do. Due to the lack of update to the government data EPC’s are not a great reflection of the efficiency of a system.