Endorsed by Which?

AOS Energy Efficient Heating Systems Limited

4.9

264 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
264 reviews
Customer Service
4.9
Quality
4.9
Value
4.8
Sort by
Quick and easy
Customer Service
Quality
Value
We had a Mitsubishi Ecodan heat pump installed. AOS gave us a quote, including the government incentive scheme, assessed our house for size, shape, insulation and number and size of windows. Told us what was needed in terms of radiators and we went ahead. We had a planned schedule of payments, visits laid out for engineers to arrive, work done and we paid everything on time. The office then rang me to say we'd overpaid and promptly repaid the money. After a month of use, we seemed to be having radiators come on randomly. We were due a follow-up site visit to check the system after a month of use and to have the chemical put in the heating system. The engineer knew immediately there was an issue, arranged for a change in a heating lock, and we're now up and running. We used AOS because it was a local business, but in the event, it all worked out excellently.
Customer in Hertfordshire Posted on 21/06/2025 , work completed 19/06/2025
Excellent work from beginning to end
Customer Service
Quality
Value
Our survey was thorough and everything was carefully explained to us. We had a whole new heating system installed and are really pleased with the results. Rhys C, Louie, Tony and Luca were competent and efficient. They were considerate and polite. Each day they tidied and cleaned everything away. I would highly recommend them as you are in safe hands with professional people and service. With the government grant and not having to pay tax, lowering your heating costs is a worthwhile investment.
Customer in Buckinghamshire Posted on 20/06/2025 , work completed 20/06/2025
Work deserves nothing but praise
Customer Service
Quality
Value
AOS installed an air source heat pump for our house. The system design was interactive to reflect our needs and was well done. The installation was completed in 5 days during which the installation team worked incredibly hard and at the same time were diligent, polite, personable, knowledgeable, friendly and neat and tidy (they also cleaned up after each day). The AOS office support was very efficient and helpful throughout. We would highly recommend AOS.
Customer in Essex Posted on 28/05/2025 , work completed 24/05/2025
Installation of heat pump, radiators and water cylinder.
Customer Service
Quality
Value
The application for a heat pump and obtaining a grant was carried out without a hitch. The survey and installation went better than expected. The engineers who removed the old system and put in the new were very obliging and completed the task on schedule. So far the system is running well, although we now need a winter to test it properly. Having completed the conversion to the heat pump system I now have a lot of paperwork/documents to store - for how long?
Customer in Buckinghamshire Posted on 14/05/2025 , work completed 09/05/2025
Emergency work
Customer Service
Quality
Value
At 11pm on 29th April we heard dripping water coming from above our Airing cupboard. It was clear that the water was coming from the water tank in our loft. By midnight AOS had arrived, diagnosed the problem and isolated the tank preventing further leakage. AOS returned the next morning with a new ball valve and finished the job. Outstanding service and done with a smile. I cannot recommend AOS more highly.
Customer in Greater London Posted on 30/04/2025 , work completed 29/04/2025
AOS Plumbing & Heating
Customer Service
Quality
Value
AOS have just replaced our ageing boiler. We've been using AOS for 19 years now and subscribe to their monthly maintenance plan. AOS have always provided a speedy service to the issues we've faced. The engineers who attend the calls out are always friendly, professional and keen to listen to my descriptions of the problem(s). Work is always tidied up and areas left clean.
Customer in Hertfordshire Posted on 27/03/2025 , work completed 17/03/2025
Installation of a new gas boiler
Customer Service
Quality
Value
AOS installed our old boiler, a 'Which? Best Buy' at the time, about 15 years ago and, in the interim, we used their maintenance system to look after it. All without a problem and with quick response when needed. It was an exemplary service. However, the time came when a replacement was needed. It was very easy dealing with the company to arrange the replacement. In the price quoted, they offered, without any request on our part, to instal the current 'Which? Best Buy', a Bosch Worcester Greenstar i System Compact boiler. We found that the price quoted was fair and reasonable and accepted the quote. It was installed today, the necessary scaffolding was installed early and before the AOS's 3 workers arrived on time and work began. We were not disturbed beyond what might be accepted for the job being done. They were quiet and friendly and taught us what we needed to be taught clearly and succinctly. By late afternoon the job was completed. Congratulations to the 3 workers and to the company for a job well done and to our complete satisfaction.
Customer in Essex Posted on 24/03/2025 , work completed 24/03/2025
Replaced Existing Worcester Bosch Boiler after 17 years use
Customer Service
Quality
Value
Very happy with good service and advice replaced with an updated new Worcester Bosch unit and improved condensate drainage for freezing temperatures. Engineers on site were efficient with help and assistance for some remedial work needing attention. Also my annual maintenance call out contract premium reduced due to the new installation for next 2 years. Very happy.
Customer in Hertfordshire Posted on 13/03/2025 , work completed 20/02/2025
Installation of Air Source Pump
Customer Service
Quality
Value
We had an Air Source pump fitted In August 2024. This has exceeded our expectations. It keeps the house at a constant temperature. The AOS team were exceptional from the initial survey to the completion of the project. The staff were courteous and worked extremely hard always updating us on what they were doing. I have no hesitation in recommending them.
Customer in Hertfordshire Posted on 19/02/2025 , work completed 30/08/2024
Great Service
Customer Service
Quality
Value
I have been a customer of AOS Heating for some years, and have always been very happy with their service. We have a maintenance contract with them so this morning I rang for help because the central heating wasn’t working. An engineer arrived within 30 minutes, found the problem, fixed it and left - all within a hour of my phone call! It’s a cold morning so to say I am pleased is an understatement!!
Customer in Hertfordshire Posted on 05/02/2025 , work completed 05/02/2025