‘My buy-to-let only generates £450 per month – should I bother improving its energy efficiency rating?’

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The race is on for landlords such as Karron Lovatt-Fraser. Within the next five years, investors hoping to let out a property to tenants must achieve a minimum level of energy efficiency – and many will be forced to either pay thousands towards renovations or simply sell up.

Ms Lovatt-Fraser’s three-bed semi-detached house in Worthing, which she has let out to a family for the last 11 years, was built in the mid-1960s. It has a traditional cavity wall construction and an extension was added in 2004 to the kitchen and living room.

Housing secretary Michael Gove has recently suggested that the energy efficiency deadline for landlords could be delayed after critics said the target was unrealistic and unfair. The rule, requiring rental properties to have an Energy Performance Certificate rating of at least a C, was due to come into force on April 1, 2025 for new leases and April 1, 2028 for existing leases.

The target is of a particular burden to self-described “accidental landlords” such as Ms Lovatt-Fraser, who earns just £450 a month from the rental income in addition to her £18,000 salary. But she is still eager to make improvements to the former local authority house before the 2028 deadline.

“The roof slopes at a low gradient and often I’ve wondered if this would rule out solar panels,” she says. “The double glazing was installed in 2003, so not the most efficient. The whole ground floor is concrete, with floorboards to the first floor.”

Ms Lovatt-Fraser’s tenant has done her best to keep bills low, setting the condensing gas combi boiler to eco mode, and making sure it is maintained annually. However, the 1960s house is to a degree inefficient by design – some of the walls have no insulation at all, while other “alternative” walls, made of hung tile, are tricky to insulate.

The contrasting types of walls and varying insulation have resulted in condensation in the bedrooms and bathrooms, two rooms which the tenant struggles to heat when the temperature drops. Ultimately, she battles the resultant mould the old-fashioned way – by opening windows and using bleach – but this can make the house even colder.

Prior to Telegraph Money’s involvement, the property had an EPC rating of D, just one band short of the target set out by the Government.

Greig Millar, Ovo energy expert, says:

I started the survey in the loft space where I noted that the insulation was below the recommended 380mm. This is mainly due to large parts of the loft being floored/boarded.

Improving insulation within a loft with boarded storage areas can be costly and labour-intensive (comparison site Household Quotes estimates this can be between £450 to £1,300 depending on the size of the loft). You’ll need to raise joists, add additional loft insulation and then relay the boards on top of higher joists. It can be a challenge but is really worthwhile.

As the property was built in the mid-60s, it would have been built with little-to-no insulation but there was clear evidence that the cavity wall had been retrofitted with it. Although this is a recommended and effective method of insulating the property, I noted that the alternative walls have no insulation.

Having a mix of insulated and uninsulated areas within a property can lead to issues such as condensation, dampness and even mould. The front bedroom and bathroom both had hung tile external walls and the tenant noted that these two rooms were noticeably harder to heat than the rear of the property.

There is evidence of condensation, dampness and mould in the rooms with the alternative walls – the upstairs bathroom and the front bedroom. This can be caused by warm, moist air within the property being drawn to the cold un-insulated wall. This is a major challenge in properties with many differing wall types, all with unique thermal transition values.

Increased ventilation could help resolve the issue. However, Mrs Lovatt-Fraser’s tenant has windows open more often than not to help with ventilation. The tenant mentioned that she uses a bleach wash to keep on top of this issue and also used a specialist paint to minimise the problem.

The gable end had a small utility room with a single-skin brick wall where again, the tenant stated that this is a particularly cold part of the home.

My recommendation would be to add solid wall insulation either to the parts of the walls unsuitable for cavity wall insulation or, if possible, to add external wall insulation to the full property (directory website Checkatrade estimates this would cost £9,000 on average for a semi-detached property).

But a further, more intrusive technical survey would need to be carried out by an accredited contractor before making a call about which solution is best.

The garage has been built into the property at the front of the home. This is another challenging space because it is completely uninsulated. The walls and ceiling of the garage will draw heat from the internal property and as the garage door is not airtight, this heat will be lost to the elements.

Preventing the heat from escaping into the space would be the most ideal solution. This could be done using an insulation board on the internal garage walls and ceiling (Building Materials Nationwide says insulation boards cost £10 per square metre on average).

Before bigger and most costly measures such as heat pumps and solar panels are taken though, the property has lots of room for improvement when it comes to efficiency and insulation. I recommend focusing on loft insulation and draught proofing to start with, before moving on to more expensive updates such as replacing the windows, adding external wall insulation, installing Solar PV with a battery and electrifying the heating system.

Paul Ansell, EPC assessor at Greenfish, says:

When I arrived, I immediately noticed holes in the cavity brickwork – cavity wall insulation has been installed which gains huge points in the EPC survey due to being the main area where every property suffers from heat loss.

The property also has a built-in garage with a habitable room over it, this immediately was an area to check as this was an unheated garage and there was no insulation between the floors to keep the heat contained in the bedroom.

It’s recommended to use Celotex boards as the U-values on these are low enough that whatever thickness you use, you gain double the effectiveness due to the thermal conductivity.

This brings me to the loft area, upon inspection the loft hatch was insulated with Celotex board which is good for keeping out drafts from the roof area, but the entire roof space was boarded up with Quilted Insulation underneath: this reduces the thermal performance by over 50pc.

If loft areas are considered for storage or even extending the dwelling to more habitable space, then again Celotex boards are to be considered due to the effectiveness of their thermal conductivity without reducing area space.

The property has had new UPVC-framed double-glazed windows in the last 20 years which is great as these windows have trickle vents which are background ventilators integrated into window frames to allow a “trickle-feed” of constant airflow from the outside to an internal space.

The property’s modern A-rated condensing combi boiler was installed within the last 10 years, condensing boilers are great as they are far more efficient than non-condensing boilers, with this model reaching around 90pc efficiency.

Non-condensing boilers are only able to achieve between 70-80pc efficiency so they can save you a potential saving of £349 a year. Heating controls are installed with a programmer, thermostat and thermostatic valves (TRVs) in radiators. The key benefits of TRVs are that they can help you stop heating parts of your home that you don’t need to. Which means you’ll be reducing your energy usage and saving money.

The house has LED lighting throughout, which has a much longer lifespan than traditional lighting. An average LED lasts a lot longer than a traditional incandescent bulb. Saving large amounts of money whilst giving the equivalent wattage output. Overall, I gave this property an EPC rating of C-71.