The Carbon Footprint of a Renovation vs New Construction

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People on ladders painting the white siding of a house

 Hill Street Studios / Getty Images

Thousands of houses stand empty in the Great Lakes States; in Buffalo they are demolishing 5,000 of them. It is bad enough that they are in sight of fresh water and have access to canals, railroads and highway infrastructure galore; a new British study, 'New Tricks With Old Bricks' (PDF) , says reusing and refurbishing existing and empty properties could actually save more carbon dioxide than constructing new ones.

According to the Guardian, the study found that the construction of a new house generated 50 tonnes of CO2, but the renovation of an existing house emitted only 15 tonnes. In actual use, there was little difference in the performance of the older house than in the new one, and that it could take decades for the operational savings to offset the carbon load of the initial construction. The renovated house will probably last longer too, because so much of what we build today is crap.

Bill Dunster, designer of the RuralZED, told the Guardian:

"If you are buying a flat made from chip-foam panelled walls as a low-cost housing solution, then yes, it might not last forever. We do have to stop this "dash for trash" and stop people building homes which look good but will become unlivable. We have to go back to quality." ::Guardian

Key findings of the report:

This study compared the CO2 given off in building new homes and creating new homes through refurbishing old properties. The key findings are:

Reusing empty homes could make an initial saving of 35 tonnes of carbon dioxide (CO2) per property by removing the need for the energy locked into new build materials and construction.

Over a 50-year period, this means there almost no difference in the average emissions of new compared with refurbished housing.

Carbon dioxide (CO2) emissions from new homes fall into two distinct sources: "embodied" CO2 given off during the housebuilding process, and "operational" CO2 given off from normal energy use in the house once it is occupied. The new homes each gave off 50 tonnes of embodied CO2. The refurbished homes each gave off 15 tonnes.

Well-insulated new homes eventually make up for their high embodied energy costs through lower operational CO2 but it takes several decades - in most cases more than 50 years.

Embodied CO2 is not widely understood but this study shows that it accounts for 28% of CO2 emissions over the first 50 years' lifetime of a new house.

Embodied CO2 is an investment in the environmental sustainability of a house. Refurbished old homes have lower embodied CO2 and therefore a distinct head start over new homes.

Empty homes in England provide an opportunity to create 150,000 new sustainable homes.

If the rate of VAT on repairs and renovation had been 5% instead of 17.5%, it would have cut the average cost of refurbishment by approximately £10,000 for each house.

Many house builders claim that new homes are four times more efficient than older houses. This study shows that refurbished houses can be as just efficient as new homes.