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How do I make my home more energy efficient? Green Deal or independent assessment

Posted by Cathy Debenham on 27 June 2013 at 8:34 am

Our 1950s chalet bungalow home is cold and quite expensive to heat even though we have installed cavity wall and loft insulation, and it is double glazed. It would be warmer if we put the heating on longer, but it would also cost more to heat, and emit more carbon dioxide, and we're want to avoid both.

We are keen to improve its energy efficiency, and even more keen to improve its comfort and warmth, but having done the easy stuff we weren't sure what would be most effective. As a result I recently had two very different home energy assessments done:

  • Green Deal Assessment (GDA). This is part of the government's scheme to make our housing stock more energy efficient, reducing carbon emissions and fuel poverty. Costs from £99 depending on who you go with. I paid £120.
  • Home Energy Masterplan. This has been developed by Parity Projects, which won an Ashden Award last year for its work increasing energy efficiency. Its analysis and report take into account not only your home’s physical details, but also the way it is used, your specific aims and budgets and any wider plans you may have for its renovation. Costs start at £250, I paid £261. 

The assessment process

From the view of the homeowner, the assessment process seemed pretty similar for both. The assessors did a lot of measuring, had a look at the boiler, the loft, the hot water cylinder, and all around the house. They both took a lot of photographs and asked questions about our energy usage - how long we spent watching TV, how long the heating was on, how often we bathed and showered, and so on. While the data was the same, the way it was used couldn't have been more different.

The green deal advice report

The green deal assessment is based on an energy performance certificate (EPC). This tells you how energy efficient a building is, and its impact on the environment. It is derived from an assessment of the fuel cost per square meter of floor space, and makes standard assumptions of occupancy rates and heating and electricity use. 

As well as an EPC, the assessor also does an occupancy assessment which applies your personal circumstances to the EPC and generates a four page green deal advice report. This takes into account your energy usage and the number of people living in the property.

The first page compares our last year's energy bills with a typical household of the same size and type (about the same in our case), and lists recommended improvements, with estimated costs, annual savings, and a maximum green deal repayment in year one, if you were to use it to finance (or part finance) any work you get done.

The report also compares your household to a 'typical' household (a typical household has the central heating on for a (rather surprising) average 11 hours a day, compared to our six, for example). It also gives some very generic ideas of ways to save today, such as turning down your thermostat by 1 degree C, or turning off lights when not needed. Page three explains the green deal process, and page four lists all the home improvements listed on the EPC, and whether or not they are eligible for green deal finance.

The home energy masterplan report

In contrast, the home energy masterplan is a whopping 70 pages long. Parity's methodology starts with a similar building survey and client interview. Where the latter differs is that the assessor asked us what our goals are (carbon reduction, increased comfort, or money saved) and what our budget for renovation is. They appear to have a wider range of measures, and having identified all the suitable ones, the computer model evaluates them and groups them into recommended packages.  

The report starts with a summary of four recommended bespoke packages, ranging from no brainer (cost less than £400 per measure, and payback in less than 5 years) to Green Halo + (money no object, and 97% annual CO2 savings).

It then takes a detailed look at the energy use and carbon emissions of our house - both in numbers and in graphs, and breaks it down in a number of different ways. Unlike the green deal advice report the HEMP took our solar generated hot water and electricity, our log burner and our income from the feed-in tariff into account when comparing, so we ended up with annual fuel costs of £-61 compared with the UK average of £1,620.

It also broke down the energy use of the house into interesting pie charts, so we could see that the roof, draughts and windows are costing us more than average, while appliances and hot water cost less than average. I was also struck by how big a chunk (30%)is taken up by appliances.

The next section examines the various elements of the house one by one, comments on what's currently in place, discusses options available and lists the options that have been evaluated, assigning them labels such as no brainer, some consideration, green halo or green halo+. 

Section 4 outlines the bespoke recommendations under the above headings, and gives estimates of annual savings, CO2 saving, fuel bill reductions and payback period. It also displays graphs showing annual CO2 emmissions before and after installation.

The rest of the report is made up of useful information about how to put your masterplan into action. This isn't personalised, but is aimed to equip you with the knowledge necessary to approach installers and contractors and get quotes for your renovation. There is more interesting reading and an excel spreadsheet with your recommendations on a CD that comes with the report.

How did the recommendations compare?

The difference was stark. While my EPC acknowledged in the number of stars it gave the upstairs rooms (2 out of a possible 5) that they are the weakest link in terms of energy efficiency, there was no recommendation for what I could do about it. I was hoping that it might recommend internal wall insulation for the bedroom, and there might be ECO funding available under the hard to treat category. In fact there were just two recommendations:

Underfloor insulation (100mm)
Wind turbine (roof mounted)

The indicative cost of the floor insulation is £800-£1,200, which would save me about £39 per year. It's not clear if the recommendation is for the whole ground floor (none of it is insulated). If it is, I find it difficult to believe anyone could do it for that cost. I asked five green deal providers to quote for doing the living room, and will report back on progress in due course. 

I was surprised (and horrified) to see the wind turbine recommended. Firstly because roof-mounted turbines have been thoroughly discredited. Secondly because, even if they were effective, our house is very sheltered and totally unsuitable.

Neither of these recommendations appeared on the home energy masterplan. It took into account what we wanted: primarily to improve warmth, with reducing energy bills and CO2 as secondary concerns.

The no brainer (cost up to £400, payback of 5 years) was to internally insulate the roof and sides of the dormer window in our bedroom (see picture above), which I was surprised to hear would save us £80 per year. Among the recommendations 'worth considering' was internally insulating the unfilled cavity walls and sloping ceiling sections of the parts of upstairs that are in the roof. A new A++ freezer was also suggested, which surprised me, as our current one is only 7 years old.

While underfloor insulation wasn't suggested, the report did recommend sealing floors and skirtings on the ground floor under the green halo heading. While that won't make a significant difference to bills, it would probably be one of the biggest contributors to increased comfort, as the living room floor is full of gaps and despite my best efforts to proof it, is pretty cold and draughty.

I asked Parity director, Chris Newman, why they didn't recommend underfloor insulation. It's because it's so disruptive, and expensive, that most people don't want to tackle it. Replacing the tatty old boards has always been on our to do list, so we are getting quotes for that. If they are too much, we'll get out the clear mastic.

Other suggested measures included installing a voltage optimisation device, replacing the fridge and TV, adding weather compensator to the heating system, changing all lights to LEDs, and thicker internal wall insulation. If we wanted to reduce our carbon emissions by 97% we could go for all the Green Halo recommendations plus a log gasification boiler instead of our current gas boiler.

Which is best?

For our circumstances - where we'd done all the easy things to improve energy efficiency, and have already installed both types of solar panels it's a no brainer. The home energy masterplan was really useful, and has highlighted lots of options (and prevented us going off on harebrained tangents). The opportunity to go back and ask questions after reading the report is invaluable. 

What I particularly like about it is that it's tailored to us, and what we want, and how we live. It takes into consideration our priorities, and also whether we would go for DIY or a professional installation. Most of the recommended insulation options are DIY, which will help us keep it affordable.

In comparison, the green deal advice report is a very blunt instrument, and not really any help to someone like me, who has done the basics. If you know nothing about energy efficiency, and want an introduction, or want help financing a new boiler, loft insulation or cavity wall insulation, then you will probably learn quite a lot from a green deal assessment.

However, if you want to put together a long term plan on how to improve the energy efficiency of your property, with advice about what order to do it in, and you want an assessment that is tailored to your priorities, then it's definitely worth paying a bit more and getting a thorough assessment from a specialist.


If you have a question about anything in the above blog, please ask it in the comments section below.

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9 comments - read them below or add one


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rippa700Comment left on: 30 July 2013 at 6:19 pm

We recently had a Green Deal Assessment and EPC done on our old Devon cob and stone farmhouse. The assessor had never seen cob before so my faith in his findings were pretty low. His recomendations were tick-box driven and he clearly knew a lot less about insulation, energy savings etc than I did. But it was a formality I needed to progress with RHI on a biomass boiler. Glad it was free as I felt it was a useless procedure and I gained more from an online assessment process from a log-boiler installers site. The green deal itself is just an expensive loan, so only useful if you cannot raise money any other way. The commercial RHI on biomass seems to encourage consultants to go round saying 'install and burn as much as possible - open the windows if too hot - you will make a fortune. Hardly the way forward! So I'm glad the domestic RHI is based on a deemed generation value - you can burn less and still earn enough to recuperate costs. Seems like a messy process but lets hope it helps to move things in the right (lower carbon) direction. I have my doubts about the effect of too many wood boilers in the UK. Can't be all that clean....

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Anthony525Comment left on: 28 June 2013 at 6:04 pm

As of the 16th June 2013, 38,259 assesments have been made, of which 4 have signed up for the Green Deal.

Most like you have probably decided against it! Its not a good deal!

The Government doesn't recomend cavity wall insulation for homes in the west of the UK especially those in exposed places. Cavity walls were built to ensure wind blown rain does not enter the home. Filling the cavity provides an easy route for rain to cross the cavity - damp walls provide an express route outwards for your expensive heat.

Water is 4,000 times better at conducting heat than dry air - check for damp walls.

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Linn Rafferty

Linn Rafferty from JTec Energy PerformanceComment left on: 27 June 2013 at 10:56 pm

How odd that the most appropriate measure for your home, & which is available under Green Deal, wasn't recommended. As the list of recommendations you received was exactly the same on both EPC and GDAR, I strongly suspect that you've received a report that only considered EPC options, not Green Deal.

In Green Deal, there is a much wider range of improvement options than is considered by the EPC, and insulation to the sloping parts of the room-in-the-roof certainly is an available measure. If you did want to take up this improvement via a Green Deal plan, you might like to consider getting back to the organisation that provided your report and asking why this improvement was missed.

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