Understanding the real value of U-values
Countries across the Middle East boast some of the highest CO2 emissions per capita. Out of the top fifteen in the world, six countries within the Middle East feature. As per data from 2014, Bahrain, Qatar, Kuwait, U.A.E., Saudi Arabia and Oman topped the poll with emissions per capita of 73.1, 41.9, 28.5, 25.8, 20.2 and 15.1 mtCO2 per million people, respectively[i]. It is essential to reduce our energy consumption and the subsequent CO2 emissions as quickly and as effectively as possible. CO2 emissions threaten the planet that we live on, and for our future to be environmentally sustainable we need to do something about it… and now.
A study from Mott MacDonald covering Dubai and Abu Dhabi, U.A.E, Muscat, Oman, Doha, Qatar and Riyadh, Saudi Arabia has shown that, in all instances, improving building envelope U-values will reduce the carbon emissions and energy demand of the GCC building stock and can even produce an instant Return on Investment on the additional cost of the insulation.
Quantifying the Positive Impact of Improving U-values
For its study, Mott MacDonald modelled six buildings, representative of common building types across the Gulf – a villa, low-rise residential, low-rise commercial, high-rise residential, high-rise commercial and hotel. The study looks at four different constructions within the six buildings. Two build-ups within the walls, one using an insulated cladding façade and one using an External Insulation Finishing System (EFIS), one roof construction comprising a concrete deck and one floor construction comprising a concrete slab were considered.
The firm then compared the effects of improving U-value specifications, by using additional insulation, in the roof, floor and external walls of the buildings. The model considered a wide range of physical, environmental and financial building characteristics such as building size and use, energy consumption and cost, elemental cost and regional environmental profiles.
For each of the 1,241 scenarios, an energy consumption comparison was made between the regional baseline U-value specification and an improved U-value specification. The construction cost for each build-up was entered into the model, and the ROI for the improved U-value was then calculated by subtracting the savings that resulted from a reduction in cooling plant size from the added cost of the insulation, and dividing this by the value of the energy savings over the life time of the building.
As would be expected, the study showed an initial rise in projects costs of between, 0.01% and 3.23% of the overall project developments. However despite these increases, the calculated results for the modelled buildings showed that an overwhelming ROI could be achieved by improving the U-value specification. In total, 100% of the calculations showed energy and carbon emissions savings, additionally up to 84% of a building’s calculations showed an ROI of over 100%, and more than 1 in 5 of the total calculations displayed an ROI exceeding 200%, with instant returns being observed and, in absence of that, returns of over 6,500% were identified.
One iteration Mott MacDonald looked at was a new, five storey, low-rise residential building, located in Muscat, Oman. The building is constructed using concrete blockwork walls and utilises an External Insulation Finishing System (EIFS), a concrete slab floor insulated above and a concrete deck roof insulation above.
The energy use of 5,711 m2 building was calculated for the baseline U-value specification required in Muscat, Oman, of 0.22 W/m2.K, 1.825 W/m2.K and 1.48 W/m2.K in the roof, floor an external wall respectively. The energy use was then calculated for the building after improving the U-values to 0.20 W/m2.K, 0.45 W/m2.K and 0.45 W/m2.K.
The improved U-value specifications concluded in an energy saving of 32,370 kwh/year and a carbon emission saving of 18,549 kgCO2/year. The results also represented a massive ROI of 3,242% on the cost of the additional insulation.
Across the Gulf
The rest of Mott MacDonald’s study showed the strongest financial returns were seen in residential buildings, however the study also revealed significant returns in commercial buildings. For example, the ROI for improving U-value specifications in a hotel, resulted in ROI’s of up to 1,334% in Dubai, 888% in Muscat, 2,999% in Riyadh and 507% in Doha. Additionally, for the hotel model, up to 68 tonnes of carbon emissions savings could be made annually in a single location.
The energy consumption and carbon emissions of building stock in the Gulf needs to be tackled now and reducing the cooling demand is the most effective way of doing this. Raising the initial construction cost of a project is never an easy decision for specifiers, however, as Mott MacDonald’s study shows, improving the U-value specifications can deliver a considerable ROI for all buildings, regardless of the building type or location, and will reduce carbon emissions and energy demand in every occasion, making it well worthwhile investment.