The Whole-house Approach
Take a straw poll and most homeowners would say that the key to reducing their energy use is to install solar panels or change their windows, and to be honest, from us to you, it doesn't make much sense, not with regards to total energy use and not financially, although there will be properties where this strategy would be the best solution, it really isn't the case for the majority.
Though even very similar properties show a wide range of energy uses, on average a UK property uses 60% of its energy for space heating, with hot water heating second at 24%. Fridges/freezers, laptops and other consumer electronics, lighting, and cooking account for roughly 3% each with 4% “Other”.
For this reason, if you want to reduce your home energy use, home and water heating should be your main focus.
We find the best strategy is to reduce energy demand. This means needing less energy to start with, and this means following a “fabric first” approach to reduce the amount of energy you need to heat (and in future, cool) your home --a combination of reasonable building fabric (insulation, double glazing, draught proofing, controlled ventilation), and good habits (paying attention to heating and lighting controls and hot water use; essentially managing the home well).
Reducing demand has a range of co-benefits including improving people’s overall comfort and health (non-draughty rooms, good ventilation, etc) and those fabric upgrades might last until the end of the property’s life so it has the best “embodied carbon”, meaning the amount of carbon that goes into achieving the upgrade. Some improvements like installing sheep’s’ wool insulation can be extremely-low carbon and improve air quality at the same time.
These improvements unfortunately can be a hassle to install. External insulation might be inappropriate for a period home or encounter planning issues. Internal insulation can uproot occupants for weeks or months on end and reduce internal area. Window upgrades are seen as high-cost, low payback and the lack of options can stress out the calmest owner living in a conservation area.
Furthermore, to install a better piece of kit-- an air source or ground source heat pump-- your home needs to be reasonably efficient (basic draught-proofing and some double glazing at minimum, helped significantly but not necessarily by underfloor heating) whereas a combi will tick away no matter what shape your home is in.
People often bypass these meaningful and long-impact, low carbon choices, and try to do the heavy lifting by installing new gas boilers or solar panels, but these solutions will achieve less overall if the home itself isn’t efficient to run. Plus there really are no co-benefits. A new combi boiler can result in significantly lower bills, and it does comparatively reduce carbon use as well. But its life-span is shorter than new windows, and will be shorter still as gas boilers will be on the way out soon. Furthermore it maintains the home on a high-carbon trajectory since gas is no longer the low-carbon energy source it once was (when compared with electricity).
Equipment upgrades can sometimes be carried out without improving the fabric, but you’ll lose out on long-term benefits. It's a simple math problem. If you can reduce your energy demand by 30%, you need a smaller heating system in the first place, and the end result will be much lower carbon and much lower bills. If you reduce your energy use by 60% then you might need only a couple of solar panels to get you to net zero, where you haven’t a hope of that
So what is the best way forward?
We’d argue that since the “first first step” is to repair leaks and damp areas before any other building fabric improvements are made. This way of thinking absolutely ensures that homeowners protect not only their health but the longevity of their property as well. We’re constantly surprised that people with shockingly expensive properties don’t maintain them as they would their car. Homes should ideally have a yearly MOT.
We’d urge people to make improvements using a “whole house” approach. So-called “single measures” –this could be installing insulation to the front room or upgrading your boiler—can potentially limit choices later, and in the worst cases, be counter-productive (installing insulation without removing sources of damp can be catastrophic, barely less so if big differences in insulated and non-insulated walls exist in the same property). Work done poorly can require costly re-work. So it is vital to put improvements in the right order and according to a realistic calendar for the owners and occupiers so that work done now is still going to be viable in the future. Improvements can be built up as funds become available. In some cases it’s even possible to pay for future upgrades with savings made from “low hanging fruit”.
And quality of upgrades will almost always outweigh quantity—a great example of this is the thickness of insulation where the first 50mm provides by far the most impact and the thicker the insulation the less added benefit for each additional increment.
We are strongly in favour of the “fabric first” approach, this can be summed up with the points below.
Get a whole-property assessment. This weighs the options and puts them in the order that makes sense for the building and for your pocket.
Make repairs where needed before doing anything else.
Draughtproof but ensure healthy ventilation is maintained.
Low-energy lighting is a no-brainer. LEDs save up to 90% of energy compared to halogens and they last infinitely longer.
“Stand alone” insulation could be useful (loft insulation for example usually doesn't impact other improvements, though it has to be installed correctly)
Other improvements need to be scheduled properly and may need design details to ensure they interact with the existing building in the right way.
Seek qualified installers only
In most cases, we don’t advocate making very expensive upgrades unless there is a case for it. It is much clearer for example, to advocate putting in internal insulation if you are already renovating your home, when added costs are minimized. But there is usually a compelling financial case for sensible upgrades . It is absolutely untrue that most homes need triple glazing (this can even be detrimental in older homes) or mechanical ventilation. It is untrue that historic homes have to be compromised in order to improve energy use significantly. There is a unique solution for each home, based on who owns the property, what plans they have for that property, the state of maintenance, and other considerations. We think this is a far kinder, better, more equitable way forward than imposing single solutions on the majority of home-owners.
Source: Retrofit Academy
