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Limpley Stoke Eco-House displays impressive approach to energy efficiency


February 25, 2014

The UK-based Limpley Stoke Eco House has been designed from scratch with sustainability in mind (Photo: Hewitt Studios LLP)

The UK-based Limpley Stoke Eco House has been designed from scratch with sustainability in mind (Photo: Hewitt Studios LLP)

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British architectural firm Hewitt Studios LLP recently completed work on the 400 sq m (4,305 sq ft) UK-based Limpley Stoke Eco-House. Designed with a focus on sustainability and energy efficiency, the futuristic home features more green technology than you can shake a (sustainably-sourced) stick at, including rainwater collection, passive ventilation, solar power, and an EV charging point.

The house derives its name from the tiny village in southwest England in which it is located, and was built using a combination of prefabricated and renewable construction materials, some of which was sourced locally. The walls of the second floor incorporate prefab timber panels, and sustainably-grown timber from certified forests was also used in the build.

Insulation comes courtesy of environmentally-friendly straw bales, and the ground floor features concrete made using pulverized fuel ash – a waste product of coal-fired power stations that offers excellent insulation values.

As is the case in some similar energy-efficient properties such as the Tighthouse, Limpley Stoke Eco-House's near air-tight envelope allows it to maintain a more stable temperature than a typical home. A mechanical ventilation and heat recovery (MVHR) system expels unwanted warm moist air, and draws in new fresh air from outside. The outside air then passes through a heat exchanger system and warms the interior of the house efficiently. This mechanical system is also complemented by passive natural ventilation.

When the weather turns too cold for the MVHR system alone, a log burner is available, and the home's extensive grounds include a woodland area slated to provide a sustainable source of firewood. Elsewhere in the grounds are a bat roost, and a small garden studio complete with composting toilet and log burner.

Solar power is harnessed for both electricity and water heating needs. The front edge of the Limpley Stoke Eco-House sports a sun shade which has 2 kW solar photovoltaic panels affixed. The roof supports a solar water system that creates hot water for domestic use, with a standard electric immersion system kicking in when solar power proves inadequate.

Other sustainable features present in the Limpley Stoke Eco-House include a green roof that's home to hardy low-maintenance plants native to the north of England. The green roof both reduces the visual impact of the building and provides an additional layer of insulation.

Also on the roof is a rainwater harvesting system, which processes water with an onboard filtration system before it is then used as irrigation for the vegetable and herb garden, and for washing the owner's BMW i3 electric car. The BMW i3 is charged by an EV charging point that's located toward the front of the property, itself supplied with power from the building’s PV panels when weather permits.

Hewitt Studios states that the annual predicted CO2 emissions of the home are 774 kg (1,706 lb) of CO2 per year, and that its predicted energy demands are 4,880 kWh per year. The construction of the house took 18 months to complete and cost a total of £1.5 million (roughly US$2.5 million).

Source: Hewitt Studios LLP

About the Author
Adam Williams Adam scours the globe from his home in North Wales in order to bring the best of innovative architecture and sustainable design to the pages of Gizmag. Most of his spare time is spent dabbling in music, tinkering with old Macintosh computers and trying to keep his even older VW bus on the road. All articles by Adam Williams

This is impressive, a model for what the standard building of the future should be.

One question I have is about the ground floor, which has concrete made from pulverized fuel ash. Were the hazardous substances generated as a byproduct of coal power generation, such as mercury and lead, filtered out before the concrete was made?


All good and well for a very expensive house, for (rich) first world folk.

Where is the effective, energy efficient house for the low end of the market? And don't give me a camper trailer with 1kW solar panels.

Lets showcase houses like this that don't cost 1.5 million pounds, (or was it 1.2 million) costs a lot for some straw bales, timber and a bit of heavy furnace ash these days.. Give the general public something to live for, something they can one day afford.

An insulated slab and house using polystyrene/etc and aluminium foil, with a decent solar system (PV plus thermal) would actually be affordable.

NB. the ash (most likely fly-ash, though they may be correct that it is pulverised heavy furnace ash) in the concrete appears to be used to lower the need for CO2 emitting limestone in the manufacture of cement (grey powder).

Good example of greenwashing.


Ideally, technologies such as these will fall in price as they become more desirable. The price tag is beyond most, but if it fell by 80% to 90%, it would be much more doable. This is the direction we have seen before and wish to see again, though the pace of change needs to speed up if many my age wish to see it become commonplace.


While I love to see proof of concept eco friendly designs, I must agree that a house that costs $2,500,000 is not going to have a significant impact on global warming. I am especially disappointed that at that price, it is not even carbon neutral. The effort would have been better spent designing a home that people might actually produce in a quantity that will have some effect. Of course, I can see that this is a luxury home, but building this home will have no other effect than to give climate change deniers more fuel for their trumped up claims that sustainable living is too expensive to be practical. I can just see the claims on Fox news now: "Energy efficient homes proven to cost $2,500,000."

David Leithauser

I'm just amazed when I see this type of story. Where in the "sustainable" regs does it say a house needs to be 4305 s/f and cost $2,500,000? And the "sustainable" log heat puts out 400x more pollution than a standard natural gas furnace. In reading about coal, and its resultant ash, I find that more radioactivity and heavy metals are released from our coal furnaces than from our entire bevy of nuclear power plants worldwide. (Yes, that's one year of coal vs. the entirety of nuclear energy since its inception.) I don't think I'd sleep on that floor, but I'd certainly like to see the safety testing which was performed on it before doing so.


Good to see various options being explored as we certainly need to do something. However, somewhat concerned about the pulverised ash floor. Isn't coal ash toxic? Or have I got the wrong end of that sustainable stick they were talking about. And, in my experience, straw bales disintegrate and collapse after a few years, so do they need to be routinely replaced ? Still, for £1.5M, it will hardly be a major concern for the proud owners.


Only eco if at least ten people live in it


Are the 18 months of CO2 emmisions from the construction as well as the CO2 emmisions from the manufacture of all the materials amortized with the 1706 pounds of predicted CO2 emmisions of the house or have they somehow magically disappeared?


Impressive in many ways, but not stunning in any, the grounds are large and I do not think that it is really practical for use by the general public. Maybe it's features could be incorporated into a everybody home?


like the idea of the sunshade consisting of PVs,but 4000 sq ft,you have got to be kidding,save the straw bales for the guest house,interesting though,my designs are somewhat like this -but not nearly as huge and do not require a huge air to air heat exchanger(and nix the toxic fly ash in the concrete)-Kevin

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