What’s the true cost for landlords to get properties to EPC C by 2030?

I’ve been digging into the EPC open data register to work out what the EPC C 2030 deadline actually means in practice for a typical small portfolio. Not the headline figures from government consultations, the actual numbers from real EPC certificates in real postcodes.

Thought it might be useful to share what I found, because the picture is more nuanced than “it’ll cost you £6,000-7,000” that keeps getting quoted.

The government publishes every EPC certificate through their open data portal (epc.opendatacommunities.org). It’s free to access. Each certificate includes the current rating, the potential rating after improvements, and a list of specific recommended upgrades with estimated cost ranges.

I pulled every domestic EPC in my local authority area and filtered for properties currently rated D, E, F, or G , the ones that need upgrading.

The spread of upgrade costs is enormous. A D-rated mid-terrace from the 1930s with reasonable loft insulation and double glazing might only need a boiler upgrade and cavity wall insulation to hit C, potentially £2,500-4,000 total. A solid-wall Victorian end-terrace rated E with single-glazed sash windows and no loft insulation could easily exceed the £10,000 cost cap.

The single biggest factor in whether your upgrade is affordable is wall type. Cavity wall insulation costs £350-500 and can shift your rating by 5-10 points. Solid wall insulation (internal or external) costs £5,000-15,000 and many landlords on Property118 have rightly pointed out it can cause damp issues in older properties.

The second factor is your current heating system. If you’ve got a modern condensing gas boiler rated A, you’ve already banked those points. If you’re still on an old non-condensing boiler, the swap alone (£2,000-3,000) can add 10-15 points to your score.

Properties that achieve EPC C under the current assessment method (EER) before October 2029 will be deemed compliant until their EPC expires, which is 10 years. That means if you get assessed at C under the current system before the new Home Energy Model kicks in, you’re potentially covered until 2039.

The new HEM system requires you to meet two criteria: fabric performance AND either smart readiness (solar panels, battery storage) OR heating system performance (heat pumps). This is likely to be harder and more expensive to pass. Several people on webinars have confirmed this interpretation.

So there’s a genuine argument for getting your properties assessed sooner rather than later under the current system, even if your EPCs aren’t due for renewal.

What I’d actually want to know per property after going through this exercise, I realised what would actually help me (and I suspect many landlords) is a simple per-property view.

The specific upgrades recommended for THIS property (not generic advice)

What I’d actually want to know per property:

• The specific upgrades recommended for that property (not generic advice)
• How many points each upgrade would add
• Whether it’s enough to reach EPC C or trigger a cost cap exemption
• What grants might apply (e.g. ECO4, Warm Homes Local Grant) based on the property and tenant

I’m curious, how many of you have actually looked up your properties on the EPC register and gone through the specific recommendations?

And for those who’ve already started upgrading, did the recommended improvements actually move the needle the way the certificate predicted, or was the reality different?

Interested to hear real experiences. The government estimates feel very average-based and I suspect the property-by-property variation is huge.

Thanks,

Kshitig