The Energy Efficiency of SIPs
Written by Dave Stevenson, @DStevensonSIP
Welcome again to the Plasti-Fab Insulspan SIPs’ blog. I’d like to continue the discussion with an installment on ‘Energy Efficiency’. Last time, if you recall we looked at ‘Sustainability’ in the context of ‘Green Building’ and many may wonder what the difference is between ‘Energy Efficiency’ and ‘Sustainability’.
My take on it is that Energy Efficiency is perhaps the one measurable entity of an abstract and difficult to quantify, far reaching sustainable green building strategy. Sustainability includes energy efficiency, of course, but also raw material use, recyclability, pollution and toxicity (the list goes on). Building a structure as sustainable as our budgets will allow makes us feel good about ourselves on an emotional level as well as contributing to the goal of sustainability. We all want to do our part for the environment by leaving a smaller footprint. Building ‘energy efficiently’, on the other hand, is a more tangible reality we can evaluate when we are considering what to use when it is time for us to build. We all want to save money by using less energy, and the savings can easily be quantified.
Did you know that buildings account for almost 40% of total energy consumption? If we can reduce the amount of energy required to manufacture the material used to construct the building in the first place and then reduce the energy to operate our buildings, not only can we save money, but we can simultaneously reduce the amount of carbon dioxide entering the atmosphere.
SIP Buildings Use Less Energy
Starting with the EPS insulation used to manufacture SIPs –
The Expanded Polystyrene (EPS) used to manufacture most SIPs takes less energy to produce than glass fiber insulation.
EPS also provides exceptional long term thermal resistance so that when used in SIP applications it will save many times the energy embodied in the petroleum used to manufacture it.
Download the SIPS LCA Brochure, explaining the Life Cycle Benefits of SIPS, and the impact on reducing global warming.
This is a function of R-Value –
The R-value of a wall or roof is a measure of its ability to keep heat from flowing through it. Higher R-value for the walls and roof means less heat loss and less energy needed for heating and cooling.
There is also heat loss, and therefore energy consumption, due to conduction or Thermal Bridging –
SIPs wall and roof assemblies contain less dimensional lumber. In wood-framed construction a thermal bridge is created between the exterior of the building and the finished interior when insulation is interrupted by wood studs which leave up to 20% of the wall and roof area uninsulated. SIP wall and roof assemblies lose less heat to conduction and provide higher R-values because there are significantly fewer thermal bridges.
Finally, and perhaps most importantly, there can be significant heat loss due to air leakage –
Up to 40% of a home’s heat loss is due to air leakage, and heating and cooling account for the largest part of a family’s energy use. The closed cavity wall and roof design of SIP building significantly reduces air movement. In wood-framed construction, wall and roof R-value is decreased by insulation gaps around wood framing and by settling of insulation. These defects increase air leakage through the construction. This not only increases energy use, but can lead to condensation on the surfaces of wood components within assemblies. The continuous core of EPS insulation in a SIP vastly reduces air leakage and heat loss, while also allowing better control of indoor air quality.
So there you have it.
Structural Insulated Panels are one of the most airtight and well insulated building materials available. The Insulspan SIP System provides airtight wall and roof assemblies with higher effective thermal resistance and less thermal bridging than typical construction methods. These properties allow Insulspan’s SIPs to work in concert with other energy efficient building components to reduce heat loss by up to 60% over wood framed construction, while significantly reducing energy consumption.
Build with SIPs, look at your energy bill, and be amazed.
Manufacturers of Insulspan SIPs
Stay tuned for our next SIP topic in a few weeks!