Renewables are crucial when it comes to achieving the very highest EPC ratings. This means solar PV, solar thermal, wind, heat pumps and biomass. Which ones will help you get the best rating however, and what can hold back your property from achieving that A rating?
Solar PV is one of the most popular renewable technologies for the home. You can see them on many homes across the UK and they really do help cut your home’s electricity costs. PV can be input into the EPC using either assumed defaults based on the observed sized of the system, or using precise figures from the installer and MCS certificate. Solar will usually provide a good boost to the EPC rating, taking the score up by a whole rating band in many cases, but this will depend on the size of the system. There is a limit to how many panels you can fit on the average roof!
Solar thermal heats hot water directly, rather than creating electricity. Like PV, it can be entered into the software using defaults or by entering the specifications of the system in question. Solar thermal has much less of a bearing on the final EPC rating for most properties, usually only making a couple of points’ difference. Whilst there are plenty of good reasons to get a solar thermal system, improving the EPC rating should rank pretty low down on the list for this reason.
Wind turbines are not particularly common in a domestic setting, and if they are it is usually on quite a small scale, or in combination with commercial activity like farming.
If you do happen to have a wind turbine, the rating will depend on a couple of factor: how big the diameter of the turbine is, how many turbines you have, and the height of the turbine. If your area is classified as rural rather than suburban, there will be a big bump in the rating as a result, presumably because there are likely to be less obstructions and a higher wind speed in these areas. Likewise, if the turbine is in a dense urban area, there will be a considerable negative hit on the rating.
If you have a small turbine with a span of just a metre or so, the EPC rating is not going to change much. If you have a larger turbine with a span of 4-5m, then you will see a big uptick in your EPC rating, and could even exceed the 100-point rating, meaning that the home is actually generating more energy than it is using. If you have the space, a turbine can be a good choice to improve your rating, but it is only practical in a small number of properties – and it will take a good size turbine to really make the difference.
Biomass and Heat Pumps
Other forms of renewable heating, like heat pumps and biomass, could also help improve the rating on the EPC in some situations. Generally speaking, they will only improve the rating in properties that are off the gas grid. Gas heating is always going to be the cheapest way to heat and therefore electric forms of heating will reduce the energy rating, even if they are particularly efficient electric heating systems. Biomass is similar in that the cost of a unit of biomass is still more than a unit of gas, but it is less than oil or LPG, making it a good substitute for rural areas.
The rating increase will vary based on a number of factors, but you are not likely to get up to the very highest ratings using only these renewable technologies, you will likely need to combine with solar or wind to make the property A-rated.
Getting an A rating
Getting up to an A rating is incredibly tough. It is true that you can get there with a ton of solar and wind, but the best way is to go for a holistic approach. Combining high levels of insulation surrounding the thermal envelope of the property, an efficient heating system and a generous renewable energy system is the way to get to the higher levels without creating your own renewable power plant in your back garden!
We should also note that if your renewable system is used in conjunction with a industrial use, (like helping to power a farm or holiday homes), then it would not be considered part of the EPC for the domestic property.