Condensing technology offers the most effective answer to our heating needs for a financially sustainable low-energy future, says Mark Northcott, director - commercial products at Broag.
The UK's focus on ecology is by no means new; the history of green issues goes back more than half a century with the introduction of the Clean Air Acts and to the 1960s when laid-back,
long-haired, caftan-wearing hippies literally made environmentalism fashionable.

But, although ecological concerns have been around for a while, sustainable development is a more recent concept. It was first defined in a meaningful way in 1987 by the United Nations World Commission on Environment and Development.

The Brundtland Commission report, which resulted from a decisive meeting of this organisation, came up with this definition: 'Sustainable development meets the needs of the present without compromising the ability of future generations to meet their own needs.'

So, if the solution to the problem of climate change is sustainability, then the solution itself must also be sustainable. That is why it is key to specify condensing boilers in heating systems wherever possible.

There are essentially two reasons why condensing technology is inherently more sustainable than other forms of heating. These have been expressed concisely by the Energy Saving Trust. Condensing boilers offer tangible benefits by:

· Reducing CO2 emissions and helping to combat climate change.

· Improving household efficiency thus reducing fuel bills.

Condensing boilers are also relatively cheap to buy; can be sited virtually anywhere; comprise familiar, well tested technology; generally have excellent fault diagnosis facilities, and are easy to install (making them more likely to be fitted than many so-called renewable technologies). This results in two positive practical outcomes:

· More jobs get completed because condensing technology is cheaper and easier to install.

· The energy efficiency of the technology will release money for more energy saving and carbon cutting measures to be taken.

After all, projects that don't go ahead because of excessive cost save no greenhouse gases and strategies that are too costly per project are not sustainable.

Condensing boilers recover much of the waste heat normally rejected to the atmosphere from the flue of a conventional boiler.

This is accomplished by using an extra-large heat exchanger, or two heat exchangers. The result is that heat transfer from the burner is maximised and useful heat that would normally be lost with the flue gases is recovered.

Condensing boilers also produce fewer harmful emissions. Our own Remeha condensing boiler, for example, offers potential NOx and carbon savings of more than 80% and up to 50% respectively.

This means that, say, 500 schools in the UK using condensing boilers could produce annual gas savings of 4,194,500m3 and electrical savings of 351,999kWh at 33% efficiency.

Using condensing boilers will also offer annual savings of £1.2M compared with pressure jet boilers. These savings would be around 25% higher if the comparison was made against old atmospheric boilers. And the Remeha boiler produces NOx at less than 37mg/kWh at 91% GCV. This compares with NOx emissions of around:

· 180-250mg/kWh at 50% GCV for a traditional atmospheric boiler nearing the end of its service life.

· 160-220mg/kWh at 80% GCV for a pressure jet boiler.

· 220mg/kWh at 80% GCV for a new wood-burning boiler using pellets as fuel.

NOx gases - comprising NO, NO2 and N2O - are far more effective at trapping heat than CO2 and hang around in the atmosphere for about a century and a half.

But emissions are only one side of the equation. More than 55% of energy losses occur between the power station and the end user's property.

Losses in transmission and distribution networks make siting flexibility a critical consideration in the specification of any heating product since network losses amount to 4-10% of electricity generated (making them the single biggest consumer of electricity).

That is what makes micro-CHP boilers - which generate electricity locally as well as providing heat and hot water - such an exciting prospect.

Although still in the early stages of development, and currently more applicable to the domestic rather than the commercial sector, these boilers - which we are planning to introduce in the next year or so - have the potential to cut energy usage and produce significant savings.