Hi,
 

A passive solar home is designed to use the energy of the sun. The home, its position and the building materials work together to create an energy-efficient environment. Solar design capitalizes on heat's natural capacity to move from warm materials to cool ones to create a temperature balance. Active solar systems use collectors to divert the energy. A complete passive solar design includes five elements working together -- aperture, absorber, thermal mass, distribution and control.


 

I work for a major supplier of Rainwater harvesting equipment. I have studied the document in question in depth. Unfortunately it misses many key issues, leading to the findings being distorted.
Firstly, the study used dated and old fashioned RWH equipment. The latest RWH systems use roughly 15% of the energy used in the study. We are literally begging the agencies involved to update it, with latest technology, but it seems to fall on deaf ears.
Secondly, all factors contributing to emissions for a RWH system were considered, manufacture of all parts, installation, running emissions etc.
Yet only the emissions for pumping the water to a household were included for mains water.
No infulstructure emissions or set up emissions for water companies were included eg building a pumping station or reservoir. The water companies also lose around 1/3 of water they produce due to poor quality piping, this was ignored in the study. The results also ignored other factors such as the chorination process, another energy intensive process.
Altogether, you can see the frustration for our company. We welcome a new study ASAP.

 

Climate change, population growth plus our hunger for water-greedy appliances in the home have all put a great strain on our aged mains water supply network. Even with modernisation, our mains water supply will not be able to fulfil our needs in the future. Rainwater harvesting could be a key way to supplement mains water supply. 30% of mains water goes down the toilet, and by using rainwater not only for WCs but also for the washing machine and outdoors, we can save 50% on mains water. Rainwater can be used for any use that does not require drinking quality water.
 

It is very discouraging to find yet another negative view of rainwater harvesting. In the long run, water is our most precious resource and discouraging people from making the most of rainwater to save on mains water use seems a very destructive attitude currently the fashion in official circles. There are various interpretations of the carbon footprint issue: think of the implications of creating huge new reservoirs, desalination plants and transporting water from one part of the country to the other. I don't suppose the draft bill announced in the Queen's speech today reforming the water industry will give much prominence to rainwater harvesting: a great pity.
 

would be interested in links to study thats pro RWH , I believe AECB currently suggest similar to whats in article,
 

the latest EAW research finds comparability in wales between RWH and domestic mains water supplies. Indeed, for systems involving SuDS elements (to prevent massive C-footprint floods) the RWH systems have a lower footprint compared to new mains water supplies. GBP needs to be kept up to date, and recognize that new water suplies will all have huge impacts, carbon and otherwise. RWH system owners will learn to conserve their own water, as part of learning to manage the water running off from their own plot.
 

The UK has suffered from multiple drought warnings. We hear of plans to transport water from the north of england to the south of england. What will be the financial cost of implementing these schemes. Who will pay for land purchase, building new resevoirs, new pumping stations and the pipe network required to tranport this water? Does the NHBC really believe all that cost and infrastructure is less than installing rainwater harvesting systems in a new home while it is being built?
If there isn't any water in a resevoir and the homeowner has to go and use a stand pipe in the street they would be very envious of the person next door with a rainwater harvesting system who can still flush their toilets, use their washing machine and water their expensive plants, all using harvested rainwater? When water prices start to rise and people are reciving larger bills they will wonder why the house builder did not fit a Rainwater Harvesting system during construction of the building?
 

A typical response from NHBC who are more interested in the profits of their members than the health and wellbeing of their respective customers. It's all very well installing water efficient fittings, which is always to be recommended, but it is well documented that these are often replaced by homeowners with their less efficient counter parts, especially full flow shower heads. Rain harvesting allows these fittings to be used whilst still saving up to 50% of daily potable water consumption. I wonder what the EA study would havce found igf it had compared the CO2 footprint of RWH with de-salination?
 

A massive carbon footprint is the price we pay for the freedom to travel; a tiny carbon footprint is possibly the price we need to pay for the freedom to wash.

Using the very worst assumptions, the energy penalty for substituting harvested rainwater for around 40% of mains water consumption is no more than 20kWh per year for a two-person household; if the stresses on water supply result in the need to incur the carbon impact of infrastructure improvements or the need for inter-utility transfers, the penalty would be even less.

Rainwater harvesting provides an elegent and carbon-efficient solution to both water-shortage isses and surface-water management issues; NHBC, get over it!