Boiler Efficiency Tips for Landlords: Maximising Return On Investment (ROI)

According to the English Private Landlord Survey of 2024, 52% of landlords bought their first property with the intention of renting it out for a possible passive income.

With more than half of private landlords wanting to profit from their rental property, how can they maximise their boiler’s efficiency to improve their Return On Investment (ROI)?

After all, a property’s boiler is one of the most expensive appliances to run.

Ofgem’s energy price cap increased by 1.2% for the year’s first quarter of 2025. Currently, this means that the annual energy bills paid by direct debit will be around £1,738 for a typical dual-fuel household in Great Britain.

Maximising your ROI as a landlord requires keeping your rental property’s operational costs low while ensuring your tenant/s satisfaction. One way landlords can achieve this is by improving boiler efficiency.

Here are some tips for landlords to increase their boiler’s efficiency.

Annual Service And Maintenance

Landlords are legally required to service and regularly maintain their property’s boiler, which helps the boiler maintain its efficiency.

Private landlords must comply with various legal requirements. First, let’s discuss the requirement for a valid Gas Safety Certificate (CP12).

Annual Service For A Gas Safety Certificate CP12

Under the Gas Safety (Installation and Use) Regulations 1998, landlords must ensure that gas appliances, including boilers, are inspected annually.

Your tenants must receive a copy of the Gas Safety Certificate (CP12) within 28 days of the annual inspection and be presented with a valid copy when moving into the property.

Landlords must keep records of these safety checks, or CP12, for at least two years. If you do fail to provide a valid certificate, you can be liable for:

• A hefty fine;
• Imprisonment;
• Or be legally required to pay for a tenant’s injuries if a gas-related incident caused it.

The Landlord and Tenant Act 1985 also stipulates that landlords must maintain the heating and hot water systems in good working order and repair them within 24 to 48 hours.

This can be challenging during the busy season. But are there any environmental legal requirements?

Energy Performance Certificates (EPCs) Matter

Another legal requirement for landlords is to ensure their property meets the minimum energy efficiency standard or gain an Energy Performance Certificate (EPC) above ‘E”.

However, this EPC requirement could change as soon as 2030, with all new rental tenancies requiring a rating of ‘C’.

This change aligns with the UK Government’s Net Zero 2050 target and aims to financially assist private renters financially, potentially saving them an average of £240 per year on energy bills.

If this new EPC requirement becomes legal, landlords will be required to:

• Upgrade their property’s installation,
• Replace the heating system,
• And ensure that every efficiency measure has been taken.

Another element of the EPC requirement that could be changed is increased fines for non-compliance.

It should be mentioned that 48% of all privately rented homes in England already have an EPC rating of ‘C”.

You need a qualified Domestic Energy Assessor to issue an EPC rating.

Depending on the property’s size and location, these inspections can cost between £50 and £120, and EPCs are valid for 10 years.

While it may seem like a nightmare, there will be benefits for landlords, which include:

• Asking for higher rental values depending on your EPC rating.
• Potentially increasing your property’s value when it comes time to sell.
• Reducing running costs over time.
• And being able to tap into government grants and incentive plans.

All landlords should work towards improving their properties’ EPC ratings before the upcoming deadline, which has yet to be confirmed.

Carbon Monoxide Alarms

As of October 1, 2022, landlords must install at least one carbon monoxide (CO) alarm for every storey of their property where a room is used for living accommodation.

Landlords must ensure alarms are tested at the start of each tenancy. Also, as a new legal requirement, those who fail to compile could be liable for a £5,000 fine issued by local authorities.

Generally speaking, to improve your boiler’s efficiency, ensure it is serviced annually and that maintenance is carried out regularly.

While coordinating with tenants to let in the Gas Safe registered engineer can be problematic, it’s better than being non-compliant and risking heavy fines or jail time.

Now that we’ve covered the legal requirements, what can you install to improve the efficiency of your rental property’s boiler?

Install Smart Thermostats, Filters, And Better Insulation

The Department of Business, Energy and Industrial Strategy (BEIS) anticipates smart meters will reduce energy consumption by 2.2% for gas and 0.5% for gas prepay meter clients.

However, other energy experts (e.g. drawdown, Oasis Heating & Cooling) are currently projecting an average energy cost savings of 10% to 25%.

Installing smart thermostats has several benefits, including:

• Remote temperature control
• Preventing waste
• Geofencing technology
• Real-time monitoring and energy reports
• Benefiting the environment
• And extending the lifespan of your boiler

Also, you can program notifications to appear on your phone as the landlord when there is an issue with the boiler.

Installing a magnetic filter can help landlords minimise potential blockage issues in their heating systems.

Magnetic filters help remove metal debris that can form blockages. Generally, they ensure that your system is clean and working efficiently.

When blockages form, you might need to contract a professional to perform a power flush. As the name suggests, it is when a Gas Safe registered engineer uses a machine to pump water with inhibitors to clear pipes.

Insulation is the last element you can install into your property to improve heating efficiency. Insulating your system’s piping network and boiler will mean you retain heat for longer and require less energy to heat the water supply.

Educating Tenants

For landlords, the only way to guarantee that their property’s boiler will be used efficiently is to educate their tenants.

Quick tips that your tenants can follow are:

Adjusting The Thermostat To An Average Temperature

It’s always best to set your thermostat to 18-21°C for a comfortable and efficient temperature. When you constantly make extreme temperature adjustments, you waste energy.

A programmable or smart thermostat automatically adjusts temperature levels, allowing you to fall asleep or leave the property without wasting fuel trying to maintain a higher temperature.

Another method of lowering fuel usage is to reduce the temperature of your boiler’s hot water. It is warm enough for showers at around 55°C and 60°C.

If your boiler allows it, you can also reduce the flow temperature of your boiler to the same level as your boiler’s hot water.

Tenants Can Bleed Radiators And Monitor Pressure Level

Bleeding a radiator is a simple task that anyone can perform. A clear sign that you need to bleed your radiators are:

• Cold spots at the top of the radiator while it is still warm at the bottom.
• Gurgling or bubbling noises indicate there are air pockets trapped inside.
• Your radiators are taking longer to heat up compared to the usual time.
• Uneven heating is distributed around the home.
• And a lower boiler pressure.

To bleed a radiator, you’ll need the following:

• Radiator key or a flat-head screwdriver
• Towel or cloth to protect your floor from potential spills
• And a small container to catch any water that escapes

The steps to bleeding your radiators are easy to follow.

When you’re done bleeding your heating system, you should monitor the pressure level. Your boiler circulates water within an enclosed pressurised system.

Ensure the pressure is between 1.0 and 1.5 bars when off and around 2.0 bars when on. If it drops below 1.0 bars, your boiler will most likely need to be repressurised.

Install A New Boiler

Upgrading an outdated boiler can significantly improve energy efficiency and reduce heating costs. However, a boiler over 10–15 years old will operate much less efficiently.

Replacing an inefficient unit with an A-rated condensing boiler can make a big difference. Also, as of April 2018, you cannot install a gas boiler with an ErP rating below 92%.

According to Energy Saving Trust the figures below (based on fuel prices of gas prices of 6.29 p/kWh), you can see the savings in the table depending on the upgrade from an old to a new efficient boiler:

But what if you’ve recently replaced your property’s boiler?

Consider Taking Out A Boiler Cover Plan – With WarmZilla

Unexpected boiler breakdowns can be expensive and inconvenient, often requiring urgent repairs.

WarmZilla offers comprehensive boil cover plans for landlords, which include:

• Free annual boiler service
• Unlimited callouts
• Boiler, flue and control installations
• Gas pipework
• If WarmZilla deems your boiler unrepairable and under 7 years old, you will receive a free replacement.
• And a two-year fixed price from the date of purchase.

With over 10,000 Gas Safe registered engineers nationwide, WarmZilla can send a professional to your home within 48 hours.

If you have any other questions, feel free to chat with one of our call centre professionals.