Why are EPCs Important?

By Ian on Saturday 5th August 2023

Wind turbines on a clear day

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I think about this subject a lot. Putting climate change to one side, lets discuss how EPCs can help not only reduce the country’s dependancy on imported energy but also help individuals reduce their bills by reducing dependancy on the country’s energy infrastructure.

It’s approaching 10am on a Saturday morning in August and Great Britain is currently using 26.6GW (gigawatts) of electricity. 6.8GW, or one quarter of our energy is being imported from other countries, mainly France.

Also, today we are expected to use almost 134 million cubic meters of gas. On average each year we import around half of the natural gas that we use. Norway is the country that we import most of our natural gas from.

France and Norway have put themselves in positions to secure their own energy independence and sell exported excess capacity to their neighbours. The UK, has not done this. We heavily rely on imports. Without these imports we’d experience power cuts year round and have no heating at for significant lengths in winter.

Its worth taking a moment here to consider the importance of energy independence. Highlighted recently by instability in eastern Europe. Our former dependence on Russian gas then the removal of that supply caused the market rate per KW/h to sky rocket. We all felt the effects of this on our pocket. Would things have been different if we we’re a net exporter of energy? Probably.

So, what can we do as individuals? First and foremost, we need to reduce the total amount of energy that we consume as a nation. I see this as coming in three forms. The first, cut wasted energy as much as possible. The second, invest in higher efficiency technology. Finally, self generation. If every household did these three things, the country would not only be able to become a self sufficient, energy independent country, we’d save a ton of money on our energy bills.

How can we reduce wasted energy?

Lets talk about insulation first. If you’re spending your money on any energy source, it’s wise to make sure as little of that heat escapes as possible. Theres no point installing a heat pump if your home is leaking heat. As an EPC Assessor, I see loads of houses that have way less than the minimum amount of recommended loft insulation. I see houses with no cavity wall insulation. Very few have floor insulation.

Loft insulation is the easiest to tackle. With a couple of hundred £££ spent on materials and a days work, increasing loft insulation to 270mm can make a huge difference. The energy saving trust say that increasing loft insulation from nothing to 270mm can make that following savings for households.

  • Detached House – £475 per year
  • Detached Bungalow – £470 per year
  • Semi Detached House – £285 per year
  • Mid Terrace House – £260 per year

Cavity wall insulation will need a specialist firm to install and will cost a bit more money, but grants are available under some circumstances. Again, according to the energy saving trust, estimated savings after installing cavity wall insulation will be in the region of

  • Detached House – £500 per year
  • Detached Bungalow – £225 per year
  • Semi Detached House – £300 per year
  • Mid Terrace House – £180 per year

Floor insulation is the most disruptive, labour intensive type of insulation to retrofit to a home. It also generally has the least cost saving benefit. Therefore, it’s not a measure we usually recommend unless the floor is being lifted for other reasons. You can expect a saving of around £100 a year.

An EPC will highlight the main areas of your home that can be improved. You can book an EPC with me!

You can also reduce the amount of energy that you waste through making sure lights and appliances are only on when you’re using them. My favourite way to do this is by using smart home technology.

With smart home technology like the Philips Hue system, you can control all your light bulbs from your phone or Alexa. I’ve got mine set up in a schedule where all the lights turn off at 11pm, just in case I miss one when going up to bed. I like that they can be dimmed to any level too. Smart plugs can be used to completely turn off appliances like TVs, microwaves, washing machines etc, to keep them from consuming power on standby mode. You can set their own schedules or manually control them, again with your phone or Alexa. The savings may not be large, but it all adds up over the year.

My favourite way to reduce my wasted energy is to control my central heating using my nest thermostat. Hives and other similar products do the same thing. My home is warm when I get home and no energy is wasted whilst I’m out at work.

Energy Efficient Appliances

When it comes to an EPC, an efficient boiler can move the house a full banding level. Modern, efficient, A rated boilers are typically more than 90% efficient. Whereas older, D rated appliances have an efficiency of around 80%. With the typical heating bill of £1,000 a year in the UK, households could save around £250 a year (25%!) by upgrading their boiler.

Now lets take a look at heat pumps. They use the same technology as refrigerators and air conditioning units. The process they use is just reversed. The two most popular versions of heat pumps are ground source heat pumps (GSHP) and air source heat pumps (ASHP).

GSHPs are great if you’ve got a bit of land that you can lay a series of coils to collect the heat from the ground to heat a refrigerant with a low boiling point. The refrigerant gas can then be compressed which in turn heats up water to 60 degrees C plus! If you’ve not got land, but you have loads of money, you can drill vertically in to the ground for your heat collecting coils. The cheapest heat pumps, ASHPs, hardly take up any space and use the same process as GSHPs but use air to heat up the refrigerant. They work to temps as low as -7 degrees C.

Grants are available to help homeowners with the cost of installing heat pumps through the Microgeneration Certification Scheme (MCS).

Typically, they cost around the same to run as an A rated boiler, but they remove the need for a home to have a gas supply at all. They are also way more efficient per unit than a gas boiler reducing the amount of carbon dioxide produced. For every unit of energy a heat pump uses, it outputs around 4 times as much. No combustion is involved with a heat pump. This means no dangerous gasses like carbon monoxide are emitted. With the average life span of a traditional boiler around the ten year mark, your looking around double that with a heat pump. There’s less maintenance with a heat pump too.

If you can pair a heat pump with your own electricity generation method too…

Self Generation

You’re EPC score will rocket with a method of self generation of electricity. Solar panels or a wind turbine will drastically improve the energy efficiency of your home and reduce your energy bills. If you pair the system with battery storage it is possible to completely remove your reliance on the grid. Though the EPC currently doesn’t account for battery storage, in my opinion that it is well worth having. The amount of electricity generated varies massively from home to home. For solar panels, you need to consider the amount of roof space available, the roofs pitch and the direction of the panels. Also, ask yourself if there are any overhanging trees or other obstructions. Wind turbines are best in semi rural or rural areas. Its best to consult with an MCS Assessor to determine what system would be best for your property.


To summarise, individuals can save a significant amount of money on their energy bills, reduce their own reliance on the energy grid and contribute to the energy independence of the UK by embracing simple technologies like smart thermostats and light bulbs through to significant measures such as air source heat pumps and solar panels. Pay back can often take a long time but the benefits far outweigh just the cost saving. An EPC is at the heart of these improvements and will outline specific areas where the home can be improved.

About the Author

About Ian Kay

Ian is a seasoned energy assessor helping his customers, reduce energy usage and save money on their bills. He holds qualifications from both City & Guilds and ABBE for Domestic EPCs and Commercial EPCs (Level 3 NDEA and Level 4 NDEA). With a background in the building trade he can provide his customers with a unique perspective and advice. Ian combines his deep industry knowledge with practical advice to create blog posts that help visitors understand the complexities of energy performance certificates and reducing operating costs. When not immersed in the world of energy assessments, Ian enjoys exploring the great outdoors and spending quality time with his family.

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