Heating houses | Brussels Blog

Heating houses

posted by on 2nd Oct 2011
2nd,Oct

Professor Kim Swales told me that provisional results gave the long-run elasticity of demand for household energy as 1.0 or greater. He also told me:

This means that you get backfire in the long run for energy efficiency but that tax would be effective in reducing household energy use.

What does this mean and why is it important?

What is backfire?

In this case backfire means that an increase in energy efficiency will cause an increase rather than a decrease in energy consumption.

The inquiry Social Justice in the Low Carbon Transition (by FPEEG and PRASEG) comments:

This Inquiry is of the opinion that, since energy efficiency improvements represent the most effective long-term solution to fuel poverty, the Coalition Government’s new Energy Bill provides a unique opportunity to lower household energy costs and reduce domestic carbon emissions.

If energy efficiency measures do cause backfire then the Inquiry has come to one wrong conclusion. They will reduce household energy costs but they will not reduce carbon emissions. Householders may well increase the temperature of their dwellings but they may also buy or rent a bigger television to increase carbon emissions to offset any saving.

The aim to alleviate fuel poverty is laudable but improving energy efficiency alone will do little to cut carbon emissions – it may very well increase them.

In this case improving energy efficiency is taken to mean increasing the thermal insulation of the building envelopes. What follows is some examples from the real world and the issues that arise from this approach.

Example: Kirklees Warm Zone

Through phone calls to Kirklees Environment Department in April 2009 I discovered

  • The £150 pa savings for households in Kirklees through the Warm Front programme is probably now £200.

  • Kirklees use software (S2000 Maxim) to estimate these savings.

  • NEA say average annual UK bill is £1065.

This means a saving of approximately 20% on energy for heating before any rebound effect has been taken into account. In this context a rebound effect is where the cash savings are partly spent by keeping homes warmer. Government targets are for a 80% reduction on CO2e emissions by 2050. These improvements will last well in the period ahead.

I know of no follow up studies which actually measure any savings.

Example: Social housing in York

One inhabitant in social housing near the centre of York has, along with five of his neighbours, had a 26,000 watt condensing boiler installed. The flats are in an old refurbished house. Coming in in the evening my contact turns on a halogen heater – on a 600w setting. He sits down in an armchair facing this fire. He is warm instantly.

He found that putting on the 26,000 watt gas boiler to feed into his central heating meant the flat took an hour to heat up and the heat was not as pleasant. He never now puts on the gas boiler. He says his neighbours do not use their central heating either – it simply costs too much.

Issue: Embodied carbon.

An email to me from BRE, May 2009, says

BREEAM does not put an absolute value on the embodied carbon, it’s true. Partly because the science behind the process is still open to debate. It aims to provide a relative assessment, and gives credit to those buildings which choose the lowest impact solutions out of the available options.

I have found that most people think that BREEM calculate embodied carbon. The fact that it doesn’t suggests to me that there is no assessment of the greenhouse gas emissions associated with home insulation schemes.

Issue: Warming the whole dwelling.

Current insulation schemes encourage take the view that the whole dwelling must be heated to a target temperature. Traditionally this has not been the case. Heating the whole house puts extra strain on insulation by increasing the average temperature gradient from inside to outside.

People occupy a few cubic metres each. Their homes occupy a few hundred of cubic metres. The warmth should be directed to people not bricks and mortar.

Issue: Warmer people in cooler houses.

Following the example of the social housing above, the concept of warmer people in cooler homes should be examined. See Warm people in cool houses http://www.nohighbuildings.org.uk/wordpress/?p=49. Here Christine Tacon has recounted examples of keeping warm in Japan and Barcelona which do not just rely on heating the whole building envelope.

Another example can be found in the Champagne Bar at St. Pancras Station. St Pancras is not enclosed by a complete building envelope so in the winter the Champagne Bar is cold but sit down at one of the tables and a heater automatically switches on for the duration of your stay. This is a variation of the approach taken by the residents of the social housing in York mentioned above.

comment

Currently thermostatic valves on radiators allow, at a crude level, the creation of temperature zones within buildings. However the current generation of valves depend on manual intervention.

The increase in temperature is also relatively slow. It ought to be possible to create thermostatic valves that are triggered when the presence or absence of a person in a space is detected.

Coupled with more efficient thermal transmission this may address the issue of warmer people/ cooler houses

John Oxley ( October 2, 2011 at 3:21 pm )

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