From this weekend, pioneering owners of some of the UK's most energy efficient SuperHomeswill be hosting free Open Days.

SuperHomes are older homes that have been refurbished for greater comfort, lower bills and reduced emissions (at least 60% less). Joining a tour will give you actionable ideas for greening your own home.

Georgian, Victorian, Edwardian and post-war houses are amongst the 65 renovated homes open to the public. Most have superior insulation; many have alternative heating sources and some produce their own energy.

To find out more or to pre-book a place on a tour, visit www.superhomes.org.uk.

Today at Parity Projects we have launched, in collaboration with Keepmoat and Sustainable Homes, a new guide for Registered Providers and Local Authorities on the practical steps they should be taking to prepare for the Green Deal. The guide includes a summary of both the Green Deal and Energy Company Obligation, along with information on financing the Green Deal, preparing supply chains, and becoming Green Deal provider.

The idea of writing the guide came about following a series of workshops that we held with the partners for RPs and LAs where it became clear that many across the industry were desperate for answers on what the scheme would mean for their organisations. The argument for publishing a no-nonsense guide was strengthened by last week launch of the Green Deal and ECO consultation documents, which totalled many hundreds of pages of detailed information.

Launching the document, Richard Griffiths - our Business Development Manager - said:

“After attending so many events where Registered Providers were clearly concerned about the implications of the Green Deal but overwhelmed by the policy detail, it has been great to work with Keepmoat and Sustainable Homes – first in putting on the practical workshops, and then in developing this guide. We hope that the guide proves as helpful for Registered Providers as hearing their issues and concerns have been for us when thinking about the support we can offer them with the Green Deal.”

You can download a copy of  the guide here: "The Green Deal A summary guide to the big decisions for Registered Providers and Local Authorities"

More details on our CROHM stock assessment service - a key step in preparing for the Green Deal.

We've recently been carrying out some analysis of a house for a couple who use their heating system very differently to how it should be used - this is partly due to costs and party due to having lived in the house before the central heating actually went in.  We decided to do some additional 'what if' Green Deal scenario analysis.

Luckily the occupiers were able to provide details of their annual gas consumption ~ 17,519kWh.  What I did was use our Home Energy Masterplan to model the house with their actual use and then also modelled the house using standard heat settings and standard use of the heating system based on what was actually there - this was a RdSAP/SAP proxy. It is acknowledged that we did not do a current RdSAP calculation or a Green Deal assessment but we expect that our proxy is not all that far away. Here are the initial results of the baseline consumption are shown left.

The difference between their actual consumption and the potential consumption of the house under standard use is pretty dramatic. The Parity model was then calibrated so that it matched the actual use.

The next thing was to evaluate two standard measures and see what the predicted savings were under the different usage regimes.

The savings predicted using standard modelled use of the house are huge compared to those that our model predicts - for the boiler upgrade over 6 times as much and for the wall insulation also over 6 times.

Finally we looked at the expected annual charge for the two measures based on 25 year repayment and a 5% interest rate and compare this to the annual savings.

What do these figures mean?  They indicate that this couple could be told that a boiler upgrade will save then over £500 pounds a year and that the repayments will be £144 a year. Seems like a no brainer and definitely would meet the Golden Rule.  But our analysis shows that their actual savings might only be £85 a year - leaving then £59 worse off.

Similarly for the wall insulation.  They indicate that they could be told they would get a saving over £700 a year and only have repayments of around £400.  All looks good again. But they may actually only achieve savings of £238 a year - leaving them £158 worse off a year.

Conclusion
As we've said before, using tools that have actually been designed to benchmark properties to give financial advice may in some circumstances lead to very bad advice being given - especially to vulnerable people. Other than that we think the results speak for themselves.

The green airwaves are all a buzz with the potential impact of the Government’s Green Deal  - both on carbon dioxide emissions and creating jobs. Our experience of analysing homes shows it will have to be carefully thought out to make sure it ends up being more than a boiler upgrade, loft insulation and cavity wall insulation scheme – essentially an expanded Warm Front. We believe it can and will continue to explain how through this blog.

Spend £6,500 on eco or energy measures for 25 million homes could undoubtedly make a big impact....but what could you actually do with that money which also meets the ‘Golden Rule’ ?

'The “core principle” of the Green Deal is the “golden rule”; that the instalment payment for the energy saving measures, including the cost of finance, labour and products, should not exceed the projected associated cost savings on an average bill for the duration of the green finance arrangement. The arrangement could be for as long as 25 years for houses'

We have carried out the analysis for two schemes which are effectively Green Deal prototypes – one of the  Pay As You Save trials and for Whitehilll and Bordon Eco-Fit Loans.

The first involved interest free loans up to £20,000 and 40% discounts on works, and the second interest free loans up to £10,000.  Both offer greater incentives that that proposed for the Green Deal.

We performed detailed modelling and analysis, including behaviour and calibrating to actual bills, for these projects and many hundreds of others for private client and these are our high level thoughts on what would be recommended under a £6,500 Green Deal scheme or similar.

What we find is that - as you might expect - the 'usual suspect' measures that are already often covered by schemes such as Warm Front  and CERT, i.e. loft insulation, cavity walls insulation and boilers, will usually come top of the list.

• Loft insulation in an empty or slightly filled loft and cavity filling walls will almost always meet the Golden Rule and cost less than the proposed loan amount.
• An inefficient heating system would also usually come near the top of the recommendations and would necessarily mop up most of the money available for a loan.
• Other minor measures may meet the budget and Golden Rule but not always – e.g. draughtproofing.

This leads to two general findings:

1. Where heating systems have been upgraded already, major measures such as solid wall insulation will not usually fit within a £6500 budget (even if they meet the Golden Rule).
2. Where heating systems have not already been upgraded they will be the priority and will swallow most of the loan amount leaving little for major measures.  
3. Many major measures will also only meet the Golden Rule in this situation if they are evaluated against the house before any heating system upgrade.
   

This means that there is a risk that one of the key problems with Britain’s housing stock – uninsulated solid walls – 
 may not be addressed by a simple budget limited Golden Rule 'In or Out' Green Deal.

Some quick thoughts about things that could be included:

• Raise the £6,500 limit.
• Allow measures that have over 25 year paybacks but only allow the Green Deal to cover the portion of the cost that will be offset by savings in less than 25 years. (For example, hardwood sash windows with a payback of 122 years costing £12,500 and savings of £102 could have a Green Deal loan of £2,561. This loan would be offset by savings in 25 years).
• Allow secondary measures (where there will be reduced installation costs if works are combined) to have longer Golden Rule thresholds (e.g. underfloor insulation where solid wall insulation is taking place).

If Green Deal advice (or any other for that matter) is based on 'standard usages' of properties, it may be extremely inaccurate.  In this posting we have taken a real property that we have surveyed, then amended the heating, hot water and electrical behaviour in various ways to see what the effect on difference upgrades would be....all modelling was done using our own home energy software.

A lot of housing energy analysis is performed on properties with 'standard usages'.  That's all well and good for benchmarking or extrapolating but can lead to inaccurate advice when applied to real houses and real people.

The two key questions are:
a) do behavioural differences really have significant effect on the energy use of a property and hence what we would advise to do with them and;
b) are standard usages (e.g. as per BREDEM, SAP, RdSAP) reflective of average usages?

Our experiences says that for a)  the answer is a categorical YES and for b) we don't know if they reflect an average of all people but our clients have certainly deviated from the 'standard usages' significantly and regularly.

The house
We took a standard 2 bed semi detached late Victorian property with 2 residents.  The gas boiler was about 78% efficient, the walls solid and the actual electrical use a little below national average.  The residents mainly showered using a standard shower.

Heating
The first thing we looked at was altering the residents' heating patterns. We predicted their annual total energy use using our model as 20,868kWh which was actually within 5% of their latest annual use based on meter readings.

We then altered the heat settings to reflect BREDEM standard daytime and weekend on/off times and temperatures, and also a high use scenario and a low use scenario.  The graph below shows the large differences in annual kWh predictions.

What we did next was to apply two seperate measures to each of the above four scenarios - a boiler upgrade and 50mm of PIR insulation onto the solid walls.  We then also looked at carrying out both a boiler upgrade and the internal wall insulation together as a package.  The total cost of the two measures has been set at £5,000 (£1,500 for the boiler and £3,500 for the IWI).  The figures show that the paybacks will range from around 4.5 years to 12 years depending on the different behavioural use.  More importantly the client may have thought they were going to save around £776 if they had been modelled against 'standard usages' but actually will only save £443 a year - the consequences for people taking out financing are obvious.

Hot Water Use
Heating isn't the only thing that varies with behavioural use.  We have looked at differences in hot water use too. Although not as dramatic, we hope the figures show that actual use of hot water is also important.  The range after tweaking behaviour but without changing the number of people in the house or how frequently they wash changes from 2681kWh to 3625kWh annually. That's a rise of 35% !

We applied two different measures to each of these scenarios.  A simple one which upgraded the showerhead and the the upgrading the boiler.  The most obvious aspect here is that the showerhead measure has no affect on the base case as only baths are taken.  It's obvious, but it does highlight the importance of differences between actual use and 'assumed use' quite bluntly.

Electricity Use
Finally we looked at the same house with just two different lighting use intensities. The actual use is not excessive so we compared that to a situation where they left the lights on more.  For simplicity we didn't change any appliances modelled usages.

As expected, the results show us that the expected savings are much greater when the lights are used a lot more.  The key point again is the actual savings would not be known when the actual usage is not taken into account.  When you are spending £15-£20 on an LED lamp knowing that the kitchen ones will payback in 2.5 years and the loft room in 25 years is important.

One of the proposed models for the Green Deal has been to evaluate energy savings based on individual measures installed. In this posting we've presented a worked example calculation showing the importance of evaluating installed energy saving measures as packages in evaluating savings and paybacks e.g. for the Green Deal.

When we look at all the options for a property we first of all evaluate the individual effects that each will have if carried out on their own.  Importantly we then use our judgement to build packages or suites of complementary measures to understand the net effect of them on the energy consumption and CO2 emissions.

To begin with we looked at 6 things that were possible for the house using our domestic energy modeling software (3 bed end of terrace Victoria solid wall....again).  This isn't an exhaustive list obviously.  The modelled energy cost of the house is £1,766 a year - its a pretty inefficient house.
 
The measures evaluatded were:

1. Upgrading the boiler from one with a permanent pilot light to a top specification boiler - install cost ~ £2,000
   
2. Installing 300mm of mineral wool loft insulation - install cost ~ £300
3. Internally insulating the solid external walls with 50mm of PIR insulation - install cost ~ £4,000
4. Zoning the house using thermostatic radiator valves to keep upstairs 2 degrees lower than downstairs - install cost ~ £0
   
5. Sealing the leaky ground floor floorboards - install cost ~ £2850
   
6. Insulating under the ground floor suspended floorboards - install cost ~ £1,300

The first graph shows the savings that you could expect by making each of the amendments on their own and keeping everything else constant - the boiler and the walls each are expected to save over 25% of energy bills.

If you add all of these up the total is not far off the total fuel bill costs of the house - yet none of them affect the electricity - alarm bells should be ringing.

Next we built a range of packages of measures and evaluated the net effect of each package.  The results and comparisons to what you would get if you just added the individual savings for the measure in each package together are show in the graph below.

As you can see the variance increases the more measures you add into the package - by the package with 7 measures the variance is around 30% of the actual savings.  In our Masterplans we often build packages with upwards of 30 measures so it's clearly essential to calculate the combined effect of recommended measures rather than just adding up the individual savings.

Do the regional variations in the climate of the UK have a significant effect on the potential savings from different measures?  We think so and that is why our Home Energy Masterplan modelling uses design weather years for different regions of the UK.

As an example we've taken a pretty standard 3 bedroom Victorian end of terrace in London (85m2 floor area), surveyed and then modelled it and then analysed the predicted effect of upgrading the boiler - an annual saving of £495 from an initial annual fuel bill of £1,766.

Background on the house:
Solid brick, no loft insulation, uninsulated solid and suspended floors
Single sash windows in good condition
Old boiler with permanent pilot light providing heating and hot water
Programmable heating on twice during the week and most of the day at weekends, thermostat set at 19 degrees throughout.

What we did next was to hypothetically move it around the country and carry out exactly the same boiler upgrade for the house in each location.

The image below shows where the different locations we chose and the graphs and figures show the £ sum of the variance from London over a 20 year timescale - chosen to represent a Green Deal style loan although it is expected that these may be up to 25 years.

These results are for single measures only and with everything else about the house and its use being kept constant.

We believe that the figures are large enough to make taking regional climate into account if accurate predictions are going to be made - especially if they have a financial implication.

There's been a lot of talk recently about what sort of budget is required per house to make major CO2 savings. We do this sort of assessment for individual houses every day, so we thought we'd present some analysis of our database of Home Energy Masterplans. This produced some graphs which we found interesting, and so thought we'd share them.  

In these graphs we aren't showing individual measures (e.g. boiler upgrades, changing fridges or installing different showerheads), but whole packages that we put together for each client based on their timescales, budgets, ambitions etc. Our recommendation packages are categorised on some of the graphs below: recommendations are usually chosen based on payback of component measures (eg No Brainer < 5 years, Some Consideration 5 - 15 years, Green Halo 15 - 25/30 years) but we also make recommendations based on individual client priorities as requested (e.g. CO2 reduction cost effect, or budget available).

If you are thinking of commissioning a masterplan these charts will show roughly what sort of results you might expect, or also for those looking more strategically they might help you see the scale of savings might be possible for a given budget. The charts may also be useful for those thinking about or planning for the Green Deal.

For each graph we've added our thoughts: we'd very much appreciate your thoughts and comments too.