It's a strange fact that private clients don't ask us about how our Home Energy Masterplan (HEMP) compares to analyses based on EPCs or SAP.  Perhaps they are very astute or they just don't know the connection.

Contrary to this, organisations who should know better are constantly comparing our HEMP price to the price of an EPC or SAP assessment.  In this blog I'll seek to show whey our HEMP, starting at £290, is great value and why advice based on EPCs or SAP is not good value for money whatever the price - even free.

Blunt Instruments?
I'll start by getting a few things straight - and explaining and apologising for my title.  It's important to realise that EPCs (based on RdSAP) and SAP were never designed to be used to offer advice to individual households. They are supposed to be cost effective ways of benchmarking buildings and we believe they are often unfairly denigrated for not being good at something they aren't meant to do.  We also believe they are pretty good at what they are supposed to do. Why apologise for my title?  Well its falling into the same trap - EPCs and SAP are only blunt instruments when used for something other than their purpose - similar to criticising a cold chisel for not carving wood very well!

Below I'll highlight the reasons why a HEMP is what you need and why you shouldn't compare cold chisels to wood chisels.

How you use your building
As already pointed out RdSAP and SAP are used to be benchmark buildings. They necessarily apply a number of rules about how the buildings are used - especially the heating systems and controls.  Day-in, day-out, we survey properties and each and every one is used differently from how RdSAP and SAP would model them. Often it's the heating times, often the bits of the house that are heated, sometimes it  is secondary heaters, very often its the thermostat settings....the list goes on. Suffice to say if you are heating your house very differently from how it is modelled, the results of any analysis are going to reflect a situation other that yours.

The same thing applies to hot water, lights and appliances.  Whereas these are based on floor area for RdSAP and SAP we actually model how much hot water you actually use and what appliances and lighting you have. We find there is a really big range of hot water use and very wide normal range for electricity use - 3-bedroom houses often range from 2,000kWh pre annum to 9,000kWh (these also effect the heating calcs which is something we also take into account). Its important to add that this detail cannot be carried out in SAP or RdSAP.

Calibration
Even with the best surveying (and customers who try and tell you the truth) bills sometimes tell a different story from what has been modelled. Our process includes collecting annual bills so we can check that the modelling is correct.  50% of the time this highlights something that has been missed - hidden electric underfloor heating or fridge freezers in the shed - so is a good sense check. We then use this data to calibrate the model, partly making informed adjustments, partly adding additional miscellaneous items and party by adjusting the overall losses.  This all helps us get as close as possible to your real situation.

Lights, Appliances and Products
We've packed out software with a wide range of different lights, appliances and products so that firstly your home can be accurately 'built' with what it actually contains and party so that we can analyses lots of different options for you.  Xbox360 in gaming mode - we've got it, woodfibreboard insulation 40mm thick - yep, and also fishtanks, Celcon blocks, recycled cotton insulation......

Fuel prices, tariffs and subsidies
Fuel prices are constantly changing (usually upwards) and at different rates.  We change our prices to match the prices you are actually experiencing (or what you want to guess what prices might be). If British Gas raises its prices 18% - we can reflect that. The inability to model actual prices changes can mean that any calculations can be very inaccurate.

One of the biggest things to impact paybacks at the moment are Feed In Tariffs and the proposed Renewable Heat Incentive.  We model both.  We don't know anyone else who can accurately model what you might expect to get from the Renewable Heat Incentive.  Why not?  Well the payments will be based on your actual use not your use deemed by SAP or RdSAP.  Because we model your building and how you use it really really accurately we therefore are in a great position to model your potential RHI payments too!

If you aren't able to do all this then your analysis is severely limited.

How much will measures cost?
We've packed a database full of prices for a very wide range of measures, and we are constantly updating them.  Prices we provide are based on the surveyed data, not just huge static ranges.  An example is solid wall insulation.  The price will be based on the material, the thickness and the area to be covered.  Another is windows - prices dependent on the number of windows, the size of each and the type of window to be installed.  We can, and often do, override our prices either because you already have a quote or we want to take into account additional information about your situation.

This goes to the heart of what makes our process different.  It has been designed from its inception to offer advice rather then being shoe-horned into attempting to give advice.

There are other aspects too which set the Home Energy Masterplan apart and lead us to get feedback such as 'This is amazing', but I think you probably get the idea.

Just to finish, its worth reflecting that whilst each of the areas above in their own right firstly set the HEMP apart and secondly show weaknesses in using RdSAP and SAP, in reality all of them apply and those weaknesses add up. 

We often work with local people to provide the Home Energy Masterplan across the country. They know their local people and the types of buildings in their areas.

We are really pleased to announce that  Joe Lewis has completed his Masterplan surveyor training and so Greener Build, part of the extremely well know and respected Green Shop Group, will be offering the home energy masterplan from their base near Stroud, Gloucestershire.

Contact them directly to arrange a survey 01452 772040.

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.

Following the recent rise in VAT we've decided to reduce our pre-VAT prices for our Home Energy Masterplans to ensure that the final prices to individual homeowners and small organisations without VAT registration remain the same as they were last year. 

Happy New Year!

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.

At the moment we think our Home Energy Masterplan is unique in the UK, as it is the only widely available detailed energy analysis tool of its kind. We know of nothing currently available that:

• evaluates the cost and energy/CO2/fuel bill effect of the wide range of energy improvements tailored on individual houses 
  
• includes actual occupant usages of heating, hot water, appliances and lighting
  
• draws on a database of implementation costs in order to provide economic paybacks and cost per unit CO2 saved for each recommendation.
  

We thought we would use this blog to pass on some of our findings from the hundreds of analyses we have completed to date as we believe that our unique experience may give a real insight into what will be needed for the Green Deal - and might be interesting to readers too. Filter the blog on the categories Green Deal and Parity Opinion.

The Green Deal currently seems to be planned based on a ‘golden rule’ where people should be saving more on their fuel bills than they are paying out in loan repayments. In order for people to be able to make the correct choices they will need to be given realistic estimates for the savings that are probable for their house, taking into account the way they live in it - as well as the savings that might be expected given ‘typical’ occupancy.  In order to achieve this we believe software will need to be available for the Green Deal, and it will need to include the following:

• An ability to calibrate the model of the house’s energy use to the actual energy use of the house
  
• An ability to model the actual behavioural use of the property – lighting, appliances, temperature settings, timings and zoning, actual hot water use, and so on – alongside ‘typical’ use for a house of that kind.
  
• Regional temperature and insolation (sunshine) data
  
• An ability to provide realistic costings for measures and groups of measures so that paybacks can be calculated
  
• An ability to evaluate packages of measures alongside individual measures
  

We’ll be elaborating on the points above in subsequent blogs postings as our experience has shown that without all of the above there is a risk that the projected savings could be very different from those actually achieved.  The Green Deal will be essentially a financial product, and we believe that people deserve to get the best possible estimate of the savings they are likely to achieve, especially if the Green Deal is offered to vulnerable people who are taking part in order to save money – as they may end up paying out more in loan repayments than they are savings from the measures.