Building a greener future

In December 2006, the Department for Communities issued a audience paper titled Constructing a Greener Future: Towards Zero Carbon Development. It included proposals to fasten Part L of the current Building Regulations so that from 2016 new places would breathe zero C, with the ambitious proposal that all new non-dwelling edifices will breathe zero C by 2019. This was chiefly introduced in order to make the Governments marks to cut down emanations as a consequence from human actions. These marks have to be reached by 2050 as these marks are lawfully adhering under the Climate Change Act. “ The UK ‘s 21 million homes are responsible for 27 % of CO2 emanations, consume half of H2O supplies and bring forth 8 % of waste ” ( Communities and Local Government, 2008 ) With more than 200,000 houses planned to be built every twelvemonth to house a turning population, ‘sustainable places ‘ seem to be the lone reply. The complex energy salvaging engineering employed in such houses frequently claim to be able to execute against the Government ‘s marks, nevertheless sometimes they are unable to execute due to their complexness, invariably altering markets and compatibility with other engineerings.

Established in 1975, the Stewart Milne Group is one of the UK ‘s largest independent home-builders which is renowned for its invention of lumber system engineerings. In response to the Government ‘s aspirations, the Stewart Milne Group designed the Sigma Home. It has been constructed as a three floor townhouse, arranged over four floors to understate the edifices footmark whilst still maximizing populating adjustment. It has an unfastened program layout which makes effectual usage of natural visible radiation and besides allows for the edifice to be flexible in offering assorted layouts from household place, house portion or even office infinite. The Sigma Home took merely 8 hebdomads ( compared to the normal 24 hebdomads ) to construct due to the usage of offsite engineerings including the closed lumber frame walls and the pre-fabricated bathroom cods. In order to keep the conformity for Level 5, the Sigma Home offers ternary glassy Windowss, low energy contraptions and micro renewable engineering. Water salvaging devices have been used throughout to accomplish the 80 liters of H2O use per individual per twenty-four hours required for Code 5. Fabric insularity at 0.15w/m2k provided by the wall, floor and roof elements with high public presentation lumber Windowss and an air tightness scope of 1-3m3/m2/h agencies that the building is “ 10 times better than current Building Regulations demands ” ( Stewart Milne Group, n.d. ) A solar chimney on the roof positioned above the stairway optimises the inactive airing by utilizing the stack consequence in the step instance enabling air to be drawn throughout the place for chilling. Lighting, hot H2O and infinite warming are provided by solar thermal, photovoltaic roof panels and roof mounted air current turbines.

In December 2007, the Stewart Milne Group commissioned the Oxford Institute for Sustainable Development and Architecture ( OISDA ) to measure and supervise the Sigma Home whilst it was occupied by a household of four. They occupied the house for four two hebdomad periods, one in each season of the twelvemonth. The place was lived in every bit normal as possible with the household partaking in typical day-to-day activities. The residents experiences were recorded utilizing several research methods including ; pictures, interviews, log sheets and thermic comfort studies. OISDA monitored the temperature, humidness, indoor air quality, energy, gas and H2O ingestion and window/door gaps. This meant that a better apprehension of how residents respond to moo energy contraptions and complex energy salvaging engineering could be ascertained and used for future research and design.

The energy public presentation of the Sigma Home is an betterment upon conventional houses, but failed to accomplish the predicted energy public presentation set out in the design phases of the undertaking. It was suggested that betterments need to be made in the air stringency and the cloth of the building through heat keeping in order to better on the energy public presentation. Thermal images were produced during the trial on the belongings whilst the household were populating at that place. These revealed that the “ heat loss parametric quantity was approx 40 % worse than the predicted design phase appraisal ” ( Stewart Milne Group, 2009. ) As the edifice is unfastened program it is hard to lock air into peculiar suites and with warm air lifting, heat would necessarily be lost through window and door adjustments and the roof. One solution would be to better the air tight seals around window and door adjustments every bit good as put ining an air membrane in the roof to cut down heat loss.

However, the belongings does maximize the usage of solar addition by using big countries of glazing, in peculiar on the land floor at the forepart of the edifice. But, by holding so much glass in the edifice struggles with involvements of privateness as one of the life countries is at the forepart of the belongings. The glass is ternary glazed ; it is improbable that solar addition would act upon the temperature within the edifice. This engineering means that unreal lighting is improbable to be used during daylight hours, nevertheless would merely be truly effectual if the belongings was south facing. The Sigma Home is east facing so would non have the maximal sum of daylight all twenty-four hours. When unreal lighting is required in the edifice, low energy visible radiation bulbs are used throughout. However, in some countries of the belongings these bulbs are non appropriate. They are by and large slow to react and in suites where there is small solar addition such as the bathroom, by the clip the bulbs have responded and are able to breathe sufficient visible radiation, the user has most likely turned the light off.

Quite a high proportion of the electricity used in the Sigma Home is generated by micro renewable engineering. Wind turbines are located on the roof of the edifice and generates “ small effectual electricity ” ( Stewart Milne, 2009. ) This engineering is non suited to the low rise urban location of the Sigma Home where the edifice is shielded from the air current by environing edifices, therefore merely able to bring forth really small electricity. There used to be three wind turbines on the roof, but ironically strong air currents brought down one of the turbines and have damaged another. This raises a Health and Safety issue with this engineering particularly if this paradigm is to be rolled out on a larger undertaking. The tallness of the belongings besides suggests that the occupier of the belongings would be unable to keep and mend this engineering which would necessitate the expertness of specializer contractors.

Photovoltaic panels have been installed on the roof and the south facing gable wall and norm at bring forthing 27kWh/m2/year over the twelvemonth. The photovoltaic ‘s are good in the manner that they generate a high per centum ( about 50 % ) of the electricity used within the edifice. However, the cost of put ining photovoltaic engineering and keeping it can frequently outweigh any benefit. Besides the panels public presentation are frequently dependent on the sum of sunshine they have entree to. Since installing of the panels on the south facing wall, the Barrett Green House has been built next to the Sigma Home. This severely reduces the sum of sunshine able to be absorbed by the photovoltaic ‘s and besides reduces the handiness to the panels for care excessively.

Solar thermal panels are besides located on the roof. The energy from the panels preheats the H2O for warming and domestic usage. The solar thermic engineering is equal for its intent and is regarded as one of the most successful and cost effectual sustainable engineerings. However, the peculiar merchandise nowadays at the Sigma Home has been discontinued from the market which raises issues associated with future care and replacing. It seems that merchandises on the sustainable engineerings market are systematically altering and are likely to go out-of-date rapidly and newer and more efficient engineerings are adopted for other undertakings, go forthing earlier merchandises excess. Solar thermic engineering does hold its restrictions though. Often sufficient heat storage is non installed significance it is hard to synchronize the end product with the resident ‘s demands, which may include heating the edifice in summer to utilize the energy from the panels.

Underfloor heating engineering has been adopted throughout the belongings. The heat is supplied from a low NOx gas boiler that is capable of providing up to 14kW, nevertheless the mean demand would merely be about 4kW. Underfloor heating tends to hold a clip slowdown in reacting to the resident ‘s coveted temperature and residents may invariably set the thermoregulator because of this and utilize more energy that is required. By utilizing this engineering excessively besides means that care and replacing would be debatable by holding to raise the flooring. Low H2O content radiators may hold been more preferred to heat the edifice alternatively of underfloor warming. Low H2O radiators require really small energy to heat the little sums of H2O within the radiator ; nevertheless, this would intend that lasting fitted radiators would cut down the flexibleness of the edifice.

Rooms by and large retain their heat due to the cloth and stuffs of the edifice. By utilizing heavy panels and tiles on blockwork would retain heat which is a positive in some facets, nevertheless this temperature may non be comfy in sleeping rooms. Louvered and meshed airing panels in Windowss are frequently adopted to better the airing of the belongings twenty-four hours or dark whilst keeping security. These engineerings are non adopted in the Sigma Home, nevertheless the interior decorators have envisaged airing by building a balcony for the maestro sleeping room on the 3rd floor which would supply some shading. By opening the balcony doors in the maestro sleeping room, internal heat additions. The placement of the doors is effectual in the maestro sleeping room as it means warm lifting air from the edifice can go forth via the balcony doors. The life room on the first floor has been designed to overhang the living/ dining country on the land floor which would supply shadowing on cheery yearss. Throughout the belongings there are LED room temperature panels which tell the occupier the room temperature and the demand ( if any ) to supply airing or warming. The lone hazard of overheating in the edifice aside from solar additions is from internal heat additions such as heat generated from family contraptions. The Sigma Home purposes at understating internal heat additions by utilizing low energy electrical goods and low energy lighting. By utilizing low energy contraptions and lighting, it lowers the demand to command overheating and to guarantee that the residents do non necessitate extra air conditioning which would utilize more energy.

The Stewart Milne Group did experiment with the usage of stage alteration stuffs in the Sigma Home. Energain ( manufactured from Dupont ) uses wax that thaws at about 26 & A ; deg ; degree Celsiuss and Acts of the Apostless as a signifier of latent heat storage that absorbs heat from the edifice as it starts to overheat. As the temperature so lowers, Energain changes its belongings from a liquid to a solid once more and releases the stored heat back into the room. Unfortunately the wax is flammable so the merchandise needs to be protected by gypsum board which raises inquiries of its effectivity and its ability to be used in sustainable places if the Sigma Home is a paradigm to be rolled out on larger undertakings.

If the edifice does overheat, a solar stack has been installed at the top of the edifice and its chief map is to let warm air to air out out. The stack sits above the stairwell and takes in warm air as it rises. A heat detector clears and closes a blowhole at the top of the stack to pull off the optimal temperature in the edifice. However, the stack can move as a funnel which channels external noise to air out down in the belongings. As the M25 and M1 are all close the noise can be rather annoying. The many Windowss located within the belongings besides reduces the hazard of overheating. It was established though, that merely 4 out of the 25 Windowss were used systematically whilst the edifice was being tested. This could so cut down the sum of Windowss required within the belongings which would be addressed in the design phases of farther physiques. A mechanical airing with heat recovery system has been installed in the Sigma Home which is required for Code 5 and 6 houses. Extractors for the mechanical airing systems have been fitted in wet countries such as the bathroom. They extract warm, damp air to the heat recovery unit where the heat is transferred to warm the fresh entrance air, which is so supplied at low force per unit area to habitable suites through blowholes.

The H2O use is good within the Code for Sustainable Homes bounds for Code 5 of 80 liters per individual per twenty-four hours. The edifice operates a gray H2O recycling unit which takes waste H2O from lights-outs and the showers and cleans and filters it for re-use in blushing the lavatory. The Ecoplay system is self monitoring and shops the Grey H2O for a upper limit of 24 hours before being removed from the system to guarantee hygiene criterions are maintained in the belongings. Some of the electrical contraptions have H2O use clippers on them, to guarantee the H2O use for Code 5 is besides maintained. The dish washer uses 10 liters of H2O per rhythm, the lavation machine uses 40 liters. One negative of utilizing H2O usage decrease engineering is that frequently occupants necessitate to utilize more H2O to carry through activities within the place such as blushing the lavatory. Depending on the burden of rinsing, more H2O may be required excessively. However, if the residents exceed utilizing 80 liters of H2O per individual per twenty-four hours, the Sigma Home would lose its Code 5 position.

It is clear that belongingss such as the Sigma Home have a repute of utilizing complex and specialist engineering. Such engineerings should be explained to the residents before the handover to guarantee that the residents are cognizant of what the edifices engineering is capable of and how to understate energy usage. Simple but elaborate accounts and diagrams should be available in the edifice with an aftercare hotline, to guarantee residents are capable of utilizing the engineering. After having feedback from the probe, Stewart Milne ( 2009 ) have now developed the KISS attack “ Keep It Simple Stupid ” and besides believe that place care understandings could be compulsory in the hereafter, which would enable residents to go familiar with the engineering.

Using the Sigma Home research undertaking to inform the following phase of research and development, Stewart Milne Group has now embarked on making the Sigma II Build System. This is designed to larn from the yesteryear of the Sigma Home and to foster the demand for low energy places, low C places whilst supplying a solution that is easy to construct, maintain and usage by residents.

BRE ( 2009 ) believes that “ accomplishing a low energy usage society will depend on consumers themselves altering the manner they use their places to do a positive impact on cut downing their energy ingestion. ”

Code for sustainable places



  • Communities and Local Government
  • Stewart Milne Group ( n.d ) Advancing Tomorrows Home
  • Stewart Milne 2009 the hereafter of low energy, C impersonal places.


The experimental household commented that there was a deficiency of drying installations within the belongings which would so increase energy use by utilizing a tumble drier. Their recommendations were to optimize the infinite at the top of the belongings. As the belongings is four floor high and heat rises, this would be suited, nevertheless transporting wet rinsing from the kitchen on the land floor to a room on the 4th floor is non practical.

It would besides be reasonable to hold designed the sleeping rooms so that they would hold been on the land and first floors. This would intend that the sleeping rooms would be kept at a comfy temperature. This would intend the heat would lift to the upper floors and the contact with the land would besides better its imperturbability. However, this agreement of suites is non conventional as this would intend sleeping rooms would be following to the kitchen and as the belongings is tall it would be unacceptable for the kitchen to be farther up in the belongings.