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2023 Guide To Dealing With Faulty/Dated Boilers In Rental Property

The RMA reported more than 20,000 boiler issues between October 1st 2022 and Jan 5th 2023. More than 9,000 boilers needed replacing with 55% organising a repair or short term fix. (figures accurate as of 09th Jan 2023). Full results can be provided by emailing

All landlords know that one of the most expensive individual items to replace in any rental property is the boiler. Many landlords hate boilers for denting their rental income but, love them or hate them, boiler maintenance is important for any landlord.

Failure to ensure your boiler is fit for purpose will either see you in trouble with the law or dealing with distressed calls from tenants when you’re trying to relax, neither of which is particularly desirable.

Combi boilers have a lifespan of between 10-15 years depending on the brand and how well-maintained it’s been. If you are a landlord that is thinking about replacing your boiler, make sure you do your research before committing to the expense and hassle of getting a new boiler installed.

Prevention is always better than cure, so be sure to follow our tips for maintaining your boiler and save yourself some money in the long-term.

Stay on the right side of the law

Ensuring your tenants have access to ‘Thermal comfort’ is a part of your responsibility as a landlord. You are legally responsible for repairs to gas appliances, heating, hot water, pipes, ventilation, wiring and sanitation.

You must also provide an annual Gas Safety Check and provide a copy to your tenants. This must be carried out by a registered Gas Safe engineer. You can find Gas Safe engineers near you by checking Gas Safe Register.

Maintain your boilers

To get the most value out of your boiler and to limit the number of breakdowns, it’s important to keep any boiler(s) in your rental property well-maintained.


As a landlord you’re obliged to regularly service any boiler in your rental properties. This is primarily for safety reasons, but it also means the boiler is given it’s MOT for the year and any minor issues can be picked up before they go on to become major issues.

Find Reviewed & Approved Rental Market Providers, Suppliers & Services, including reviews for New Boiler Providers & Boiler Maintenance Providers right here on – the biggest forum for rental market reviews in the UK.

Bleed the radiators

Over time, air can get into your system and form pockets in your radiators. This means that they aren’t outputting as much heat and tenants are more likely to turn the heating up to compensate. Your boiler will be working harder to maintain the same temperature and over time, this will shorten the lifespan of the boiler.

Install A Magnetic Filter

A magnetic filter is fitted on the return pipework to your boiler and via a powerful internal magnet attracts sludge (metallic system waste) before it goes into your boiler. This prolongs the lifespan of your boiler. A system filter is cleaned out annually during a service. Supply and fitting of a system filter can cost anywhere between £120 – £200 depending on brand and installer.

Add Annihilator

Inhibitor is an anti-corrosive solution that is added to your central heating system which helps prevent corrosion and scale. It can also aid in the reduction of sludge building up in your radiators. A heating system is made up of dissimilar metals and over time, bits of metal can break off into the system. Inhibitor fights this by applying a protective coat against the metals.


Under certain circumstances a powerflush might be worth trying. If your system is relatively new or has been well maintained, then the cost probably won’t be worth it (£300-£500). However, if you have an older system it might be worth your while trying a powerflush, which, through a high-pressure water flow, attempts to dislodge sludge build-up. Given the amount of money involved, you’re probably better off putting it toward a new boiler or putting it aside as a repair fund.

Get Your Tenants To Run The Heating In The Summer

This one can sound counter-intuitive, but it’s the same as any piece of complex machinery, if it’s not used regularly things can start to go wrong. Think of it like leaving a car in the garage for 3 months, you would expect some issues when starting it up again. Get your tenants to run the heating once a week during Summer just to keep the heating ticking over.

Insulate Pipes

By lagging your pipes, you are helping to minimise heat loss and protecting against the cold in the winter, where pipes can split and cause major leaks. This only applies to central heating pipes or water pipes, there is no need to lag a gas pipe.

Symptoms Of A Dying Boiler

There are a few regular signs that your boiler may not be in the best of health. If your tenant or heating engineer calls you and warns you of any of the following, then it may be time to start thinking of a replacement boiler.

01. Banging, whistling, gurgling noises

02. Energy efficiency lower than ‘A-rated’

03. Taking longer to heat up than it used to

04. Boiler is leaking

05. Fuel costs are increasing

06. Rooms not heated evenly throughout the house

07. More frequent repairs required

08. Parts are no longer available

In addition, if your boiler is over 15 years old it may be worth considering getting it replaced before it starts costing you. It’s certainly not worth getting it repaired beyond this point.

Boiler cover

If you know that a boiler in one of your properties is getting on in years, then you may consider getting boiler cover for peace of mind. In addition, being ‘on-call’ for one or more rental properties spread across wide expanses of the UK during all hours of the night and day can be a massive expense in money and time and travel.

Find Reviewed & Approved Rental Market Providers, Suppliers & Services, including reviews for Boiler Cover (Home Emergency Cover) right here on – the biggest forum for rental market reviews in the UK.

Is it worth repairing?

Whether it’s worth fixing depends on the age of the boiler, how serious the issue is and whether you’d rather start putting the money toward a new boiler.

Depending on the issue there are a few things you can try to fix yourself. Please note that only a Gas Safe registered engineer can remove the cover of a boiler, under no circumstances should you try and tinker around with your boiler, no matter how handy you may think you are!

Is It Still Under Warranty/Guarantee?

This may sound obvious but it’s always worth checking whether your boiler is still under warranty. If you aren’t sure call the manufacturer with the serial number to hand and check.

Frozen Condensate Pipe

During colder weather a boiler condensate pipe can freeze, this will lead to a backup of fluid into the boiler, which will cause it to lockout. Find the small plastic pipe leaving your boiler and if there is an area that’s frozen, just pour some warm water on it until it thaws and reset your boiler.

Check The Thermostat

This one may sound obvious but check the thermostat is set to the right time, or, in the case of a smart thermostat – make sure it hasn’t dropped its connection to the boiler. They are reliant on internet connection, so if the internet has gone down it may have lost the connection.

Boiler Losing Pressure

If your boiler is losing pressure regularly causing you to need to keep repressurising the system, then there is probably a leak somewhere in the system. Check the pipes coming out of the boiler and the pipes connecting to your radiators to make sure there are no leaks.

If these fixes don’t work, then it may be time to call out a Gas Safe engineer or look at purchasing a new boiler.

What boiler type do I need to replace?

If you decide that you want to replace your old boiler then you need the first step is to understand what boiler type you need for your property.

There are four main types of boiler – combi, system, regular (heat only) or back boilers.

Here is a handy video for identifying which boiler type you currently have:

What size boiler do I need?

You will need to choose a boiler that can cope with the heating demands of your property. This depends on the size of your home, how many radiators and how many baths there are. Below is a very rough guide on the size of boiler that will cater to your home.

24 – 27 Kw Combi

Suitable for most flats, apartments and smaller houses with up to 10 radiators and 1 bathroom.

28 – 34 Kw Combi

Suitable for 3-4 bed houses with up to 15 radiators and 2 bathrooms.

35+ Kw Combi

Suitable for large houses with up to 20 radiators and 3 bathrooms.

Can I get a boiler for free?

Under the ECO scheme (Energy Companies Obligation) – low income tenants may be eligible for an upgrade to an energy-efficient A-rated boiler free of charge or in some cases – heavily subsidised.

To check whether your tenants may be eligible, contact the Energy Saving Advice Service on 0300 123 1234. If you live in Scotland contact Home Energy Scotland on 0808 808 2282.

Who do I get to install a new boiler?

The easiest way (and the cheapest) is to buy a new boiler from an online company. You can view rated & reviewed boiler providers right here on – the biggest forum for rental market reviews in the UK.

Landlords are finding that they make the process of purchasing a boiler simpler, cheaper and easier than more old-fashioned alternatives. We have more reviews for rental market providers & suppliers than any other website in the world.

Don’t buy too cheap!

As a landlord, we understand that you might have multiple properties in your portfolio and the temptation may be to buy a boiler as cheaply as possible. This can be a false economy, as many experienced landlords have found out to their cost.

There are budget boilers and there are BUDGET BOILERS. For example, an Ideal Logic, despite being a budget boiler is a reliable boiler, it also has the Ideal customer service behind it, so if something goes wrong while the boiler is under warranty you will actually be able to speak to someone. Many budget boilers have awful customer service and if something should go wrong with the boiler, you’ll wish you paid a little more for a more reputable brand.

There’s a reason why brands like Worcester Bosch have won the Which? Best Buy Award for ten years running. They are reliable, they have been around for years and they offer excellent customer service.

According to Which? regarding boiler faults:

“If you choose the most reliable brand of boiler, according to our survey, an impressive 63% are likely to still be fault free after six and a half years. Get unlucky and pick the least reliable brand, and this falls to a disappointing 45%.”

Repair bills cost between £150-£400 on average according to Money Supermarket with the difference in purchase prices often being between £200 – £300, so is it worth the additional risk and hassle to save a bit on a new boiler that’s going to cost you in the future.


Getting a boiler repaired or replaced is a decision only you as a landlord can make but we hope that this article will have helped you to make a more informed decision.

Factors such as how distressed your tenant is, what time of year it is (how cold it is), how old the boiler is, how much you’ve already spent repairing it will all play a part in your decision but it’s always worth doing some research and ensuring you get the best deal for your money.

Remember the cheapest price isn’t necessarily the best deal as a few hundred on the purchase price could save you a few hundred or more on repair bills and headaches in the future.

Find Reviewed & Approved Rental Market Providers, Suppliers & Services, including reviews for New Boiler Providers & Boiler Maintenance Providers right here on – the biggest forum for rental market reviews in the UK.