Gas and Heating Services

Ensuring your gas boiler and heating system is functioning safely, effectively and efficiently is crucial and THT Ltd are experts in doing just that.

Our qualified, experienced engineers can recommend the best solutions for your property and budget, carry out repairs and maintenance and install new gas boilers and central heating systems.

THT Ltd offer a range of gas and heating services, including boiler installation and maintenance.
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Gas Boilers

If your gas boiler is over 10 years old, or has not been regularly serviced it is highly likely that it is using too much energy and working too hard to supply your home with sufficient heating and hot water. THT Ltd’s qualified GasSafe engineers can help improve the safety, energy efficiency and effectiveness of your gas boiler, or advise on the best replacement if that’s the best solution for you.

Gas Boiler Installation

Hearing the news that you need a new gas boiler can be daunting and it’s likely that you will be worried about the cost. The good news is that THT Ltd can offer interest free finance for your new gas boiler installation making it easier for you to have the warm and cosy home your dream of whilst reducing your energy bills. As specialists in the installation of condensing boilers by Vaillant you can be confident in choosing THT Ltd to supply and install your new gas boiler.

For more information, or to book a visit from an engineer who will be able to recommend the right gas boiler for your property, call 023 8001 5008.

During a Service Our Gas Boiler Engineer Will:

  • Inspect the boiler and controls to make sure they are working properly

  • Check for leaks and corrosion

  • Check the gas pressure

  • Check inside the boiler casing to ensure the components are in good working order

  • Test the flue, ensuring there are no unsafe fumes and measure the emissions

  • Clean and test your boiler

  • Replace the casing and check all seals

You will receive a record of the gas boiler service together with a Gas Safety Certificate.

With a THT Ltd Service Care plan you need never worry about remembering to book your gas boiler service again.

As a THT Service Plan customer we’ll send you an appointment each year. Find out about the additional benefits and choose the best service plan to meet your needs today.

Residential Landlords and Letting Agents

In addition to domestic work we serve commercial clients across the Southampton area providing maintenance services to letting and estate agents, local businesses and landlords. If you are a residential landlord you are legally required to undertake gas safety inspections. To find out more about our Landlord Gas Safety Service Plan click here.

Gas Boiler Repairs

There’s never a good time for your boiler to break down. But if it happens, you need to know that you are calling a reputable firm to carry out a safe and effective repair.

THT Ltd’s GasSafe engineers are qualified and experienced which means that they will do all they can to get your gas boiler back up and running quickly and safely. Our repairs are covered by the manufacturer’s warranty for the parts and our one year labour guarantee.

To book your appointment for a GasSafe engineer, call 023 8001 5008. Emergency appointments are available on a first come, first served basis.

With a THT Ltd Service Care plan you need never worry about your gas boiler breaking down again.

Find out more and choose the best service plan to meet your needs today.

Immersion Tanks

Immersion tanks can be a useful back-up hot water supply if you have an older boiler or, if you live in a property without mains gas, it will be your primary source of hot water. In simple terms, immersion tanks work like a kettle with an element keeping the water hot ready for use on demand. Immersion systems will be either vented or unvented.

Due to the pressurised nature of immersion tanks, you need to ensure that any servicing or repairs are carried out by engineers holding specialist qualifications. All of the team at THT Ltd are G3 qualified engineers meaning we have the correct qualifications to install all types of cylinders including unvented.

Central Heating

Gas Central Heating Installation

Installing a new gas central heating system can be a daunting prospect which is why you need an expert team to advise you. From choosing the right size and specification of boiler to what and where to place the radiators, there’s a lot to consider. And that’s before you think about how to run the necessary pipework!

THT Ltd can advise, supply and install any aspect of your gas central heating system, from heated towel radiators or individual radiator replacements through to entire systems.

We are happy to provide a comprehensive, no obligation quote for your specific requirements.

To arrange an appointment with a THT Ltd central heating engineer call 023 8001 5008.

Gas Central Heating Repairs

Are you suffering from cold, or partially cold, radiators?
Does your heating system make strange noises?
Is your gas central heating system becoming a bit unreliable?

There are many reasons why your gas central heating system may not be working as well as it should. You’ll be glad to know it doesn’t necessarily mean you need a whole new heating system.

Call 023 8001 5008 with a brief description of the problems you’re experiencing and we will arrange a convenient time for an engineer to visit you and test the system. Where possible, repairs will be carried out during that visit, although we may need to come back another time if new parts have to be ordered.

With a THT Ltd Service Care plan you need never worry about your gas central heating breaking down again.

Find out more and choose the best service plan to meet your needs today.

Power Flushing

Power Flushing is a cleaning process that uses a Power Flush pump to clean your gas central heating system. Dirt, sludge, debris and rust from inside your heating system is removed helping your boiler to be more efficient.

More importantly, if the inside of your gas central heating system isn’t clean, over time the diary and sludge builds up making your heating system inefficient and eventually damaging your boiler.

The Benefits of Power Flushing Include:

  • Improved energy efficiency

  • Better heat distribution throughout your home

  • Reduced energy bills

  • Longer lifespan for your boiler

To find out if a Power Flush is suitable for your system, and to book your appointment, call 023 8001 5008.

MagnaCleanse - The THT Difference

At THT Ltd, alongside a standard Power Flush, we also incorporate MagnaCleanse to the process as standard and at no extra cost.

What is MagnaCleanse?

The MagnaCleanse system flush is the process of clearing your system of those harsh, unwanted materials. It thoroughly cleans your entire system – providing consistent protection to your pipes and boiler. The added benefit of a MagnaCleanse filter helps to collect sludgy residue away from your system for easy disposal.

With the heating system on, water is swirled past a strong magnet in the MagnaCleanse equipment. The magnet is positioned in what is known as the ‘swill chamber.’ Whilst the water is being pumped around the system and swirling past the magnet in the swill chamber the technician visits every radiator, in turn, and vibrates them for a few seconds each, using a device known as an agitator.

This ensures that not only is the pipework cleaned of debris and rust but any stubborn debris is loosened and pulled out of the system.

To find out if a Power Flush with MagnaCleanse is suitable for your system, and to book your appointment, call 023 8001 5008.

Underfloor Heating


If you are planning to add underfloor heating to your home THT Ltd work with a range of reputable suppliers to ensure the best match for your home. Our team are able to help with measuring up and providing plans for the most effective way to incorporate underfloor heating in your home.

To find out more, simply call 023 8001 5008.


If you have underfloor heating in your home – either throughout or in specific rooms – and are experiencing problems with it working effectively, one of our engineers will be happy to help. If you need a specialist to visit, we have a selection of recommended suppliers we can connect you with.

If the problem is related to your gas central heating system, we can work with the underfloor heating specialists to resolve it.

To find out more, simply call 023 8001 5008.

Selling Your Home

If you are thinking about selling your home, providing evidence that your gas boiler and central heating system is in good working order, with a regular service history, can offer real peace of mind to your potential buyer.

Call 023 8001 5008 to arrange an appointment for a boiler service, central heating inspection and report.

Buying a New Home?

Imagine waking up on your first day in your new home only to find there’s no heating or hot water!

Checking the heating system doesn’t usually form part of the survey of the property and unless your lender requests evidence that the boiler and heating system has been properly maintained, you could be walking into a potential nightmare.

Why not give yourself the peace of mind of knowing the system has been properly checked before you move in, allowing you to negotiate any repairs that might be necessary before completion.

Call 023 8001 5008 to arrange an appointment for a visual inspection and report.

Gas Hobs, Ovens and Gas Fired Stoves

Do you need a new gas oven, gas hob or gas fired stove installed?

Our team of qualified and experienced Gas Safe engineers can help to install, repair and carry out safety checks on gas hobs, ovens and stoves.

You’ll receive the relevant documentation to show that the appliance has been installed and commissioned by an engineer with the required qualifications, giving you peace of mind that the appliance is safe for you and your family to use.

If you are a landlord and require gas safety checks for appliances in your property

Ask for details or refer to our Landlord Gas Safety Service Plan.